Am Fam Physician. 2007;75(7):1057-1058
Background: Secondhand smoke has been implicated in the development of cardiovascular disease and lung cancer. In addition, it has been found to impair glucose tolerance, interfere with fetal lung development, and exacerbate preexisting respiratory conditions. These risks have led to the proscription of smoking in public places, notably bars. The authors of this prospective study examined the impact of a smoking ban on the health of bar workers.
The Study: Participants were nonsmoking bar staff with no respiratory health problems other than allergic rhinitis or asthma. The baseline assessment took place one month before the smoking ban was implemented. Participants provided information on hours worked that week, estimated secondary smoke exposure at work and elsewhere during the same period, and, using an established questionnaire, respiratory and sensory symptoms. In addition, spirometry was used to determine forced expiratory volume in one second (FEV1). A subgroup of partici pants with asthma also took a methacholine (Provocholine) challenge test and completed an asthma questionnaire. Follow-up evaluations were performed one and two months after the ban's implementation.
Results: Seventy-seven of the eligible participants completed the study. Twelve had mild to moderate asthma and composed the asthma subgroup. Serum cotinine levels decreased from 5.15 ng per mL (29.23 nmol per L) before the ban to 3.22 (18.27 nmol per L) at one month and 2.93 (16.63 nmol per L) at two months after the ban. The percentage of participants experiencing respiratory or sensory symptoms decreased from 79.2 before the ban to 53.2 and 46.8 at months 1 and 2 after the ban, respectively, and the median number of symptoms decreased from two to one to zero. Questionnaire scores among the asthma subgroup improved significantly. FEV1 improved 15.7 percent in those with asthma and 5.7 percent in the other participants. Methacholine challenge test values did not change.
Conclusion: The authors conclude that, although the participants had been bar workers for an average of nine years, health improvements were apparent just one month after a smoking ban, as measured by objective and subjective symptoms. The most marked improvements occurred in participants with asthma. An accompanying editorial notes that mandating smoke-free workplaces also results in higher rates of smoking cessation. However, there still is a high rate of exposure to secondhand smoke, especially among children and non-Hispanic blacks.