Several specific population interventions that achieved a Class I or IIa recommendation with grade A or B evidence were identified , providing a set of specific evidence -based strategies that deserve close attention and prioritization for wider implementation .
Effective interventions included specific approaches in all 6 domains evaluated for improving diet , increasing activity , and reducing tobacco use .
The writing group also identified several specific interventions in each of these domains for which current evidence was less robust , as well as other inconsistencies and evidence gaps , informing the need for further rigorous and interdisciplinary approaches to evaluate population programs and policies .
This systematic review identified and grade d the evidence for a range of population -based strategies to promote lifestyle change .
BACKGROUND Poor lifestyle behaviors , including suboptimal diet , physical inactivity , and tobacco use , are leading causes of preventable diseases globally .
Although even modest population shifts in risk substantially alter health outcomes , the optimal population -level approaches to improve lifestyle are not well established .
The impact of school smoking policies and student perceptions of enforcement on school smoking prevalence and location of smoking.
The purpose of this study was to comprehensively assess the impact of school  tobacco policy intention , implementation and students ' perceptions of policy enforcement on smoking rates and location of tobacco use during the school day . Data were obtained from all students in Grade s 10 - 11 ( n = 22,318 ) in 81 r and omly selected schools from five Canadian provinces . Policy intention was assessed by coding written school tobacco policies . School administrators most familiar with the tobacco policy completed a survey to assess policy implementation . Results revealed policy intention and implementation subscales did not significantly predict school smoking prevalence but result ed in moderate prediction of tobacco use on school property ( R(2 ) = 0.21 - 0.27 ) . Students ' perceptions of  policy enforcement significantly predicted school smoking prevalence ( R(2 ) = 0.36 ) and location of tobacco use ( R(2 ) = 0.23 - 0.63 ) . The research findings emphasize : ( i ) the need to consider both written policy intention and actual policy implementation and ( ii ) the existence of a policy is not effective in controlling tobacco use unless the policy is implemented and is perceived to be strongly enforced
Several specific population interventions that achieved a Class I or IIa recommendation with grade A or B evidence were identified , providing a set of specific evidence -based strategies that deserve close attention and prioritization for wider implementation .
Effective interventions included specific approaches in all 6 domains evaluated for improving diet , increasing activity , and reducing tobacco use .
The writing group also identified several specific interventions in each of these domains for which current evidence was less robust , as well as other inconsistencies and evidence gaps , informing the need for further rigorous and interdisciplinary approaches to evaluate population programs and policies .
This systematic review identified and grade d the evidence for a range of population -based strategies to promote lifestyle change .
BACKGROUND Poor lifestyle behaviors , including suboptimal diet , physical inactivity , and tobacco use , are leading causes of preventable diseases globally .
Although even modest population shifts in risk substantially alter health outcomes , the optimal population -level approaches to improve lifestyle are not well established .