Fruit as a Source of Organophosphate Pesticide Exposure in Pregnant Urban-Dwelling Women

by | Apr 1, 2019 | 2018, Environmental Health, Pesticides and Solvents, Pregnancy and Lactation, Women's Health

Written by Angeline A. De Leon, Staff Writer. This study strengthens the hypothesis that dietary intake plays an important role in prenatal OP pesticides exposure among women living in an urban environment.

pesticidesOrganophosphate (OP) pesticides are the most widely used pesticides today. Particularly in countries like the Netherlands, the most common type of insecticide used for agriculture is OP pesticides. Studies have confirmed that high levels of exposure to OP pesticides present a neurotoxic risk, both to animals and humans 1, but now research shows that even low-level exposure can be harmful. Newer evidence indicates that low levels of OP exposure are associated with oxidative stress 2, alterations in neuronal cells 3 and changes in the thyroid and reproductive system 4. In animals, low-level exposure can cause cognitive impairment 5 and negative behavioral and neurochemical changes 6. Epidemiological studies show that fetuses and young children are particularly susceptible to neurotoxic exposure 7, and pre-natal exposure has been linked to adverse neurodevelopmental problems 8. A growing body of research is now focused on better understanding prenatal exposure to OP pesticides and determining which food groups and food items might be contributing most to exposure. To this end, researchers in the Netherlands carried out a cohort study 9 examining the primary sources of OP pesticide exposure in an urban population of pregnant women and the concentration levels of dialkyl phosphate (DAP) metabolites (non-specific biomarkers of OP pesticides) over the course of pregnancy.

A prospective population-based cohort study was carried out with 784 women (majority between 30- and 35- years-old) in Rotterdam, the Netherlands. Urine samples were collected at < 18, 18, 25, and > 25 weeks of pregnancy, and the concentrations of six non-specific DAP metabolites were measured using gas chromatography: three dimethyl (DM) metabolites (dimethylphosphate, DMP; dimethylthiophosphate, DMTP; and dimethyldithiophosphate, DMDTP) and three diethyl (DE) metabolites (diethylphosphate; DEP; diethylthiophosphate, DETP; and diethyldithiophosphate, DEDTP). Researchers also examined maternal demographic and lifestyle data using questionnaires (assessing pet ownership, occupational exposure to pesticides, etc.) and measured maternal dietary intake during the first trimester of pregnancy using the Food Frequency Questionnaire (FFQ) (administered at a median gestational age of 13.5 weeks).

Analysis of the data indicated that median total DAP metabolite concentrations for < 18, 18-25, and > 25 weeks of gestation were 311, 317, and 310 nmol/g creatinine, respectively. Maternal age was positively correlated with total DAP, with a one year higher maternal age associated with a 1% increase (95% Confidence Interval: 0-2%) in total DAP concentration. Women with higher education levels had 15% higher DAP (95% CI: 2-30%), compared to women with low education levels, and non-smoking women showed 23% higher total DAP (95% CI: 10-38%) than women who continued to smoke during pregnancy. High total DAP, as well as DM and DE metabolite concentrations, were found also to vary as a function of season, with urine samples collected during summer showing 11% more DAP (95% CI: 3-20%) and 16% more DM (95% CI: 7-26%) metabolite concentrations, relative to samples collected in the fall. Urine samples collected during winter were 14% higher in DE (95% CI: 3-25%) metabolite concentrations, compared to those collected in the spring. Finally, consumption of fruit was found to be associated with total DAP concentrations, DM, and DE metabolite concentrations: a 100 g/d increase in fruit intake was associated with a 7% increase in DAP (95% CI: 4-11%), 7% increase in DM (95% CI: 4-11%), and 7% increase in DE (95% CI: 3-12%) concentrations. More specifically, consumption of oranges/grapefruits, and apples showed the strongest association with total DAP concentrations, with 100 g/d higher intake of oranges/grapefruits linked to 13% higher DAP (95% CI: 3-24%) and 100 g/d higher intake of apples linked to 14% (95% CI: 4-26%) higher DAP.

This investigation on prenatal levels of DAP revealed that factors such as maternal age, education level, smoking status, and even season, are determinants of DAP concentration levels in pregnant, urban-dwelling women. In the study, the primary dietary source of OP exposure was found to be fruit, particularly oranges/grapefruits and apples. A limitation of the study, however, relates to the fact that investigators did not verify whether participants were consuming organic foods. Moreover, since dietary intake was assessed during the first trimester rather than tracked over the entire course of pregnancy, it is unclear whether observed dietary patterns are reflective of overall eating habits. The study also could have been strengthened by assessing other possible sources of pesticide exposure in the house, besides pet ownership (e.g., insecticides for the lawn, pest products, etc.). Overall, the present study provides evidence to support the key role of dietary intake in prenatal OP pesticides exposure. Follow-up studies investigating the health effects associated with the offspring of women in the present cohort would be of value.

Source: van den Dries MA, Pronk A, Guxens M, et al. Determinants of organophosphate pesticide exposure in pregnant women: A population-based cohort study in the Netherlands. International Journal of Hygiene and Environmental Health. 2018; 221: 489-501. DOI: 10.1016/j.ijheh.2018.01.013.

© 2018 The Author. Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/)

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Posted April 1, 2019.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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