Fig. 1: Restricted cubic spline plots of the association between dietary copper intake and low muscle mass.

All models were adjusted for age (continuous), sex (except in the sex subgroup analyses), race/ethnicity, education, family income, smoking, alcohol intake, physical activity, total energy intake (in quintiles), healthy eating index (in quintiles), BMI (<18.5, 18.5–24.9, 25–29.9, or ≥30 kg/m2), hypertension, dyslipidemia, diabetes, cancer, albuminuria, and eGFR (in quintiles).