Pesticide Urinary Metabolite Concentration and Asthma Morbidity in Socially Disadvantaged Children

Abstract

Background: Little is known about urinary pesticide (UP) concentration in socially disadvantaged children. These children may be at greater exposure risk because low income is associated with more household pest exposure. Urinary pesticide concentration and its association with asthma morbidity was measured in 161 children with asthma (7-12 years) residing in subsidized housing in three U.S. cities (Boston, Cincinnati, New Orleans).Methods: Morning void and convenience spot samples were collected at three time points over one year. Urine samples were analyzed for seven pesticide metabolites; 3 organophosphates (OPs): TCPY, IMPY, PNP; 3 pyrethroids (PYR): 4-F-3-PBA, 3-PBA, trans-DCCA; and 1 herbicide: 2,4-D. Total PYR was calculated as the sum of 4-F-3PBA, 3-PBA, and trans-DCCA and total OP as the sum of TCPY, IMPY, and PNP. Outcomes were forced expiratory volume in one second (FEV1), and respiratory inflammation measured as fractional exhaled nitric oxide (FeNO).Results: A total of eight hundred and ten urine samples were collected. The proportion with detectable metabolites ranged from 35% (trans-DCCA) to 97% (TCPY and PNP). Geomeans of each pesticide were higher in this cohort compared to a national sample (NHANES 2009-2010) of children 6-11 years. In models adjusting for socio-demographic factors, a 1 µg/mL increase in TCPy, IMPY, trans-DCCA, 2,4-D, total OPs and PNP was associated with a reduction in FEV1 (-0.004 to -0.158) although no model reached statistical significance (p<0.05). An increase in TCPY, total OPs, and 4-F-3-PBA, resulted in a non-statistically significant increase in FeNO (0.0004 to 0.0675) .Conclusion: Results demonstrate these low-income children with asthma residing in subsidized housing are exposed to higher concentrations of pesticides compared to a general population sample. Additionally, the evidence suggests negative respiratory outcomes with increasing levels of UPs. Reducing exposure to pesticides is important to mitigate the potential negative health effects for vulnerable populations.