Overall and class-specific scores of pesticide residues from fruits and vegetables as a tool to rank intake of pesticide residues in United States: A validation study

Pesticide residues in fruits and vegetables are among the primary sources of pesticide exposure through diet, but the lack of adequate measurements hinder the research on health effects of pesticide residues. Pesticide Residue Burden Score (PRBS) for estimating overall dietary pesticide intake, organochlorine pesticide score (OC-PRBS) and organophosphate pesticide score (OP-PRBS) for estimating organochlorine and organophosphate pesticides-specific intake, respectively, were derived using U.S. Department of Agriculture Pesticide Data Program data and National Health and Nutrition Examination Survey (NHANES) food frequency questionnaire data. We evaluated the performance of these scores by validating the scores against pesticide metabolites measured in urine or serum among 3,679 participants in NHANES using generalized linear regression. The PRBS was positively associated with a score summarizing the ranks of all pesticide metabolites in a linear fashion (p for linear trend <0.001). Furthermore, individuals in the top quintile of this score had urinary pesticide metabolite levels 13.0% (95% CI 8.3%-17.7%) higher than individuals in the lowest quintile. Similarly, we observed significant associations of the OC-PRBS and OP-PRBS with the levels of lipid-adjusted total serum organochlorine pesticides and urinary creatinine-adjusted organophosphate pesticides, respectively. The relative difference (RD) in average pesticide metabolite rank between extreme quintiles was 17.8% (95% CI: 11.1%-24.4%, p for trend <0.001) for the OP-PRBS, whereas the RD was marginally significant at 7.0% (95% CI: -0.5%-14.4%, p for trend 0.07) for the OC-PRBS. The PRBS and OP-PRBS had similar performance when they were derived from fruits and vegetables with high vs. low pesticide residues, respectively (p for trend <0.001 for all associations). The OP-PRBS was associated with all measured organophosphate pesticides, whereas the positive association between OC-PRBS and averaged measured organochlorine pesticide residue rank was primarily driven by hexachlorobenzene. OC-PRBS had better performance when derived from more contaminated fruits and vegetables (p for trend 0.07) than from less contaminated Fruits and vegetables (p for trend 0.63), although neither of the associations achieved statistical significance. The PRBS and the class-specific scores for two major types of pesticides were significantly associated with pesticide biomarkers. These scores can reasonably rank study participants by their pesticide residue exposures from fruits and vegetables in large-scale environmental epidemiological studies.