The reliability of body mass index in the diagnosis of obesity and metabolic risk in children.

BACKGROUND

Body mass index (BMI) is the most widespread and the simplest method for the evaluation of body mass; it is often used as a sole technique in the diagnosis of obesity in children. The objective of the study was to evaluate the relationship between anthropometric and biochemical parameters and the incidence of the metabolic syndrome in obese children.

METHODOLOGY

A total of 110 children, aged 2-17 years, participated in the study. No overweight children (BMI 85-95 percentiles) were included. BMI was interpreted using the 2000 Centers for Disease Control and Prevention Growth Charts. The skinfold measurements were performed using an John Bull British Indicators Ltd. calipers, and interpreted using an the reference table values.

RESULTS

In addition to lower sensitivity (mentioned in several earlier studies), BMI also shows a lower specificity in the diagnosis of obesity in children: BMI showed at least 10% of non-concomitance with skinfold thickness and waist circumferences and 8% with waist-to-height ratio. In addition, subscapular skinfold thickness, waist circumference, and waist/height ratio showed stronger correlations with serum insulin levels, low-density lipoprotein cholesterol, and family history than BMI itself.

CONCLUSION

The unreliability of BMI as the sole parameter for diagnosing obesity in children was found in our study. Even when overweight children were excluded from the study, the lack of specificity of BMI was demonstrated. We propose utilization of waist circumference and waist/height ratio along with the BMI for definitive diagnosis instead of relying on BMI only. In addition, waist circumference and subscapular fold thickness may be even better in estimation of metabolic risk than BMI.