Leptin and high-sensitivity C-reactive protein and their interaction in the metabolic syndrome in middle-aged subjects.

High-sensitivity C-reactive protein (hsCRP) and leptin, known to interact at the molecular level, have been associated with the metabolic syndrome (MS). We examined the independent and joint effects of high leptin and hsCRP levels on the development of MS in a population-based cohort of middle-aged subjects (N = 1035). Leptin and hsCRP levels increased with an increase in the number of metabolic abnormalities (P < .001). However, additional adjustment for body mass index diluted the association of leptin with MS in women. In men, the association of high leptin with insulin resistance and waist circumference (P < .001), and in women, the association of high hsCRP with insulin resistance (P = .029) and waist circumference (P = .009) persisted in the multivariate logistic regression models. High leptin in men and high hsCRP in women were significant predictors of MS in logistic regression analysis (P < .001). The highest prevalence of MS (86% in men and 71% in women) was observed in the subjects who belonged to the highest quartile in both leptin and hsCRP. MS is associated independently with high leptin in men and with hsCRP in women, whereas individuals with both of these markers belong to the highest risk of metabolic cluster. The study suggests sex-specific interplay between metabolic and inflammatory markers in the pathogenesis of MS.