Associations of nickel exposure and kidney function in U.S. adults, NHANES 2017–2018

Nickel (Ni) is a ubiquitous heavy metal, but epidemiological studies on the association between Ni and kidney function are limited and controversial.We aimed to explore the relationship between urinary Ni concentrations and kidney function in U.S. adults.This was a cross-sectional study based on the 2017-2018 National Health and Nutrition Examination Survey (NHANES) (n = 1588). Multiple linear regression models, logistic regression models, and restricted cubic spline models (RCS) were fitted to explore the associations between urinary Ni and estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (UACR), and the odds of impaired kidney function, which was defined as an eGFR ≤ 60 mL/min per 1.73 m2, or UACR ≥ 30.0 mg/g. Bayesian kernel machine regression (BKMR) was used to account for joint-metal effects.Compared with the lowest quartile, urinary Ni at the third quartile was associated with increased eGFR (β = 2.42, 95 % CI: 0.23-4.19); the highest quartile of urinary Ni was correlated with increased UACR (β = 0.10, 95 % CI: 0.02-0.18), as well as higher odds of impaired kidney function (OR=1.65, 95 % CI:1.08-2.54). Urinary Ni had a nonlinear inverted U-shape relationship with eGFR (Pnonlinear = 0.007), and linear J-shape associations with UACR (Pnonlinear = 0.063) and impaired kidney function (Pnonlinear= 0.215). Metal interaction of urinary Ni with cadmium (Cd) on eGFR was observed.Our findings provided evidence that Ni exposure linked with declined kidney function and might interact with Cd exposure. Considering the cross-sectional design of the NHANES study, further prospective studies are necessary.