Background: To establish whether life course adiposity, including birth weight (BW), childhood and adulthood body mass index (BMI), waist-hip ratio (WHR), and body fat percentage (BF%), has a causal influence on periodontitis.
Methods: We used single-nucleotide polymorphisms with significant associations with life course adiposity as instrumental variables. We examined their association with periodontitis risk in a genome-wide association study involving periodontitis cases (n = 17,353) and healthy controls (n = 28,210) using a two-sample Mendelian randomization (MR) strategy. The association of life course adiposity with periodontitis risk was estimated with inverse-variance weighting with random effects. We performed sensitivity analyses using MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO), weighted median, and MR-Egger methods. We calculated the odds ratios (ORs) for one standard deviation (SD) increase per risk factor to estimate the effect on the risk of periodontitis.
Results: After correction for multiple testing, there was an association between each SD increase in gene-predicted adulthood BMI with a higher periodontitis risk (OR = 1.15, 95% confidence interval [CI]: 1.06-1.23, p = 3.1 × 10-4), with a similar influence for BF% on periodontitis risk (OR = 1.29, 95% CI: 1.12-1.49, p = 3.3 × 10-4). No causal association was detected for gene-predicted BW, childhood BMI, or WHR with periodontitis risk.
Conclusion: We present new proof supporting a causal function of greater adiposity, especially high BMI and BF%, being associated with higher periodontitis risk. We recommend that future studies focus on periodontitis from a life course perspective.
Keywords: Mendelian randomization; adiposity; periodontitis.
© 2022 American Academy of Periodontology.