title: An examination of sex and racial/ethnic differences in the metabolic syndrome among adults: a confirmatory factor analysis and a resulting continuous severity score.
abstract: OBJECTIVE
  The metabolic syndrome (MetS) is typically diagnosed based on abnormalities in specific clustered clinical measures that are associated with increased risk for coronary heart disease (CHD) and Type 2 diabetes mellitus (T2DM). However, current MetS criteria result in racial/ethnic discrepancies. Our goals were to use confirmatory factor analysis (CFA) to delineate differential contributions to MetS by sub-group, and if contributions were discovered, develop sex and racial/ethnic-specific equations to calculate MetS severity.
  
  
  METHODS
  Using data on adults from the National Health and Nutrition Examination Survey 1999-2010, we performed a CFA of a single MetS factor that allowed differential loadings across groups, resulting in a sex and race/ethnicity-specific continuous MetS severity score.
  
  
  RESULTS
  Loadings to the single MetS factor differed by sub-group for each MetS component (p<0.001), with lower factor loadings among non-Hispanic-blacks for triglycerides and among Hispanics for waist circumference. Systolic blood pressure exhibited low factor loadings among all groups. MetS severity scores were correlated with biomarkers of future disease (high-sensitivity C-reactive-protein, uric acid, insulin resistance). Non-Hispanic-black-males with diabetics had a low prevalence of MetS but high MetS severity scores that were not significantly different from other racial/ethnic groups.
  
  
  CONCLUSIONS
  This analysis among adults uniquely demonstrated differences between sexes and racial/ethnic groups regarding contributions of traditional MetS components to an assumed single factor. The resulting equations provide a clinically-accessible and interpretable continuous measure of MetS for potential use in identifying adults at higher risk for MetS-related diseases and following changes within individuals over time. These equations hold potential to be a powerful new outcome for use in MetS-focused research and interventions.
authors.affiliation: Department of Biostatistics, School of Public Health, West Virginia University, Morgantown, West Virginia. Electronic address: mgurka@hsc.wvu.edu.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gurka
authors.affiliation: Department of Biostatistics, School of Public Health, West Virginia University, Morgantown, West Virginia.
authors.forename: Christa L
authors.initials: CL
authors.lastname: Lilly
authors.affiliation: Department of Family Medicine, School of Medicine, University of Virginia, Charlottesville, Virginia.
authors.forename: M Norman
authors.initials: MN
authors.lastname: Oliver
authors.affiliation: Department of Pediatrics, School of Medicine, University of Virginia, Charlottesville, Virginia.
authors.forename: Mark D
authors.initials: MD
authors.lastname: DeBoer
mesh_terms: D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D005163:Factor Analysis, Statistical; D005260:Female; D006630:Hispanic or Latino / Q000706:statistics & numerical data*; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology*; D008875:Middle Aged; D009749:Nutrition Surveys; D012720:Severity of Illness Index; D012737:Sex Factors; D014280:Triglycerides / Q000097:blood; D014481:United States / Q000453:epidemiology; D055105:Waist Circumference; D044465:White People / Q000706:statistics & numerical data*
chemical_list: D014280:Triglycerides
keywords: AIC; ATP-III; AUC; Adult Treatment Panel III; Akaike’s Information Criteria; Area under the curve; Bentler–Bonett Normed Fit Index; CDC; CFA; CHD; CHF; CVD; Cardiovascular disease; Centers for Disease Control; Clinical studies; Confirmatory Factor Analysis; Congestive heart failure; Coronary heart disease; Epidemiology; GFI; Goodness of Fit Index; HOMA-IR; High-sensitivity C-reactive protein; Hisp; Hispanic; Homeostasis model of insulin resistance; MI; MetS; Metabolic syndrome; Myocardial infarction; NFI; NHANES; NHB; NHW; National Health and Nutrition Examination Survey; Non-Hispanic Black; Non-Hispanic White; Obesity; RMSEA; ROC; Racial/ethnic differences; Receiver operating characteristic; Root Mean Square Error of Approximation; SBP; SRMR; Standardized Root Mean Square Residual; Systolic blood pressure; T2DM; Type 2 diabetes mellitus; WC; Waist circumference; hsCRP