Associations of nickel exposure and kidney function in US adults, NHANES 2017-2018

Backgrounds: Nickel (Ni) is a ubiquitous heavy metal, but epidemiological studies on the association between Ni and kidney function are limited and controversial. Aim: We aimed to explore the relationship between urinary Ni concentrations and kidney function in U.S. adults. Methods: 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 & LE; 60 mL/min per 1.73 m(2), or UACR & GE; 30.0 mg/g. Bayesian kernel machine regression (BKMR) was used to account for joint-metal effects. Results: Compared with the lowest quartile, urinary Ni at the third quartile was associated with increased eGFR (beta = 2.42, 95 % CI: 0.23-4.19); the highest quartile of urinary Ni was correlated with increased UACR (beta = 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.Conclusions: 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.