Background: Malnutrition seen in chronic alcoholics is partly due to reduced energy intake. Leptin is a peptide hormone implicated in the regulation of appetite and expenditure of energy. The prevalence and significance of abnormal circulating leptin levels in alcoholics, as well as the relationship of these levels with nutritional status, liver disease, and ethanol consumption, remain uncertain.
Methods: Serum leptin levels were measured in 60 active asymptomatic alcoholics, 20 active alcoholics with cirrhosis of the liver, 20 abstinent alcoholics, and 60 controls. Nutritional status and ethanol consumption also were assessed.
Results: In the control group, circulating leptin levels (mean 4.7+/-0.3 microg/liter) correlated with body fat stores. Despite showing a lower fat area of the arm, active alcoholics had significantly higher leptin levels than the controls (p < 0.001), regardless of the presence of cirrhosis. By contrast, none of the abstinent alcoholics showed hyperleptinemia. In the multivariate regression analysis, the fat area of the arm (p < 0.001), the lifetime ethanol consumption (p = 0.007), and the number of cigarettes smoked per day (p = 0.02) were found to be independent factors that influenced leptin levels in active alcoholics. After we adjusted for age, fat area of the arm, and tobacco consumption, a significant correlation was observed between lifetime consumption of ethanol and serum leptin concentrations (r = 0.36, p < 0.001).
Conclusions: Circulating leptin levels are increased in a dose-dependent manner in chronic alcoholism, regardless of nutritional status or the presence of compensated liver disease.