Legislative Indoor Smoking Bans: Preliminary Findings from a 10-Year Systematic Review Update

Tobacco use is the leading preventable cause of death worldwide, accounting for over 8.7 million deaths annually, including 1.3 million deaths among non-smokers exposed to secondhand smoke (SHS). It is responsible for over 200 million disability-adjusted life years and remains the leading cause of death among males globally. There is no safe level of SHS exposure which is associated with cardiovascular and respiratory disease, cancer, and increases in the risk of premature birth, low birth weight, and sudden infant death syndrome. Despite progress, global challenges remain in securing health and clean-air rights consistent with the Sustainable Development Goals. This review assesses the evidence reporting the effect of legislative bans prohibiting smoking in enclosed indoor spaces on morbidity and mortality outcomes. A systematic search was conducted of four databases [Central, Medline, Embase, PsycInfo] from 2015 to October 2024, following Cochrane methodology. N = 14,513 records were identified, and N = 9547 screened after removal of duplicates. N = 274 full-text papers were reviewed, and N = 64 studies [represented by 66 papers] were added to the 2016 review (77 studies). The evidence represents N = 141 studies. Most studies were conducted in six countries: USA (41), UK (22), Spain (11), Switzerland (11), Ireland (10), and China (7), accounting for 72.34% of included studies (102/141). No studies were excluded after risk-of-bias assessment [ROBINS V2]. New studies from Chile, Russia, Japan, Poland, Hungary, and Greece broaden the geographic scope of evidence. Reports on cardiac outcomes increased by 33.3% (66 studies), stroke by 53.8% (13 studies), and perinatal/postnatal outcomes by 66.6% (21 studies). Four studies reporting cancer outcomes were added. The evidence supports the benefits of smoke-free laws for health outcomes, aligning with Bradford Hill criteria, especially temporality, consistency, and coherence, and showing stronger effects with comprehensive bans.

Key messages

• Strengthening smoke-free legislation is a proven, evidence-based strategy to protect non-smokers and support progress towards the global Sustainable Development Goals.

• By implementing comprehensive indoor smoking policies, governments can achieve substantial public health outcomes.