Publications by authors named "John A Baron"

323 Publications

Immune Responses Vary in Preinvasive Colorectal Lesions by Tumor Location and Histology.

Cancer Prev Res (Phila) 2021 Sep 2;14(9):885-892. Epub 2021 Aug 2.

Hollings Cancer Center, Medical University of South Carolina (MUSC), Charleston, South Carolina.

Immune responses vary in colorectal cancers, which strongly influence prognosis. However, little is known about the variance in immune response within preinvasive lesions. The study aims to investigate how the immune contexture differs by clinicopathologic features (location, histology, dysplasia) associated with progression and recurrence in early carcinogenesis. We performed a cross-sectional study using preinvasive lesions from the surgical pathology laboratory at the Medical University of South Carolina. We stained the tissues with immunofluorescence antibodies, then scanned and analyzed expression using automated image analysis software. We stained CD117 as a marker of mast cells, CD4/RORC to indicate Th17 cells, MICA/B as a marker of NK-cell ligands, and also used antibodies directed against cytokines IL6, IL17A, and IFNγ. We used negative binomial regression analysis to compare analyte density counts by location, histology, degree of dysplasia adjusted for age, sex, race, and batch. All immune markers studied (except IL17a) had significantly higher density counts in the proximal colon than distal colon and rectum. Increases in villous histology were associated with significant decreases in immune responses for IL6, IL17a, NK ligand, and mast cells. No differences were observed in lesions with low- and high-grade dysplasia, except in mast cells. The lesions of the proximal colon were rich in immune infiltrate, paralleling the responses observed in normal mucosa and invasive disease. The diminishing immune response with increasing villous histology suggests an immunologically suppressive tumor environment. Our findings highlight the heterogeneity of the immune responses in preinvasive lesions, which may have implications for prevention strategies. PREVENTION RELEVANCE: Our study is focused on immune infiltrate expression in preinvasive colorectal lesions; our results suggest important differences by clinicopathologic features that have implications for immune prevention research.
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http://dx.doi.org/10.1158/1940-6207.CAPR-20-0592DOI Listing
September 2021

Fracture risk across a wide range of physical activity levels, from sedentary individuals to elite athletes.

Bone 2021 Jul 22;153:116128. Epub 2021 Jul 22.

Department of Surgical Sciences, Medical Epidemiology, Uppsala University, Uppsala, Sweden. Electronic address:

Objective: To examine how physical activity is associated with risk of different fracture outcomes across the full range of physical activity.

Methods: By combining information from three cohort studies and using generalized structural equation modelling, we estimated a continuous unitless latent variable reflecting physical activity that ranged from sedentary through elite athlete levels. Associations between physical activity and fracture outcomes were assessed with proportional hazards regression using restricted cubic splines with the mean physical activity (corresponding to 20-40 min walking or bicycling/day or 2-3 h exercise/week) as reference.

Results: Among 63,980 men and women (49-68 years) and during 13 years of follow-up, 8506 fractures occurred, including 2164 distal forearm, 779 proximal humerus, 346 clinical spine, and 908 hip fractures. Both lower and higher physical activity was associated with higher risk of any fracture compared to the mean. Physical activity at 1 standard deviation (SD) below the mean, corresponding to walking/bicycling <20 min/day or exercising <1-1 h/week, was associated with a lower risk of distal forearm fracture (hazard ratio [HR]: 0.92, 95% confidence interval [CI]: 0.85-0.99) and higher risk of hip fracture (HR: 1.24, 95% CI: 1.13-1.37), but no associations were seen above the mean physical activity level for these fractures. Physical activity was not associated with proximal humerus fracture but had a possible U-shaped association with clinical spine fracture.

Conclusion: Physical activity was non-linearly associated with fracture risk and the association differed across fracture sites. Up to 2-3 h weekly exercise is beneficial for the prevention of hip fracture but may increase the risk of distal forearm fracture.
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http://dx.doi.org/10.1016/j.bone.2021.116128DOI Listing
July 2021

Oral Antibiotics and Risk of New Colorectal Adenomas During Surveillance Follow-up.

Cancer Epidemiol Biomarkers Prev 2021 Jul 21. Epub 2021 Jul 21.

Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.

Background: Antibiotics may increase colorectal neoplasia risk by modifying the gut microbiome. It is unknown whether use is associated with the risk of new colorectal adenomas among individuals with prior adenomas.

Methods: We performed a secondary analysis of four randomized clinical trials for the chemoprevention of colorectal adenomas. Participants self-reported all currently used prescription drugs shortly after an initial colorectal adenoma diagnosis and two or three times a year thereafter over 3 to 5 years of follow-up. We estimated adjusted risk ratios (RR) with 95% confidence intervals (CI) for incident adenomas, analyzing the four trials together.

Results: Cumulatively, the four trials enrolled 5,174 participants (3,491 men and 1,683 women), of whom 4,769 (92%) completed ≥1 follow-up colonoscopy. A total of 763 (15%) participants reported using oral antibiotics on ≥2 occasions. Overall, 39% of those using oral antibiotics at least twice developed new colorectal adenomas compared with 40% of those with no use or a single report of use (RR, 0.99; 95% CI, 0.90-1.10). No statistically significant associations were found in study-specific analyses, and results were similar for high- and low-risk adenoma findings, antibiotic class, anatomic location of adenomas, and analyses excluding those with interim colorectal exams.

Conclusions: Oral antibiotic use during colonoscopic surveillance after an initial adenoma diagnosis was not associated with risk of these polyps.

Impact: Any changes to the gut microbiome as a consequence of oral antibiotic use during surveillance may not affect the development of metachronous colorectal adenomas.
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http://dx.doi.org/10.1158/1055-9965.EPI-21-0323DOI Listing
July 2021

Serum 25-hydroxyvitamin D is associated with fracture risk only during periods of seasonally high levels in women with a high body mass index.

J Bone Miner Res 2021 Jun 25. Epub 2021 Jun 25.

Department of Medical Sciences, Uppsala University, Uppsala, Sweden.

Serum 25-hydroxyvitamin D (S-25OHD) is used to assess vitamin D status and is known to be affected by season and fat mass. Because these factors are often ignored when interpreting S-25OHD, assessment of vitamin D associations with disease outcomes may be distorted. We aimed to investigate the impact of season of blood draw and fat mass on the association of S25OHD with fracture risk. We enrolled 5000 women, mean ± SD age 68 ± 7 years, with dual-energy x-ray absorptiometry (DXA) scans and blood collection in a population-based cohort. Proportional hazards regression, stratified by season and fat mass, was used to determine hazard ratios (HRs) of fracture according to categories of S-25OHD. Our secondary exposures were serum 1,25-dihydroxycholecalciferol (1,25-(OH) D ), the most active vitamin D metabolite and plasma parathyroid hormone (P-PTH). During an average of 9.2 years of follow-up, 1080 women had a fracture. Women with S-25OHD <30 nmol/L drawn during sunny months (May-October) had a multivariable-adjusted fracture HR of 2.06 (95% CI, 1.27-3.35) compared with those with S-25OHD >60 nmol/L; those with S-25OHD 30-40 nmol/L had an HR of 1.59 (95% CI, 1.12-2.26). In contrast, S-25OHD drawn during November through April was unrelated to fracture risk. The increased risk with low sunny season S-25OHD was seen only among women with body mass index (BMI) ≥25 kg/m or fat mass index (FMI) ≥9.8 kg/m . High fat mass and low S-25OHD were independently related to lower S-1,25-dihydroxycholecalciferol, which itself predicted fracture risk with samples collected during the sunny season. Irrespective of season, P-PTH was unrelated to fracture risk. We conclude that S-25OHD is associated with fracture risk only if drawn during periods of seasonally high levels in women with a high BMI. These results have implications for the evaluation of vitamin D status and can explain the lack of effect seen with vitamin D supplementation in many fracture trials. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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http://dx.doi.org/10.1002/jbmr.4400DOI Listing
June 2021

Cigarette Smoking and Estrogen-Related Cancer.

Cancer Epidemiol Biomarkers Prev 2021 Aug 14;30(8):1462-1471. Epub 2021 May 14.

Department of Veterinary Physiology & Pharmacology, Texas A&M University, College Station, Texas.

Cigarette smoking is a known cause of many cancers, yet epidemiologic studies have found protective associations with the risk of four "estrogen-related" malignancies: endometrial cancer, endometrioid and clear cell ovarian cancers, and thyroid cancer. This review considers epidemiologic and biological aspects of these associations, focusing particularly on estrogen signaling, and contrasts them with those for breast cancer, another estrogen-related malignancy. The observational findings regarding the inverse associations are consistent and remain after adjustment for possible confounding factors. In general, women who smoke do not have lower circulating estrogen levels than nonsmokers, eliminating one possible explanation for reduced risks of these malignancies. For endometrial and endometrioid ovarian cancer, the negative associations could plausibly be explained by interference with signaling through the estrogen receptor α. However, this is unlikely to explain the lower risks of thyroid and clear cell ovarian cancers. For thyroid cancer, an anti-inflammatory effect of nicotine and reduced TSH levels from smoking have been proposed explanations for the inverse association, but both lack convincing evidence. While the overall impact of cigarette smoking is overwhelmingly negative, protective associations such as those discussed here can provide potential clues to disease etiology, treatment, and prevention.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-1803DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8338753PMC
August 2021

Preinvasive Colorectal Lesions of African Americans Display an Immunosuppressive Signature Compared to Caucasian Americans.

Front Oncol 2021 27;11:659036. Epub 2021 Apr 27.

Department of Public Health Sciences, MUSC, Charleston, SC, United States.

Background: African Americans (AAs) have higher colorectal cancer (CRC) incidence and mortality rate than Caucasian Americans (CAs). Recent studies suggest that immune responses within CRCs contribute to the disparities. If racially distinct immune signatures are present in the early phases of carcinogenesis, they could be used to develop interventions to prevent or slow disease.

Methods: We selected a convenience sample of 95 patients (48 CAs, 47 AAs) with preinvasive colorectal adenomas from the surgical pathology laboratory at the Medical University of South Carolina. Using immunofluorescent-conjugated antibodies on tissue slides from the lesions, we quantified specific immune cell populations: mast cells (CD117), Th17 cells (CD4RORC), and NK cell ligand (MICA/B) and inflammatory cytokines, including , and . We compared the mean density counts (MDCs) and density rate ratios (RR) and 95% CI of immune markers between AAs to CAs using negative binomial regression analysis. We adjusted our models for age, sex, clinicopathologic characteristics (histology, location, dysplasia), and batch.

Results: We observed no racial differences in age or sex at the baseline endoscopic exam. AAs compared to CAs had a higher prevalence of proximal adenomas (66% 40%) and a lower prevalence of rectal adenomas (11% 23%) (p =0.04) but no other differences in pathologic characteristics. In age, sex, and batch adjusted models, AAs CAs had lower RRs for cells labeled with IFNγ (RR 0.50 (95% CI 0.32-0.81); p=0.004) and NK cell ligand (RR 0.67 (0.43-1.04); p=0.07). In models adjusted for age, sex, and clinicopathologic variables, AAs had reduced RRs relative to CAs for CD4 (p=0.02), NK cell ligands (p=0.01), Th17 (p=0.005), mast cells (p=0.04) and IFN-γ (p< 0.0001).

Conclusions: Overall, the lower RRs in AAs CAs suggests reduced effector response capacity and an immunosuppressive ('cold') tumor environment. Our results also highlight the importance of colonic location of adenoma in influencing these differences; the reduced immune responses in AAs relative to CAs may indicate impaired immune surveillance in early carcinogenesis. Future studies are needed to understand the role of risk factors (such as obesity) in influencing differences in immune responses by race.
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http://dx.doi.org/10.3389/fonc.2021.659036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8112239PMC
April 2021

Swedish snuff (snus) and risk of cardiovascular disease and mortality: prospective cohort study of middle-aged and older individuals.

BMC Med 2021 May 7;19(1):111. Epub 2021 May 7.

Department of Surgical Sciences, Unit of Medical Epidemiology, The EpiHub, Uppsala University, Dag Hammarskjölds väg 14 B, 75185, Uppsala, Sweden.

Background: Cigarette smoking is a well-known risk factor for cardiovascular disease (CVD), but whether smokeless tobacco such as snuff is associated with the risk of CVD is still unclear. We investigated the association of the use of Swedish oral moist snuff (snus) with a broad range of CVDs and CVD mortality.

Methods: We used data from a population-based cohort of 41,162 Swedish adults with a mean baseline age of 70 (56-94) years who completed questionnaires regarding snus use and other lifestyle habits and health characteristics. Participants were followed up for incident cardiovascular outcomes and death over 8 years through linkage to the Swedish National Patient and Death Registers. Hazard ratios (HR) were estimated by Cox proportional hazards regression. We conducted analyses among all subjects as well as among never smokers to reduce residual confounding from smoking.

Results: After adjustment for smoking and other confounders, snus use was not associated with myocardial infarction, heart failure, atrial fibrillation, aortic valve stenosis, abdominal aortic aneurysm, stroke, or CVD mortality. However, in never smokers, snus use was associated with a statistically significant increased risk of total and ischemic stroke (HRs [95% confidence intervals] = 1.52 [1.01-2.30] and 1.63 [1.05-2.54], respectively) and non-significantly positively associated with some other CVDs.

Conclusions: In this middle-aged and elderly Swedish population, current Swedish snus use was not associated with the risk of major heart and valvular diseases, abdominal aortic aneurysm, or CVD mortality in the entire study population, but was linked to an increased risk of stroke in never smokers.
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http://dx.doi.org/10.1186/s12916-021-01979-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8103653PMC
May 2021

Prior loss of body mass index, low body mass index, and central obesity independently contribute to higher rates of fractures in elderly women and men.

J Bone Miner Res 2021 07 4;36(7):1288-1299. Epub 2021 May 4.

Department of Surgical Sciences, Unit of Medical Epidemiology, Uppsala University, Uppsala, Sweden.

We aimed to comprehensively evaluate the association of body composition with fracture risk using longitudinal data from a Swedish cohort of 44,366 women and men (mean age of 70 years) and a subcohort of 5022 women. We estimated hazard ratios (HRs) of fracture for baseline body mass index (BMI), BMI change during the prior 12 and 18 years, baseline waist-to-height ratio, total and regional distribution of fat and lean mass, with and without areal bone mineral density (BMD) adjustment. During follow-up (median 8.7 years), 7290 individuals sustained a fracture, including 4279 fragility fractures, of which 1813 were hip fractures. Higher baseline BMI and prior gain in BMI were inversely associated with all types of fracture. Lower fracture rate with higher baseline BMI was seen within every category of prior BMI change, whereas higher prior BMI gain conferred a lower rate of fracture within those with normal baseline BMI. Each standard deviation (SD) higher baseline waist-to-height ratio, after adjustment for BMI, was associated with higher rates of hip fracture in both women and men (HR 1.12; 95% CI, 1.05-1.19). In the subcohort (median follow-up 10 years), higher baseline fat mass index (FMI) and appendicular lean mass index (LMI) showed fracture-protective effects. After BMD adjustment, higher baseline BMI, total LMI, FMI, and higher prior BMI gain were associated with higher fracture rate. Baseline fat distribution also was associated with fracture rate; a 1-SD higher android to gynoid fat mass ratio in prior BMI gainers was associated with BMD-adjusted HRs of 1.16 (95% CI, 1.05-1.28) for any fracture and 1.48 (95% CI, 1.16-1.89) for hip fracture. This pattern was not observed among prior BMI losers. These findings indicate that for optimal fracture prevention, low baseline BMI, prior BMI loss and high baseline central obesity should be avoided in both women and men. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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http://dx.doi.org/10.1002/jbmr.4298DOI Listing
July 2021

Genetic architectures of proximal and distal colorectal cancer are partly distinct.

Gut 2021 Jul 25;70(7):1325-1334. Epub 2021 Feb 25.

Cancer Prevention and Control Program, Catalan Institute of Oncology - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain.

Objective: An understanding of the etiologic heterogeneity of colorectal cancer (CRC) is critical for improving precision prevention, including individualized screening recommendations and the discovery of novel drug targets and repurposable drug candidates for chemoprevention. Known differences in molecular characteristics and environmental risk factors among tumors arising in different locations of the colorectum suggest partly distinct mechanisms of carcinogenesis. The extent to which the contribution of inherited genetic risk factors for CRC differs by anatomical subsite of the primary tumor has not been examined.

Design: To identify new anatomical subsite-specific risk loci, we performed genome-wide association study (GWAS) meta-analyses including data of 48 214 CRC cases and 64 159 controls of European ancestry. We characterised effect heterogeneity at CRC risk loci using multinomial modelling.

Results: We identified 13 loci that reached genome-wide significance (p<5×10) and that were not reported by previous GWASs for overall CRC risk. Multiple lines of evidence support candidate genes at several of these loci. We detected substantial heterogeneity between anatomical subsites. Just over half (61) of 109 known and new risk variants showed no evidence for heterogeneity. In contrast, 22 variants showed association with distal CRC (including rectal cancer), but no evidence for association or an attenuated association with proximal CRC. For two loci, there was strong evidence for effects confined to proximal colon cancer.

Conclusion: Genetic architectures of proximal and distal CRC are partly distinct. Studies of risk factors and mechanisms of carcinogenesis, and precision prevention strategies should take into consideration the anatomical subsite of the tumour.
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http://dx.doi.org/10.1136/gutjnl-2020-321534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8223655PMC
July 2021

Circulating 27-hydroxycholesterol and Risk of Colorectal Adenomas and Serrated Polyps.

Cancer Prev Res (Phila) 2021 Apr 6;14(4):479-488. Epub 2021 Jan 6.

Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.

The oxysterol 27-hydroxycholesterol (27-OHC) is an endogenous selective estrogen receptor modulator implicated in breast cancer etiology. It is unknown whether circulating 27-OHC is associated with colorectal neoplasia risk. Circulating 27-OHC was measured using LC/MS in fasting plasma collected at baseline from participants of the Vitamin D/Calcium Polyp Prevention Study, a completed randomized clinical trial. Participants were between 45 and 75 years old, recently diagnosed with ≥1 colorectal adenoma, and followed for new colorectal polyps during colonoscopic surveillance. Adjusted risk ratios (RR) with 95% confidence intervals (CI) of new colorectal polyps were estimated for quartiles of circulating 27-OHC using log-linear regression for repeated outcomes. Polyp phenotypes included any adenomas, advanced adenomas, hyperplastic polyps, and sessile serrated adenomas/polyps. Circulating 27-OHC was measured at baseline for 1,246 participants. Compared with participants with circulating 27-OHC below the first quartile (<138 ng/mL), those with circulating 27-OHC at or above the fourth quartile (≥201 ng/mL) had 24% higher risk of adenomas (RR, 1.24; 95% CI, 1.05-1.47) and 89% higher risk of advanced adenomas (RR, 1.89; 95% CI, 1.17-3.06). Stronger associations were observed among participants with advanced adenomas at baseline. Circulating 27-OHC was not associated with risk of hyperplastic polyps (RR, 0.90; 95% CI, 0.66-1.22) or sessile serrated adenomas/polyps (RR, 1.02; 95% CI, 0.50-2.07). Circulating 27-OHC may be a risk factor for colorectal adenomas but not serrated polyps. PREVENTION RELEVANCE: This study found that plasma concentration of 27-hydroxycholesterol, a metabolite of cholesterol that regulates lipid metabolism and acts as a selective estrogen receptor modulator, is associated with the risk of developing precursor lesions for colorectal cancer.
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http://dx.doi.org/10.1158/1940-6207.CAPR-20-0414DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8026496PMC
April 2021

A Combined Proteomics and Mendelian Randomization Approach to Investigate the Effects of Aspirin-Targeted Proteins on Colorectal Cancer.

Cancer Epidemiol Biomarkers Prev 2021 03 14;30(3):564-575. Epub 2020 Dec 14.

Nutrition and Metabolism Section, International Agency for Research on Cancer, World Health Organization, Lyon, France.

Background: Evidence for aspirin's chemopreventative properties on colorectal cancer (CRC) is substantial, but its mechanism of action is not well-understood. We combined a proteomic approach with Mendelian randomization (MR) to identify possible new aspirin targets that decrease CRC risk.

Methods: Human colorectal adenoma cells (RG/C2) were treated with aspirin (24 hours) and a stable isotope labeling with amino acids in cell culture (SILAC) based proteomics approach identified altered protein expression. Protein quantitative trait loci (pQTLs) from INTERVAL ( = 3,301) and expression QTLs (eQTLs) from the eQTLGen Consortium ( = 31,684) were used as genetic proxies for protein and mRNA expression levels. Two-sample MR of mRNA/protein expression on CRC risk was performed using eQTL/pQTL data combined with CRC genetic summary data from the Colon Cancer Family Registry (CCFR), Colorectal Transdisciplinary (CORECT), Genetics and Epidemiology of Colorectal Cancer (GECCO) consortia and UK Biobank (55,168 cases and 65,160 controls).

Results: Altered expression was detected for 125/5886 proteins. Of these, aspirin decreased MCM6, RRM2, and ARFIP2 expression, and MR analysis showed that a standard deviation increase in mRNA/protein expression was associated with increased CRC risk (OR: 1.08, 95% CI, 1.03-1.13; OR: 3.33, 95% CI, 2.46-4.50; and OR: 1.15, 95% CI, 1.02-1.29, respectively).

Conclusions: MCM6 and RRM2 are involved in DNA repair whereby reduced expression may lead to increased DNA aberrations and ultimately cancer cell death, whereas ARFIP2 is involved in actin cytoskeletal regulation, indicating a possible role in aspirin's reduction of metastasis.

Impact: Our approach has shown how laboratory experiments and population-based approaches can combine to identify aspirin-targeted proteins possibly affecting CRC risk.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-1176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8086774PMC
March 2021

Genetically proxied milk consumption and risk of colorectal, bladder, breast, and prostate cancer: a two-sample Mendelian randomization study.

BMC Med 2020 12 2;18(1):370. Epub 2020 Dec 2.

Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Background: Observational studies have shown that milk consumption is inversely associated with colorectal, bladder, and breast cancer risk, but positively associated with prostate cancer. However, whether the associations reflect causality remains debatable. We investigated the potential causal associations of milk consumption with the risk of colorectal, bladder, breast, and prostate cancer using a genetic variant near the LCT gene as proxy for milk consumption.

Methods: We obtained genetic association estimates for cancer from the UK Biobank (n = 367,643 women and men), FinnGen consortium (n = 135,638 women and men), Breast Cancer Association Consortium (n = 228,951 women), and Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome consortium (n = 140,254 men). Milk consumption was proxied by a genetic variant (rs4988235 or rs182549) upstream of the gene encoding lactase, which catalyzes the breakdown of lactose.

Results: Genetically proxied milk consumption was associated with a reduced risk of colorectal cancer. The odds ratio (OR) for each additional milk intake increasing allele was 0.95 (95% confidence interval [CI] 0.91-0.99; P = 0.009). There was no overall association of genetically predicted milk consumption with bladder (OR 0.99; 95% CI 0.94-1.05; P = 0.836), breast (OR 1.01; 95% CI 1.00-1.02; P = 0.113), and prostate cancer (OR 1.01; 95% CI 0.99-1.02; P = 0.389), but a positive association with prostate cancer was observed in the FinnGen consortium (OR 1.07; 95% CI 1.01-1.13; P = 0.026).

Conclusions: Our findings strengthen the evidence for a protective role of milk consumption on colorectal cancer risk. There was no or limited evidence that milk consumption affects the risk of bladder, breast, and prostate cancer.
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http://dx.doi.org/10.1186/s12916-020-01839-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7709312PMC
December 2020

Genetically predicted plasma phospholipid arachidonic acid concentrations and 10 site-specific cancers in UK biobank and genetic consortia participants: A mendelian randomization study.

Clin Nutr 2021 05 7;40(5):3332-3337. Epub 2020 Nov 7.

Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK; MRC Biostatistics Unit, University of Cambridge, Cambridge, UK. Electronic address:

Background & Aims: Arachidonic acid (AA) is metabolized by cyclooxygenases and lipoxygenases to pro-inflammatory eicosanoids, which according to experimental research modulate tumor cell proliferation, differentiation, and apoptosis. We employed the Mendelian randomization design to test the hypothesis that higher plasma phospholipid AA concentrations are associated with increased risk of 10 site-specific cancers.

Methods: Two genetic variants associated with plasma phospholipid concentrations of AA (rs174547 in FADS1 [P = 3.0 × 10] and rs16966952 in PDXDC1 [P = 2.4 × 10]) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium were used as genetic instruments. The associations of those variants with cancer were taken from the UK Biobank (n = 367,643), FinnGen consortium (n = 135,638), International Lung Cancer Consortium (n = 27,209), Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome consortium (n = 140,254), Breast Cancer Association Consortium (n = 228,951), Ovarian Cancer Association Consortium (n = 66,450), and BioBank Japan (n = 212,453).

Results: Higher genetically predicted plasma phospholipid AA concentrations were associated with increased risk of colorectal and lung cancer. Results were consistent across data sources and variants. The combined odds ratios per standard deviation increase of AA concentrations were 1.08 (95% CI 1.05-1.11; P = 6.3 × 10) for colorectal cancer and 1.07 (95%CI 1.05-1.10; P = 3.5 × 10) for lung cancer. Genetically predicted AA concentrations had a suggestive positive association with esophageal cancer (odds ratio 1.09; 95% CI 1.02-1.17; P = 0.016) but were not associated with cancers of the stomach, pancreas, bladder, prostate, breast, uterus, or ovary.

Conclusion: These results indicate that AA may be implicated in the development of colorectal and lung cancer and possibly esophageal cancer. Treatments with plasma AA-lowering properties should be evaluated for clinical benefit.
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http://dx.doi.org/10.1016/j.clnu.2020.11.004DOI Listing
May 2021

Risk of keratinocyte carcinomas with vitamin D and calcium supplementation: a secondary analysis of a randomized clinical trial.

Am J Clin Nutr 2020 12;112(6):1532-1539

Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.

Background: It is unknown whether dietary supplementation with vitamin D or calcium prevents keratinocyte carcinomas, also known as nonmelanoma skin cancers.

Objectives: This study aimed to determine whether daily vitamin D or calcium supplementation alters the risk of basal cell carcinoma (BCC) or invasive cutaneous squamous cell carcinoma (SCC).

Methods: The Vitamin D/Calcium Polyp Prevention Study is a completed multicenter, double-blind, placebo-controlled, partial 2 × 2 factorial, randomized clinical trial of vitamin D, calcium, or both for the prevention of colorectal adenomas. During 2004-2008, a total of 2259 men and women, 45-75 y of age, recently diagnosed with a colorectal adenoma, were randomly assigned to 1000 IU/d of vitamin D3 or placebo and 1200 mg/d of calcium carbonate or placebo for 3 or 5 y, and followed after treatment ended. Reports of incident BCC or SCC were confirmed from pathology records.

Results: During a median follow-up of 8 y, 200 (9%) participants were diagnosed with BCC and 68 (3%) participants were diagnosed with SCC. BCC incidence was unrelated to treatment with vitamin D compared with no vitamin D (HR: 0.96; 95% CI: 0.73, 1.26), calcium compared with no calcium (HR: 1.01; 95% CI: 0.74, 1.39), and both agents compared with neither (HR: 0.99; 95% CI: 0.65, 1.51). SCC incidence was unrelated to treatment with vitamin D compared with no vitamin D (HR: 0.79; 95% CI: 0.49, 1.27), but there was suggestive evidence of beneficial treatment effects for calcium compared with no calcium (HR: 0.60; 95% CI: 0.36, 1.01) and both agents compared with neither (HR: 0.42; 95% CI: 0.19, 0.91).

Conclusions: Calcium alone or in combination with vitamin D may reduce the risk of SCC, but not BCC. This trial was registered at clinicaltrials.gov as NCT00153816.
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http://dx.doi.org/10.1093/ajcn/nqaa267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7727481PMC
December 2020

Combined associations of body mass index and adherence to a Mediterranean-like diet with all-cause and cardiovascular mortality: A cohort study.

PLoS Med 2020 09 17;17(9):e1003331. Epub 2020 Sep 17.

Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.

Background: It is unclear whether the effect on mortality of a higher body mass index (BMI) can be compensated for by adherence to a healthy diet and whether the effect on mortality by a low adherence to a healthy diet can be compensated for by a normal weight. We aimed to evaluate the associations of BMI combined with adherence to a Mediterranean-like diet on all-cause and cardiovascular disease (CVD) mortality.

Methods And Findings: Our longitudinal cohort design included the Swedish Mammography Cohort (SMC) and the Cohort of Swedish Men (COSM) (1997-2017), with a total of 79,003 women (44%) and men (56%) and a mean baseline age of 61 years. BMI was categorized into normal weight (20-24.9 kg/m2), overweight (25-29.9 kg/m2), and obesity (30+ kg/m2). Adherence to a Mediterranean-like diet was assessed by means of the modified Mediterranean-like diet (mMED) score, ranging from 0 to 8; mMED was classified into 3 categories (0 to <4, 4 to <6, and 6-8 score points), forming a total of 9 BMI × mMED combinations. We identified mortality by use of national Swedish registers. Cox proportional hazard models with time-updated information on exposure and covariates were used to calculate the adjusted hazard ratios (HRs) of mortality with their 95% confidence intervals (CIs). Our HRs were adjusted for age, baseline educational level, marital status, leisure time physical exercise, walking/cycling, height, energy intake, smoking habits, baseline Charlson's weighted comorbidity index, and baseline diabetes mellitus. During up to 21 years of follow-up, 30,389 (38%) participants died, corresponding to 22 deaths per 1,000 person-years. We found the lowest HR of all-cause mortality among overweight individuals with high mMED (HR 0.94; 95% CI 0.90, 0.98) compared with those with normal weight and high mMED. Using the same reference, obese individuals with high mMED did not experience significantly higher all-cause mortality (HR 1.03; 95% CI 0.96-1.11). In contrast, compared with those with normal weight and high mMED, individuals with a low mMED had a high mortality despite a normal BMI (HR 1.60; 95% CI 1.48-1.74). We found similar estimates among women and men. For CVD mortality (12,064 deaths) the findings were broadly similar, though obese individuals with high mMED retained a modestly increased risk of CVD death (HR 1.29; 95% CI 1.16-1.44) compared with those with normal weight and high mMED. A main limitation of the present study is the observational design with self-reported lifestyle information with risk of residual or unmeasured confounding (e.g., genetic liability), and no causal inferences can be made based on this study alone.

Conclusions: These findings suggest that diet quality modifies the association between BMI and all-cause mortality in women and men. A healthy diet may, however, not completely counter higher CVD mortality related to obesity.
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http://dx.doi.org/10.1371/journal.pmed.1003331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7497998PMC
September 2020

Inflammation Modulation by Vitamin D and Calcium in the Morphologically Normal Colorectal Mucosa of Patients with Colorectal Adenoma in a Clinical Trial.

Cancer Prev Res (Phila) 2021 Jan 11;14(1):65-76. Epub 2020 Sep 11.

Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.

Increased COX-2 and decreased 15-hydroxyprostaglandin dehydrogenase (15-HPGD) expression promote prostaglandin-mediated inflammation and colorectal carcinogenesis. Experimental studies suggest that vitamin D and calcium may inhibit these pathways, but their effects on colorectal tissue COX-2 and 15-HPGD expression in humans are unknown. We tested the effects of supplemental vitamin D (1,000 IU/day) and/or calcium (1,200 mg/day) on COX-2 and 15-HPGD expression in the morphologically normal rectal mucosa from 62 paients with colorectal adenoma in a placebo-controlled chemoprevention trial. We measured biomarker expression using automated IHC and quantitative image analysis at baseline and 1-year follow-up, and assessed treatment effects using mixed linear models. The primary outcome was the COX-2/15-HPGD expression ratio, because these enzymes function as physiologic antagonists. After 1 year of treatment, the mean COX-2/15-HPGD expression ratio in full-length crypts proportionately decreased 47% in the vitamin D group ( = 0.001), 46% in the calcium group ( = 0.002), and 34% in the calcium + vitamin D group ( = 0.03), relative to the placebo group. Among individuals with the functional vitamin D-binding protein isoform DBP2 ( rs4588*A), the COX-2/15-HPDG ratio decreased 70% ( = 0.0006), 75% ( = 0.0002), and 60% ( = 0.006) in the vitamin D, calcium, and combined supplementation groups, respectively, relative to placebo. These results show that vitamin D and calcium favorably modulate the balance of expression of COX-2 and 15-HPGD-biomarkers of inflammation that are strongly linked to colorectal carcinogenesis-in the normal-appearing colorectal mucosa of patients with colorectal adenoma (perhaps especially those with the DBP2 isoform). PREVENTION RELEVANCE: Supplemental calcium and vitamin D reduce indicators of cancer-promoting inflammation in normal colorectal tissue in humans, thus furthering our understanding of how they may help prevent colorectal cancer.
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http://dx.doi.org/10.1158/1940-6207.CAPR-20-0140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7947029PMC
January 2021

Circulating bilirubin levels and risk of colorectal cancer: serological and Mendelian randomization analyses.

BMC Med 2020 09 3;18(1):229. Epub 2020 Sep 3.

Public Health Directorate, Asturias, Spain.

Background: Bilirubin, a byproduct of hemoglobin breakdown and purported anti-oxidant, is thought to be cancer preventive. We conducted complementary serological and Mendelian randomization (MR) analyses to investigate whether alterations in circulating levels of bilirubin are associated with risk of colorectal cancer (CRC). We decided a priori to perform analyses separately in men and women based on suggestive evidence that associations may differ by sex.

Methods: In a case-control study nested in the European Prospective Investigation into Cancer and Nutrition (EPIC), pre-diagnostic unconjugated bilirubin (UCB, the main component of total bilirubin) concentrations were measured by high-performance liquid chromatography in plasma samples of 1386 CRC cases and their individually matched controls. Additionally, 115 single-nucleotide polymorphisms (SNPs) robustly associated (P < 5 × 10) with circulating total bilirubin were instrumented in a 2-sample MR to test for a potential causal effect of bilirubin on CRC risk in 52,775 CRC cases and 45,940 matched controls in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), the Colon Cancer Family Registry (CCFR), and the Colorectal Transdisciplinary (CORECT) study.

Results: The associations between circulating UCB levels and CRC risk differed by sex (P = 0.008). Among men, higher levels of UCB were positively associated with CRC risk (odds ratio [OR] = 1.19, 95% confidence interval [CI] = 1.04-1.36; per 1-SD increment of log-UCB). In women, an inverse association was observed (OR = 0.86 (0.76-0.97)). In the MR analysis of the main UGT1A1 SNP (rs6431625), genetically predicted higher levels of total bilirubin were associated with a 7% increase in CRC risk in men (OR = 1.07 (1.02-1.12); P = 0.006; per 1-SD increment of total bilirubin), while there was no association in women (OR = 1.01 (0.96-1.06); P = 0.73). Raised bilirubin levels, predicted by instrumental variables excluding rs6431625, were suggestive of an inverse association with CRC in men, but not in women. These differences by sex did not reach formal statistical significance (P ≥ 0.2).

Conclusions: Additional insight into the relationship between circulating bilirubin and CRC is needed in order to conclude on a potential causal role of bilirubin in CRC development.
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http://dx.doi.org/10.1186/s12916-020-01703-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469292PMC
September 2020

Metabolomics Analysis of Aspirin's Effects in Human Colon Tissue and Associations with Adenoma Risk.

Cancer Prev Res (Phila) 2020 10 12;13(10):863-876. Epub 2020 Jul 12.

Department of Medicine, Emory University, Atlanta, Georgia.

Although substantial evidence supports aspirin's efficacy in colorectal cancer chemoprevention, key molecular mechanisms are uncertain. An untargeted metabolomics approach with high-resolution mass spectrometry was used to elucidate metabolic effects of aspirin treatment in human colon tissue. We measured 10,269 metabolic features in normal mucosal biopsies collected at colonoscopy after approximately 3 years of randomized treatment with placebo, 81 or 325 mg/day aspirin from 325 participants in the Aspirin/Folate Polyp Prevention Study. Linear regression was used to identify aspirin-associated metabolic features and network analysis was used to identify pathways and predict metabolite identities. Poisson regression was used to examine metabolic features associations with colorectal adenoma risk. We detected 471 aspirin-associated metabolic features. Aside from the carnitine shuttle, aspirin-associated metabolic pathways were largely distinct for 81 mg aspirin (e.g., pyrimidine metabolism) and 325 mg (e.g., arachidonic acid metabolism). Among aspirin-associated metabolic features, we discovered three that were associated with adenoma risk and could contribute to the chemopreventive effect of aspirin treatment, and which have also previously been associated with colorectal cancer: creatinine, glycerol 3-phosphate, and linoleate. The last two of these are in the glycerophospholipid metabolism pathway, which was associated with 81 mg aspirin treatment and provides precursors for the synthesis of eicosanoids from arachidonic acid upstream of cyclooxygenase inhibition by aspirin. Conversely, carnitine shuttle metabolites were increased with aspirin treatment and associated with increased adenoma risk. Thus, our untargeted metabolomics approach has identified novel metabolites and pathways that may underlie the effects of aspirin during early colorectal carcinogenesis.
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http://dx.doi.org/10.1158/1940-6207.CAPR-20-0014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7541578PMC
October 2020

How subgroup analyses can miss the trees for the forest plots: A simulation study.

J Clin Epidemiol 2020 10 19;126:65-70. Epub 2020 Jun 19.

Department of Epidemiology, UNC-Chapel Hill, Chapel Hill, NC 27599.

Objectives: Subgroup analyses of clinical trial data can be an important tool for understanding when treatment effects differ across populations. That said, even effect estimates from prespecified subgroups in well-conducted trials may not apply to corresponding subgroups in the source population. While this divergence may simply reflect statistical imprecision, there has been less discussion of systematic or structural sources of misleading subgroup estimates.

Study Design And Setting: We use directed acyclic graphs to show how selection bias caused by associations between effect measure modifiers and trial selection, whether explicit (e.g., eligibility criteria) or implicit (e.g., self-selection based on race), can result in subgroup estimates that do not correspond to subgroup effects in the source population. To demonstrate this point, we provide a hypothetical example illustrating the sorts of erroneous conclusions that can result, as well as their potential consequences. We also provide a tool for readers to explore additional cases.

Conclusion: Treating subgroups within a trial essentially as random samples of the corresponding subgroups in the wider population can be misleading, even when analyses are conducted rigorously and all findings are internally valid. Researchers should carefully examine associations between (and consider adjusting for) variables when attempting to identify heterogeneous treatment effects.
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http://dx.doi.org/10.1016/j.jclinepi.2020.06.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7529905PMC
October 2020

Evaluation of a Deep Neural Network for Automated Classification of Colorectal Polyps on Histopathologic Slides.

JAMA Netw Open 2020 04 1;3(4):e203398. Epub 2020 Apr 1.

Department of Biomedical Data Science, Dartmouth College, Hanover, New Hampshire.

Importance: Histologic classification of colorectal polyps plays a critical role in screening for colorectal cancer and care of affected patients. An accurate and automated algorithm for the classification of colorectal polyps on digitized histopathologic slides could benefit practitioners and patients.

Objective: To evaluate the performance and generalizability of a deep neural network for colorectal polyp classification on histopathologic slide images using a multi-institutional data set.

Design, Setting, And Participants: This prognostic study used histopathologic slides collected from January 1, 2016, to June 31, 2016, from Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, with 326 slides used for training, 157 slides for an internal data set, and 25 for a validation set. For the external data set, 238 slides for 179 distinct patients were obtained from 24 institutions across 13 US states. Data analysis was performed from April 9 to November 23, 2019.

Main Outcomes And Measures: Accuracy, sensitivity, and specificity of the model to classify 4 major colorectal polyp types: tubular adenoma, tubulovillous or villous adenoma, hyperplastic polyp, and sessile serrated adenoma. Performance was compared with that of local pathologists' at the point of care identified from corresponding pathology laboratories.

Results: For the internal evaluation on the 157 slides with ground truth labels from 5 pathologists, the deep neural network had a mean accuracy of 93.5% (95% CI, 89.6%-97.4%) compared with local pathologists' accuracy of 91.4% (95% CI, 87.0%-95.8%). On the external test set of 238 slides with ground truth labels from 5 pathologists, the deep neural network achieved an accuracy of 87.0% (95% CI, 82.7%-91.3%), which was comparable with local pathologists' accuracy of 86.6% (95% CI, 82.3%-90.9%).

Conclusions And Relevance: The findings suggest that this model may assist pathologists by improving the diagnostic efficiency, reproducibility, and accuracy of colorectal cancer screenings.
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http://dx.doi.org/10.1001/jamanetworkopen.2020.3398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7180424PMC
April 2020

A New Comprehensive Colorectal Cancer Risk Prediction Model Incorporating Family History, Personal Characteristics, and Environmental Factors.

Cancer Epidemiol Biomarkers Prev 2020 03 13;29(3):549-557. Epub 2020 Jan 13.

Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington.

Purpose: Reducing colorectal cancer incidence and mortality through early detection would improve efficacy if targeted. We developed a colorectal cancer risk prediction model incorporating personal, family, genetic, and environmental risk factors to enhance prevention.

Methods: A familial risk profile (FRP) was calculated to summarize individuals' risk based on detailed cancer family history (FH), family structure, probabilities of mutation in major colorectal cancer susceptibility genes, and a polygenic component. We developed risk models, including individuals' FRP or binary colorectal cancer FH, and colorectal cancer risk factors collected at enrollment using population-based colorectal cancer cases ( = 4,445) and controls ( = 3,967) recruited by the Colon Cancer Family Registry Cohort (CCFRC). Model validation used CCFRC follow-up data for population-based ( = 12,052) and clinic-based ( = 5,584) relatives with no cancer history at recruitment to assess model calibration [expected/observed rate ratio (E/O)] and discrimination [area under the receiver-operating-characteristic curve (AUC)].

Results: The E/O [95% confidence interval (CI)] for FRP models for population-based relatives were 1.04 (0.74-1.45) for men and 0.86 (0.64-1.20) for women, and for clinic-based relatives were 1.15 (0.87-1.58) for men and 1.04 (0.76-1.45) for women. The age-adjusted AUCs (95% CI) for FRP models for population-based relatives were 0.69 (0.60-0.78) for men and 0.70 (0.62-0.77) for women, and for clinic-based relatives were 0.77 (0.69-0.84) for men and 0.68 (0.60-0.76) for women. The incremental values of AUC for FRP over FH models for population-based relatives were 0.08 (0.01-0.15) for men and 0.10 (0.04-0.16) for women, and for clinic-based relatives were 0.11 (0.05-0.17) for men and 0.11 (0.06-0.17) for women.

Conclusions: Both models calibrated well. The FRP-based model provided better risk stratification and risk discrimination than the FH-based model.

Impact: Our findings suggest detailed FH may be useful for targeted risk-based screening and clinical management.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-0929DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060114PMC
March 2020

Cumulative Burden of Colorectal Cancer-Associated Genetic Variants Is More Strongly Associated With Early-Onset vs Late-Onset Cancer.

Gastroenterology 2020 04 19;158(5):1274-1286.e12. Epub 2019 Dec 19.

Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington.

Background & Aims: Early-onset colorectal cancer (CRC, in persons younger than 50 years old) is increasing in incidence; yet, in the absence of a family history of CRC, this population lacks harmonized recommendations for prevention. We aimed to determine whether a polygenic risk score (PRS) developed from 95 CRC-associated common genetic risk variants was associated with risk for early-onset CRC.

Methods: We studied risk for CRC associated with a weighted PRS in 12,197 participants younger than 50 years old vs 95,865 participants 50 years or older. PRS was calculated based on single nucleotide polymorphisms associated with CRC in a large-scale genome-wide association study as of January 2019. Participants were pooled from 3 large consortia that provided clinical and genotyping data: the Colon Cancer Family Registry, the Colorectal Transdisciplinary Study, and the Genetics and Epidemiology of Colorectal Cancer Consortium and were all of genetically defined European descent. Findings were replicated in an independent cohort of 72,573 participants.

Results: Overall associations with CRC per standard deviation of PRS were significant for early-onset cancer, and were stronger compared with late-onset cancer (P for interaction = .01); when we compared the highest PRS quartile with the lowest, risk increased 3.7-fold for early-onset CRC (95% CI 3.28-4.24) vs 2.9-fold for late-onset CRC (95% CI 2.80-3.04). This association was strongest for participants without a first-degree family history of CRC (P for interaction = 5.61 × 10). When we compared the highest with the lowest quartiles in this group, risk increased 4.3-fold for early-onset CRC (95% CI 3.61-5.01) vs 2.9-fold for late-onset CRC (95% CI 2.70-3.00). Sensitivity analyses were consistent with these findings.

Conclusions: In an analysis of associations with CRC per standard deviation of PRS, we found the cumulative burden of CRC-associated common genetic variants to associate with early-onset cancer, and to be more strongly associated with early-onset than late-onset cancer, particularly in the absence of CRC family history. Analyses of PRS, along with environmental and lifestyle risk factors, might identify younger individuals who would benefit from preventive measures.
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http://dx.doi.org/10.1053/j.gastro.2019.12.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7103489PMC
April 2020

The effect of age on DNA methylation in whole blood among Bangladeshi men and women.

BMC Genomics 2019 Sep 10;20(1):704. Epub 2019 Sep 10.

Department of Public Health Sciences, University of Chicago, 5841 S. Maryland Ave., W264, MC2000, Chicago, IL, 60637, USA.

Background: It is well-known that methylation changes occur as humans age, however, understanding how age-related changes in DNA methylation vary by sex is lacking. In this study, we characterize the effect of age on DNA methylation in a sex-specific manner and determine if these effects vary by genomic context. We used the Illumina HumanMethylation 450 K array and DNA derived from whole blood for 400 adult participants (189 males and 211 females) from Bangladesh to identify age-associated CpG sites and regions and characterize the location of these age-associated sites with respect to CpG islands (vs. shore, shelf, or open sea) and gene regions (vs. intergenic). We conducted a genome-wide search for age-associated CpG sites (among 423,604 sites) using a reference-free approach to adjust for cell type composition (the R package RefFreeEWAS) and performed an independent replication analysis of age-associated CpGs.

Results: The number of age-associated CpGs (p < 5 x 10) were 986 among men and 3479 among women of which 2027(63.8%) and 572 (64.1%) replicated (using Bonferroni adjusted p < 1.2 × 10). For both sexes, age-associated CpG sites were more likely to be hyper-methylated with increasing age (compared to hypo-methylated) and were enriched in CpG islands and promoter regions compared with other locations and all CpGs on the array. Although we observed strong correlation between chronological age and previously-developed epigenetic age models (r ≈ 0.8), among our top (based on lowest p-value) age-associated CpG sites only 12 for males and 44 for females are included in these prediction models, and the median chronological age compared to predicted age was 44 vs. 51.7 in males and 45 vs. 52.1 in females.

Conclusions: Our results describe genome-wide features of age-related changes in DNA methylation. The observed associations between age and methylation were generally consistent for both sexes, although the associations tended to be stronger among women. Our population may have unique age-related methylation changes that are not captured in the established methylation-based age prediction model we used, which was developed to be non-tissue-specific.
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http://dx.doi.org/10.1186/s12864-019-6039-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6734473PMC
September 2019

Genome-wide association study of circulating folate one-carbon metabolites.

Genet Epidemiol 2019 12 10;43(8):1030-1045. Epub 2019 Sep 10.

Department of Preventive Medicine, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California.

Experimental, observational, and clinical trials support a critical role of folate one-carbon metabolism (FOCM) in colorectal cancer (CRC) development. In this report, we focus on understanding the relationship between common genetic variants and metabolites of FOCM. We conducted a genome-wide association study of FOCM biomarkers among 1,788 unaffected (without CRC) individuals of European ancestry from the Colon Cancer Family Registry. Twelve metabolites, including 5-methyltetrahydrofolate, vitamin B (flavin mononucleotide and riboflavin), vitamin B (4-pyridoxic acid, pyridoxal, and pyridoxamine), total homocysteine, methionine, S-adenosylmethionine, S-adenosylhomocysteine, cystathionine, and creatinine were measured from plasma using liquid chromatography-mass spectrometry (LC-MS) or LC-MS/MS. For each individual biomarker, we estimated genotype array-specific associations followed by a fixed-effect meta-analysis. We identified the variant rs35976024 (at 2p11.2 and intronic of ATOH8) associated with total homocysteine (p = 4.9 × 10 ). We found a group of six highly correlated variants on chromosome 15q14 associated with cystathionine (all p < 5 × 10 ), with the most significant variant rs28391580 (p = 2.8 × 10 ). Two variants (rs139435405 and rs149119426) on chromosome 14q13 showed significant (p < 5 × 10 ) associations with S-adenosylhomocysteine. These three biomarkers with significant associations are closely involved in homocysteine metabolism. Furthermore, when assessing the principal components (PCs) derived from seven individual biomarkers, we identified the variant rs12665366 (at 6p25.3 and intronic of EXOC2) associated with the first PC (p = 2.3 × 10 ). Our data suggest that common genetic variants may play an important role in FOCM, particularly in homocysteine metabolism.
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http://dx.doi.org/10.1002/gepi.22249DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829035PMC
December 2019

Rapid Recurrence of Eosinophilic Esophagitis Activity After Successful Treatment in the Observation Phase of a Randomized, Double-Blind, Double-Dummy Trial.

Clin Gastroenterol Hepatol 2020 06 6;18(7):1483-1492.e2. Epub 2019 Sep 6.

Center for Esophageal Diseases and Swallowing, Center for Gastrointestinal Biology and Disease, Division of Gastroenterology and Hepatology, Chapel Hill, North Carolina.

Background & Aims: Eosinophilic esophagitis (EoE) is chronic and recurs if treatment is discontinued. We aimed to determine rates of recurrence, and whether initial treatment with oral viscous budesonide (OVB) resulted in less recurrence than fluticasone from a multidose inhaler (MDI).

Methods: This was the observation phase of a randomized, double-blind, double-dummy trial comparing OVB with MDI for initial EoE treatment. Subjects with a histologic response (<15 eosinophils/high-power field) in the trial entered an observation phase in which treatment was discontinued and symptoms were monitored. Patients underwent an endoscopy or a biopsy when symptoms recurred or at 1 year. We analyzed time to symptom recurrence and assessed endoscopic severity and histologic relapse (≥15 eosinophils/high-power field) at follow-up endoscopy.

Results: Thirty-three of the 58 subjects (57%) had symptom recurrence before 1 year. The overall median time to symptom recurrence was 244 days. There was no difference in the rate of symptom recurrence for subjects treated with OVB vs MDI (hazard ratio, 1.04; 95% CI, 0.52-2.08). At symptom recurrence, 78% of patients had histologic relapse. The patients had significant increases in mean Dysphagia Symptom Questionnaire score (3.8 vs 8.7; P < .001), and the EoE Endoscopic Reference Score (1.3 vs 4.6; P < .001) compared with end of treatment.

Conclusions: EoE disease activity recurred rapidly after initial histologic response to topical steroids (either OVB or MDI). Because most subjects had recurrent endoscopic and histologic signs not reliably detected by symptoms, maintenance therapy should be recommended in EoE patients achieving histologic response to topical steroids. Clinicaltrials.gov no: NCT02019758.
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http://dx.doi.org/10.1016/j.cgh.2019.08.050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7058486PMC
June 2020

Folic acid supplementation and risk of colorectal neoplasia during long-term follow-up of a randomized clinical trial.

Am J Clin Nutr 2019 10;110(4):903-911

Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.

Background: The Aspirin/Folate Polyp Prevention Study previously found folic acid increased risk of advanced and multiple colorectal adenomas during a surveillance colonoscopy interval starting about 3 y after randomization.

Objective: We conducted secondary analyses to evaluate folic acid effects with additional follow-up after treatment was stopped.

Methods: In total, 1021 participants recently diagnosed with colorectal adenomas were randomly assigned to 1 mg/d of folic acid (n = 516) or placebo (n = 505), with or without aspirin, beginning 6 July 1994. The original 3-y treatment period was extended into a subsequent colonoscopy interval, but eventually stopped prematurely on 1 October 2004. With additional post-treatment follow-up, a total of 663 participants who extended treatment completed a second colonoscopic surveillance interval after the initial 3-y follow-up. In addition, 490 participants provided information regarding a subsequent surveillance colonoscopy occurring before completion of follow-up on 31 May 2012, including 325 who had agreed to extended treatment. Study endpoints included conventional adenomas, sessile serrated adenomas/polyps (SSA/Ps), or colorectal cancer, and RRs with 95% CIs were adjusted for baseline characteristics associated with availability of follow-up.

Results: Among those who extended treatment, any colorectal neoplasia was found in 118 (36%) participants assigned to placebo and 146 (43%) assigned to folic acid during the second surveillance interval (RR: 1.21; 95% CI: 0.99, 1.47; P = 0.06). Increased risk of SSA/P with extended folic acid supplementation was statistically significant during the second surveillance interval (RR: 1.94; 95% CI: 1.02, 3.68; P = 0.04). There was no evidence of post-treatment effects for any colorectal neoplasia (RR: 1.01; 95% CI: 0.80, 1.28; P = 0.94), and the post-treatment effect for SSA/P was no longer statistically significant (RR: 1.38; 95% CI: 0.59, 3.19; P = 0.46).

Conclusions: Delayed treatment effects were not observed, but folic acid may increase SSA/P risk. This trial was registered at clinicaltrials.gov as NCT00272324.
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http://dx.doi.org/10.1093/ajcn/nqz160DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6766439PMC
October 2019

Body Composition and Aspirin Dose for Colorectal Adenoma Prevention in a Randomized Clinical Trial.

Cancer Epidemiol Biomarkers Prev 2019 07;28(7):1262-1265

Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.

Background: Visceral adiposity is a risk factor for colorectal adenomas, and aspirin is an established chemopreventive agent. Evidence from clinical trials suggests the effectiveness of aspirin at preventing cardiovascular disease and cancer may require higher doses for higher body weight.

Methods: Body mass index, body surface area, fat-free mass, and fat mass were calculated from baseline height and weight in 1,121 participants of the Aspirin/Folate Polyp Prevention Study, a double-blind, placebo-controlled, 3 × 2 factorial randomized clinical trial of low-dose (81 mg/day) or high-dose (325 mg/day) aspirin and/or 1 mg/day folic acid to prevent metachronous colorectal adenomas. Participants were treated during a surveillance colonoscopy interval of approximately 3 years. Risk ratios (RR) with 95% confidence intervals (CI) for any colorectal neoplasia and high-risk adenoma (HRA, advanced or ≥3 adenomas) were estimated from log-linear regression.

Results: We did not find evidence to suggest aspirin dose-response differed by body composition measurements, including weight alone. Among those weighing ≥ 80 kg, treatment effects for low-dose aspirin (RR for colorectal neoplasia, 0.75; 95% CI, 0.60-0.94; RR for HRA, 0.52; 95% CI, 0.31-0.86) and high-dose aspirin (RR for colorectal neoplasia, 0.88; 95% CI, 0.72-1.08; RR for HRA, 0.68; 95% CI, 0.43-1.09) were not meaningfully different than for those weighing 70-79 kg or <70 kg.

Conclusions: Measurements of body composition calculated from height and weight did not modify aspirin treatment effects for colorectal adenoma prevention.

Impact: Aspirin dosing strategies accounting for body weight suggested in previous trials of colorectal cancer may not apply to adenomas.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-0205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6608598PMC
July 2019

Vitamin D as Cancer Therapy?: Insights From 2 New Trials.

JAMA 2019 04;321(14):1354-1355

Department of Epidemiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire.

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http://dx.doi.org/10.1001/jama.2019.2589DOI Listing
April 2019

Effects of supplemental calcium and vitamin D on tight-junction proteins and mucin-12 expression in the normal rectal mucosa of colorectal adenoma patients.

Mol Carcinog 2019 07 2;58(7):1279-1290. Epub 2019 Apr 2.

Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.

The physical gut barrier, comprised of a thick mucus layer and the epithelium, plays an important role in defense against microbes and foreign antigens. Calcium and vitamin D may be involved in maintaining the integrity of the intestinal mucosal barrier, the dysfunction of which may lead to endotoxemia and inflammation, and contribute to colorectal carcinogenesis. We investigated supplemental calcium (1200 mg, daily) and/or vitamin D (1000 IU daily) effects on intestinal barrier function-related biomarkers in a subset of 105 participants from a large colorectal adenoma recurrence chemoprevention clinical trial. We assessed expression of the tight junction proteins claudin-1 (CLDN1), occludin (OCLD), and mucin-12 (MUC12) in the normal-appearing colorectal mucosa using standardized, automated immunohistochemistry and quantitative image analysis. Following 1 year of treatment, in the calcium relative to the no calcium group, the CLDN1, OCLD, and MUC12 expression increased by 14% (P = 0.17), 23% (P = 0.11), and 22% (P = 0.07), respectively. In secondary analyses, the estimated calcium treatment effects were greater among participants with baseline serum 25-OH-vitamin D concentrations below the median value of 22.69 ng/mL (CLDN1: 29%, P = 0.04; OCLD: 36%, P = 0.06; MUC12: 35%, P = 0.05). There were no biomarker expression changes in the vitamin D alone group; however, modest increases were found in the combined calcium/vitamin D group. At baseline, obesity, history of a sessile-serrated adenoma, colorectal MIB-1/Ki-67 expression, and a family history of colorectal cancer were associated with CLDN1, OCLD, and MUC12 expression. Our study supports continued investigation of factors that could affect intestinal mucosal barrier integrity relevant to colorectal carcinogenesis.
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http://dx.doi.org/10.1002/mc.23010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548635PMC
July 2019

Efficacy of Budesonide vs Fluticasone for Initial Treatment of Eosinophilic Esophagitis in a Randomized Controlled Trial.

Gastroenterology 2019 07 11;157(1):65-73.e5. Epub 2019 Mar 11.

Center for Esophageal Diseases and Swallowing, and Center for Gastrointestinal Biology and Disease, Division of Gastroenterology and Hepatology, University of North Carolina School of Medicine, Chapel Hill, North Carolina.

Background And Aims: Topical steroid treatments for eosinophilic esophagitis (EoE) include swallowed fluticasone from a multi-dose inhaler (MDI) or oral viscous budesonide (OVB) slurry, but the 2 have never been compared. We assessed whether OVB was more effective than MDI for initial treatment of patients with EoE.

Methods: In a double-blind, double-dummy trial, patients with a new diagnosis of EoE were randomly assigned to groups given 8 weeks of either OVB (1 mg/4 mL) twice daily plus a placebo inhaler (n = 56) or fluticasone MDI (880 μg) twice daily plus a placebo slurry (n = 55). Primary outcomes were post-treatment maximum eosinophil counts per high-power field (eos/hpf) and a validated dysphagia score (dysphagia symptom questionnaire [DSQ]) at week 8. Secondary outcomes included endoscopic severity (validated EoE endoscopic reference score), histologic response (<15 eos/hpf), and safety.

Results: In a modified intention-to-treat analysis, the subjects had baseline peak eosinophil counts of 73 and 77 eos/hpf in the OVB and MDI groups, respectively, and DSQ scores of 11 and 8. Post-treatment eosinophil counts were 15 and 21 in the OVB and MDI groups, respectively (P = .31), with 71% and 64% achieving histologic response (P = .38). DSQ scores were 5 and 4 in the OVB and MDI groups (P = .70). Similar trends were noted for post-treatment total EoE endoscopic reference scores (2 vs 3; P = .06). Esophageal candidiasis developed in 12% of patients receiving OVB and 16% receiving MDI; oral thrush was observed in 3% and 2%, respectively.

Conclusions: In a randomized clinical trial, initial treatment of EoE with either OVB or fluticasone MDI produced a significant decrease in esophageal eosinophil counts and improved dysphagia and endoscopic features. However, OVB was not superior to MDI, so either is an acceptable treatment for EoE. ClinicalTrials.gov ID NCT02019758.
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http://dx.doi.org/10.1053/j.gastro.2019.03.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6581596PMC
July 2019
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