Context: Obesity is an independent risk factor for cardiovascular disease, which may be mediated by increased secretion of proinflammatory cytokines by adipose tissue.
Objective: To determine the effect of a program of changes in lifestyle designed to obtain a sustained reduction of body weight on markers of systemic vascular inflammation and insulin resistance.
Design and setting: Randomized single-blind trial conducted from February 1999 to February 2002 at a university hospital in Italy.
Patients: One hundred twenty premenopausal obese women (body mass index > or =30) aged 20 to 46 years without diabetes, hypertension, or hyperlipidemia.
Interventions: The 60 women randomly assigned to the intervention group received detailed advice about how to achieve a reduction of weight of 10% or more through a low-energy Mediterranean-style diet and increased physical activity. The control group (n = 60) was given general information about healthy food choices and exercise.
Main outcome measures: Lipid and glucose intake; blood pressure; homeostatic model assessment of insulin sensitivity; and circulating levels of interleukin 6 (IL-6), interleukin 18 (IL-18), C-reactive protein (CRP), and adiponectin.
Results: After 2 years, women in the intervention group consumed more foods rich in complex carbohydrates (9% corrected difference; P<.001), monounsaturated fat (2%; P =.009), and fiber (7 g/d; P<.001); had a lower ratio of omega-6 to omega-3 fatty acids (-5; P<.001); and had lower energy (-310 kcal/d; P<.001), saturated fat (-3.5%; P =.007), and cholesterol intake (-92 mg/d; P<.001) than controls. Body mass index decreased more in the intervention group than in controls (-4.2; P<.001), as did serum concentrations of IL-6 (-1.1 pg/mL; P =.009), IL-18 (-57 pg/mL; P =.02), and CRP (-1.6 mg/L; P =.008), while adiponectin levels increased significantly (2.2 microg/mL; P =.01). In multivariate analyses, changes in free fatty acids (P =.008), IL-6 (P =.02), and adiponectin (P =.007) levels were independently associated with changes in insulin sensitivity.
Conclusion: In this study, a multidisciplinary program aimed to reduce body weight in obese women through lifestyle changes was associated with a reduction in markers of vascular inflammation and insulin resistance.