Low serum leptin levels and malnutrition in chronic alcohol misusers hospitalized by somatic complications

Aims: Leptin is a peptide produced by fat cells which regulates fat mass by decreasing food intake and increasing resting energy expenditure, so an increase of serum leptin could be an indicator of malnutrition. Our objective was to determine serum leptin levels (at admission and on the 15th day) in 79 male alcohol misusers, hospitalized by somatic complications, who drink more than 80 g ethanol/day, and to analyse its relationships with nutritional status assessed by anthropometry and dual-energy X-ray absortiometry (DEXA), insulin-like growth factor (IGF-1) and its binding protein (IGF1BP-3); acute phase reaction assessed by C-reactive protein (CRP), interleukin-6 (IL-6) and type II soluble receptor of turnout necrosis factor (TNF) (sTNFRII); serum oestradiol and testosterone; and the amount and duration of ethanol intake, the smoking habit and the presence of liver cirrhosis. Methods: Patients were admitted through the emergency room, and blood for the above-mentioned determinations was taken at 08.00 on the following day, so none of the patients was acutely intoxicated at this time. The control group was composed of 32 healthy male (age-matched) subjects. Results: Malnutrition was frequent among alcoholics. Serum leptin levels were closely related to total fat both in controls and in alcoholics. Serum leptin levels were decreased in alcoholics, even after adjusting for the amount of fat. Those alcoholics who reported anorexia and weight loss showed decreased leptin levels. After 15 days of hospitalization, serum leptin did not increase, in contrast with LDL cholesterol, serum albumin, prealbumin, IGF-1, IGFIBP-3 and testosterone which increased, whereas oestradiol and acute phase reactants, such as CRP, IL-6 and sTNFRII, were decreased. Serum leptin was not related to gonadal hormones at admission, but on day 15 we found a negative correlation between leptin and testosterone, and a positive one with oestradiol. Conclusions: Serum leptin levels are related to many factors, e.g. fat mass, age, smoking, serum testosterone and oestradiol levels, growth factors such as IGF-1 and CRP, and cytokines, such as IL-6 and sTNFRII. The most important of these is fat mass, as shown by multivariate analysis. Since serum leptin levels are decreased in alcohol misusers, we consider this decrease to be a consequence of a low fat mass.