Leptin concentrations in relation to overall adiposity, fat distribution, and blood pressure in a rural Chinese population

OBJECTIVE: To examine the associations between leptin levels and body mass index (BMI), fat distribution (reflected by waist to hip ratio and skinfold measurements), and blood pressure in a rural Chinese population. DESIGN AND SUBJECTS: A cross-sectional study of 294 participants who provided blood samples. MEASUREMENTS: Plasma concentrations of leptin, BMI, waist to hip ratio, skinfold thickness, and blood pressure. RESULTS: The average leptin concentration was 5.2 mug/l (3.1 for men and 7.3 for women). In univariate analyses, leptin levels were significantly correlated with BMI (r = 0.47), abdominal skinfold thickness (r = 0.53), triceps skinfold thickness (r = 0.56), waist circumference (r = 0.41), hip circumference (r = 0.51), waist to hip ratio (r = 0.17), and diastolic blood pressure (r = 0.13). In multivariate analyses controlling for age, sex, education, current smoking, and alcohol use, independent associations between leptin levels and BMI, waist to hip ratio, waist circumference, and abdominal skinfold thickness remained. However, the significant association between leptin and blood pressure disappeared after adjusting for BMI, whereas the association between BMI and blood pressure persisted after adjusting for leptin level. CONCLUSIONS: We observed a strong positive relationship between overall adiposity and leptin levels in both men and women in a rural Chinese population. In addition, leptin concentrations were significantly associated with central obesity measured by waist to hip ratio and abdominal skinfold, independent of overall obesity. The observed positive association between leptin and blood pressure was largely explained by BMI.