Applying the new WHO child growth standards in Canada: What is our prevalence of obesity?

Dramatic increases in childhood obesity in Canada have been observed in recent years (Tremblay and Willms, 2000; Tremblay et al., 2002; Shields, 2006) but the prevalence of childhood obesity is not clear. Different cut-points (Tremblay and Willms, 2000; Tremblay et al., 2002) and different measurement methodologies (Shields, 2006) produce different results. The 95th percentile of recognized normative growth curves (e.g. U.S. Centers for Disease Control; Kuczmarski et al., 2002) or the International Obesity Task Force (IOTF) age-and sex-specific cut-points established by Cole et al. (2000) are typically used to determine the prevalence of obesity, but the two methods yield different results (Flegal et al., 2001). In contrast to the CDC curves, the IOTF curves predict a trajectory which is forced to intersect with established health-related cut-points (85th percentile to intercept a body mass index (BMI) of 25 and 95th percentile at 30 kg/m2) for adults at 18 years of age. The new Canadian clinical practice guidelines on themanagement andpreventionof obesity in children recommendusing the IOTF cut-points for establishing the prevalence of childhood obesity (Katzmarzyk et al., 2007).