Normal-weight obese syndrome: early inflammation?

Background: In obese subjects, the adipose mass represents an important source of proinflammatory cytokines. We have identified a new syndrome-the normal-weight obese (NWO) syndrome-in women with normal weight and body mass index but whose fat mass is > 30% of their total body weight and whose risk of developing obesity-related diseases is likely increased. Objective: The aim of the present study was to verify the hypothesis that NWO women are characterized by early inflammation, related to body fat mass, and that their plasma proinflammatory cytokine concentrations are greater than those of nonobese women. Design: Twenty NWO, 20 preobese-obese, and 20 healthy (nonobese), age-matched white Italian women were studied. Anthropometric variables and plasma concentrations of proinflammatory cytokines and cardiovascular disease (CVD) risk factors were measured and compared between groups. Results: Plasma values and body-composition measures were significantly different between the preobese-obese and nonobese women. No significant differences in body weight, laboratory values, or CVD risk factors were found between the NWO and nonobese groups. Compared with concentrations in the NWO women, plasma concentrations of interleukin (IL)- 1 alpha, IL- 1 beta, IL-6, IL-8, and TNF-alpha were significantly lower in the nonobese group and were significantly greater in the preobese-obese group. IL-6 and TNF-alpha concentrations were related to fat mass distribution in the NWO women. Conclusions: The proinflammatory cytokines could be regarded as significant prognostic indicators of the risk of obesity, CVD, and the metabolic syndrome in NWO women.