Assessment of dietary exposure to organophosphorus pesticides using food frequency questionnaires and information on organic food consumption habits

Abstract

Background. Consumption of organically grown food has been shown to result in significant reductions in organophosphate (OP) pesticide exposure in non-occupationally exposed populations, and 40% of Americans consume organic food at least occasionally. Aims. The purpose of this study was to assess dietary exposure to OP pesticides based on data from food frequency questionnaires (FFQ) and information on organic food consumption habits, and to empirically compare those exposure assessments with measurements of urinary OP pesticide biomarkers. Methods. Dietary exposure to OP pesticides was assessed in 800 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) in two ways:1)by measurement of urinary dialkylphosphate (DAP) concentrations, and 2)by multiplying average dietary intake of each of 20 food items by average residue levels of each of 10 OP pesticides in those items, and summing across foods and pesticides. Dietary intake was based on individual FFQ responses, and residue levels were obtained from the USDA’s Pesticide Data Program. Participants were categorized as “often or always”, “sometimes” or “seldom or never” consumers of organic food, based on self-report. Results. In preliminary analysis, we observe a significant linear relationship between predicted dietary exposure and DAP levels in participants who reported seldom or never consuming organic foods (R2=0.71). No relationship was observed between FFQ-based exposure predictions and DAP measurements for participants who reported that they sometimes, often or always consumed organic food. DAP levels in participants who reported at least occasional consumption of organic food were significantly lower than those who do not, after adjustment for food intake. Conclusions. This work suggests that OP pesticide exposure can be predicted using FFQ and residue data for people who do not consume organic diets. These data also support previous research demonstrating that consumption of organic food is associated with lower urinary DAP concentrations.