Protein Intake and Incident Frailty in the Women's Health Initiative Observational Study

Data from short-term clinical trials suggest current protein recommendations may not be optimal for elderly individuals, but few data are available from population-based cohorts. We prospectively evaluated the association between protein intake and incident frailty in the WHI-OS. Postmenopausal women aged 65-79 years at baseline who were free of frailty and with plausible self-reported energy intakes (600-5000 kcal/day) by Food Frequency Questionnaire (FFQ) were included. Protein intake was measured at baseline using the WHI FFQ and energy and protein intake were corrected for measurement error using regression calibration equations estimated from biomarker data. After three-years of follow-up, frailty was defined as having at least three components: low physical function, exhaustion, low physical activity, and unintended weight loss. Multinomial logistic regression models estimated associations for both uncalibrated and calibrated protein intake. Among the 24,417 eligible women, 3,298 (13.5%) developed frailty. After adjustment for confounders, a 20% increase in uncalibrated protein intake (%kcal) was associated with a 12% (95% CI: 8% to 16%) decrease in frailty, while a 20% increase in calibrated protein was associated with a 32% (95% CI: 23% to 44%) decrease in frailty. Insufficient protein intake may be an intervention target for frailty prevention. Funded by NHLBI and NIA.