Dairy intake and incident functional disability among older Japanese adults: the Ohsaki Cohort 2006 Study.

PURPOSE

Previous studies have investigated the association between dairy intake and functional disability, but their results were inconsistent. Our study aimed to investigate whether dairy intake may protect against incident functional disability among Japanese older adults.

METHODS

We conducted a longitudinal analysis of dairy intake with incident functional disability in a prospective cohort study of 11,911 Japanese individuals aged ≥ 65 years who were followed up for 8.2 years on average. Data on milk, yogurt, and cheese intake were collected using a validated food frequency questionnaire. Total dairy intake was the sum of the daily intake of milk, yogurt, and cheese, which was sex-specifically categorized in quintiles. Data on functional disability were retrieved from the public Long-term Care Insurance database. The Cox proportional hazards model was used to estimate the multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (95%CIs) for incident functional disability.

RESULTS

During 97,234 person-years of follow-up, 4874 persons (40.9%) were ascertained as having functional disability. Our study suggested a null association between total dairy intake and incident risk of functional disability; compared to Q1 (the lowest quintile) group, the multivariable-adjusted HRs (95%CIs) were 0.96 (0.88-1.05) for Q2, 0.93 (0.85-1.02) for Q3, 0.93 (0.85-1.02) for Q4, and 1.01 (0.92-1.10) for Q5 (p-trend = 0.840). We did not find any associations between milk, yogurt, or cheese intake and incident risk of functional disability.

CONCLUSION

We found no evidence showing that dairy intake was associated with functional disability among Japanese older adults.