Definitions

The frequency of fruit and vegetable consumption was assessed with questions from the Behavioural Risk Factor Surveillance System in the United States.²⁶ Respondents were asked:

1) “How often do you usually drink fruit juices such as orange, grapefruit or tomato?” (for example, once a day, three times a week, twice a month)

2) “Not counting juice, how often do you usually eat fruit?”

3) “How often do you (usually) eat green salad?”

4) “How often do you usually eat potatoes, not including French fries, fried potatoes, or potato chips?”

5) “How often do you (usually) eat carrots?”

6) “Not counting carrots, potatoes or salad, how many servings of other vegetables do you usually eat?”

For 6- to 11-year-olds, physical activity level was measured by asking, “About how many hours a week do you usually take part in physical activity (that makes you out of breath or warmer than usual):

1) in your free time at school (for example, lunch)?”

2) in your class time at school?”

3) outside of school while participating in lessons or league or team sports?”

4) outside of school while participating in unorganized activities, either on your own or with friends?”

For each item, the response categories were “never,” “less than 1 hour per week,” “2 to 3 hours per week,” “4 to 6 hours a week” or “7 or more hours per week.” Total physical activity was derived by taking the mid-point of the response category (0, 0.5, 2.5, 5 or 7) for each of the four items and summing the resulting values.

For 12- to 17-year-olds, physical activity level was based on total energy expenditure (EE) during leisure time. EE was calculated from the reported frequency and duration of all of a respondent’s leisure-time physical activities in the three months before his or her 2004 CCHS interview and the metabolic energy demand (MET value) of each activity, which was independently established.²⁷

EE = Σ (Ni*Di *METi / 365 days), where
Ni = number of occasions of activity i in a year,
Di = average duration in hours of activity i, and
METi = a constant value for metabolic energy cost of activity i.

An EE of 3 or more kilocalories per kilogram per day (KKD) per day was defined as active; 1.5 to 2.9 KKD, moderately active; and less than 1.5 KKD, inactive.

Screen time is the amount of time spent watching television or videos, playing video games, or using a computer. Children aged 6 to 11 were asked:

• “On average, about how many hours a day do you watch TV or videos or play video games?”

• “On average, about how many hours a day do you spend on a computer, playing games, e-mailing, chatting, surfing the Internet, etc.?”

The response categories were: “I don’t watch TV or videos or play video games/I don’t use a computer,” “less than 1 hour a day,” “1 to 2 hours a day,” “3 to 4 hours a day,” “5 to 6 hours a day,” and “7 to more hours a day.” Total daily screen time was calculated by combining the time reported in the two questions, using the mid-point of the category (0, 0.5,1.5, 3.5, 5.5 or 7).

For 12- to 17-year-olds the following questions were asked: “In a typical week in the past three months, how much time did you usually spend:

• on a computer, including playing computer games and using the Internet or the World Wide Web?”

• playing video games, such as SEGA, Nintendo and Playstation?”

• watching television or videos?”

The response categories were: “none,” “less than an hour,” “1 to 2 hours,” “3 to 5 hours,” “6 to 10 hours,” “11 to 14 hours,” “15 to 20 hours,” and “more than 20 hours.” Total weekly viewing time was derived by taking the mid-point of each response category (0, 0.5, 1.5, 4, 8, 12.5, 17.5, or 20) and summing the resulting values across the three questions.

Household income was based on the number of people in the household and total household income from all sources in the 12 months before the interview.

Respondents were grouped into three education categories based on the highest level of attainment in the household: secondary graduation or less, some postsecondary, and postsecondary graduation.

Self-perceived health was assessed with the question, “In general would you say that your health is excellent, very good, good, fair or poor?” For this analysis, children were divided into two groups: those who reported very good and excellent health, and those who did not.

Ethnicity was based on the question: “People living in Canada come from many different cultural and racial backgrounds. Are you:

1. White?”
2. Chinese?”
3. South Asian (e.g., East Indian, Pakistani, Sri Lankan, etc.?)”
4. Black?”
5. Filipino?”
6. Latin American?”
7. Southeast Asian (e.g., Cambodian, Indonesian, Laotian, Vietnamese, etc.)?”
8. Arab?”
9. West Asian (e.g., Afghan, Iranian, etc.)?”
10. Japanese?”
11. Korean?”
12. Aboriginal Peoples of North America (North American Indian, Métis, Inuit/Eskimo)?”
13. Other – specify.

In this analysis, category 1 was used for the comparison with the White population in the United States. To compare ethnic groups within Canada, the following categories were used: White (1); Black (4); Southeast/East Asian (2, 5, 7, 10, 11); off-reserve Aboriginal (12); and Other (3, 6, 8, 9, 13). Multiple responses across the categories defined here were coded to “Other.”