NEW YORK (Reuters Health) – Environmental exposure to tobacco smoke – a known risk factor for myocardial infarction and other acute coronary syndromes (ACS) – can also worsen prognosis after ACS, according to a new study.

“These findings suggest that, by reducing exposure to secondhand smoke, smoke-free legislation may not only reduce the incidence of cardiovascular events, but may also improve prognosis in those who suffer them,” Professors Jill P. Pell and Sally Haw write in a featured editorial published with the study in the September issue of Heart.

Professor Pell, head of the Public Health and Health Policy Section at University of Glasgow, UK, is also the lead author of the study. She and her colleagues examined the impact of secondhand smoke exposure on survival after ACS in 1,261 never-smokers admitted to nine Scottish hospitals over a 23-month period.

A total of 132 (10.5%) of these never-smokers had a spouse or partner who smoked.

According to the investigators, 50 patients (4%) died within 30 days of the index ACS admission and another 35 (3%) required readmission for myocardial infarction, yielding a total of 85 adverse events (7%).

There was a significant trend in the frequency of all-cause deaths by cotinine band, the researchers report, from 10 deaths (2.1%) in never-smokers with serum cotinine levels no higher than 0.1 ng/mL, to 22 (7.5%) in those with cotinine levels greater than 0.9 ng/mL (p < 0.001). This trend persisted after adjustment for potential confounders, with the result that a cotinine level greater than 0.9 ng/mL was associated with an adjusted odds ratio for mortality of 4.80, they note. “The same dose-response was observed for cardiovascular deaths and death or myocardial infarction,” they report. “These results further strengthen the argument for protecting non-smokers from environmental tobacco smoke,” Professor Pell noted in an email to Reuters Health. “Tobacco control measures, such (as) the comprehensive smoke-free legislation recently implemented in the United Kingdom, need to be adopted worldwide,” she said. Reference:
Heart 2009;95:1377-1379,1415-1418.