Beck, James D.

Background: Periodontitis is a potential modifiable factor influencing dementia risk. We examined whether improving periodontal health via regular flossing is associated with lower dementia risk. Methods: A total of 9,766 Atherosclerosis Risk in Communities (ARIC) study participants with teeth were followed from visit 4 (1996-1998) through 2021. Cox proportional hazards regression was used to estimate associations between regular dental flossing (≥1/week) and incident dementia. Covariates included age, race, gender, hypertension, diabetes, alcohol use, smoking status, obesity, physical activity, education level, income, insurance status, brushing frequency, regular dental care use and apolipoprotein E4 (APOE4) allele status . Cumulative incidence functions were estimated using death as a competing event. Results: Participants had mean age 62.6 years (SD = 5.6), 56% female, 79% white, 21% black, 63% reported regular flossing and 29.2% participants carry at least one APOE4 allele. The cumulative incidence of dementia was 52.6 % overall over 25 years. Regular flossing was independently and significantly associated with a lower hazard of developing dementia (HR = 0.90, 95% CI: 0.82–0.98, p = 0.02) after adjustment for all the covariates. In contrast, tooth brushing frequency (p=0.55) and regular dental care visit (p=0.22) were not significantly associated with dementia risk. By 25 years of follow-up, the cumulative incidence of dementia was 50% among flossers compared with 57% among non-flossers (Gray’s test p<0.0001, Figure). This translated to an Absolute Risk Reduction of 7%, Relative Risk Reduction of 12%, Number Needed to Floss 14. Conclusion: Flossing, but not tooth brushing or regular dental care, is independently associated with a reduced hazard of incident dementia. Dental flossing may be an additional strategy to reduce dementia risk. For every 14 individuals who floss ≥1/week, one fewer person will develop dementia.

Background: Periodontal disease (PD) is associated positively with neurocognitive outcomes. Few studies have investigated the relationship between PD and indicators of brain aging and vascular changes. Hypothesis: PD is associated with greater cerebral small vessel disease, lower total and regional brain volumes and elevated β-amyloid (Aβ) deposition. Methods: We included 6,793 participants who received full-mouth periodontal examinations and tooth counts at Visit 4 (1996-1998) of the Atherosclerosis Risk in Communities Study. We used a modified 3-level version of the Periodontal Profile Class to categorize PD based on severity and extent of gingival inflammation and tissue loss. Among participants who attended Visit 5 (2011-2013), n=1,306 received a brain MRI and n=248 received a PET scan. Total brain volume, Alzheimer’s disease signature volume, and presence of microhemorrhages and cerebral infarctions were ascertained via 3T MRI; Aβ deposition was assessed from PET. We regressed brain volumes on baseline PD status using weighted multivariable linear regression. Presence of cerebrovascular microhemorrhages, infarctions, or elevated Aβ (standardized uptake value ratio>1.2) were regressed on PD category using logistic models. We examined the interaction between Apolipoprotein E ε4 ( APOE ) allele possession and PD categories on the Aβ outcome. Results: Prevalence of baseline periodontal disease was 73% (959/1306) and 87% (206/248) among the MRI and PET subgroups, respectively. PD was not associated with volumetric brain measures nor microhemorrhages. PD was inversely associated with the odds of subcortical and lacunar infarctions. PD and Aβ were not associated in main effect or interaction analyses, although there was a notably stronger association among carriers of APOE . Conclusion: PD was not associated with altered brain structure, cerebral microhemorrhages or elevated Aβ deposition. Counter to the hypothesis, PD and complete tooth loss were inversely associated with cerebral infarctions.

Abstract Background Observational studies indicate that periodontal disease may increase the risk of colorectal, lung, and pancreatic cancers. Using a 2-sample Mendelian randomization (MR) analysis, we assessed whether a genetic predisposition index for periodontal disease was associated with colorectal, lung, or pancreatic cancer risks. Methods Our primary instrument included single nucleotide polymorphisms with strong genome-wide association study evidence for associations with chronic, aggressive, and/or severe periodontal disease (rs729876, rs1537415, rs2738058, rs12461706, rs16870060, rs2521634, rs3826782, and rs7762544). We used summary-level genetic data for colorectal cancer (n = 58 131 cases; Genetics and Epidemiology of Colorectal Cancer Consortium, Colon Cancer Family Registry, and Colorectal Transdisciplinary Study), lung cancer (n = 18 082 cases; International Lung Cancer Consortium), and pancreatic cancer (n = 9254 cases; Pancreatic Cancer Consortia). Four MR approaches were employed for this analysis: random-effects inverse-variance weighted (primary analyses), Mendelian Randomization-Pleiotropy RESidual Sum and Outlier, simple median, and weighted median. We conducted secondary analyses to determine if associations varied by cancer subtype (colorectal cancer location, lung cancer histology), sex (colorectal and pancreatic cancers), or smoking history (lung and pancreatic cancer). All statistical tests were 2-sided. Results The genetic predisposition index for chronic or aggressive periodontitis was statistically significantly associated with a 3% increased risk of colorectal cancer (per unit increase in genetic index of periodontal disease; P = .03), 3% increased risk of colon cancer (P = .02), 4% increased risk of proximal colon cancer (P = .01), and 3% increased risk of colorectal cancer among females (P = .04); however, it was not statistically significantly associated with the risk of lung cancer or pancreatic cancer, overall or within most subgroups. Conclusions Genetic predisposition to periodontitis may be associated with colorectal cancer risk. Further research should determine whether increased periodontitis prevention and increased cancer surveillance of patients with periodontitis is warranted.