Leptin levels are not related to risk factors for coronary heart disease in patients with type 2 diabetes mellitus or normal controls

Abstract This study investigated the relationship between leptin and risk factors for coronary heart disease (CHD) in patients with type 2 diabetes mellitus and nondiabetic controls. A total of 21 patients with diabetes mellitus (group A, 19 men and 2 women) were compared with 10 nondiabetic subjects (group B, 5 men and 5 women). Insulin-treated patients with diabetes mellitus, subjects receiving antihyperlipidemic therapy, and patients with CHD, renal, thyroid, or hepatic disorders were excluded from the study. Body-mass index (BMI), waist-to-hip ratio (WHR), glycosylated hemoglobin A 1c , total cholesterol, triglycerides, apolipoprotein A, apolipoprotein B, apolipoprotein E, fibrinogen, tissue plasminogen activator, and plasminogen inhibitor-1 levels were determined for all patients after an overnight fast. In addition, plasma levels of insulin, proinsulin, and leptin were estimated. The 2 groups were comparable in terms of age (group A, 52.52 ± 4.64 years; group B, 49.50 ± 4.90 years), BMI (group A, 27.50 ± 1.83 kg/m 2 ; group B, 25.79 ± 2.90 kg/m 2 ), and WHR (group A, 0.98 ± 0.07; group B, 0.92 ± 0.09). Plasma leptin levels were significantly higher ( P = 0.038) in nondiabetic subjects than in patients with diabetes mellitus (11.51 ± 8.14 ng/mL vs 5.96 ± 3.85 ng/mL, respectively), possibly because of the higher proportion of women in the nondiabetic group. Leptin levels were significantly correlated with BMI in patients with diabetes mellitus ( r = .51); a tendency toward a positive correlation with insulin levels was noted in this group ( r = .41). No statistically significant correlations were observed regarding leptin with the other risk factors of CHD in either group. Except for the degree of obesity in patients with diabetes mellitus, leptin does not appear to be related to most risk factors for CHD in patients with diabetes or nondiabetic subjects. Additional studies with more patients are needed to help explain the complex interactions of leptin with other CHD risk factors.