BACKGROUNDExposure to nicotine via tobacco smoking may influence leptin release and decrease food intake among smokers. However, the effect of nicotine exposure on leptin and food intake among different nicotine dependent groups is unclear.OBJECTIVEWe aimed to measure leptin and calorie intake among different nicotine dependent groups.DESIGNCross-sectional study.SETTINGResearch department in school of medical sciences.PATIENTS AND METHODSSubjects were selected by purposive (non-probability) sampling and categorized as having low, moderate and high nicotine dependency based on the Fagerstrom Test for Nicotine Dependence (FTND) score. Diet was recorded by interview. Anthropometry, blood pressure, body composition, lipid profile, and physical activity level were measured accordingly. Fasting serum leptin was measured using a commercial ELISA kit.MAIN OUTCOME MEASURE(S)Nicotine dependency, 24-hour diet, clinical anthropometric and clinical measurements.RESULTSIn 107 Malay male smokers leptin concentration was inversely correlated with nicotine dependence. However, body weight, smoking period, blood pressure, body composition, lipid profile and physical activity level were not significantly different among low, moderately and highly dependent smoking groups. Leptin concentration and total calorie intake were also not significantly different among these groups.CONCLUSIONLeptin concentration was inversely correlated with nicotine dependence, but leptin concentration and total calorie intake status were not significantly different among our different nicotine dependency subjects.LIMITATIONSPurposive sampling for subject recruitment and inaccurate information in the self-administered questionnaire.