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Tobacco Use and Secondhand Smoke Exposure: Smoke-Free Policies

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What the Task Force Found

About The Systematic Review

This Task Force finding is based on evidence from a systematic review of legislative smoke-free policies published in 2010 (Callinan et al., 50 studies, search period through-July 2009) combined with more recent evidence and evidence on additional outcomes (82 studies, search period January 2000-December 2011). The systematic review was conducted on behalf of the Task Force by a team of specialists in systematic review methods, and in research, practice and policy related to reducing tobacco use and secondhand smoke exposure. The finding updates and replaces two previous Task Force findings on smoke-free policies [PDF - 264 kB] and smoking bans and restrictions [PDF - 227 kB].

Context

As of October 2016, 27 U.S. states plus Washington, D.C., Puerto Rico, and the U.S. Virgin islands had enacted comprehensive 100% smoke-free indoor air laws covering government and private worksites, restaurants, and bars (CDC, 2016).

Summary of Results

Eighty-two studies were included in the review. Results showed that smoke-free policies were associated with decreases in: secondhand smoke exposure; tobacco use prevalence among young people and adults; and adverse health effects.

Updated Evidence (search period 2000-2011)

  • Exposure to Secondhand Smoke (search period 2009-2011)
    • Self-reported exposures (presence, frequency, or duration): median relative reduction of 50% (Interquartile interval [IQI]: -60% to -43%; 6 studies)
    • Secondhand smoke biomarkers in study participants: median relative reduction of 50% (IQI: -79% to -12%; 5 studies)
    • Indoor air pollution, as measured by vapor-phase nicotine or respirable suspended particle mass: median relative reduction of 88% (IQI: -95% to ‑81.2%; 11 studies)
  • Tobacco Use (search period 2009-2011)
    • Prevalence of tobacco use: median absolute reduction of 2.7 percentage points (IQI: -4.7 to -1.5 pct pts;11 studies)
      • Ten additional studies used different measures, eight of which reported favorable findings.
    • Cessation of tobacco use: median absolute increase of 3.8 percentage points (range: 2 to 17.4 percentage points; 4 studies)
      • Six additional studies that used different measures also reported increases in quitting activity.
    • Tobacco consumption (measured as changes in the amount of tobacco used per person): median absolute reduction of 1.2 cigarettes/day (range: -3.6 to 0 cigarettes/day; 5 studies)
      • Four additional studies that used different measures also found reductions in tobacco use.
  • Tobacco Use Among Young People (Adolescents and Young Adults) (search period 2000-2011)
    • The prevalence of tobacco use was lower among young people who were exposed to smoke-free policies: median odds ratio [OR] =0.85 (IQI: 0.68 to 0.93; 6 studies).
    • Eight additional studies used different measurements. In general, these studies found reductions in tobacco use.
  • Health Effects (search period 2000-2011)
    • Cardiovascular events: median relative reduction in hospital admissions of 5.1% (IQI: -11.6% to -2.2%; 9 studies)
      • Different measures were used in four additional studies reporting on hospital admissions for cardiovascular events. Two of these studies found reductions.
      • Three studies (two additional) reported on changes in cardiovascular mortality, two of which found reductions.
    • Asthma morbidity: median relative reduction in hospital admissions of 20.1% (range: -22.0% to -1.3%; 4 studies)
      • One additional study that used different measures of asthma related hospital admissions also found a reduction.
      • Two studies reported on self-reported asthma, one of which found a reduction.

Previous Review (Callinan et al., search period through July 2009)

Fifty studies were included in the review. Results showed that smoke-free policies were associated with decreases in exposure to secondhand smoke, tobacco use prevalence, and negative health effects.

  • Exposure to secondhand smoke
    • Self-reported exposures (presence, frequency, or duration): median relative reduction of 61% (IQI: -81% to -44%; 14 studies)
    • Secondhand smoke biomarkers in study participants: median relative reduction of 69% (IQI: -87% to -43%; 18 studies)
    • Indoor air pollution (as measured by vapor-phase nicotine or respirable suspended particle mass): median relative reduction of 88% (IQI: -97% to ‑26%; 8 studies)
  • Tobacco Use
    • Prevalence of active smoking: median absolute reduction of 3 percentage points (IQI: -5 to -0.8 percentage points; 10 studies)
      • One additional study that used different measurements reported favorable findings.
    • Smoking cessation: median absolute change of 0 percentage points (range: -2 to 4 percentage points; 3 studies)
      • Two additional studies provided different measurements and reported favorable findings.
    • Tobacco consumption (measured as changes in the amount of tobacco used: median absolute reduction of -2 cigarettes/day (IQI: -3 to -0.4 cigarettes/day; 8 studies)
  • Health Effects
    • Cardiovascular events: median relative reduction in hospital admissions of -13.5% (range: -26% to 1%; 5 studies)
      • Different measurements were used from five additional studies reporting on hospital admissions for cardiovascular events. All of these studies found reductions.
    • Asthma: two of three studies reported favorable findings in people with asthma

Summary of Economic Evidence

Eleven studies were included in the economic review, of which two assessed cost-effectiveness, one measured cost-benefit, and eight considered benefits only (costs-averted). All monetary values are reported in 2011 U.S. dollars.

  • Cost per quality-adjusted life year (QALY) gained: $1,138 (1 study)
  • Cost per life year saved (LYS): $8,803 (1 study)
  • Estimated net savings that would result from a U.S nationwide smoke-free policy ranged from $700 to $1,297 per person not currently covered by a smoke-free policy (1 study)
  • One year healthcare costs averted: median estimate of $409,000 per 100,000 persons (range of values: $148,000 to $1.6 million; 5 studies)
  • Annual healthcare costs averted over five or more years: median estimate of $1.1 million per 100,000 persons (range of values: $0.15 million to $4.8 million; 3 studies)
  • Annual smoking-related costs averted for multi-unit housing in the state of California, including averted cleaning, repair, maintenance, and other costs: $18 million (1 study)

The economic impact of smoke-free policies on hospitality establishments (restaurants, bars, hotels, tourist venues, gaming establishments) was also considered using evidence from a systematic review published in 2008 (Scollo & Lal, 158 studies, search period 1988 – January 2008) combined with more recent evidence (21 studies, search period January 2008 – July 2012).

  • Smoke-free policies did not have an adverse economic impact on the business activity of restaurants, bars, or establishments catering to tourists; some studies found a small positive effect of these policies.

Applicability

Smoke-free policies were shown to be effective in reducing exposure to secondhand smoke when implemented:

  • In the United States or other high-income countries
  • At national, state, and local levels
  • As comprehensive smoke-free policies (laws that prohibit smoking in all indoor areas of private workplaces, restaurants and bars, with no exceptions)
  • Alone, or in the setting of other interventions to reduce tobacco use and secondhand smoke exposure

Evidence Gaps

Each Community Preventive Services Task Force (Task Force) review identifies critical evidence gaps—areas where information is lacking. Evidence gaps can exist whether or not a recommendation is made. In cases when the Task Force finds insufficient evidence to determine whether an intervention strategy works, evidence gaps encourage researchers and program evaluators to conduct more effectiveness studies. When the Task Force recommends an intervention, evidence gaps highlight missing information that would help users determine if the intervention could meet their particular needs. For example, evidence may be needed to determine where the intervention will work, with which populations, how much it will cost to implement, whether it will provide adequate return on investment, or how users should structure or deliver the intervention to ensure effectiveness. Finally, evidence may be missing for outcomes different from those on which the Task Force recommendation is based.

Identified Evidence Gaps

  • More research is needed to examine the effectiveness of state and local smoke-free policies on tobacco use among young people.
  • Additional research should examine the effects of smoke-free polices on tobacco product substitution among tobacco users who do not quit (e.g., adding or switching to smokeless tobacco, including recently introduced forms such as snus and dissolvables).
  • Future policy evaluations should include assessments of dual or multiple product use among tobacco users.
  • Additional evaluations of smoke-free policies are needed to capture and quantify the broad range of health effects attributable to reductions in both secondhand smoke exposure and tobacco use in the population.
  • Additional implementation and evaluation research is needed for smoke-free policies in settings with unique issues and concerns (i.e. multi-unit housing, addiction and treatment facilities and outdoor settings such as parks and beaches).
  • Additional research is needed to identify effective strategies to encourage change in tobacco use behaviors in homes.
  • Future economic research should consider and report actual costs of implementing smoke-free policies (including efforts to disseminate information to the public and to conduct enforcement).
  • Additional economic evaluations should capture costs and economic outcomes from the tobacco user's perspective.
  • Research is needed to determine the benefits and costs of implementing smoke-free policies in new settings such as multi-unit housing

Study Characteristics

  • While most of the included studies evaluated smoke-free policies in the United States, studies also evaluated policies from Canada, England, Scotland, Wales, Australia, New Zealand, and several countries in Europe.
  • Studies evaluated policies implemented at national, state, and local levels.
  • Most studies evaluated tobacco use outcomes using large, population-based surveys with representative samples of working age adults or young people.
  • Included studies used different designs including cross-sectional comparisons between populations exposed and not exposed to smoke-free policies, before-after evaluations, interrupted time series, and other designs with longitudinal follow-up.

Publications

There are no publications for this systematic review.