Association of nickel exposure with body mass index, waist circumference and incidence of obesity in US adults

This study aimed to detect the relationship between nickel exposure and body mass index (BMI), waist circumference and incidence of obesity in the general population of the United States. The National Health and Nutrition Examination Survey (NHANES) 2017–2018 database was utilized, and the sample comprised 1702 participants aged 18 years and above with complete urinary nickel, body mass index, and waist circumference data. Obesity was determined using BMI and waist circumference data. The multivariate linear regression and logistic regression models were utilized to detect the association between urinary nickel concentration and BMI, waist circumference, and incidence of obesity. After multivariable adjustment, the log-transformed urinary nickel concentration was inversely associated with BMI [β = −0.87; 95% confidence interval (CI): (−1.36, −0.38)] and waist circumference [β = −1.51; 95% CI: (−2.93, −0.08)]. Compared with the lowest tertile of urinary nickel, the β value and 95% CI of BMI and waist circumference for the highest tertile were β = −1.65.95% CI: (−2.85, −0.45) and β = −2.78, 95% CI: (−6.17, 0.62), respectively. The log-transformed urinary nickel concentration was also negatively associated with obesity status [adjusted odds ratio (OR) = 0.81, 95% CI: (0.64, 1.01)]. Compared with the lowest tertile of urinary nickel, the adjusted OR and 95% CI of obesity status for the highest tertile were OR = 0.64 and 95% CI: (0.37, 1.12). Smooth curve fitting and the generalized additive model indicated that elevated urinary nickel concentration was associated with decreased BMI, waist circumference, and incidence of obesity. The negative association was consistent and robust in different subgroups, according to stratified analysis. This study found that nickel exposure may be negatively associated with BMI, waist circumference and incidence of obesity in US Adults.