Defining obesity in children should be based on health issues, not just BMI


Ottawa, Ontario — Tuesday April 2, 2019

Physicians are told to gauge the severity of a child’s obesity using the body mass index (BMI) that measures weight against height. But that doesn’t work well to identify health issues, especially those of mental and cardio-metabolic health, in children with obesity seeking care, according to a new paper published in The Lancet Child & Adolescent Health.

Dr. Stasia Hadjiyannakis, Medical Director of CHEO’s Centre for Healthy Active Living and Investigator with the CHEO Research Institute, is lead author on “Obesity class versus the Edmonton Obesity Staging System for Pediatrics (EOSS-P) to define health risk in childhood obesity: results from the CANPWR cross-sectional study.” The paper highlights that other medical issues, including high blood pressure, prediabetes and non-alcoholic fatty liver disease are also common, and are only slightly more frequent in those with the most severe obesity compared to those with less severe obesity.

The study was based on data collected in a large national study, called the Canadian Pediatric Weight Management Registry (CANPWR), which was led by Dr. Katherine Morrison through McMaster University with CHEO as a study site. It found two thirds of children entering weight management programs across Canada have severe obesity based on their BMI. The CANPWR study aims to identify what influences the success participants achieve in weight management programs and help improve these programs. The study followed participants for three years.

“Health exists across a wide range of body shapes and sizes,” says Dr. Hadjiyannakis. “And while BMI and weight are good markers of body size, they are imperfect markers of health, especially in the domains of metabolic and mental health.”

“We found that social and mechanical health issues were more common in those with the highest body mass index. However, mental health issues, for example, are consistent across the BMI groups,” said Katherine Morrison, principal investigator of the CANPWR study, and professor of the Department of Pediatrics at McMaster.

The 10 clinics taking part in the study are in Vancouver, Edmonton, Calgary, Toronto, Hamilton, Ottawa and Montreal.

The paper used information from 847 children with obesity and the health issues were determined at their initial visit to one of the multidisciplinary weight management clinics across Canada. Participants were aged five to 17 at the time of enrolment.

Clinical staging systems are commonly used in complex medical conditions such as cancer; cardiovascular disease and kidney disease. “In pediatric obesity a clinical staging system such as the EOSS-P provides a more comprehensive framework through which to identify the broad range of physical and psychosocial health issues that children with obesity face and may help better support clinical and administrative decisions regarding allocation of resources in pediatric obesity management, ensuring that those with the greatest health risk are adequately supported” says Hadjiyannakis.

The EOSS-P was adapted from the adult oriented tool (EOSS), which was predictive of mortality and morbidity, independent of BMI in adults living with obesity. This work was led by Dr. Arya Sharma (Scientific Director of Obesity Canada).

Obesity-related health issues were common among children participating in the study. Mental health concerns were the most common, followed by metabolic, social and mechanical health issues. The most common mental health issue identified was anxiety.

The most commonly identified metabolic health complication was dyslipidemia, followed by non-alcoholic fatty liver disease.

Bullying was the most commonly identified social health factor, followed very closely by low household income. More than one-third of children in the highest obesity group came from low income homes, which was significantly higher than those with lower levels of obesity.

Those with the most severe obesity by BMI were more likely to have experienced bullying, and more likely to report difficulties with peer relationships, compared to the less severe obesity groups.

The study is funded by the Canadian Institutes of Health Research (CIHR), McMaster University’s Faculty of Health Sciences, McMaster Children’s Hospital Foundation, and the Ontario Ministry of Health and Long-Term Care.

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