Arsenic, mercury, manganese, and lead exposure in Mexican adults aged 50 and older

Describe the levels of arsenic, mercury, manganese, and lead in the hair of older Mexican adults and analyze their association with exposure and sociodemographic factors. This cross-sectional study used a random subsample of 2474 adults aged 50 and older from the 2018 Mexican Health and Aging Study. Metal levels in hair were quantified using inductively coupled plasma mass spectrometry and an optical emission spectrometer with a hydride generator. Linear regression models were used to assess the associations between metal/metalloid levels and sociodemographic factors. Median hair levels were arsenic 0.04 μg/g, mercury 0.14 μg/g, manganese 0.79 μg/g, and lead 0.65 μg/g. Arsenic levels increased with age, while manganese and lead levels decreased. Males exhibited higher concentrations of all metalloids/metals compared to females. BMI was associated with increased arsenic levels. The use of wood or charcoal for cooking was associated with increased hair manganese. Household pesticide use was associated with elevated levels of mercury, manganese, and lead. Cooking with glazed clay pots was associated with increased lead levels. Residing near exposure sites increased mercury, manganese, and lead levels in hair. Additionally, seven or more years of schooling was associated with increased mercury levels, while low/middle socioeconomic status was associated with increased hair manganese levels. The results reveal significant metal exposure in older Mexican adults, varying according to sociodemographic and exposure factors. These findings underscore the need to implement public policies to reduce metal exposure and protect the health of these vulnerable communities.