Publications by authors named "Maria Ana Correia"

5 Publications

  • Page 1 of 1

Applying dental microwear texture analysis to the living: Challenges and prospects.

Am J Phys Anthropol 2021 Mar 13;174(3):542-554. Epub 2020 Sep 13.

Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge, Cambridge, UK.

Objectives: The food that people and animals consume leaves microscopic traces on teeth in predictable ways, and analyses of these markings-known as dental microwear analyses-allow us to reverse engineer the characteristics of diet. However, the microwear features of modern human diets are most often interpreted through the lens of ethnographic records. Given the subtle variation within human diets when compared to other species, we need better models of how foods and processing techniques produce marks on teeth. Here, we report on the second study to target the occlusal surface microwear of living human populations, and the first to target populations other than foragers.

Methods: We collected 150 dental impressions from five Kenyan communities: El Molo, Turkana (Kerio), Luhya (Webuye), Luhya (Port Victoria), and Luo (Port Victoria), representing a range of subsistence strategies and associated staple diets-fishing, pastoralism, and agriculture. Our results suggest that the occlusal microwear of these groups records differences in diet. However, biofilm obscured most of the molds obtained despite the steps taken to remove it, resulting in only 38 usable surfaces.

Results: Due to the biofilm problem and final sample size, the analysis did not have enough power to demonstrate the differences observed statistically. The results and problems encountered are here explained.

Conclusions: Considering that in vivo studies of dental microwear texture analysis have the potential to increase our understanding of the association between patterns of dental microwear and complex, mixed human diets, resolution of the current pitfalls of the technique is critical.
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March 2021

Carbon and nitrogen isotopic signatures of hair, nail, and breath from tropical African human populations.

Rapid Commun Mass Spectrom 2019 Nov;33(22):1761-1773

Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge, Fitzwilliam Street, Cambridge, CB2 1QH, UK.

Rationale: Stable isotopic analyses are increasingly used to study the diets of past and present human populations. Yet, the carbon and nitrogen isotopic data of modern human diets collected so far are biased towards Europe and North America. Here, we address this gap by reporting on the dietary isotopic signatures of six tropical African communities: El Molo, Turkana (Kerio), Luhya (Webuye), Luhya (Port Victoria), and Luo (Port Victoria) from Kenya, and Baka from Cameroon; representing four subsistence strategies: fishing, pastoralism, agriculturalism, and hunter-gatherer.

Methods: We used an elemental analyser coupled in continuous-flow mode to an isotope ratio mass spectrometer to measure the carbon and nitrogen isotopic ratios of hair (n = 134) and nail (n = 80) and the carbon isotopic ratios of breath (n = 184) from these communities, as well as the carbon and nitrogen isotopic ratios of some food samples from the Kenyan communities.

Results: We expand on the known range of δ C values in human hair through the hunter-gatherer Baka, with a diet based on C plants, and through the agriculturalist Luhya (Webuye), with a diet based on C plants. In addition, we found that the consumption of fish from East African lakes is difficult to detect isotopically due to the combined effects of high nitrogen isotopic ratios of plants and the low nitrogen isotopic ratios of fish. Finally, we found that some of the communities studied are markedly changing their diets through increasing sedentism and urbanisation.

Conclusions: Our findings contribute substantially to the understanding of the environmental, demographic, and economic dynamics that affect the dietary landscape of different tropical populations of Africa. These results highlight the importance of studying a broader sample of human populations and their diet, with a focus on their precise context - from both isotopic and more general anthropological perspectives.
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November 2019

Intermittent preventive treatment of malaria during pregnancy in central Mozambique.

Bull World Health Organ 2007 Nov;85(11):873-9

Department of Health Services, School of Public Health and Community Medicine, University of Washington, Seattle, Washington 98195, USA.

Problem: New WHO strategies for control of malaria in pregnancy (MiP) recommend intermittent preventive treatment (IPTp), bednet use and improved case management.

Approach: A pilot MiP programme in Mozambique was designed to determine requirements for scale-up.

Local Setting: The Ministry of Health worked with a nongovernmental organization and an academic institution to establish and monitor a pilot programme in two impoverished malaria-endemic districts.

Relevant Changes: Implementing the pilot programme required provision of additional sulfadoxine-pyrimethamine (SP), materials for directly observed SP administration, bednets and a modified antenatal card. National-level formulary restrictions on SP needed to be waived. The original protocol required modification because imprecision in estimation of gestational age led to missed SP doses. Multiple incompatibilities with other health initiatives (including programmes for control of syphilis, anaemia and HIV) were discovered and overcome. Key outputs and impacts were measured; 92.5% of 7911 women received at least 1 dose of SP, with the mean number of SP doses received being 2.2. At the second antenatal visit, 13.5% of women used bednets. In subgroups (1167 for laboratory analyses; 2600 births), SP use was significantly associated with higher haemoglobin levels (10.9 g/dL if 3 doses, 10.3 if none), less malaria parasitaemia (prevalence 7.5% if 3 doses, 39.3% if none), and fewer low-birth-weight infants (7.3% if 3 doses, 12.5% if none).

Lessons Learned: National-level scale-up will require attention to staffing, supplies, bednet availability, drug policy, gestational-age estimation and harmonization of vertical initiatives.
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November 2007

Prevalence and predictors of maternal peripheral malaria parasitemia in central Mozambique.

Am J Trop Med Hyg 2007 Aug;77(2):228-34

Department of Health Services, School of Public Health and Community Medicine, University of Washington, Seattle, WA 98195, USA.

Malaria infection during pregnancy (MiP) is heterogeneously distributed even in malaria-endemic countries. Program planners require data to facilitate identification of highest-priority populations for MiP control. Using data from two cross-sectional studies of 5,528 pregnant women in 8 neighboring sites in Mozambique, we described factors associated with maternal peripheral parasitemia by using logistic regression. Principal multivariate predictors of maternal peripheral parasitemia were gravidity (odds ratio [OR] = 2.29, 95% confidence interval [CI] = 1.60-3.26 for primigravidae and OR = 1.61, 95% CI = 1.29-2.01 for secundigravidae compared with gravidity > or = 3); age (OR = 0.96 per year, 95% CI = 0.94-0.99); study site (OR = 1.45, 95% CI = 1.34-1.56 to 5.32, 95% CI = 4.92-5.75) for comparison with the reference site; and no maternal education (OR = 1.38, 95% CI = 1.15-1.66) compared with any education. Other predictors (in subgroups) were bed net use (OR = 0.49, 95% CI = 0.48-0.50); preventive sulfadoxine-pyrimethamine doses (OR = 0.25, 95% CI = 0.24-0.25); and infection with human immunodeficiency virus (HIV) (OR = 1.49, 95% CI = 1.11-2.00). Programmatic priorities should respond to heterogeneous distribution of multiple risk factors, including prevalence of malaria and infection with HIV, and maternal socioeconomic status.
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August 2007

Lessons learned from bednet distribution in Central Mozambique.

Health Policy Plan 2007 Mar 8;22(2):103-10. Epub 2007 Feb 8.

Department of Health Services, School of Public Health and Community Medicine, P.O. Box 354809, University of Washington, Seattle, WA 98195, USA.

Introduction: Malaria is an important cause of mortality and morbidity in sub-Saharan Africa. Use of insecticide-treated bednets (ITNs) is an important preventive intervention. Selection of the best mechanisms for distribution and promotion of ITNs to vulnerable populations is an important strategic issue.

Methods: Commercial shopkeepers and groups of community leaders were trained to promote and sell ITNs in 19 sites in central Mozambique between 2000 and 2004. Pregnant women and children under 5 years of age comprised the target population. Sales records, household survey results and project experiences were examined to derive 'lessons learned'.


Primary Outcome: An end-of-project household survey revealed that 40.8% of households owned one or more bednets, but only 19.6% of households owned a net that had been re-treated with insecticide within the preceding 6 months. Higher levels of bednet (treated or untreated) coverage (over 50%) were achieved in urban or peri-urban sites than in rural sites (as low as 15%). Bednet ownership was significantly associated with higher socio-economic status (odds ratios for association with bednet ownership: 5.6 for highest educational level compared with no education, 0.4 for dirt floor compared with cement or other finished flooring, 2.1 for automobile ownership compared with transportation on foot), but was negatively associated with the presence of young children in the household (odds ratio 0.5). Primary output: 23 000 ITNs were sold during the course of the project. Process lessons: Nearly all of the community leader sites failed and were replaced by shopkeepers or Ministry of Health personnel. Sales were most brisk in more prosperous urban and peri-urban sites (up to 147 nets/month) but were significantly slower in poorer, rural sites (as low as three nets/month). Remote rural sites with slow sales were more expensive to serve. Logistical difficulties were related to tariffs, transport, management of cash, warehousing and organization of re-treatment campaigns.

Conclusions: This project failed to achieve adequate or equitable levels of ITN coverage in a timely manner in the programme sites. However, its findings helped support a subsequent Mozambican decision to conduct targeted distribution of long-lasting nets to the neediest populations in the provinces where the project was conducted.
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March 2007