Secondary smoke is known to increase the risk of heart attacks. But new research shows that it can also worsen the outcomes of those who do suffer heart attacks.

Jill Pell, head of the Public Health and Health Policy Section at University of Glasgow, UK, and her colleagues looked at 1,261 people who did not smoke but were admitted to Scottish hospitals for heart attacks.

About 10 percent - 132 of these non-smokers had a spouse or partner who smoked, they report in the journal Heart.

According to the investigators, in the overall group, 50 patients (4%) died within 30 days of their heart attacks, and another 35 (3%) needed to be readmitted to the hospital for a heart attack.

The researchers used measurements of cotinine, a breakdown product of nicotine, to determine exposure to second-hand smoke. Even after taking a number of other possible risk factors into account, those who had particularly high levels of cotinine - indicating a lot of exposure to second-hand smoke - had almost five times the risk of dying during the study.

“These results further strengthen the argument for protecting non-smokers from environmental tobacco smoke,” 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.

SOURCE: Heart, September 2009.