Serum levels of vitamin D and periodontal inflammation in community‐dwelling older Japanese adults: The Otassha Study

Abstract Aim To evaluate the association between vitamin D status and periodontal inflammation as determined by the periodontal inflamed surface area (PISA) in community‐dwelling older adults. Materials and Methods This cross‐sectional study included 467 Japanese adults (mean age = 73.1 years) who underwent full‐mouth periodontal examinations and measurements of serum levels of 25‐hydroxyvitamin D (25(OH)D). We used linear regression and restricted cubic spline models to analyse the association between exposure (serum 25(OH)D) and outcome (PISA). Results The linear regression model showed that, after adjusting for potential confounders, participants in the lowest quartile of serum 25(OH)D had 41.0 mm 2 more PISA (95% confidence interval [CI]: 4.6–77.5) than the reference group (the highest quartile of serum 25(OH)D). The spline model showed that the association between serum 25(OH)D and PISA was non‐linear and restricted to the low 25(OH)D range. PISA initially sharply decreased as serum 25(OH)D increased, and then the decreasing trend slowed and plateaued. The inflection point with the minimum PISA value was a serum 25(OH)D level of 27.1 ng/mL, above which there was no decreasing trend in PISA with increasing serum 25(OH)D levels. Conclusions Low vitamin D status had an L‐shaped association with periodontal inflammation in this cohort of Japanese adults.