Association between selected urinary heavy metals and asthma in adults: a retrospective cross-sectional study of the US National Health and Nutrition Examination Survey.

Heavy metal in the physical environment may alter immune function and predispose to develop asthma in human. Our study was aimed to investigate associations between urinary heavy metals and asthma in adults. A retrospective cross-sectional study was conducted with 3425 subjects aged 20 years and older in the US National Health and Nutrition Examination Survey (NHANES) 2011-2014. Binary logistic regression was applied to analyze associations between cobalt (Co), tungsten (W), and uranium (U) and asthma. We found positive associations between U and asthma (OR = 1.74, 95%CI: 1.25, 2.44, P for trend < 0.01). U was positively associated with asthma in 20-59 years group (OR = 1.65, 95%CI: 1.11, 2.46), while W and Co were related with asthma among in above 60 years group (OR = 2.39, 95%CI: 1.24, 4.58, P for trend = 0.02; OR = 1.88, 95%CI: 1.02, 3.47, respectively). U was linked with asthma in both males and females (OR = 1.93, 95%CI: 1.16, 3.20; OR = 1.59, 95%CI: 1.01, 2.51, respectively). Positive associations between U and asthma were discovered among adults with family history of asthma or not (OR = 2.15, 95%CI: 1.17, 3.95, P for trend = 0.03; OR = 1.62, 95%CI: 1.08, 2.43, P for trend = 0.03, respectively). Remarkable association was observed between U and asthma in adults without hay fever (OR = 1.79, 95%CI: 1.24, 2.60, P for trend = 0.02). Our findings provide epidemiological evidence to highlight a need to prioritize heavy metals exposure with asthma.