Correlation between serum phosphorus level and muscle mass in patients with type 2 diabetes mellitus

This study aimed to evaluate the correlation between serum phosphorus level and low muscle mass in patients with type 2 diabetes mellitus (T2DM). In this cross-sectional study, 1078 T2DM inpatients were recruited. Low muscle mass was defined as a skeletal muscle index (SMI) < 7.0 kg/m² for men and < 5.4 kg/m² for women, which measured by dual-energy X-ray absorptiometry. Serum phosphorus (P) was measured using the phosphomolybdate method. Clinical information and other biochemical characteristics were measured and recorded. The prevalence of low muscle mass was 20.2% in men and 13.6% in women. A higher serum phosphorus level was associated with a significantly lower risk of low muscle mass in both genders after multivariable adjustment. A nonlinear, threshold-dependent positive correlation was observed between serum phosphorus and SMI, with significant associations below cohort-specific thresholds of 0.98 mmol/L in men and 1.04 mmol/L in women. Higher serum phosphorus level is associated with a lower prevalence of low muscle mass (i.e., positively correlated with SMI) in T2DM patients. And this exploratory finding requires validation in longitudinal studies.