Urinary Concentrations of 2,4-Dichlorophenol and 2,5-Dichlorophenol in the U.S. Population (National Health and Nutrition Examination Survey, 2003–2010): Trends and Predictors

Abstract

Background: 2,4-Dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), and their precursors are widely used in industry and in consumer products. Urinary concentrations of these dichlorophenols (DCPs) have been measured as part of four National Health and Nutrition Examination Survey (NHANES) cycles in order to assess the exposure to these compounds or their precursors among the general U.S. population.Objectives: We identified predictors and evaluated trends in DCP concentrations according to race/ethnicity, age, sex, family income, and housing type.Methods: We used analysis of covariance to examine associations of various demographic parameters and survey cycle with urinary concentrations of DCPs during NHANES 2003–2010. We also conducted weighted logistic regressions to estimate associations of DCP concentrations above the 95th percentile with housing type, race/ethnicity, and income.Results: We detected DCPs in at least 81% of participants. Geometric mean (GM) urinary concentrations were higher for 2,5-DCP (6.1–12.9 μg/L) than 2,4-DCP (0.8–1.0 μg/L) throughout 2003–2010. Adjusted GM concentrations of the DCPs among children (6–11 years of age) and adults > 60 years of age were higher than among adolescents and other adults. Adjusted GM concentrations among non-Hispanic whites were lower than among non-Hispanic blacks and Mexican Americans, although differences according to race/ethnicity were less pronounced among participants in high-income households. Among non-Hispanic blacks and Mexican Americans, adjusted GM concentrations were lowest among high-income participants relative to other income groups, with a monotonic decrease with increasing income among Mexican Americans. Type of housing and race/ethnicity were significant predictors of DCP urinary concentrations above the 95th percentile. Furthermore, urinary DCP concentrations have showed a downward trend since 2003.Conclusions: Exposure to DCPs and their precursors was prevalent in the general U.S. population in 2003–2010. We identified age and race/ethnicity, family income, and housing type as predictors of exposure to these compounds.Citation: Ye X, Wong LY, Zhou X, Calafat AM. 2014. Urinary concentrations of 2,4-dichlorophenol and 2,5-dichlorophenol in the U.S. population (National Health and Nutrition Examination Survey, 2003–2010): trends and predictors. Environ Health Perspect 122:351–355; http://dx.doi.org/10.1289/ehp.1306816

Urinary concentrations of 2,5-dichlorophenol and diabetes in US adults

“…Social and behavioral factors might significantly contribute to p-DCB exposure, which is supported by the study conducted by Chin et al 27 in which p-DCB concentrations in indoors was found differed among households and the cities studied. In accordance with our findings, Ye et al 29 found that household income and race/ethnicity were significant predictors of urinary concentrations of DCP above the 95th percentile. Furthermore, our study shows that the geometric mean of urinary concentrations of 2,5-DCP in US adult participants (20-79 years of age, n = 3063) was much higher than that in the German population (18-69 years of age, n = 692), based on the 1998 German Environmental Survey.…”

Relationship between urine dichlorophenol levels and asthma morbidity

“…This assumption is also supported by a recent study on dichlorophenols in the US population. 37 In addition, dichlorophenols seem to be different from triclosan with respect to its effect on IgE levels. While triclosan was reported not to be significantly associated with total serum IgE levels, 30 we found that dichlorophenols were positively associated with total serum IgE levels in the entire study sample.…”

Urinary 2,5-dicholorophenol and 2,4-dichlorophenol concentrations and prevalent disease among adults in the National Health and Nutrition Examination Survey (NHANES)

“…Understanding potential health effects of 2,5-DCP and 2,4-DCP is critical, given the high prevalence (81%) of Americans with evidence of exposure to these chemicals 8. The specific mechanisms by which 2,5-DCP and 2,4-DCP may influence health are not fully understood.…”

“…Little is known about associations of these environmental exposures with other health conditions, such as lung diseases, cardiovascular diseases (CVDs) and cancer in adult humans. Considering the pervasiveness of exposure to these chemicals,8 and laboratory animal studies suggesting that they have metabolic effects,21 22 there is a need to comprehensively evaluate whether these chemicals are associated with common medical conditions.…”