Context: Although the health risks of obesity compared to normal weight have been well studied, the cumulative risk associated with chronic obesity remains unknown. Specifically, debate continues about the importance of recommending weight loss for those with metabolically healthy obesity.
Objective: We hypothesized that relatively greater severity and longer duration of obesity are associated with greater incident metabolic syndrome. Design, Setting, Participants, and Measures: Using repeated measures logistic regression with random effects, we investigated the association of time-varying obesity severity and duration with incident metabolic syndrome in 2,748 Multi-Ethnic Study of Atherosclerosis participants with obesity (body mass index ≥30 kg/m2) at any visit. Obesity duration was defined as the cumulative number of visits with measured obesity and obesity severity by the World Health Organization levels I-III based on body mass index. Metabolic syndrome was defined using Adult Treatment Panel III criteria modified to exclude waist circumference.
Results: Higher obesity severity (level II odds ratio [OR], 1.32 [95% confidence interval, 1.09-1.60]; level III OR, 1.63 [1.25-2.14] vs level I) and duration (by number of visits: two visits OR, 4.43 [3.54-5.53]; three visits OR, 5.29 [4.21-6.63]; four visits OR, 5.73 [4.52-7.27]; five visits OR, 6.15 [4.19-9.03] vs one visit duration of obesity) were both associated with a higher odds of incident metabolic syndrome.
Conclusion: Both duration and severity of obesity are positively associated with incident metabolic syndrome, suggesting that metabolically healthy obesity is a transient state in the pathway to cardiometabolic disease. Weight loss should be recommended to all individuals with obesity, including those who are currently defined as metabolically healthy.