The relationship between plasma leptin levels and chronic complication in patients with type 2 diabetes mellitus.

Objective: The aim of this study was to investigate the relationship between plasma leptin levels and the chronic complications in type 2 diabetic (T2DM) patients.
Patients and Methods: There were 157 T2DM patients (age, 56.7 ± 11.4 years; mean diabetes duration, 8.9 ± 3.6 years; mean body mass index, 28.1 ± 4.3 kg/m(2)) included to the study. Microvascular and macrovascular complications of diabetes were evaluated in all patients. There were 46 healthy subjects as control group. Plasma leptin levels were measured in both diabetic and healthy subjects.
Results: Plasma leptin levels of the diabetic patients were not significantly different from the healthy subjects (26.4 ± 18.2 vs. 29.1 ± 13.1 ng/mL, P > 0.05). Plasma leptin levels in obese diabetic patients were higher than in nonobese (37.6 ± 20.9 vs. 20.0 ± 17.2 ng/mL, P = 0.001); in hypertensive diabetic patients than normotensive (35.2 ± 19.3 vs. 19.4 ± 13.9 ng/mL, P < 0.001); dyslipidemic diabetic patients than normolipidemic diabetic subjects (38.5 ± 18.3 vs. 31.3 ± 19.5 ng/mL, P = 0.038); diabetic patients with metabolic syndrome than diabetic patients without metabolic syndrome (37.9 ± 20.1 vs. 23.2 ± 15.3 ng/mL, P = 0.001). Plasma leptin levels were lower in diabetic patients who were smokers than nonsmokers (20.0 ± 15.5 vs. 24.7 ± 17.4 ng/mL, P = 0.023). There was no significant difference between patients with and without diabetic nephropathy, retinopathy, neuropathy, coronary artery disease or peripheral vascular disease (P > 0.05).
Conclusions: Our data suggest that obesity, hypertension, dyslipidemia, and metabolic syndrome in T2DM were associated with increased plasma leptin levels. We conclude that plasma leptin levels may not be strongly associated with microangiopathy and macroangiopathy in T2DM individuals.