Two new studies appear to offer vindication for health officials and others who advocate laws banning smoking in public places, including here in Minnesota.
In a meta-analysis published in the American Heart Association’s journal Circulation on Monday, researchers analyzed the findings of more than 45 studies that looked at the health effects of 33 smoking bans implemented in the United States and other countries, including Germany and New Zealand.
That analysis found that anti-smoking laws were associated with a 15 percent decline in hospitalizations for heart attacks, a 16 percent decline in hospitalizations for stroke and a 24 percent decline in hospitalizations for respiratory diseases.
Furthermore, the more comprehensive the anti-smoking law, the greater the impact.
That finding is certainly supported by a Mayo Clinic study, which was published Monday in the Archives of Internal Medicine. Using data from Minnesota’s Olmstead County (home to the Mayo Clinic), researchers found that a 2002 smoking ban involving only restaurants had no effect on the county’s heart-attack rate. But after implementation of the state’s 2007 Freedom to Breathe Act, which banned smoking in all workplaces, the incidence of both heart attacks and sudden cardiac death declined significantly.
Specifically, the study found that heart attacks fell by 33 percent (from 150.8 to 100.7 per 100,000 people) and sudden cardiac deaths by 17 percent (from 109.1 to 92.0 per 100,000 people) from the 18-month period before implementation of the 2002 partial smoking ban to the 18-month period after implementation of the 2007 broader ban.
The rates decreased even though the incidence of diabetes and high blood pressure, two risk factors for heart disease and heart attacks, increased during that same time.
Not as impressive
These results are not as impressive, however, as reported by the same Mayo researchers in an abstract presented last fall at an American Heart Association meeting (a presentation that received a lot of press coverage, including here in Second Opinion). At that time, the researchers said their analysis of the data showed a 45 percent drop in the incidence in heart attacks and a 50 percent drop in the incidence of sudden cardiac death when comparing the 18 months before the 2002 ban with the 18 months after the 2007 one.
Why were the final numbers so different? “The peer reviewers at the Archives asked us to do additional analyses to account for any influence of secular trends,” explained the study’s lead author, Dr. Richard Hurt, director of Mayo’s Nicotine Dependence Center, in an email to MinnPost on Tuesday. “We then had to use a little different criteria to get back to the 1990s. This changed the [heart attack] outcomes but added strength showing that the 2007 law bent the secular trend curve.”
Those secular trends, as discussed in the study, include such factors as a decline since the 1990s in Minnesota (and Olmstead County’s) overall smoking rate and a rise in the number of homes as well as workplaces that have become smoke-free.
The drop in sudden cardiac deaths was much less dramatic than reported a year ago, Hurt added, because during the reanalysis the researchers discovered that some cases did not meet the study’s criteria.
But still significant
The revised findings are still significant, however, even if the percentages of decline aren’t as large as originally thought. “Secondhand smoke exposure should be considered a modifiable risk factor for [heart attacks],” Hurt and his Mayo colleagues conclude in their study. “All people should avoid secondhand smoke to the extent possible and people with coronary heart disease should have no exposure to secondhand smoke.”
Indeed, the National Cancer Institute has estimated that 46,000 non-smoking Americans die each year from heart problems related to secondhand smoke.
Advocates for smoke-free workplaces hope these new studies will encourage other states and communities to implement smoke-free ordinances and laws.
“Coming at the five-year anniversary of the Freedom to Breathe Act in Minnesota, this study clearly demonstrates the health benefits of smoke-free indoor workplaces, college campuses and multi-unit housing,” wrote Robert Moffitt, communications director for the American Lung Association in Minnesota, in an email to MinnPost on Tuesday. “I hope it also sends a clear message to our neighbors in North Dakota, who have a chance to make their state smoke-free with a “yes” vote for Measure #4 on Election Day.”
Recent polling indicates that North Dakotans are likely to pass that initiative and ban smoking in public places across the state.