medwireNews: Researchers report a dose–response relationship between body mass index (BMI) and cardiovascular risk even in severely obese adolescents, making its assessment important to limit further disease progression.

The 242 participants in the Teen Longitudinal Assessment of Bariatric Surgery study aged 13 to 19 years were all severely obese, with a median BMI of 50.5, and awaiting weight-loss surgery.

Cardiometabolic burden was high among the adolescents, with most found to have at least two cardiovascular disease (CVD) risk factors, but despite this we were “nonetheless able to detect a graded risk for elevated blood pressure and impaired fasting glucose] across categories of BMI in this cohort”, comment lead researcher Marc Michalsky (Nationwide Children’s Hospital, Columbus, Ohio, USA) and colleagues.

Elevated blood pressure (95th percentile or higher) was present in 49.0% of individuals, while 26.1% had impaired fasting glucose levels (≥100 mg/dL).

But the researchers found that, with every 5 kg/m2 increase in BMI, the risk of having high blood pressure and impaired fasting glucose levels increased significantly by 10% and 15%, respectively.

“To our knowledge, our study is the first to demonstrate a continued graded effect of extreme increases in BMI on blood pressure and impaired glucose metabolism, suggesting that reversal of severe obesity may be important in preventing future CVD in these patients”, the researchers comment in JAMA Pediatrics.

Half of the participants also had dyslipidaemia, but Michalsky and team say it is unsurprising that further grading with increasing BMI was not seen in these severely obese adolescents. High low-density lipoprotein cholesterol levels are more likely to be related to the genetic disorder familial hypercholesterolaemia, they explain, while the threshold for an elevated triglyceride to high-density lipoprotein cholesterol ratio is commonly reached at milder levels of obesity.

In addition to BMI, cardiovascular risk was also influenced by gender, with adolescent boys 60% more likely to have dyslipidaemia than adolescent girls and 48% more likely to have elevated blood pressure.

And White individuals (72% of the participants) were a significant 76% more likely to have elevated triglyceride levels (≥130 mg/dL) than non-White individuals, but 42% less likely to have impaired fasting glucose levels.

“In this first large-scale and uniform analysis, severely obese adolescents had a major burden of cardiometabolic risk factors”, say Michalsky and co-authors, adding: “The clinical assessment and medical care of severely obese adolescents should focus on the identification of these risks and control or prevention of progression of them in this vulnerable population.”

By Lucy Piper, Senior medwireNews Reporter

JAMA Pediatr 2015; Advance online publication

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