Sample

the selection of individuals in the second phase. A total of 1,538 households were removed from the APS to avoid overlap with other surveys. Of the 61,041 individuals chosen for the APS, 13,238 were children (6 to 14 years old).

This study focused on only First Nations and Métis children aged 6 to 14 years. Inuit people were excluded because their unique BMI profiles and body fat distribution would need to be separately

accounted for in the analysis (Galloway et al., 2011; Hopping et al., 2010). Inuit people typically have shorter  legs  and  high  “trunk-to-stature  proportions”  which  render  the  European  BMI  thresholds  especially   inapplicable to this population (Galloway et al., 2011). Moreover, the study focus is on Aboriginal peoples living off reserve, and the majority of Inuit people live in northern Canada where the factors impacting food security and access are dramatically different (Hopping et al., 2010; PHAC, 2011). Also, southwestern Ontario has much larger Métis and First Nations populations as compared to Inuit, thereby making the focus group and quantitative results more comparable (Statistics Canada, 2009b).

3.2.2 Data Collection

APS data were collected by Statistics Canada via telephone interviews with PMKs of Aboriginal children aged 6 to 14 years. Children 12 to 14 years old could complete the telephone survey themselves with parental permission. Personal interviews were conducted with PMKs in Labrador, the Northwest Territories (excluding Yellowknife), and Inuit regions, or if participants were unable to do the telephone interview (Statistics Canada, 2009b).

3.2.3 Measurements

Data for a wide range of social, economic, and health-related variables were collected by the APS. The outcome of interest in this study was overweight or obese BMI classification, while the predictors of interest were food insecurity, F&V intake, and junk food intake. Several other variables

were analyzed in this study as potential confounders of either weight status or food insecurity. These variables are listed in Section 3.2.3.3.

3.2.3.1 Dependent Variable

The dependent variable, BMI category, was determined using PMK-reported height and weight. The  APS  asked,  “How  tall is _____ without shoes on? (Best estimate)”  and  “How  much  does  _____   weigh? (Best estimate),”  in  order  to  calculate  BMI.  The  APS  includes  two  measures  of  BMI:  the  Centers   for Disease Control and Prevention (CDC) cut-offs and the IOTF’s  age- and sex-specific cut-off points for obesity in children and adolescents. IOTF cut-offs are internationally recognized and based on BMI centile curve data from six countries, unlike the CDC cut-offs, which are based solely on American data (Cole et al., 2000). Hence this study used IOTF cut-offs,  which  classified  children  as  being  “underweight   or  normal,”  “overweight,”  or  “obese.”  In  the  statistical  analysis,  BMI  was  coded  as  either  a  dichotomous   variable (overweight/obese versus normal/underweight) or as having three response levels (obese, obese or overweight, obese or overweight or normal/underweight) depending on the statistical procedure. Statistical analyses are discussed in Section 3.2.4.

3.2.3.2 Independent Variables

The key independent variables of interest  were  children’s  food  security  status,  F&V intake, and junk food intake. The APS measures food insecurity at the individual level rather than the household level.  Food  insecurity  was  determined  by  asking  the  question:  “Has _____ ever experienced being hungry because  the  family  has  run  out  of  food  or  money  to  buy  food?”  The limitations associated with the food insecurity measure are discussed in Section 6.2.

Studies indicate that there is not a clear consensus on what is considered a fruit, vegetable, or junk food, as these definitions vary depending on food preparation and processing, cultural perceptions,

study,  fruits  refers  to  “the  seeds  and  surrounding  tissues  of  a  plant  […]  that  have  a  sweet  or  tart  taste,”  and   vegetables  are  the  “edible  plant  parts  including  stems  and  stalks,  tubers,  bulbs,  leaves,  flowers,  some   fruits  (cucumber,  pumpkin,  tomato),  and  seeds”  (Pennington  &  Fisher,  2009).  Junk  food  includes foods that are energy-dense and nutrient-poor (i.e., candy, soft drinks), as well as some F&V that are prepared in  ways  that  significantly  alter  the  food’s  nutrient  profile  and  energy  density  (i.e., potatoes to French fries) (Pennington & Fisher, 2009; Roark & Niederhauser, 2012; Thompson et al., 2011). Using these

definitions  as  a  guide,  responses  for  the  following  foods  in  the  APS  were  analyzed:  “Fruit  (not  fruit   juices),”  “Green  salad,”  “Potatoes,”  “Other  vegetables,”  “French  fries,  potato  chips  and  pretzels,”  and   “Candy,  soft  drinks,  cakes,  pies,  etc.”  Fruit,  green  salad,  potatoes,  and  other  vegetables  formed  the  F&V category. French fries, potato chips and pretzels, and candy, soft drinks, cakes, and pies were put in the junk food category. Studies have associated F&V and junk food consumption with obesity outcomes; hence these food groups formed the focus of the analysis.

In order to determine the frequency with which children consumed particular foods, PMKs were asked:  “Last  week,  on  how  many  days  did  ______  consume  the  following  foods  and  beverages?”  The   following response options were provided: Everyday, 5 or 6 days per week, 3 or 4 days per week, 1 or 2 days per week, and Never. These five response categories were also included in the statistical analyses to avoid losing information by creating arbitrary categories such as “high,” “medium,” and” low” intake. Overall diet quality could not be assessed given the limitations of the APS data, which are discussed further in Section 6.6.

3.2.3.3 Control Variables

Potential confounders of either food insecurity or obesity were identified based on a review of previous literature. Age, gender, region, lone parent status, number of people living in the household, household income, PMK education, birth weight, breastfeeding, sports activities or lessons attended per week, and number of hours per day spent watching TV, playing on the computer, or playing video games

were controlled for in the analysis. Census Metropolitan Area (CMA) is defined as an “area  consisting  of   one  or  more  neighbouring  municipalities  situated  around  a  core”  (Statistics  Canada,  2012).  The  CMA   must have a population of at least 100,000, and 50,000 or more of these residents living in the core (Statistics Canada, 2012). All APS response categories were for these variables were kept intact for the analysis, with the exception of physical activity and sedentary behaviour variables. A new variable called “sports”  was  created  to  represent  the  frequency  with  which  children  played  sports every week.The variables TV watching, computer time, and video gaming were combined to create the variable

“sedentary.”  Reading  was  not  included  as  a  sedentary  variable  for  several  reasons.  Shields & Tremblay (2008) found that reading was not associated with obesity for adults, partially because most people did not spend large amounts of time reading per week (Shields & Tremblay, 2008). While there are currently no child-specific studies on reading and sedentary behaviour as a predictor of obesity, other behaviours such as screen time are a greater concern since children spend much more time engaging these activities. Also, the way the reading question was structured in the APS would not have allowed it to be

incorporated into the sedentary behaviour variable. The frequency response options were categorized as times a child read per week or month, as opposed to number of hours per day. Table 1 shows all of the response and predictor variables used in the statistical analysis, as well as the respective reference categories used when entering these dummy variables into the regression models. The majority of the reference categories were chosen based on ease of interpretation, with the exception of the references for region, household income, and PMK education, were the highest frequency categories in the sample were chosen. Different reference categories were used for the diet variables for First Nations and Métis

Table 1: Response and Predictor Variables

Variable Response Categories

BMI category Binary Logistic Regression:

 Overweight/Obese  Underweight/Normal* Proportional Odds Model:

 Obese

 Obese or overweight*

 Obese or overweight or normal/underweight* Food insecurity

Fruit and vegetable intakea

 Food insecure  Not food insecure  Everyday*

 5 or 6 days per week  3 or 4 days per week  1 or 2 days per week  Never*

Junk food intakeb  Everyday*

 5 or 6 days per week  3 or 4 days per week  1 or 2 days per week  Never* Gender  Male*  Female Age  6 to 8 years*  9 to 11 years  12 to 14 years

Region  Census Metropolitan Area*

 Other urban  Other rural

 Arctic (deleted from analysis)

Lone parent status  Lone parent household

 Not lone parent household* Number of people living in the household  2 people*

 3 people  4 people  5 people  6 people

Table 1 continued.

Variable Response Categories

Household income PMK education  Less than $20,000  $20,000 to $39,999*  $40,000 to $59,999  $60,000 to $79,999  $80,000 to $99,999  $100,000 and over  Lower than high school  High school diploma*

 Certificate or diploma lower than university

 University  certificate  or  diploma  below  a  Bachelor’s  University  completed,  at  least  a  Bachelor’s

 Other

Birth weight  Less than 2267 grams*

 Between 2267 and 3174 grams  Between 3174 and 4081 grams  4081 grams and over

Breastfeeding  Never*

 6 months or less  7 to 12 months  More than 13 months

 Breastfed, but length unknown  Unknown

Sports  Never*

 Less than once a week  1 to 3 times per week  4 or more times per week Sedentary activity

(Video gaming, TV or computer time)  None*  1 hour per day  2 hours per day  3 hours per day  4 hours per day  5 hours per day

*The asterisk refers to the categories which were used as reference groups.

a _{The reference categories for fruit and vegetable intake were different for First Nations and Métis children. For}

First  Nations  children,  the  reference  category  was  “Never,”  and  for Métis  children  the  reference  was  “Everyday.”

b_{Similarly,  the  reference  categories  for  junk  food  intake  were  “Never”  and  “Everyday”  for  First  Nations  and  Métis}

3.2.3.4 Additional Variables of Interest

Frequency of experience with food insecurity as well as coping strategies were not used in the regression analyses, however the sample distribution was reviewed in order to better understand the severity  of  food  insecurity  in  the  populations  studied.  PMKs  who  answered  “Yes”  to  the  food  insecurity   question  were  further  asked,  “How  often?” with  the  following  response  options:  “More  often  than  the  end   of  each  month,”  “Regularly,  end  of  the  month,”  “Every  few  months,”  “Occasionally, not a regular

occurrence,”  “Don’t  know,”  and  “Refused.”  Additionally,  those  who  answered,  “Yes,”  to  their  children   experiencing  hunger  were  also  asked:  “How  do  you  cope  with  feeding  ______  when  this  happens?”   PMKs were provided a list of options and asked  to  check  all  that  applied:  “Parent/guardian  skips  meals  or   eats  less,”  “Children  skip  meals  or  eat  less,”  “Cut  down  on  variety  of  food  family  usually  eats,”  “Seek   help  from  relatives,”  “Seek  help  from  friends,”  “Seek  help  from  social  worker/government  office,”  “Seek   help  from  food  bank  (emergency  food  program),”  “Use  school  meal  program,”  “Other,”  “Don’t  know,”   and  “Refused.”