The Impact of School Nutrition Policy on Diet Quality of Children and Youth in Canada
Abstract
Improving diet quality is an important public policy initiative targeted to enhance population health worldwide. In this regard, school nutrition policy is an important means to promote healthy diet among children and youth. In Canada, six provinces implemented mandatory school nutrition policies at different times between 2005 and 2011. We investigated the impact of mandatory school nutrition policy on diet quality of Canadian children and youth using a quasi- experimental study design. Using 24-hour dietary recall data from the 2004 Canadian Community Health Survey (CCHS) Cycle 2.2 and 2015 CCHS-Nutrition, we constructed the Diet Quality Index (DQI). We used multivariable difference-in-differences regression models to quantify the effect of school nutrition policy on diet quality. We conducted stratified analyses by sex, school grade, and household income to gain additional insights into the effect of nutrition policy. We found that the effect of mandatory school nutrition policy on diet quality, measured by DQI, increased by 4.34 points (95% CI: 1.83 - 6.85) per child during school-hours in provinces with mandatory nutrition policy compared to control provinces. Although the confidence intervals overlap, the effect was higher among males (6.51 points, 95% CI: 2.93 - 10.09) compared to females (2.14 points, 95% CI: -1.25 - 5.52), and the effect among children in elementary schools was higher (4.82 points, 95% CI: 1.97 - 7.67) compared to those in high schools (3.37 points, 95% CI: -1.22 - 7.95). Our findings suggest that other jurisdictions may consider implementing mandatory school nutrition policy.