Anti-smoking laws reduced risks of hospitalization and death for smoking-related cardiovascular and lung diseases, with the most comprehensive laws having the biggest impact on hospitalizations and deaths, according to a meta-analysis.

Comprehensive smoke-free legislation was associated with a significant reduction in admissions or death for four disease groups: acute coronary events, cerebrovascular events, respiratory disease, and other heart disease, within a median 24 months of enacting the laws, according to Stanton Glantz, PhD, and Crystal Tan, MS, both of the University of California San Francisco.

The more comprehensive a law was, the more likely areas serviced by it would see reductions in hospital admissions by individual outcomes (P=0.001) and by disease group (P=0.002), they wrote online Oct 29 in the journal Circulation: Journal of the American Heart Association.

Researchers also found no difference between men and women in the reduction of acute MI following enactment of smoke-free laws of variable comprehensiveness.

The researchers analyzed 43 studies evaluating hospitalizations or deaths for smoking-related illness in areas with or without anti-smoking laws, or comparing rates before and after a law was introduced. The studies covered 33 smoke-free laws.

Smoking-related illnesses included acute myocardial infarction, acute coronary syndrome, acute coronary events, ischemic heart disease, angina, coronary heart disease, sudden cardiac death, stroke, transient ischemic attack, chronic obstructive pulmonary disease, asthma, lung infections, and spontaneous pneumothorax.

Glantz and Tan also measured whether comprehensiveness of a law was associated with stronger reductions in risk through a random effects meta-regression analysis. Comprehensiveness of a law was established by whether it affected workplaces only; workplaces and restaurants; or workplaces, restaurants, and bars.

For the four disease groups, the relative risk reductions for hospital admission or death associated with comprehensive anti-smoking laws were:

  RR 0.84 (95% CI 0.81 to 0.88) for acute coronary events
  RR 0.84 (95% CI 0.75 to 0.93) for cerebrovascular accidents
  RR 0.76 (95% CI 0.68 to 0.84) for respiratory diseases
  RR 0.61 (95% CI 0.44 to 0.84) for other heart disease

Researchers found that anti-smoking laws resulted in risk reductions specifically for acute MI, acute coronary syndrome, ischemic heart disease, angina, coronary heart disease, sudden cardiac death, stroke, asthma, and lung infection.

The laws did not significantly reduce hospitalizations or death for transient ischemic attack, chronic obstructive pulmonary disease, or spontaneous pneumothorax, they wrote.

Time did not significantly improve outcomes in acute MI and other diseases for which researchers had the data, though the more comprehensive a law was, the greater the effects were on reducing hospitalizations for smoking-related disease.

“This study provides strong evidence not only of the health benefits of smoke-free laws but also of the need to enact comprehensive laws without exceptions,” Glantz and Tan concluded.

The authors noted that the benefits of smoke-free laws affect both smokers and those who breathe secondhand smoke.

“Smoke-free legislation per se does not produce the effects that we observed, which are due to the associated reductions in secondhand smoke exposure and increases in smoking cessation that accompany these laws,” they wrote, adding that as more areas adopt anti-smoking laws, “the marginal effects of subsequent laws will be smaller.”

The researchers noted their study was limited by lack of causation, lack of continuous effect of comprehensiveness as an ordinal, lack of consideration of multiple testing, potential misclassification between different outcomes, and possible publication biases.

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Primary source: Circulation
Source reference: Glantz SA, and Tan CE “Association between smokefree legislation and hospitalizations for cardiac, cerebrovascular, and respiratory diseases: A meta-analysis” Circulation 2012; DOI: 10.1161/CIRCULATIONAHA.112.121301.

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By Cole Petrochko, Staff Writer, MedPage Today
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner