Aging-related muscle loss is a public health problem. We investigated the association of lifestyle and hormonal factors with a prospectively assessed muscle loss in older men.

Among 608 home-dwelling men, aged 60-85 (mean 68) years, lifestyle and health status were evaluated through a questionnaire. Appendicular skeletal muscle mass was estimated using dual-energy x-ray absorptiometry and calculated as the sum of lean mass of the 4 limbs. Free testosterone concentration was calculated using concentrations of total testosterone and sex hormone-binding globulin. Longitudinal data were analyzed by hierarchical models.

Average muscle loss was 0.63 ± 0.05%/year. The results of our multivariable adjusted analyses showed that muscle loss was higher in men whose leisure physical activity was <15 hours/week versus ≥15 hours/week (−0.76 vs −0.57%/year). Age-related acceleration of muscle loss was greater in men with lower total testosterone levels (<10 vs ≥10 nmol/L: −0.10 vs −0.07%/year/year of age at baseline [age]). Men with lower free testosterone (<75 vs ≥75 pmol/L) had greater age-related acceleration of muscle loss (−0.12 vs −0.08%/year/age). Higher parathyroid hormone concentrations were associated with greater age-related acceleration of muscle loss (≥45 vs <45 pg/mL −0.14 vs −0.12%/year/age). Men with type 2 diabetes had higher age-related acceleration of muscle loss versus men without diabetes (−0.08 vs −0.03%/year/age) (All P values are <.05).

In elderly men, low leisure physical activity, type 2 diabetes, low total and free testosterone, and elevated parathyroid hormone concentrations are associated with greater age-related acceleration of muscle loss. These factors are likely to represent real determinants of aging-related muscle loss in men.