Associations between urinary concentrations of 2,5-dichlorophenol and metabolic syndrome among non-diabetic adults

We investigated in this study the relationship between exposure to para-dichlorobenzene (p-DCB), measured as urinary concentrations of 2,5-dichlorophenol (2,5-DCP), and metabolic syndrome in non-diabetic adult participants. A nationally representative subsample of 1706 non-diabetic adult participants aged 20-79 years randomly selected for measurement of urinary concentrations of 2,5-DCP in the 2007-2010 US National Health and Nutrition Examination Survey was analyzed. A dose-dependent increase in the prevalence of metabolic syndrome was observed in the study participants across quartiles of urinary 2,5-DCP (p-trend = 0.0025). After adjusting for potential confounders, individuals in the third and fourth quartile of urinary 2,5-DCP had 1.47 (95% CI 1.02, 2.14) and 1.56 (95% CI 1.10, 2.23) increased odds of metabolic syndrome, respectively, compared with individuals with the lowest quartile. Of the five components of metabolic syndrome, waist circumference and HDL-cholesterol showed a significant and monotonic association with urinary 2,5-DCP. Participants with the highest quartile of 2,5-DCP had 3.18 cm (95% CI 1.34, 5.02) higher mean waist circumference and 2.83 mg/dL (95% CI -4.68, -0.98) lower mean HDL-cholesterol than the participants in the lowest quartile. This study suggests a potential relationship between p-DCB exposure and metabolic syndrome in non-diabetic adults. Prospective epidemiological and mechanistic studies are needed to further explore these interactions.