Sarcopenia changes and incident type 2 diabetes mellitus: a prospective analysis of the CHARLS cohort

Emerging evidence suggests that sarcopenia may be a significant risk factor for Type 2 Diabetes Mellitus (T2DM). However, existing research has predominantly relied on single baseline assessments, leaving the impact of its dynamic progression over time unclear. This study aimed to prospectively evaluate how transitions in sarcopenia status influence the incidence of T2DM. We analyzed data from the China Health and Retirement Longitudinal Study (CHARLS). Sarcopenia was defined according to the 2019 AWGS criteria and classified as non-sarcopenia, possible sarcopenia, or sarcopenia. Changes in status were determined by comparing classifications at baseline (2011year) and a two-year follow-up(2013year). Incident T2DM was identified through elevated fasting plasma glucose, random plasma glucose, HbA1c levels, or self-reported physician diagnosis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression models, adjusted for multiple potential confounders. Among 3,673 eligible participants (51.3% male; mean age 68.21 years), regression analysis revealed that recovery from sarcopenia to a non-sarcopenic state was associated with a significantly lower risk of T2DM (HR = 0.61, 95% CI: 0.40–0.93) compared to those who remained sarcopenic. While progression to a worse sarcopenia state showed a trend towards higher T2DM risk, this association was not statistically significant. Subgroup analyses indicated that the protective association of sarcopenia reversal was significant in men (HR = 0.43, 95% CI: 0.24–0.78) and participants aged ≥ 65 years (HR = 0.60, 95% CI: 0.37–0.99), but not in women or those under 65. The longitudinal trajectory of sarcopenia status is associated with the risk of developing T2DM. Notably, improvement from sarcopenia is linked to a reduced risk, whereas progression may indicate an elevated risk, underscoring the potential clinical value of monitoring and managing sarcopenia dynamics.