Maternal Aflatoxin Exposure and Birth Outcomes: A Study of Diets, Agricultural Practices and Nutrition in Rural Nepal
Andrews Trevino, Johanna.
2018
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Abstract:
Despite significant reductions in child stunting over recent decades, 36% of children
remain stunted in Nepal (2016). Poor linear growth can begin in utero and continue
beyond the age of two years, making the first 1000 days of life a critical period for
stunting prevention. Recent epidemiological studies suggest that exposure to aflatoxins
could contribute to low weight at birth ... read moreand postnatal stunting. However, study findings
showing linkages between in utero aflatoxin exposure and adverse birth outcomes remain
inconclusive, and factors contributing to widespread exposure to aflatoxin during
pregnancy are inadequately understood. This dissertation contributes to the
evidence-base to inform the design of aflatoxin reduction interventions and a better
understanding of the potential influence of aflatoxin exposure on adverse birth
outcomes. All three studies used data from 1675 pregnant women and newborns
participating in the ongoing USAID-funded Mycotoxin (AflaCohort) Birth Cohort Study in
Banke, Nepal. In Study 1, we estimated pregnant women's frequency of consumption of
aflatoxin-prone foods (i.e. maize and groundnuts) and calculated dietary diversity
scores. Ordinary Least Squares (OLS) and Quantile Regression models were used to compare
the strength of associations between frequencies of consumption of maize and groundnuts
and dietary diversity, and serum aflatoxin levels (n=1648). After adjusting for wealth
and other covariates, women who had consumed maize and/or groundnuts more frequently
showed higher levels of aflatoxin albumin adducts. Findings indicated that dietary
diversity was not predictive of aflatoxin exposure. Seasonality was a strong predictor
of prenatal aflatoxin exposure, with the highest levels seen in the winter months
following maize and groundnut harvest seasons. The second study examined the
correlations between food handling procedures and good agricultural practices (GAPs) in
maize, groundnut and chili farming households, and aflatoxin exposure as measured by
aflatoxin albumin adducts during pregnancy. Multivariate OLS regression modeling
revealed no evidence that the GAPs used in a minority of maize farming households
(n=392) were associated with reduced exposure of pregnant women to aflatoxin in this
sample. The infrequent use of recommended GAPs may have limited our ability to detect
such an association. Moreover, off-farm food acquisition was common. Levels of aflatoxin
exposure observed in this study likely reflect consumption of various foods susceptible
to aflatoxin from multiple sources. Study 3 used linear and logistic regression models
to explore the relationship between prenatal aflatoxin levels and selected adverse birth
outcomes in a sub-sample of 1621 mother-newborn pairs. Twenty percent of infants were
low birth weight, 52% small-for-gestational-age, 16% stunted, and 13% were born
prematurely. None of the birth outcomes studied were associated with maternal aflatoxin
levels, which were considerably lower than those observed in Africa and the Middle East
where a relationship with low birth weight has been previously documented. Together, the
results presented in this dissertation underscore the importance of viewing aflatoxin
contamination as a component of food safety within complex food systems. Our study,
together with the mixed results from previous studies, reiterates how incomplete the
evidence of the relationship between aflatoxin and birth outcomes remains at this point.
It also suggests that additional research is necessary to elucidate the aflatoxin-fetal
growth relationship, including determination of threshold
values.
Thesis (Ph.D.)--Tufts University, 2018.
Submitted to the Dept. of Food Policy & Applied Nutrition.
Advisor: Patrick Webb.
Committee: Shibani Ghosh, Beatrice Rogers, and Gerald Shively.
Keywords: Nutrition, Public health, and Agriculture.read less - ID:
- 4b29bj654
- Component ID:
- tufts:24998
- To Cite:
- TARC Citation Guide EndNote