Association between heavy metals and metalloids in topsoil and mental health in the adult population of Spain

• Published in: Environmental research 2019-12, Vol.179 (Pt A), p.108784, Article 108784
• Main Authors: Ayuso-Álvarez, A., Simón, L., Nuñez, O., Rodríguez-Blázquez, C., Martín-Méndez, I., Bel-lán, A., López-Abente, G., Merlo, J., Fernandez-Navarro, P., Galán, I.
• Format: Article
• Language: English
• Subjects: Adult; Cadmium; Environmental Exposure - statistics & numerical data; Environmental Monitoring; Heavy metals; Humans; Mental Disorders - epidemiology; Mental health; Mental Health - statistics & numerical data; Metalloids; Metals, Heavy; Multilevel analyses; Soil Pollutants; Spain - epidemiology
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2019.108784

Despite the biological plausibility of the association between heavy metal exposure and mental health disorders, epidemiological evidence remains scarce. The objective was to estimate the association between heavy metals and metalloids in soil and the prevalence of mental disorders in the adult population of Spain. Individual data came from the Spanish National Health Survey 2011–2012, 18,073 individuals residing in 1772 census sections. Mental health was measured with the 12-item General Health Questionnaire. The concentration estimates of heavy metal and metalloid levels in topsoil (upper soil horizon) came from the Geochemical Atlas of Spain based on 13,317 soil samples. Levels of lead (Pb), arsenic (As), cadmium (Cd) and manganese (Mn) were estimated in each census section by “ordinary Kriging”. Odds ratios (OR) were calculated by multilevel logistic regression models. Compared with the lowest Pb concentration levels quartile, the OR for the second quartile was 1.29 (95%CI: 1.11–1.50), increasing progressively to 1.37 (95%CI: 1.17–1.60) and 1.51 (95%CI: 1.27–1.79) in the third and fourth quartiles, respectively. For As, the association was observed in the third and fourth quartiles: 1.21 (95%CI: 1.04–1.41) and 1.42 (95% CI: 1.21–1.65), respectively. Cd was associated also following a gradient from the second quartile: 1.34 (95%CI: 1.15–1.57) through the fourth: 1.84 (95%CI: 1.56–2.15). In contrast, Mn only showed a positive association at the second quartile. Additionally, individuals consuming vegetables > once a day the OR for the fourth quartile of Pb concentration, vs. the first, increased to 2.93 (95%CI: 1.97–4.36); similarly for As: 3.00 (95%CI: 2.08–4.31), and for Cd: 3.49 (95%CI: 2.33–5.22). Living in areas with a higher concentration of heavy metals and metalloids in soil was associated with an increased probability of having a mental disorder. These relationships were strengthened in individuals reporting consuming vegetables > once a day. •Higher concentration of heavy metals in soil was associated with mental disorders.•We observed a gradient effect for Pb, As, and Cd.•Stronger association was found in people consuming >1 daily serving of vegetables.