Overweight and obesity prevalence in children based on 6- or 12-month IOTF cut-points: does interval size matter?
The International Obesity Taskforce (IOTF) recommends using age- and gender-specific body mass index (BMI) cut-points for defining the prevalence of overweight and obesity in children. These are given in both 6- and 12-month age intervals. Since the BMI-for-age curves are nonlinear, a degree of bias will be introduced when age intervals are wide. We aimed to quantify this bias in prevalence estimates in 2178 Australian children aged 4-12 years using 12- versus 6-month age intervals. Using the 12-month interval, the prevalence of overweight and obesity was underestimated by 1.4% compared to the 6-month interval estimates; however, this was age-dependent. It overestimated prevalence for 4-year olds, but underestimated it for older ages by up to 2.6%. Overweight prevalence was generally affected more than obesity prevalence. The use of different age intervals for IOTF cut-points introduces a small but systematic bias in prevalence estimates of overweight and obesity.
School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia. peter.kremer@deakin.edu.au
P J
PJ
Kremer
A C
AC
Bell
A M
AM
Sanigorski
B A
BA
Swinburn
D000367:Age Factors; D015982:Bias; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D015995:Prevalence; D012016:Reference Values; D012737:Sex Factors; D014739:Victoria / Q000453:epidemiology