In subgroup analyses of diabetic nephropathy, study design (OR for moderate effect: 1.21; 95% CI: 1.02–1.42) and body mass index (OR of moderate effect: 0.84; 95% CI: 0.70–1.00) had significant moderate effects on ACE I/D polymorphisms and diabetic nephropathy. The gene discussed is ACE; the disease is diabetic kidney disease.