Impact of weight loss on waist circumference and the components of the metabolic syndrome.

OBJECTIVE: Central adiposity is a component of the metabolic syndrome (MetS). Little is known about the impact of medical weight loss and decreased waist circumference (WC) on the MetS. Our objective was to assess the impact of changes in WC on blood pressure, lipids and glycemia.

RESEARCH DESIGN AND METHODS: We studied 430 obese patients enrolled in a 2-year, intensive, behavioral, weight management program. We report results for participants who completed 6-month and 2-year follow-up.

RESULTS: Participants were 49±9 years of age (mean±SD), 56% were women and 85% were white. Baseline body mass index (BMI) was 41±6 kg/m and baseline WC was 120±14 cm. At 6 months, BMI decreased by 6±3 kg/m and WC by 14±9 cm. Relative change in WC was defined as the 6-month or 2-year WC minus the baseline WC divided by the baseline WC. Systolic blood pressure decreased by 8 mm Hg for the tertile of participants with the largest relative decrease in WC and by 2 mm Hg for those with the smallest relative decrease in WC (p=0.025). Similar patterns of improvement were observed in total cholesterol (-29 vs -12 mg/dL, p=0.017), low-density lipoprotein-cholesterol (-19 vs -4 mg/dL, p=0.033), and glycated hemoglobin (-1.2 vs -0.3%, p=0.006). At 2 years, BMI decreased by 5±4 kg/m and WC by 11±11 cm and similar patterns of improvements were seen in components of the MetS. At both 6 months and 2 years, larger relative decreases in WC were associated with greater improvements in lipids and glycemia independent of sex.

CONCLUSIONS: In obese people, greater relative decreases in WC with medical weight loss are associated with greater improvements in components of the MetS independent of sex.