Abstract
Background and objectivesDespite 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. MethodsIndividual 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. ResultsCompared 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). ConclusionsLiving 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.
Highlights
Mental illness is an important cause of disability and morbidity
Based on the GHQ-12 scores, 21.9% of the Spanish adult population met the criteria for mental health problems
Our results show that residing in areas with a higher soil concentration of heavy metals and metalloids was associated with an increased risk of suffering from a mental disorder
Summary
Mental illness is an important cause of disability and morbidity. According to the World Health Organization, 450 million people worldwide suffer from some type of mental disease, and psychiatric disorders account for the loss of one third of disability-free life-years. Mental disorders are characterized by their high level of heterogeneity and the variety of their causes Close examination of these causes has identified a complex network of factors associated with genetic, biological, and psychosocial characteristics of the individual, and with environmental determinants present in the area of residence (Patel et al, 2016). Conclusions: 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
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