Less Asthma, Stroke, MI Seen in Wake of Smoke-Free Laws

Nancy A. Melville

November 21, 2011

November 21, 2011 (Washington, DC) — Regions with laws that prohibit smoking have shown significant reductions in the incidence and cost of conditions such as asthma, stroke, and heart attack since the laws took effect, according to 2 studies. The results were presented here at the American Public Health Association 139th Annual Meeting.

In one study, researchers evaluated hospital discharge data from Delaware on patients admitted with myocardial infarction or asthma exacerbations from 1999 to 2004, comparing the incidence of each of the conditions before and after the Delaware Clean Indoor Act went into full effect (1999 to 2002 vs 2003 and 2004).

For Delaware residents, quarterly rates of acute myocardial infarctions (AMI) were 451 before and 430 after the ordinance — a 4.7% reduction.

For non-Delaware residents, the AMI incidence rates during the same time period showed only a negligible change.

The risk ratio for asthma in Delaware after the ordinance went into effect was 0.95 (95% confidence interval [CI], 0.90 to 0.999), which represents a significant reduction (P = 0.046). In same time period, Non-Delaware residents had an increased risk ratio for asthma of 1.62 (95% CI, 1.46 to 1.86; P < .0001).

According to lead author John Moraros, MD, PhD, from the School of Public Health at the University of Saskatchewan in Saskatoon, studies have also shown significant decreases in the incidence of AMI after the implementation of smoke-free ordinances in 4 other locations — Pueblo, Colorado; Helena, Montana; the Piedmont region of Italy; and Toronto, Ontario, Canada. Toronto showed reductions in asthma, stroke, pneumonia, and chronic obstructive pulmonary disease.

"Interestingly, all 4 studies also reported a significant improvement in cardiovascular health benefits," he said.

"In addition, studies that include asthma have shown a 22% decrease in asthma emergency department visits postlaw. These studies support our findings and confirm the longstanding assumption that comprehensive smoking ordinances represent a practical and effective tool in the fight to reduce the healthcare burden due to cardiovascular diseases."

After adjustment for the population, the reduction in the incidence of AMI in Delaware was 9%, Dr. Moraros added, which is significantly lower than the 11% seen in Piedmont, the 27% in Pueblo, the 47% in Helena, and the 17% in Toronto. However, Delaware's rates might have already been on the decline because of a partial smoking ban instituted in 1994, he said.

"By 2002, when the nonsmoking ordinance became comprehensive, the health benefits for the state would have been only modestly augmented," Dr. Moraros observed.

"Nonetheless, our study...found statistically significant decreases in both the AMI and asthma discharge rates after the statewide nonsmoking ordinance was amended from a partial to a comprehensive ban."

A second study on the effects of smoking bans presented here found significant reductions (P < .05) in the cost of healthcare use in people with asthma and stroke who lived in counties with smoke-free laws (odds ratio [OR], 0.71; 95% CI, 0.51 to 1.00), compared with those in counties without such laws (OR, 0.72; 95% CI, 0.53 to 0.93) from 1998 to 2003.

In the study, conducted at the Centers for Disease Control and Prevention in Atlanta, Georgia, the researchers evaluated data on smoke-free air laws obtained from the State Tobacco Activities Tracking and Evaluation System, Americans for Nonsmokers' Rights Foundation, and the ImpacTeen Smokeless States database. Healthcare costs were evaluated using MarketScan.

The cost reduction estimates showed that, based on smoke-free air laws in place in 1998, the average cost reductions per county for asthma and stroke were approximately $2.5 million and $1.8 million, respectively.

Respondents living in regions with a qualified smoke-free air ban were less likely to have seen a healthcare provider than those living in regions with no ban, the authors explain. They recommend that "state and local governments should develop smoke-free air laws to protect the public's health."

Dr. Moraros noted that the cost reductions related to smoking bans are also applicable to Delaware.

"It is estimated that as a direct consequence of the enactment of the Delaware Clean Indoor Air ordinance, there have been approximately 340 fewer AMI discharges and 27 lives [saved] among Delaware residents during the 2003 to 2004 postordinance period," he said.

The average hospital charge for an AMI hospital admission in 2002 was $36,700, meaning that in 2003 and 2004, the state of Delaware saved $12,478,000, Dr. Moraros reported.

Although second-hand smoke has been linked to exacerbations in all of the conditions that showed improvement in these studies, whether the improvements are attributed to reduced exposure to smoke in the environment or to reductions in the number of people who actually smoke remains unclear, Dr. Moraros said.

"It has been well established in the literature that comprehensive smoking bans like the one established in Delaware lead to rapid declines in smoking rates," he said.

"In 2007, a similar ban in Scotland and Wales led to astonishing results, with a record number of smokers not only reducing but outright quitting the habit, regardless of socioeconomic standing."

"This has a natural trickledown effect to second-hand smoke exposure as well. It is precisely evidence along these lines regarding the hazards of smoking and exposure to second-hand smoke that led many communities in the Western world to institute comprehensive nonsmoking ordinances."

The authors have disclosed no relevant financial relationships.

American Public Health Association (APHA) 139th Annual Meeting: Abstracts 236311 and 236645. Presented November 1, 2011.

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