Serum creatinine levels and risk of incident type 2 diabetes mellitus or dysglycemia in middle-aged Japanese men: a retrospective cohort study

OBJECTIVE To assess the association between low serum creatinine levels and an increased risk of type 2 diabetes mellitus and dysglycemia. RESEARCH DESIGN AND METHODS We conducted a retrospective cohort study of 3313 Japanese male workers aged 30-55 years, who underwent annual health check-ups during 2001-2008 and showed no type 2 diabetes mellitus, and underwent follow-up examinations until March 2013. Dysglycemia was defined as a fasting plasma glucose concentration of ≥110 mg/dL (6.1 mmol/L), or a non-fasting plasma glucose concentration of ≥140 mg/dL (7.8 mmol/L). A Cox proportional model was used to calculate HRs and 95% CIs for developing type 2 diabetes mellitus or dysglycemia. RESULTS During the median 6.7-year follow-up, there were 207 cases of incident type 2 diabetes mellitus and 596 cases of incident dysglycemia, including 115 cases of type 2 diabetes mellitus among the subjects with normal glucose concentrations at baseline. After adjustment for age, body mass index and known diabetes risk factors, the multivariable HR of type 2 diabetes mellitus for the lowest category of serum creatinine (<0.7 mg/dL) vs the highest category (0.9-1.1 mg/dL) was 1.9 (95% CI 1.2 to 2.9; P for trend 0.03). The multivariable HRs of dysglycemia for the lowest category of serum creatinine versus the highest category was 1.5 (95% CI 1.1 to 1.9; P for trend 0.01). CONCLUSIONS Low serum creatinine levels were associated with an increased risk of type 2 diabetes mellitus and dysglycemia.