Use of BMI as the marker of adiposity in a metabolic syndrome severity score: Derivation and validation in predicting long-term disease outcomes

• Published in: Metabolism, clinical and experimental clinical and experimental, 2018-06, Vol.83, p.68-74
• Main Authors: Gurka, Matthew J., Filipp, Stephanie L., Musani, Solomon K., Sims, Mario, DeBoer, Mark D.
• Format: Article
• Language: English
• Subjects: Adiposity - physiology; Adult; Biomarkers - analysis; Body Mass Index; Cardiovascular disease risk; Cardiovascular Diseases - diagnosis; Cardiovascular Diseases - etiology; Cardiovascular Diseases - metabolism; Disease Progression; Female; Humans; Male; Metabolic syndrome; Metabolic Syndrome - diagnosis; Metabolic Syndrome - etiology; Metabolic Syndrome - pathology; Middle Aged; Obesity; Obesity - complications; Obesity - diagnosis; Obesity - metabolism; Prognosis; Research Design; Risk Factors; Severity of Illness Index; Type 2 diabetes; Waist Circumference; Waist-Hip Ratio; Young Adult
• ISSN: 0026-0495; 1532-8600; 1532-8600
• DOI: 10.1016/j.metabol.2018.01.015

Estimates of adiposity in evaluating the metabolic syndrome (MetS) have traditionally utilized measures of waist circumference (WC), whereas body mass index (BMI) is more commonly used clinically. Our objective was to determine if a MetS severity Z-score employing BMI as its measure of adiposity (MetS-Z-BMI) would perform similarly to a WC-based score (MetS-Z-WC) in predicting future disease. To formulate the MetS-Z-BMI, we performed confirmatory factor analysis on a sex- and race/ethnicity-specific basis on MetS-related data for 6870 adult participants of the National Health and Nutrition Survey 1999–2010. We then validated this score and compared it to MetS-Z-WC in assessing correlations with future coronary heart disease (CHD) and Type 2 diabetes mellitus (T2DM) using Cox proportional hazard analysis of 13,094 participants of the Atherosclerosis Risk in Communities study and Jackson Heart Study. Loading factors, which represent the relative contribution of each component to the latent MetS factor, were lower for BMI than for WC in formulating the two respective scores (MetS-Z-BMI and MetS-Z-WC). Nevertheless, MetS-Z-BMI and MetS-Z-WC exhibited similar hazard ratios (HR) toward future disease. For each one standard-deviation-unit increase in MetS-Z-BMI, HR for CHD was 1.76 (95% confidence interval [CI]: 1.65, 1.88) and HR for T2DM was 3.39 (CI 3.16, 3.63) (both p