Shifts in BMI ‘common,’ associated with cardiometabolic risk in children
MedWire News: Changes in body mass index (BMI) category are common in middle-school children and are associated with clinically meaningful changes in cardiometabolic risk factors, report researchers.
These results indicate the need for obesity prevention programs that target children of this age, they say.
The findings arise from an analysis of the HEALTHY study, a multisite school-based intervention designed to mitigate risk for Type 2 diabetes. All students underwent health screenings at the start of the sixth and end of eighth grades (age 11-12 and 13-14 years, respectively).
For the present study, Marsha Marcus (University of Pittsburgh Medical Center, Pennsylvania, USA) and colleagues analyzed data on 3993 HEALTHY participants. They examined patterns of change in BMI categories among these children, and their impact on cardiometabolic risk factors.
At baseline, 49.8% of the students were overweight (85th-95th BMI percentile) or obese (95th-99th BMI percentile).
Shifts in BMI category over time were "common," remark the researchers. For example, 33.7% of youth who were overweight moved to the healthy (5th-85th BMI percentile) weight range, but 13.0% in the healthy weight range became overweight, they say.
These shifts were not associated with school intervention condition, household education, or youth gender, race/ethnicity, pubertal status, or changes in height, note Marcus et al. They were, however, associated with cardiometabolic risk.
Indeed, increases in BMI category (overweight to obese or healthy to overweight/obese) were associated with significant increases in insulin, systolic and diastolic blood pressure, triglycerides, and waist circumference compared with staying in the same or decreasing BMI category. They were also associated with decreases in high-density lipoprotein cholesterol, and small decreases in low-density lipoprotein and total cholesterol.
Conversely, decreases in BMI (overweight to healthy or obese to overweight/healthy) were associated with improvements in risk factors in comparison with staying the same or increasing BMI category.
Writing in Pediatrics, the team concludes: "There is compelling evidence for the relevance of universal obesity prevention efforts that target middle-school-aged children across all BMI categories to enhance downward shifts in BMI category for overweight and obese children and mitigate increases in BMI category among children in the healthy weight range."
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By Nikki Withers