We recently found that serum dehydroepiandrosterone sulfate (DHEA-S) concentration correlated inversely with the degree of urinary albumin excretion in a cross-sectional study. We therefore performed an observational study to investigate the relationship between serum DHEA-S concentrations and changes in urinary albumin excretion in male patients with type 2 diabetes to answer the question as to whether DHEA is a causal rather than simply coincidental intermediate linking urinary albumin excretion to cardiovascular disease (CVD). The relationship between serum DHEA-S concentration and changes in urinary albumin excretion was investigated in 207 consecutive male patients with type 2 diabetes. Baseline serum DHEA-S concentration and urinary albumin excretion were measured in 2003. After 12 months, urinary albumin excretion was measured and any changes in urinary albumin excretion were calculated. Patients were divided into tertiles according to DHEA-S concentration. Greater changes in urinary albumin excretion were seen in patients with low DHEA-S concentration (29.6+/-7.6mg/g creatinine) than in patients with high DHEA-S concentration (5.1+/-3.6mg/g creatinine, P=0.0091). An inverse correlation was observed between serum DHEA-S concentration and changes in urinary albumin excretion (r=-0.193, P=0.0052). Multiple regression analysis demonstrated that HbA1c (beta=0.241, P=0.0009), and serum DHEA-S concentration (beta=-0.195, P=0.0054) were independent determinants of changes in urinary albumin excretion. In conclusion, serum DHEA-S concentration was inversely correlated with changes in urinary albumin excretion, which may indicate causality in the increased CVD mortality in male patients with type 2 diabetes and low DHEA-S concentration.