Periodontal Status and the Risk of All‐Cause Dementia, Alzheimer's Disease and Vascular Dementia in a Community: The Hisayama Study

AIM: This study examined the associations of periodontal status with incident dementia and its subtypes in a Japanese community. MATERIALS AND METHODS: The 1396 participants aged ≥ 60 years without dementia were followed for 10 years. Periodontal status at baseline and 5 years was assessed using mean probing pocket depth (PPD), clinical attachment level (CAL) and percentage of bleeding on probing (%BOP), categorized into quartiles. Cox proportional hazards and time-varying Cox models were used. RESULTS: During follow-up, 267 participants developed dementia; 194 and 51 had Alzheimer's disease (AD) and vascular dementia (VaD), respectively. Compared with the lowest quartile, the highest quartiles of PPD, CAL and %BOP at baseline were associated with increased dementia risk (hazard ratio 1.72 [95% confidence interval 1.18-2.46], 1.59 [1.07-2.38] and 1.56 [1.09-2.22], respectively, all p for trend < 0.05). Elevated %BOP was associated with AD risk (p for trend = 0.023). Higher PPD tended to be associated with VaD (p for trend = 0.076). Similar associations for all-cause dementia were observed in time-varying Cox analyses. CONCLUSIONS: Poor periodontal status was associated with dementia in older Japanese adults. These findings highlight the potential public health importance of preventing periodontitis to reduce the risk of dementia.