A Mendelian randomization study on the association of bone mineral density with periodontitis

Objective Observational studies indicated that individuals with osteoporosis could be at an increased risk of periodontitis. This study aimed to investigate whether there is a causal association of bone mineral density (BMD) with periodontitis using Mendelian randomization (MR). Materials and Methods Summary statistics were sourced from genome‐wide association study on BMD measured at different skeletal sites, including estimated heel BMD (eBMD, N = 426,824), forearm BMD (FA‐BMD, N = 8143), femoral neck BMD (FN‐BMD, N = 32,735), and lumbar spine BMD (LS‐BMD, N = 28,498). Genetic variants of periodontitis (N = 45,563) and loose teeth (N = 461,031) were used as outcome surrogates. Inverse variance weighted meta‐analysis (IVW) was adopted as main analyses. Other sensitivity MR approaches were used to boost power and account for pleiotropy. Results IVW results suggested no evidence for a causal association of any phenotypes of BMD with periodontitis (eBMD, odds ratio [OR] = 0.984, 95% confidence interval [CI] = 0.885–1.083; FA‐BMD, OR = 1.028, 95%CI = 0.864–1.193; FN‐BMD, OR = 1.033, 95%CI = 0.896–1.169; LS‐BMD, OR = 0.991, 95%CI =0.878–1.103; all P > 0.65). Such null associations were consistent through other sensitivity MR approaches. Similarly, no significant causal effects of BMD on loose teeth were found. Conclusions Within the limitation of the study, our MR estimates suggested that a decreased BMD is unlikely to substantially increase the risk of periodontitis.