Metals and metalloids concentrations in adults aged 50 and older from Mexico

Objectives. Quantify concentrations of metals/metalloids in hair samples from Mexican adults aged 50 years and older and analyze their relationship with sociodemographic characteristics. Methods. A cross-sectional study with 2,474 participants from the 2018 Mexican Health and Aging. Metals/metalloids in hair samples were analyzed using inductively coupled plasma mass spectrometry and optical emission spectroscopy . Concentrations were compared by sex, age, locality size, educational attainment, marital status, and socioeconomic status, using nonparametric statistical methods. Results. Lead, titanium, manganese, and copper were detected in most samples (≥95%), with copper exhibiting the highest median concentration (7.83 µg/g). Differences by sex were observed in 13 elements: males showed higher concentrations, except for copper and titanium, which were higher in females. Increasing age was associated with lower concentrations of copper, manganese, nickel, titanium, and vanadium. In contrast, higher education and a middle-to-high socioeconomic status were linked with increased concentrations of several elements; notably, manganese concentrations were highest among those with low socioeconomic status. Locality size showed minimal effects, except for slightly higher manganese concentrations in urban participants. Regarding marital status, individuals who were married or in a consensual union displayed higher concentrations of chromium, manganese, nickel, and lead. Conclusions. This study provides reference values for exposure to metals and metalloids in older Mexican adults, highlighting sociodemographic patterns of accumulation. Age, sex, education, socioeconomic status, and marital status were relevant factors. Findings underscore the need for population-based biomonitoring, additional research on the health impacts, and targeted public health interventions.