Urinary triclosan is associated with elevated body mass index in NHANES

Abstract

Background: Triclosan - a ubiquitous chemical in toothpastes, soaps, and household cleaning supplies - has the potential to alter both gut microbiota and endocrine function and thereby affect body weight. Methods: We investigated the relationship between triclosan and body mass index (BMI) using National Health and Nutrition Examination Surveys (NHANES) from 2003-2008. BMI and spot urinary triclosan levels were obtained from adults. Using two different exposure measures - either presence vs. absence or quartiles of triclosan - we assessed the association between triclosan and BMI. We also screened all NHANES serum and urine biomarkers to identify correlated factors that might confound observed associations. Results: Compared with undetectable triclosan, a detectable level was associated with a 0.9-point increase in BMI (p<0.001). In analysis by quartile, compared to the lowest quartile, the 2nd, 3rd and 4th quartiles of urinary triclosan were associated with BMI increases of 1.5 (p<0.001), 1.0 (p = 0.002), and 0.3 (p = 0.33) respectively. The one strong correlate of triclosan identified in NHANES was its metabolite, 2,4-dichlorophenol (r = 0.4); its association with BMI, however, was weaker than that of triclosan. No other likely confounder was identified. Conclusions: Triclosan exposure is associated with increased BMI. Stronger effect at moderate than high levels suggests a complex mechanism of action. © 2013 Lankester et al.