Family-Based Weight Management in the Pediatric Healthcare Setting

BMI is a poor predictor of adiposity in young overweight and obese children

BACKGROUND

The body mass index (BMI) is a simple and widely utilized screening tool for obesity in children and adults. The purpose of this investigation was to evaluate if BMI could predict total fat mass (TFM) and percent body fat (%FAT) in a sample of overweight and obese children.

METHODS

In this observational study, body composition was measured by dual energy x-ray absorptiometry (DXA) in 663 male and female overweight and obese children at baseline within a multidisciplinary, pediatric fitness clinic at an academic medical center. Univariate and multivariate regression analyses were conducted to evaluate whether BMI z-score (BMIz) predicts TFM or %FAT.

RESULTS

The BMIz, sex and age of subjects were identified as significant predictors for both TFM and %FAT. In subjects younger than 9 years, the BMIz was a weak to moderate predictor for both TFM (R² = 0.03 for males and 0.26 for females) and %FAT (R² = 0.22 for males and 0.38 for females). For subjects between 9 and 18 years, the BMIz was a strong predictor for TFM (R² between 0.57 and 0.73) while BMIz remained only moderately predictive for %FAT (R² between 0.22 and 0.42).

CONCLUSIONS

These findings advance the understanding of the utility and limitations of BMI in children and adolescents. In youth (9-18y), BMIz is a strong predictor for TFM, but a weaker predictor of relative body fat (%FAT). In children younger than 9y, BMIz is only a weak to moderate predictor for both TFM and %FAT. This study cautions the use of BMIz as a predictor of %FAT in children younger than 9 years.

Tertiary paediatric obesity services in Australia

AIM

To examine the nature and availability of paediatric obesity services in tertiary care settings across the states/territories of Australia.

METHODS

Surveys were sent to all clinicians identified as offering obesity services to children and adolescents. Respondents were asked to identify other service providers in their area, who were also asked to complete the survey.

RESULTS

Sixteen clinicians responded to the survey, from 20 requests. The clinicians who responded identified nine services in three of the eight states/territories of Australia. Existing services are limited to children and adolescents with severe obesity, with an average of 12 new referrals per service each month and an average waiting time of 5 months for an appointment. Most services involve a multidisciplinary approach, although the mix of staff varies considerably and emphasises nutrition rather than physical activity approaches.

CONCLUSIONS

Despite the public attention devoted to paediatric obesity, tertiary services in Australia are inadequate to meet the increasing incidence and prevalence of this complex condition. The development of tertiary services as part of service delivery arrangements for paediatric obesity and its associated morbidities must become a priority within the health system.