Diet-related quality of life may directly and indirectly affect health-related quality of life through protein intake and frailty in patients with osteoporosis: Results from a prospective cohort study.

Aim: We aimed to examine the direct and indirect associations between diet-related quality of life (DRQOL) and health-related quality of life (HRQOL) in patients with osteoporosis.

Methods: Cross-sectional and longitudinal analyses were conducted using data from a 1-year prospective cohort survey of 532 consecutive patients with osteoporosis. The DRQOL was assessed using a short version of the Diet-Related Quality of Life Scale. Dietary intake statuses were assessed using the brief-type self-administered diet history questionnaire. Frailty was assessed using the Kihon Checklist (KCL). HRQOL was assessed using the EuroQol 5-dimensions 5-level (EQ-5D-5L) score. The association between the DRQOL scores and each item was analyzed using multivariable logistic regression, path analysis, and a cross-lagged panel model.

Results: In the baseline cross-sectional analysis, DRQOL scores at the ≥75th percentile of the cohort were associated with protein intake (odds ratio [OR] 2.18; 95% confidence intervals [CIs]: 1.20, 3.96), frailty (OR: 0.14; 95% CIs: 0.06, 0.33), and having a full EQ-5D-5L score (OR: 2.37; 95% CIs: 1.33, 4.21). In the path analysis, the DRQOL score was directly related to the EQ-5D-5L score and indirectly related via protein intake and the KCL score (standardized direct effect: 0.08, standardized indirect effect: 0.11). In the cross-lagged panel model, DRQOL scores at baseline were indirectly positively associated with EQ-5D-5L scores at 1 year (standardized direct effect: -0.06, standardized indirect effect: 0.23).

Conclusions: The DRQOL in patients with osteoporosis may be directly and indirectly related to the HRQOL via protein intake and frailty. Geriatr Gerontol Int 2025; ••: ••-••.