Association between dental floss use, dental visits, and a five-year Alzheimer's disease risk prediction score among United States adults aged 65 years and older

Background Alzheimer's disease (AD) imposes substantial societal and healthcare burdens. Emerging evidence links poor oral hygiene to AD risk, but further research is still required to clarify this link. Objective To examine the associations between dental floss use, regular dental visits, and their combined effects on 5-year AD risk among United States (US) adults aged ≥65. Methods A cross-sectional analysis included 3356 adults aged 65 + from NHANES (2013–2018). Predicted five-year AD risk scores (0–44) combined sociodemographic, psychological, behavioral, and medical factors, categorized as low (0–20) or high risk (21–44) groups. Dental floss use and past-year dental visits were assessed. Associations were evaluated using weighted logistic regression models to account for complex survey design and US representativeness. Results Higher rates of dental floss use and past-year dental visits were each associated with lower predicted 5-year AD risk scores. After adjustment, flossing reduced the odds of high predicted risk by 32% (OR = 0.68, 95% CI: 0.56–0.84) and dental visits by 28% (OR = 0.72, 95% CI: 0.58–0.90). Compared to those with neither behavior, participants who flossed alone (OR = 0.63, 95% CI: 0.48–0.83), had dental visits only (OR = 0.69, 95% CI: 0.52–0.92), or engaged in both behaviors (OR = 0.58, 95% CI: 0.45–0.74) showed progressively lower odds of being classified in the high predicted risk group. Conclusions Regular dental flossing and visits were independently associated with reduced predicted 5-year AD risk, with partially additive effects when combined, supporting routine oral hygiene promotion as a potential preventive strategy in older adults.