Association between blood manganese levels and stroke in US adults: a national cross‑sectional study

Background: Stroke is a severe cerebrovascular disease that imposes a substantial strain on society and the economy. The relationship between blood manganese levels and stroke has been inadequately researched, and the findings are inconsistent. The purpose of this study was to determine the relationship between blood manganese levels and stroke risk based on data from the National Health and Nutrition Examination Survey (NHANES).Methods: The association between blood manganese levels and stroke was explored using univariate analysis, multifactorial logistic regression equations, and smoothed-fit curves. After identifying a non-linear relationship, the inflection point was calculated using a recursive algorithm. Further stratified analyses were conducted to explore differences between groups. Results: After adjusting for all covariates, the association between blood manganese levels and stroke was not statistically significant (OR = 0.99, 95 % CI: 0.96-1.02). However, the linear trend results indicated that there may be a non-linear correlation between the two. Smoothed fitted curves confirmed this non-linear relationship and an inflection point (7.25 μg/L) was discovered. Blood manganese levels were negatively correlated with stroke before the inflection point (OR = 0.87, 95 % CI: 0.77-0.98). And there was no statistical significance between the two after the inflection point. This non-linear association persisted in men, and women, age ≥60 years, BMI ≥30, and BMI <30.Conclusions: A nonlinear association was discovered between blood manganese levels and stroke risk.