Introduction Asian populations tend to be more susceptible to type 2 diabetes. In Asians low muscle-mass may also be a contributory factor. In a rapidly developing southern Chinese population, we examined whether skeletal muscle-mass, proxied by serum creatinine, was associated with diabetes or adiposity.

Methods In 9768 older (≥50 years) adults from the Guangzhou Biobank Cohort Study (phase 1) examined in 2003–2004, we used multivariable logistic, linear and censored regression to assess the adjusted associations of serum creatinine with diabetes, waist-hip ratio, body mass index and fasting blood glucose. We also examined whether these associations varied by sex and age.

Results The association of serum creatinine with diabetes did not vary by sex. Serum creatinine was negatively associated with diabetes (OR 0.65, 95% CI 0.56 to 0.75) and fasting glucose (−0.43 mmol/l, 95% CI −0.53 to −0.34) for highest compared with lowest tertile, adjusted for age, education, occupation and lifestyle. Serum creatinine had sex-specific associations with waist-hip ratio, negatively associated (−0.10 SDs, 95% CI −0.15 to −0.04) in women only.

Conclusions The observed pattern of associations is compatible with the hypothesis that nutritionally driven increases in muscle-mass, reduces diabetes risk while having sex-specific effects on central obesity, with corresponding implications for prevention.