Plasma leptin and blood pressure in men: graded association independent of body mass and fat pattern

OBJECTIVE: The role of leptin in the association between body mass, central adiposity, and blood pressure (BP) is controversial. This study evaluated the relationship between leptin and BP in relation to body mass index (BMI) and fat distribution in a large sample of untreated male adults. RESEARCH METHODS AND PROCEDURES: The study population was made up of 457 untreated male employees of the Olivetti factory in Naples. Plasma leptin, complete anthropometry, BP, and relevant biochemical variables were measured. RESULTS: Log-transformed plasma leptin levels were directly associated with BMI (r=0.661, p<0.001) and waist circumference (r=0.630; p<0.001). Leptin also correlated with systolic (r=0.258) and diastolic (r=0.277) BP (p<0.001). The association between leptin and BP was maintained after accounting for age, BMI (or waist circumference), log-insulin, and serum creatinine (p < 0.01); this association was stronger than that with BMI. Logistic regression analysis showed that an increased prevalence of hypertension (BP=<140 and/or 90 mm Hg) was associated with high plasma leptin levels when controlling for age and waist circumference (odds ratio, 1.99; 95%CI, 1.06 to 3.72) or for age and BMI (odds ratio, 1.92; 95%CI, 1.02 to 3.61). DISCUSSION: A graded positive relationship between plasma leptin levels and BP was observed in this sample of untreated male adults. This association was independent of age, BMI, abdominal adiposity, and fasting plasma insulin. Moreover, elevated plasma leptin concentrations were associated with greater probability of hypertension, again independently of potential confounders.