Metal mixtures and adiposity indicators in women from Northern Mexico

Exposure to individual metals has been inconsistently associated with adiposity. However, populations are exposed to more than one metal at a time, thus recent studies have been conducted to assess more comprehensively metal exposure through a mixture approach. To explore the association between Body Mass Index (BMI), Waist-Hip Ratio (WHIR) and Waist-Height Ratio (WHER) with urinary metal concentrations, using individual and mixture approaches, as well as identifying the most important metals within the mixtures, in women from Northern Mexico. This is a secondary cross-sectional analysis that included 439 women residents of five states in Northern Mexico. We weighed and measured participants to estimate BMI, WHIR, and WHER. We determined the concentrations of 19 urinary metals using inductively coupled plasma triple quadrupole. We used Weighted Quantile Sum regression to evaluate the association between adiposity indicators and metal mixtures, as well as to identify the metals of concern within the mixtures. We identified a mixture of metals that was negatively associated with BMI (ß:-0.96, 95% CI:-1.90,-0.01), where the most prominent were lead, molybdenum and magnesium. Furthermore, WHIR was negatively and suggestively associated with a mixture where the predominant metals were aluminum, cadmium, arsenic and nickel (ß:- 7.12, 95% CI: - 1.75,0.00), likewise WHER was associated with a mixture where the important metals were arsenic and nickel (ß: - 1.03, 95% CI: - 2.24,0.00). Our results provide evidence about the associations between metal mixtures and some anthropometric indicators of adiposity. Experimental studies are warranted to identify the underlying biological mechanisms.