Diet and root surface caries in a cohort of older Japanese.

Objectives: Root surface caries experience tends to increase with age. The purpose of this longitudinal study was to evaluate the relationship between aspects of dietary intake, including milk and sucrose in coffee or tea (SCT), and root surface caries in older Japanese individuals.

Methods: 303 community-dwelling older individuals (age 75 years) were enrolled for analysis. All participants underwent a dental examination at baseline and then annually from 2003 to 2008 (ie six times over a 5-year period). A disease event was considered to have occurred when root surface caries was detected on a previously sound or nonexposed root surface. Over the observation period, disease events in each year were counted. Dietary habits during the preceding month were evaluated using a brief self-administered diet history questionnaire (BDHQ) in 2003 and 2008. Poisson regression analysis performed crude and adjusted increment-rate ratios (IRRs) for root surface caries and the intake of milk and SCT.

Results: The adjusted increment-rate ratio (IRR) of the increment of root surface caries for participants in the highest SCT tertile was 1.72 (95%CI: 1.40-2.14) compared with the referent group. In addition, for the amount of milk intake, the adjusted IRR in the highest tertile was 0.63 (95% CI: 0.51-0.78) compared with the referent group.

Conclusions: Much SCT and low milk intake were associated with the increment of root surface caries in community-dwelling older people in Japan. These findings suggest that to help prevent root surface caries, community-dwelling older people in Japan should consume adequate amounts of milk daily and limit their intake of SCT.