Sung CE, et al. - The National Health and Nutrition Examination Survey (NHANES) database was evaluated after adjustment for potential confounding variables, including age and other systemic co-morbidities, to explore the connection between periodontitis and cognition impairment. The study sample consisted of 4,663 candidates (aged 20 to 59 years) who had received full mouth periodontal examination and undergone the cognitive functional test. Periodontitis was significantly associated with elevated Symbol Digit Substitution Test and Serial Digit Learning Test scores by generalized linear regression models after adjusting for demographic factors, education, smoking, cardiovascular diseases, and laboratory data. In a nationally representative sample of US adults, an association was found between periodontal status and cognitive impairment.