Limitations

The response rate to the 2004 Canadian Community Health Survey (CCHS) was 76.5%. For various reasons (availability of the child; parents refusing to have their child measured; adolescents refusing to be measured; and operational problems), directly measured height and weight were obtained for only 65.5% of 2- to 17-year-olds.

Percentage distribution of respondents aged 2 to 17, by response and reasons for non-response to measured height and weight

Response rates to directly measured height and weight differed significantly by sex, age group and province. Measured data were slightly more likely to have been obtained for boys than for girls. The response rate was lowest for 2- to 5-year-olds (55%), and highest for adolescents (71%). At 56%, Ontario 's response rate was particularly low.

Response rates to directly measured height and weight

The response rate was not associated with fruit and vegetable consumption, leisure-time physical activity, screen time, household income, highest level of education in the household, the presence of a chronic condition, or self-perceived health.

Because it is difficult to measure physical activity, evidence of a relationship between energy expenditure and overweight and obesity among children and adolescents is lacking in many studies.²⁸ In the 2004 CCHS, parents of children aged 6 to 11 were asked about activities that increased the child’s heart rate and made him/her feel out of breath some of the time (see Definitions). The child was encouraged to participate in answering these questions. The degree to which parents and/or children can accurately recall and report such information is unknown and may affect associations with overweight and obesity. Adolescents were asked about their leisure-time physical activities over the past three months. Again, there may have been recall problems, and leisure-time may not reflect overall physical activity because school and work were excluded.

The questions about fruit and vegetable consumption asked the number of times fruit and vegetables were consumed per day, but not the amounts consumed. Because the questions did not specify portion size, compliance with daily intake recommendations, such as the Canada Food Guide, cannot be assessed.