Smokers present with transient ischemic attacks (TIAs) much earlier in life than ex-smokers and nonsmokers - raising concerns that smoking may make even modest plaque vulnerable to injury and thrombus formation causing TIA at an earlier age, researchers said.

Smoking is a major modifiable stroke risk factor. However there is limited stroke literature comparing current smokers, ex-smokers and non-smokers. In this retrospective study, researchers compared the profile of ischemic strokes and transient ischemic attacks (TIAs) in current smokers, ex-smokers and nonsmokers.

Acute ischemic stroke was defined as a brain attack characterized by persistent neurological deficits with no evidence of hemorrhage on CT scan of the head. TIA was defined as a temporary neurologic dysfunction lasting less than 24 hours, secondary to reduced blood supply of the brain and CT scan of the brain showing no changes.

Researchers identified 1,047 acute ischemic stroke and TIA patients who presented to the Foothills Medical Center in Calgary from April 2002 to May 2007. All patients underwent CT of the head and a CT angiogram of the head and neck at presentation. The demographic, clinical and imaging details were obtained from chart review. Researchers divided the patients into three categories depending on their smoking habits: current smokers, ex-smokers (patients who had quit smoking for at least three months or longer) and nonsmokers.

Of the 1,047 patients, they found:

• 233 (22.3 percent) were current smokers
• 131 (12.5 percent) were ex-smokers
• 683 (65.2 percent) were nonsmokers

The average age of stroke presentation among smokers, ex-smokers and nonsmokers was 65.5, 68 and 67.6 years, respectively. The average age of TIA presentation among smokers, ex-smokers and nonsmokers was 56.7, 72.2 and 69.1 years, respectively.

The age at presentation of current smokers with TIAs was significantly lower than the other two groups suggesting a role of smoking induced thrombus formation in even modest plaques. This risk subsided with smoking cessation as evidenced by a later age at presentation of ex smokers. Although the age at presentation of ex smokers with TIA was higher compared to non-smokers, researchers said the difference was not statistically significant.

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