Publications by authors named "Melanie R Simpson"

3 Publications

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The effect of sleep-wake intraindividial variability in digital cognitive behaviour therapy for insomnia: A mediation analysis of a large-scale RCT.

Sleep 2021 May 8. Epub 2021 May 8.

Department of Mental Health, Norwegian University of Science and Technology, Trondheim, Norway.

Study Objectives: Digital Cognitive Behavioural Therapy for Insomnia (dCBT-I) is an effective treatment for insomnia. However, less is known about mediators of its benefits. The aim of the present study was to test if intraindividual variability in sleep (IIV) was reduced with dCBT-I, and whether any identified reduction was a mediator of dCBT-I on insomnia severity and psychological distress.

Methods: In a two-arm randomized controlled trial (RCT), 1720 adults with insomnia (dCBT-I = 867; patient education about sleep = 853) completed the Insomnia Severity Index (ISI), the Hospital Anxiety and Depression Scale (HADS) and sleep diaries, at baseline and 9-week follow-up. Changes in IIV were analysed using linear mixed modelling followed by mediation analyses of ISI, HADS, and IIV in singular sleep metrics and composite measures (Behavioural Indices (BI-Z) and Sleep-disturbance Indices (SI-Z)).

Results: dCBT-I was associated with reduced IIV across all singular sleep metrics, with the largest between-group effect sizes observed for sleep onset latency (SOL). Reduced IIV for SOL and wake after sleep onset had the overall greatest singular mediating effect. For composite measures, SI-Z mediated change in ISI (b = -0.74; 95% Confidence Interval (CI) -1.04 to -0.52; 13.3%) and HADS (b = -0.40; 95% CI -0.73 to -0.18; 29.2%), whilst BI-Z mediated minor changes.

Conclusion: Reductions in IIV in key sleep metrics mediate significant changes in insomnia severity and especially psychological distress when using dCBT-I. These findings offer important evidence regarding the therapeutic action of dCBT-I and may guide the future development of this intervention.
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May 2021

Statistical Approaches in the Studies Assessing Associations between Human Milk Immune Composition and Allergic Diseases: A Scoping Review.

Nutrients 2019 Oct 10;11(10). Epub 2019 Oct 10.

Department of Paediatrics and Paediatric Infectious Diseases, Institute of Child's Health, Sechenov First Moscow State Medical University (Sechenov University), 123337 Moscow, Russia.

A growing number of studies are focusing on the associations between human milk (HM) immunological composition and allergic diseases. This scoping review aims to identify statistical methods applied in the field and highlight pitfalls and unmet needs. A comprehensive literature search in MEDLINE and Embase retrieved 13,607 unique records. Following title/abstract screening, 29 studies met the selection criteria and were included in this review. We found that definitions of colostrum and mature milk varied across the studies. A total of 17 out of 29 (59%) studies collected samples longitudinally, but only 12% of these used serial (longitudinal) analyses. Multivariable analysis was used in 45% of the studies, but statistical approaches to modelling varied largely across the studies. Types of variables included as potential confounding factors differed considerably between models. Discrimination analysis was absent from all studies and only a single study reported classification measures. Outcomes of this scoping review highlight lack of standardization, both in data collection and handling, which remains one of the main challenges in the field. Improved standardization could be obtained by a consensus group of researchers and clinicians that could recommend appropriate methods to be applied in future prospective studies, as well as already existing datasets.
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October 2019

Does Maternal Perinatal Probiotic Supplementation Alter the Intestinal Microbiota of Mother and Child?

J Pediatr Gastroenterol Nutr 2015 Aug;61(2):200-7

*Department of Public Health and General Practice, Norwegian University of Science and Technology, Trondheim †Department of Chemistry, Biotechnology and Food Science, University of Life Sciences, Aas, Norway.

Objectives: Maternal probiotic supplementation has been shown to prevent the development of atopic dermatitis in the offspring. We aimed to investigate whether probiotics in pregnant and breast-feeding mothers altered the colonization pattern and the diversity of the mothers' and children's intestinal microbiota.

Methods: In a randomized, double-blind trial, women received probiotic milk or placebo from 36 weeks of gestation up to 3 months postnatally while breast-feeding. The probiotic milk contained Lactobacillus rhamnosus GG, L acidophilus La-5, and Bifidobacterium animalis subsp. lactis Bb-12. Stool samples were collected from the mothers at 30 to 36 weeks of gestation and 3 months after birth, and from the child at age 10 days, 3 months, 1 year, and 2 years, and bacteria were analyzed by quantitative polymerase chain reaction. Additionally, stool samples from 3-month-old and 2-year-old children were characterized using 16S ribosomal RNA gene deep sequencing to estimate the bacterial classes and genera, and the α- and β-diversity.

Results: Three months after birth, both the prevalence and the relative abundance of the administered probiotic bacteria were significantly increased among the mothers in the probiotic group compared with among those in the placebo group. Only the Lactobacillus rhamnosus GG bacteria colonized the children at 10 days and at 3 months of age. There were no significant differences in the abundance of the administered probiotic bacteria between the groups at 1 and 2 years of age. For the bacterial classes and genera, and α- and β-diversity, there were no significant differences between the groups.

Conclusions: Different probiotic bacteria seem to have different ability to transfer from the mother to the child. We found no evidence that the probiotics altered the microbial composition or α- and β-diversity of the children.
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August 2015