Blood Lead Levels and Associated Sociodemographic and Occupational Factors in Children from Two Mexican Communities: A Comparative Study.

Lead is a neurotoxic metal. No safe blood lead level (BLL) has been identified in children; the CDC reference value was lowered to 3.5 µg/dL in 2021, while Mexico's regulatory threshold remains at 10 µg/dL. Lead-glazed earthenware is the main documented source of pediatric exposure in Mexico. We studied children 0-15 years insured by the Mexican Social Security Institute (IMSS) in two Jalisco municipalities: Tonalá (n = 500), historically a ceramic-producing center, and Zapopan (n = 374), an urban area without this tradition. BLL was measured by graphite furnace atomic absorption spectrophotometry, and sociodemographic, environmental, occupational, and household exposure data were collected by questionnaire and analyzed with bivariate tests and multivariable models. Median BLL was 1.16 µg/dL in Tonalá and 2.08 µg/dL in Zapopan. Few children reached 5 µg/dL (3.2% and 6.4%), roughly twice as many exceeded 3.5 µg/dL (6.6% and 16.3%), and most exceeded 1 µg/dL (59.4% and 93.6%). In Zapopan, household glazed earthenware use and younger age were independently associated with a higher BLL in every model; in Tonalá, paternal professional occupation was associated with a lower BLL, an exploratory finding given its small subgroup. Widespread low-level exposure at both sites supports sustained facility-level surveillance and alignment of Mexico's regulatory criterion with current reference values.