New Tool Bests BMI for Assessing Obesity-Linked Health in Kids

Troy Brown, RN

April 05, 2019

Using body mass index (BMI) alone to evaluate the severity of a child's obesity may underestimate the risk for related health concerns, including mental health problems, new data show.

Researchers conducted a cross-sectional study of data from the Canadian Pediatric Weight Management Registry (CANPWR), a prospective, multicenter cohort study of children who were overweight or obese and were undergoing clinical weight management.

"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," Katherine Morrison, principal investigator of the CANPWR study and professor in the Department of Pediatrics at McMaster University, Hamilton, Ontario, Canada, said in a university news release.

"If you are only using BMI to identify the youth who need the most care, you would be presuming the kids with the lowest BMI class would be the least likely to have mental health issues or metabolic issues, but our findings suggest this is not true. This study suggests that using a clinical staging system, one that evaluates the health of the child and not just the BMI, is likely the best approach," she said.

The researchers used the Edmonton Obesity Staging System for Pediatrics (EOSS-P), which assesses coexisting metabolic, mechanical, mental health, and social milieu problems, to evaluate 847 children and adolescents aged 5 to 17 years who were in World Health Organization obesity classes I to III.

The findings of the study, by Stasia Hadjiyannakis, MD, FRCPC, investigator at Children's Hospital Eastern Ontario Research Institute and assistant professor in the Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ontario, Canada, and colleagues, were published online April 2 in Lancet Child and Adolescent Health.

More than half of the participants (64%; 546 children and adolescents) had severe obesity (BMI class II or III), and 80% (678 children) were in EOSS-P stage 2/3. Stage 2/3 obesity-linked health problems were seen frequently; among 847 children, the most common problems involved mental health (520 children; 61%), followed by metabolic disturbances (349 children; 41%), social milieu problems (179 children; 21%), and mechanical health problems (86 children; 10%).

Mental health problems, such as anxiety and attention-deficit/hyperactivity disorder, were found to occur equally among BMI classes, whereas metabolic health problems were seen slightly more frequently among those in higher BMI classes. Mechanical problems, such as musculoskeletal problems and sleep apnea, and problems regarding social milieu, such as bullying and low household income, rose with increasing BMI class.

Three fourths of children (76%; 206 of 270)with class I obesity were of overall EOSS-P stage 2/3, as were 195 of 229 children (85%) with class III obesity.

"The main finding is that, although participants with the highest BMI category had the greatest mechanical and social milieu risk, the metabolic and mental health risks were more evenly distributed across BMI categories. Thus, use of BMI alone would have underestimated health risk disease burden in children with mild to moderate obesity and might have overestimated risk in those with severe obesity," Louise A. Baur, AM, BSc(Med), PhD, FRACP, Discipline of Child and Adolescent Health, University of Sydney, Clinical School, the Children's Hospital at Westmead, Australia, writes in an accompanying comment.

Although the importance of assessment of health risks and comorbidities is well recognized for patients with obesity, until now, clinicians have lacked a standardized clinical staging tool that would enable "comparisons within and between clinical centres," Baur explains. "The EOSS-P could indeed be this tool, although investigation of its prognostic value and usefulness in routine clinical practice is needed," she writes.

Additional work is needed to determine how to adjust treatment on the basis of this standardized clinical staging system. Baur recommends a step-up approach. "For example, bariatric surgery is appropriate for some adolescents with severe obesity and very low energy diets will be used in others, whereas family-based behavioural lifestyle intervention is the foundation treatment for all patients. Can the EOSS-P or a similar tool be used to facilitate more precise phenotyping of patients with obesity and hence more focused tailoring of treatment strategies?" Baur writes.

She applauds the researchers for their study design, which relied on the registry. "Only with such a coordinated approach were the study investigators able to gather a sufficient sample size for the research questions. Further findings from CANPWR and other similar national registries are anticipated to facilitate more effective management of children and adolescents with severe obesity," Baur concludes.

The CANPWR study is supported by the Canadian Institutes of Health Research and the MAC Obesity Research program, which is funded by McMaster Childrens Hospital and McMaster University. The research was supported in part by a grant from the CIHR Institute of Nutrition, Metabolism and Diabetes, the Public Health Agency of Canada, Alberta Health Services, Alberta Innovates–Health Solutions, the Canadian Obesity Network, the Ontario Ministry of Health and Long-Term Care, and the Women and Children's Health Research Institute of the University of Alberta. One author reports being a site investigator for a clinical trial sponsored by Eli Lilly. One author reports having received grants from Merck, Sanofi, and AstraZeneca and personal fees from DexCom. One author reports personal fees from Akcea Therapeutics Canada. The remaining authors and Baur have disclosed no relevant financial relationships.

Lancet Child Adol Health. Published online April 2, 2019. Abstract, Comment

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