Associations between exposure to multiple metals/metalloid and periodontitis risk in US adults: an NHANES study using multipollutant approaches

Background: Periodontitis is a common chronic inflammatory disease affected by multiple factors. Heavy metals exposure may be environmental risk factors for periodontitis. However, relationships between multiple metals/metalloid and periodontitis risk remain unclear. Methods: We analyzed associations between blood levels of cadmium, lead, manganese, mercury and selenium and periodontitis prevalence in 4,982 adults aged 30–80 years from National Health and Nutrition Examination Survey (NHANES) 2011–2018. Multivariable logistic regression assessed individual and combined metals/metalloid effects. Restricted cubic splines (RCS) and weighted quantile sum (WQS) regression evaluated potential non-linear and joint relationships. Mediation analysis was used to explore their potential mediated effects of neutrophils with periodontitis. Results: With increasing blood cadmium and lead, periodontitis risk increased significantly, while decreasing selenium was associated with elevated risk. Combined exposure to cadmium and lead conferred greater risk than individual metals. RCS confirmed monotonically increasing trends between cadmium, lead and periodontitis risk at higher levels. WQS found cadmium and lead positively correlated and selenium negatively correlated with periodontitis. Conclusion: Increased environmental exposure to cadmium and lead as well as insufficient selenium may be independent risk factors for periodontitis. This study provided important evidence regarding relationships between environmental pollutants, nutritional factors and periodontal health. Further research is warranted to validate our findings and elucidate underlying mechanisms.