Smoke-free policies in restaurants, bars, workplaces cut SBP on a population-wide scale
Smoke-free policies that ensure reductions in exposure to secondhand smoke may yield improvements in population-level cardiovascular health, with minimal effects on the individual-level health, according to a recent study.
“Smoke-free policies in bars, restaurants and workplaces were associated with significantly lower systolic blood pressure (SBP) at the end of follow-up, and with small within-person reductions in SBP, among a cohort of black and white US nonsmokers. Results underscore the potential benefit at a population level of smoke-free policies as a prevention measure for high SBP,” said researchers.
Linking census data with state-, county- and local-level data of 100-percent smoke-free policies, researchers longitudinally followed 2,606 nonsmokers. Over the 15-year study period SBP increased from 109.7 to 121.0 mm Hg, as did diastolic blood pressure (DBP; 72.5 to 75.2 mm Hg). The percentage of participants with hypertension also increased from 22.6 percent to 44.4 percent. [J Am Heart Assoc 2018;doi:10.1161/JAHA.118.009829]
Smoke-free policies likewise increased in prevalence. At baseline, 1.5 percent, 0.8 percent and 7.3 percent of participants lived in areas with restaurants, bars and workplaces that implemented smoke-free policies. By study end, these corresponding numbers grew to 88 percent, 75 percent and 73 percent.
At the final follow-up, participants who lived in areas with smoke-free restaurant policies showed reduced SBP values by an average of 1.14 mm Hg. The same was true for those who lived in areas with bar and workplace policies, with differences of 1.52 and 1.41 mm Hg, respectively. All comparisons were made against nonsmokers who lived in areas with no smoke-free policies.
These findings were further confirmed through mixed-effects linear regression modelling. For all three policy types, SBP showed a gentler slope in those who lived in areas with smoke-free policies, resulting in noticeable 5-year differences (restaurants: –0.32 mm Hg; p=0.3; bar: –0.53 mm Hg; p=0.08; workplace: –0.82 mm Hg; p=0.002).
Fixed-effects modelling further showed that after controlling for time and time-varying sociodemographic, clinical and geographic confounders, living in an area with smoke-free restaurant policies results in a mean drop in SBP of –0.85 mm Hg. This effect was slightly stronger for bar policies (–1.08 mm Hg) and slightly weaker for workplace policies (–0.60 mm Hg).
Patterns of effect of smoke-free policies on mean DBP and risk of hypertension were less clear.
“Smoke-free policies have been shown to reduce environmental tobacco smoke exposure among hospitality workers and the general population. Smoke-free policies have also been associated with reductions in hospital admissions for cardiovascular diseases (CVD), particularly for acute myocardial infarction,” said researchers. [Cochrane Database Syst Rev 2016;2:CD005992; BMC Public Health 2013;13:529; Swiss Med Wkly 2011;141:w13317; Am J Respir Crit Care Med 2007;175:840-845]
That smoke-free policies significantly affect SBP but not DBP does not diminish the associated health benefits, they continued. Recent reports have connected SBP with CVD more strongly than DBP, particularly in middle age. Even small improvements in SBP may thus be clinically valuable in reducing CVD risk.
The findings of the present study thus show that smoke-free policies in restaurants, bars and workplaces effectively cut SBP in nonsmokers possibly through limiting exposure to second hand smoke, researchers said. In turn, these effects may potentially be a mechanism of attenuating CVD risk.