Analysis Of The Compass Study On Weight Perception
The COMPASS is a nine-year study which started in 2012-2013, whose aim is to examine how young individuals’ weight perception influences physical activity (PA) and dietary behaviours. Hierarchical longitudinal data were collected from student and school guidelines questionnaires, observational data of school’s facilities, and individualized school health profiles of secondary school students in Ontario and Alberta, Canada. Endpoints are used to measure the outcomes of a study. Thus, the exposure and endpoint of the study was weight perception within students, and the outcomes were PA and dietary behaviours. Linked data from secondary students’ year 2 (Y2:2013-2014) and year 3 (Y3:2014-2015) were used in the study. Purposeful sampling is non-randomly selecting individuals based on a similar set of characteristics at interest. Whereas randomized sampling selects individuals at random; with everyone having an equal chance of being selected.
The study’s subjects were young secondary students, thus specific subjects prohibited the use of randomized sampling. Various features such as enrollment in PE class, league teams, intramurals, amount of PA performed, and dietary intake were purposefully selected for the study. Enrollment of subjects depended whether school boards allowed active-information passive-consent parental permission protocols, allowing students to drop the study at any time.
Data collection occurred through student-level questionnaires regarding behavioural domains, correlates, and sociodemographic characteristics. Weight perceptions included “very underweight, ” “slightly underweight, ” “about right, ” “slightly overweight, ” and “very overweight”. The statistical package SAS 9. 4 analyzed the collected data; using gender and BMI for descriptive statistics and generalized estimating equations identified any association between Y3 weight perception and outcomes while adjusting for Y2 outcomes and Y3 covariates.
Covariates are independent variables with a direct interest to the study and are advantageous to include in the analysis to increase its accuracy. Grade, race/ethnicity, weekly spending money, school area, and household income were covariates in the study. The proportion of girls with normal weights but self-perceived as underweight was 10. 6% and 30. 8% for boys. While the proportion of girls with normal weights but self-perceiving as overweight was 20. 1% and 6. 2% for boys. Boys self-perceiving as underweight were less likely to meet the recommended healthy exercise guidelines, and to engage in vigorous PA and PE classes. Whereas girls self-perceiving as underweight barely met resistance training recommendations nor participated in intramurals. Both boys and girls were likely to buy snacks from vending machines or stores. Similarly, students self-perceiving as overweight were unlikely to engage in vigorous PA and PE classes and to meet resistance training recommendations. Yet, students perceiving their body weight as underweight or overweight skipped breakfast regularly; due to the fear of gaining extra weight. Using large sample sizes, various outcome measures from years 2 and 3, and linked data strengthened the study. However, limitations exist due to results not being representative, questionnaires were subjected to recall bias, inaccurate weight-height data provided, removal of weight perceptions which lowered the study’s variability, and students comparing weight to ideal bodies.
Ultimately, the results illustrated favourable outcomes in health behaviours with weight perceptions of about right, whereas overweight and underweight perceptions were less favourable with physical activity and healthy nutrition. I perceive my weight as “about right” and regardless of BMI, a healthy nutrition and physically active lifestyle are performed to be healthy in general.
