1. From 1999 to 2012, there was a significant linear trend of decreasing metabolic syndrome severity and of increasing Body Mass Index (BMI) z scores and HDL levels among U.S. adolescents.
2. Over the same time period, there was a significant decrease in overall calorie and carbohydrate consumption, and an increase in unsaturated fat and protein consumption.
Evidence Rating Level: 2 (Good)
Study Rundown: Among adults, metabolic syndrome is highly associated with the development of both cardiovascular disease and type 2 diabetes mellitus. Adolescence is a time in which the foundation for future health is often established, and it therefore bears significant effects on long-term health outcomes. As such, observing trends in metabolic syndrome (MetS) severity among adolescents has far-reaching clinical significance. This study observed trends in MetS as well as BMI z scores, HDL, triglycerides, and calorie consumption and distribution among adolescents over a 13-year period. Over this period, there was a significant decrease in MetS severity among adolescents and a significant increase in BMI z score. At the same time, there were significant increases in high density lipoprotein (HDL) and significant decreases in triglyceride levels. Overall calorie consumption was decreased, with fewer calories coming from carbohydrates and more from protein and unsaturated fat. There were significant associations between caloric consumption and distribution with declining MetS. While this study provides valuable insight into general trends among adolescents, it is limited by the self-reported nature of subjects’ meals and portion size.
Click to read the study, published today in Pediatrics
Relevant Reading: Metabolic syndrome in childhood predicts adult cardiovascular disease 25 years later: the Princeton Lipid Research Clinics Follow-up Study
In-Depth [retrospective cohort]: Participants included adolescents ages 12 to 19 years completing the Centers for Disease Control and Prevention (CDC) National Health and Nutritional Examination survey (NHANES) from 1999 through 2012. Of the 5117 subjects (51% male), 68% were non-Hispanic white, 18% were non-Hispanic black, and 22% were Hispanic. Clinical measurements characterizing MetS according to modified National Cholesterol Education Program Adult Treatment Panel (ATP-III) criteria were obtained, including BMI, fasting triglycerides and glucose, HDL, and blood pressure. MetS severity was calculated via the Pediatric MetS z Score. MetS prevalence was found to be 9.83% in this sample, with a Hispanic predominance (9.97% vs 9.04% non-Hispanic whites and 4.45% non-Hispanic blacks, P<.0001). Over the study period, results indicated decreasing MetS z scores (-0.02, 95% CI -0.03 to 0.00) and fasting triglycerides (-1.79 95% CI -.29 to -0.63), and increasing BMI z score (.02, 95% CI 0.00 to 0.04) and HDL levels (0.71 95% CI 0.48 to 0.94). There was no significant relationship between MetS severity and obesity or physical activity. A general trend of decreasing calorie consumption was also noted, although trends in fasting blood glucose and systolic BP were not significant. Percentage of total calories from protein increased from 13.2% to 14.7% (P<.0001), while calories from carbohydrates trended down (-0.444, P<.0001); in contrast, there was and an increasing trend of unsaturated fat consumption (0.222, P=.002).
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