Self-reported physical function score over time, by quintiles of protein intake, calculated using GEE. Models were adjusted for age, income, education, race/ethnicity, BMI (height only for g/kg models), smoking status, alcohol consumption, physical activity, hormone therapy use, whether the participant lived alone, having a healthcare provider, number of falls, disability, depression, and self-reported history of medical conditions (emphysema, diabetes, hypertension, arthritis, and cancer), calibrated total energy intake, and clinical trial arm.