Physical activity and 3-year BMI change in overweight and obese children

Area of Science:

• Pediatrics
• Obesity Research
• Public Health

Background:

• Physical activity (PA) is crucial for obesity management, but its long-term impact on Body Mass Index (BMI) in children is not well understood.
• Overweight and obese children often receive primary care interventions focused on PA, yet their effectiveness on BMI requires further quantification.

Purpose of the Study:

• To investigate the predictive relationship between physical activity and BMI changes over three years in overweight/obese children.
• To quantify the BMI benefits of targeting physical activity in primary care settings for pediatric obesity.

Main Methods:

• A three-year follow-up study involving 182 overweight/obese children aged 5-10 years from general practices.
• Physical activity was measured using 7-day accelerometry (counts per minute, cpm).
• Linear and logistic regression analyses were used to assess changes in BMI z-score and BMI category.

Main Results:

• Baseline physical activity did not predict BMI changes. However, a sustained increase in moderate-to-vigorous physical activity (MVPA) over three years was associated with a reduction in BMI z-score.
• For every 100 cpm increase in activity change, BMI z-score decreased by 0.11 (P = .006).
• Increased MVPA predicted reduced BMI z-score, while sedentary or light activity did not.

Conclusions:

• Sustained increases in moderate-to-vigorous physical activity are linked to reduced BMI z-scores in overweight/obese children in primary care.
• The modest BMI changes observed, even with significant activity increases, may explain the limited success of brief primary care interventions focused on physical activity for pediatric obesity.