Quitting could cut SAH risk for some smokers

By Eleanor McDermid, Senior medwireNews Reporter

Stopping smoking may help to attenuate people's risk for subarachnoid hemorrhage (SAH), say researchers.

Similar to many previous studies, Byung-Woo Yoon (Seoul National University Hospital, Republic of Korea) and co-workers found that smoking increases the risk for SAH, with the risk increasing the longer and more heavily people smoke.

But their case-control study involving 426 SAH patients and 426 age- and gender-matched controls also shows a marked risk reduction in smokers who quit.

"Vigorous efforts of government officials and health workers to promote smoking cessation should be performed to reduce the risk of SAH, a disastrous disease for patients and family members," the team writes in the Journal of Neurology, Neurosurgery, and Psychiatry.

Yoon et al found that 37.4% of the patients in their study were smokers, compared with 24.2% of controls, giving a 2.84-fold increased likelihood for SAH among smokers versus nonsmokers after accounting for confounders including family history of stroke, hypertension, cardiovascular diseases, body mass index, and alcohol consumption.

The effect was dose-dependent, with the adjusted odds ratio for SAH association with smoking rising from 2.09 for 1‑9 pack‑years to 5.69 for 30 or more pack‑years.

Overall, former smokers did not have increased odds for SAH relative to nonsmokers (nonsignificant 1.79-fold increase). On closer analysis, former smokers continued to have a 2.71-fold increase in the odds for SAH for the first 5 years after they quit, but after this time their likelihood for SAH fell to a level in line with that of nonsmokers.

However, the benefits of quitting were less clear for heavy smokers. Those who formerly smoked at least 20 cigarettes per day had a 2.34-fold increased odds for SAH, whereas the SAH risk in former smokers of 1‑19 cigarettes per day was equivalent to that of nonsmokers.

"Although the decreased risk of SAH in past smokers was time dependent, which may reflect reversible structural changes and physiological effects, our finding of the decreased effect in heavy smokers may be explained by long term irreversible effects of cigarette smoking on vessel walls," say Yoon and team.

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