title: Trends in Metabolic Syndrome Severity and Lifestyle Factors Among Adolescents.
abstract: OBJECTIVE
  Childhood metabolic syndrome (MetS) is a risk factor for adverse outcomes later in life. Our goal was to identify temporal trends among US adolescents in the severity of MetS, its individual components, and factors related to diet and physical activity.
  
  
  METHODS
  We analyzed 5117 participants aged 12 to 19 from NHANES. We used regression analysis of individual waves of data, 1999 to 2012. MetS severity was calculated using a gender- and race/ethnicity-specific MetS severity z score.
  
  
  RESULTS
  There was a linear trend of decreasing MetS severity in US adolescents from 1999 to 2012 (P = .030). This occurred despite a trend of increasing BMI z score (P = .005); instead, the decrease in MetS severity appeared to be due to trends in increasing high-density lipoprotein (HDL; P < .0001) and decreasing triglyceride (P = .0001) levels. In considering lifestyle factors, there was no change in physical activity over the time period. Regarding dietary patterns, total calorie consumption and carbohydrate consumption were positively associated with triglyceride levels and negatively associated with HDL levels, whereas unsaturated fat consumption exhibited the opposite associations. Consistent with these associations, there was a trend of decreasing total calorie consumption (P < .0001), decreasing carbohydrate consumption (P < .0001), and increasing unsaturated fat consumption (P = .002).
  
  
  CONCLUSIONS
  The healthier trend of declining MetS severity in adolescents appeared to be due to favorable increases in HDL and decreases in fasting triglyceride measurements. These were in turn associated with favorable changes in dietary patterns among US adolescents. Future studies should investigate the causality of dietary differences on changes in MetS severity in adolescents.
authors.affiliation: Department of Pediatrics, University of Virginia, Charlottesville, Virginia; and.
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Lee
authors.affiliation: Department of Health Outcomes and Policy, College of Medicine, University of Florida, Gainesville, Florida.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gurka
authors.affiliation: Department of Pediatrics, University of Virginia, Charlottesville, Virginia; and deboer@virginia.edu.
authors.forename: Mark D
authors.initials: MD
authors.lastname: DeBoer
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008019:Life Style; D008297:Male; D024821:Metabolic Syndrome / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D009043:Motor Activity / Q000502:physiology*; D009749:Nutrition Surveys; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult