Abstract
Arsenic is a naturally occurring chemical in the environment. The International Agency for Research on Cancer (IARC) declared arsenic a class 1 human carcinogen. The inorganic form of arsenic is considered toxic to the human population; arsenic is a neurotoxin and can cause memory dysfunction. Very few studies have investigated the association between exposure to arsenic and depression in humans. The purpose of this study was to assess the association between urinary speciated arsenic and depression among adults in the USA using the 2015–2016 National Health and Nutrition Examination Survey (NHANES) III dataset. Depression was measured using the nine-item Patient Health Questionnaire (PHQ-9). We computed a total depression score from the PHQ-9 and categorized individuals with a score ≥ 10 as depressed. The exposure included six different speciated arsenic concentrations dichotomized as at or above the limit of detection and below the limit of detection. We conducted a crude and multivariate logistic regression analysis using complex survey procedures to assess the association between speciated arsenic concentrations and depression. The sample included 1619 adults, of whom approximately half were females (51.69%) and married (53.29%). Seven percent of the sample had depression. Urinary arsenous acid was significantly associated with depression. In the adjusted model, arsenous acid was associated with depression with an odds ratio of 1.76 (95% CI 1.05–2.96, p = 0.035). No other forms of arsenic were significantly associated with depression. In this study, urinary arsenous acid was significantly associated with depression. Future research in humans is required to confirm or refute this finding.