Franks PW et al. (2005) Leptin predicts a worsening of the features of the metabolic syndrome independently of obesity. Obes Res 13: 1476–1484

Several studies have linked obesity with the metabolic syndrome. Obesity, however, is not a prerequisite for the metabolic syndrome and little is known about the underlying mechanisms and pathways that relate to development of this syndrome. Franks and colleagues, therefore, tested the hypothesis that leptin is associated with the development of features of the metabolic syndrome, independently of obesity.

Franks and colleagues used data from a prospective population-based cohort, which consisted of 748 adults. Data included participants height, weight and blood pressure, insulin, glucose and lipid levels, and plasma leptin levels, collected at baseline and at 5 and 10 years follow-up. At the end of the last available follow-up, there were 105 incident cases of the metabolic syndrome.

Baseline leptin levels were significantly associated with development of obesity. After adjusting for BMI, baseline leptin levels significantly predicted the development of insulin resistance and glucose intolerance. Leptin levels, however, did not significantly predict changes in blood pressure or lipidemia. More importantly, leptin levels significantly predicted the development of the metabolic syndrome, after controlling for obesity, in a dose-dependent manner.

The authors conclude that leptin levels predict the development of the metabolic syndrome and this is specifically related to glucose intolerance and insulin resistance. This association is independent of baseline obesity. Further studies are, however, required to confirm the independence of these associations.