The association between blood heavy metals and gallstones: A cross-sectional study.

BACKGROUND AND AIMS: Exposure to heavy metals has been widely recognized as a risk factor for human health. However, there is limited information on the effects of blood heavy metals on gallstones. This study aims to investigate the relationship between blood heavy metals and gallstones using data from the National Health and Nutrition Examination Survey (NHANES). METHODS: 7192 participants aged 20 years or older with complete information were included in the study. Serum concentrations of heavy metals were determined by inductively coupled plasma kinetic reaction cell mass spectrometry. Gallstones were presented by standard questionnaires. Logistic regression, nonlinear, subgroup, and sensitivity analyses were used to estimate the association between blood heavy metals and gallstones. RESULTS: Multivariate logistic regression showed that the highest quintile of blood selenium (Se) was associated with a higher risk of gallstones compared with the lowest quintile (OR = 1.66, 95% CI: 1.16-2.36), particularly in individuals who were under 65 years of age, females, non-Hispanic Whites, non-drinkers, obese, and had a college education or higher. There was no correlation between blood cadmium (Cd), mercury (Hg), lead (Pb), manganese (Mn), and gallstones in the total population. Restricted cubic spline curves showed that a negative correlation was observed between blood Cd (OR = 0.84, 95% CI: 0.710-1.00), Hg (OR = 0.87, 95% CI: 0.78-0.97) and gallstones when Cd < 0.302 µg/L and Hg < 3.160 µg/L. CONCLUSIONS: Blood Se was an independent risk factor for gallstones, particularly in individuals under 65 years old, females, non-Hispanic Whites, non-drinkers, obese, and had a college education or higher. Furthermore, blood Cd and Hg were associated with a reduced risk of gallstones within a certain range.