Body mass index and Blount disease.

As the increasing prevalence of overweight and obese children is approaching epidemic proportions in North America, this study was designed to investigate whether Body Mass Index (BMI) and age- and gender-specific percentile Body Mass Index (BMI %) are associated with the likelihood of being listed for surgery for Blount disease after initial presentation to a tertiary referral centre. In a restrospective consecutive sample of 102 children with an average age of 5.9 +/- 4.3 years, it was determined that there was a significant association between BMI and BMI% and being listed for surgery, after adjusting for the effects of the child's age and gender, with mean odds ratios of 1.30 (95% confidence interval 1.02-1.60) and 1.05 (95% confidence interval 1.01-1.09) respectively. When the sample was subgrouped into infantile (less than 3 years of age) and late-onset (greater than 3 years of age), BMI and BMI% were still significantly associated with the children being listed for surgery in the late-onset group with mean odds ratios 2.75 (95% confidence interval 1.03-7.33) and 1.09 (95% confidence interval 1.01-1.18) respectively. However, of the two measures only the BMI was significant in the infantile group with an odds ratio of 1.27 (95% confidence interval 1.01-1.60). Should these associations be real then measures aimed at decreasing weight in children may have some effect on the number of children undergoing surgery for the treatment of Blount disease.