Association between periodontitis and cognitive impairment: Analysis of national health and nutrition examination survey (NHANES) III

Objectives Periodontitis has been hypothesized as being one of the most common potential risk factors for the development of dementia and cognitive impairment. In order to investigate the relationship between periodontitis and cognition impairment, the National Health and Nutrition Examination Survey (NHANES) database was analysed after adjusting for potential confounding factors, including age and other systemic co-morbidities. Materials and Methods In total, 4,663 participants aged 20-59 years who had received full-mouth periodontal examination and undergone the cognitive functional test were enrolled. The grade of periodontal disease was categorized into severe, moderate, and mild. Cognitive function examinations, including the simple reaction time test (SRTT), symbol digit substitution test (SDST), and serial digit learning test (SDLT), were adopted for the evaluation of cognitive impairment. Results The subjects with mild and moderate to severe periodontitis had higher SDLT and SDST scores, which indicated decreased cognitive function, compared with the healthy group. After adjusting for demographic factors, education, smoking, cardiovascular diseases, and laboratory data, periodontitis was significantly correlated with elevated SDST and SDLT scores (p values for trend = 0.014 and 0.038, respectively) by generalized linear regression models. Conclusion Our study highlighted that periodontal status was associated with cognitive impairment in a nationally representative sample of US adults.