Two-year follow-up of a randomised controlled trial to assess the sustainability of a school intervention to improve the implementation of a school-based nutrition policy

Issue addressed: School-based nutrition policies can have a positive effect on the school food environment. The primary aim of this study was to assess the primary school adherence to a mandatory state-wide healthy canteen policy 12 months after an effective multi-strategic implementation intervention concluded. Methods: Primary schools were randomised to (a) a 12-14 months multi-strategic intervention or (b) no-intervention (control). The intervention aimed to improve implementation of a state-wide canteen policy by encouraging schools to remove unhealthy food and beverages (classified as "red" or "banned") from canteen menus and replace with healthy items (classified as "green"). No implementation support was provided to either group by the research team between the 12 and 24 months data collection period. Results: Seventy schools participated, of which 56 schools were assessed at 24-month follow-up. Intervention schools were less likely to have a menu which contained "red/banned" items at 24-month follow-up (RR = 2.28; 95% CI: 1.18-4.40; P = 0.01). Intervention schools, however, were not more likely than controls to have a menu which contained >50% "green" items at 24-month follow-up (RR = 1.29; 95% CI: 0.98-1.70; P = 0.10). Intervention schools were more likely to adhere to both policy components (no red/banned items and >50% green items on the menu) than control schools (RR = 2.61; 95% CI: 1.29-5.29; P = 0.006). Among intervention schools that were fully adherent to the policy following implementation support (12-month post baseline), all were also adherent at the 24-month follow-up. Conclusion: The intervention was effective in achieving long-term school adherence to a state-wide canteen policy at 24-month follow-up. So what?: The findings suggest that sustained improvements in implementation of school nutrition policies is possible following a period (12 months) of comprehensive implementation support.