The levels of the liporegulatory
hormone leptin are increased in
obesity, which contributes to the
metabolic syndrome; the latter is associated with elevated cardiovascular risk and morbidity.
Leptin may play a role in the
metabolic syndrome since correlations have been observed between serum
leptin levels and several components of the
metabolic syndrome. The association of leptinemia and
hypertension or diabetes is inconsistent.
Leptin levels are higher in females versus males and obese versus lean individuals. We investigated if correlations exist between
leptin levels and several indices of the
metabolic syndrome in obese and lean Moroccan subjects with (63 males, 129 females) and without (123 males, 234 females) diabetes and/or
hypertension. Plasma
glucose and
insulin and systolic and diastolic blood pressures were higher in obese versus lean individuals.
Obesity had no effect on
lipid profile, plasma
IGF-1, or
C-peptide levels.
Leptin levels were higher in females versus males and in obese versus lean individuals. The levels correlated significantly with body mass index. Serum
leptin concentration did not correlate with either systolic or diastolic blood pressure, although there was a trend for higher blood pressure with increased
leptin levels in females. There was no significant difference in
leptin levels between
NIDDM patients and healthy controls. However, in hypertensive patients,
leptin levels were significantly higher in both lean males and females with diabetes as compared to those without diabetes. Similarly, the higher
leptin levels paralleled elevated
insulin levels in obese nondiabetic males and females, and in male and female diabetics with
hypertension. Correlations were observed between
leptin levels and
C-peptide (an estimate of endogenous insulin secretion), but not with serum
IGF-1. The calculated values of HOMA-IR, a marker of
insulin resistance, were somewhat higher, parallel with elevated
leptin levels, in obese male and female individuals compared to their lean counterparts. There was no relationship between
leptin levels and serum
lipids. There was a trend for increased serum
uric acid levels with higher
leptin concentrations. Thus, leptinemia is related to some components of
metabolic syndrome, and in turn, it may contribute to the syndrome. This study is novel in that relationships were determined between
leptin levels and various indices of metaboli syndrome in a large population of the same ethnic/regional background.