Comparative Effectiveness of BMI and Weight/Length Ratio in Predicting Childhood Obesity Risk

Anthropometric references are crucial for recognizing children at risk for overweight and obesity, yet there is no agreement on whether body mass index (BMI) or weight/length ratio (W/L ratio) is the better predictor in early childhood. This study investigated these two measurements to assess more reliable predictor for forecasting future obesity.

The research involved a retrospective cohort of children aged 5 to 15 years, with anthropometric records at 0, 2, and 5 years, and at least one record at 6, 12, or 18 months. A correlation analysis was conducted between the BMI z-score (z-BMI) and the W/L ratio z-score (z-W/L), and logistic regression was used to evaluate the link between these scores and the incidence of overweight/obesity by ages 5/6.

The findings of the study revealed:

• The results showed a prevalence of 12% overweight and 13% obesity by ages 5/6.
• A strong correlation was found between z-BMI and z-W/L (r = 0.908 - 0.997).
• Linear analysis revealed that z-BMI was significantly related to higher obesity rates by age 5/6. 
• Logistic regression indicated that both z-BMI and z-W/L were significant predictors of overweight and obesity by ages 2 and 5/6, with z-BMI at birth being the only measure linked to obesity outcomes by age 5/6. 

Thus, the study concluded while both measures are effective predictors of overweight/obesity by 2 and 5/6 years of age, BMI appears to be a stronger predictor of future obesity risk in late childhood compared to the W/L ratio.

Source: Cardoso L, Couto D, Gonçalves P, Cabrita AL, Simões P, Ferreira D, Ferreira S. Weight-for-length ratio or body mass index - which one is the best predictor of future overweight and obesity?. Int. J. Pediatr. Neonatology 2024;6(2):11-18. DOI: 10.33545/26648350.2024.v6.i2a.75