The Dietary Inflammatory Index and Periodontal Inflammation in Community-Dwelling Older Adults in Japan: The Otassha Study.

AIM: To investigate the association between the dietary inflammatory index (DII) and periodontal inflammation (periodontal inflamed surface area [PISA]) in community-dwelling older adults in Japan.

MATERIALS AND

METHODS

DII scores, derived from a validated questionnaire-based dietary assessment, were categorised into quartiles. Linear regression models were used to assess the associations between DII (exposure) and log-transformed PISA (outcome) calculated from full-mouth periodontal examinations. Restricted cubic spline (RCS) models were applied to examine potential nonlinearity.

RESULTS

Among the 466 participants (mean age = 73.1 years), the median PISA was 37.8 mm2, and the median values for whole-mouth average probing pocket depth, clinical attachment loss and bleeding on probing were 1.8 mm, 2.0 mm and 3.3%, respectively. After adjustment for covariates, participants in the third [regression coefficient (95% confidence interval) = 0.49 (0.03-0.95)] and fourth [0.83 (0.34-1.32)] DII quartiles had significantly higher PISA values. Although the test for nonlinearity was not significant, the RCS analysis revealed a largely flat association below DII ≈ -1.5, followed by a near-linear increase with increasing DII.

CONCLUSIONS

Diets with greater inflammatory potential were associated with higher periodontal inflammatory burdens among older adults in Japan. DII may serve as a modifiable dietary indicator to support periodontal health in ageing populations.