Skeletal Muscle Mass Negatively Associated With Diabetes and Insulin Resistance

There is a significant and negative association observed between skeletal muscle mass and diabetes mellitus incidence, according to study findings in Diabetes/Metabolism Research and Reviews.

Several studies have been conducted regarding the correlation between skeletal muscle mass, diabetes incidence, and hemoglobin A_1c (HbA_1c), but results have not been generalizable to an Asian population. Researchers conducted a cross-sectional study to determine the association between skeletal mass, diabetes prevalence, and insulin resistance in young and middle-aged Korean men and women.

Of the 372,399 individuals who received a routine health check-up, 228,323 were excluded from the analysis due to incomplete diabetes history, chronic kidney disease, cancer, thyroid disease, or steroid use. A total of 144,076 individuals were included in the final analysis. 

All study participants answered a questionnaire regarding lifestyle habits, medical history, and demographic questions at the Kangbuk Samsung Hospital, Seoul, Republic of Korea. Participants were assessed based on their respective skeletal muscle index (SMI) quantile. 

The outcomes assessed in this study were diabetes incidence, HbA_1c, and homeostasis model assessment of insulin resistance (HOMA‐IR).

The average age of participants was 38.92 years (standard deviation [SD], 8.54 years) and 3.93% of participants had diabetes. The average HbA_1C was 5.47 (SD, 0.52%) and HOMA‐IR was 1.47.

Researchers found that SMI had a negative association with diabetes prevalence. After adjusting for potential confounders, researchers found that, compared with the lowest quantile (Q1), the diabetes incidence in Q2, Q3, and Q4 were 0.95 (95% CI, 0.85-1.05), 0.88 (95% CI, 0.78-0.99), and 0.79 (95% CI, 0.69-0.9), respectively (P <0.001). 

When assessing HOMA-IR compared with Q1, the beta coefficients were reported as 0.05 (95% CI, 0.03-0.07) for Q2, -0.06 (95% CI, -0.09 to -0.04) for Q3, and -0.19 (95% CI, -0.22 to -0.16) for Q4 (P <0.001).

A dose-response relationship was found between the SMI quantile and HbA_1c, with the beta coefficients for Q2, Q3, and Q4 reported as -0.09 (95% CI, -0.1 to -0.08), -0.17 (95% CI, -0.18 to -0.17), and -0.27 (95% CI, -0.28 to -0.27), respectively, when compared with Q1 (P <0.001).

Study limitations include lack of generalizability, recall bias, and the exclusion of patients taking steroids. 

“Because of limited evidence of the causal relationship, further investigations are required to determine the effect of skeletal muscle mass on dysglycemia,” study authors wrote.