Smoke-Free Policies Associated with Lower Blood Pressure Among Nonsmokers

By Jane Farrell

Smoke-free policies have now been linked to lower blood pressure readings among non-smokers.

It’s already known that these policies, which prohibit smoking in public places like bars and restaurants, are linked with fewer hospitalizations for heart disease among non-smokers. But this is the first study to associate the policies with lower systolic (top number) blood pressure readings among non-smokers.

The findings appeared in the Journal of the American Heart Association.

In reaching their conclusion, the researchers linked data from the Coronary Artery Risk Development in Young Adults (CARDIA, 1995-2011) study to state, county and local smoke-free policies in restaurants, bars and workplaces.

“We found that nonsmoking adults in the study who lived in areas with smoke-free laws in restaurants, bars or workplaces had lower systolic blood pressure by the end of the follow-up period compared to those who lived in areas without smoke-free laws,” said Stephanie Mayne, Ph.D., study lead author and research scientist at PolicyLab and the Center for Pediatric Clinical Effectiveness at Children’s Hospital of Philadelphia.

“Systolic blood pressure was lower on average when they lived in an area with smoke-free laws.”

“Smoke-free laws were associated with reduced systolic blood pressure, but surprisingly not with reductions in diastolic [lower number] blood pressure or high blood pressure. It’s not entirely certain why this was the case,” Mayne said.

Nonetheless, higher systolic blood pressure increases the risk of cardiovascular disease even when it is below the hypertension threshold, so the reductions in systolic blood pressure can be beneficial.

Mayne said that when researchers “looked at differences in blood pressure over time within individuals, comparing years when they lived in an area with a smoke-free law to years when they didn’t, systolic blood pressure was lower on average when they lived in an area with smoke-free laws, after accounting for overall trends in blood pressure and for how people’s levels of risk factors like diet and physical activity changed over the study period.”

The CARDIA study enrolled 5,115 black and white adults (age 18 to 30) in 1985-86 from four U.S. cities: Birmingham, Alabama; Chicago; Minneapolis; and Oakland, California.

Follow-up exams were conducted up to 30 years later. Researchers analyzed data drawn from years 10-25 (1995-2011) to align with the timing of smoke-free policies and excluded participants who didn’t have at least two blood pressure readings during that period.

A total of 2,606 CARDIA participants were used for this study. At each exam, participants living in areas with smoke-free policies affecting public places had lower systolic blood pressure on average than those in areas without smoke-free policies, and the difference increased over time. By year 25, participants in smoke-free areas had systolic blood pressure values on average 1.14 mm Hg to 1.52 mm Hg lower than those in areas without smoke-free environments, depending on the places covered by the law (restaurants, bars, or workplaces).