Smoking Causes Worse Outcomes After Ischemic Stroke, Gene Study Finds

A genetic predisposition to smoking increases the risk of worse recovery from ischemic stroke, according to study results published online ahead of print in Neurology.

“Our results provide genetic support for the theory that smoking causes poor recovery after ischemic stroke,” study author Xinfeng Liu, PhD, Nanjing University in China. “These findings have important implications for stroke recovery. Not only should doctors encourage all people to not smoke, people who have had a stroke should be encouraged to quit smoking.”

The study investigated the association of genetically predicted smoking as well as alcohol consumption, and functional outcomes after ischemic stroke. To do so, researchers analyzed the results from a meta-analysis of 12 studies from the United States, Europe, and Australia that examined genetics and stroke recovery. The studies spanned 6021 people of European genetic ancestry, and recovery was measured 3 months after stroke. Among participants, 3741 had good recovery, meaning they had recovered completely or had slight disability but needed no assistance, and 2280 had poor recovery, meaning they had moderate disability and required help, had severe disability, or had died.

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A genetic predisposition to smoking initiation was associated with a 48% greater risk of worse stroke recovery after adjusting for age, sex, and stroke severity, Mendelian randomization revealed. Genetically predicted alcohol consumption, however, was not linked with functional outcome after stroke, according to the study.

“Stroke recovery can vary widely among people, from full recovery to serious disability or death,” said Dr Liu. “While previous studies have found links between smoking and worse stroke recovery, it has been unclear if smoking is a cause. By examining gene variants that increase a person’s risk of smoking, we found that smoking does cause worse stroke outcomes.”

Researchers advised the need for larger studies involving patients of other ethnicities, since this study was limited to patients of European ancestry.

References

Zhang Z, Wang M, Gill D, Liu X. Genetically predicted smoking and alcohol consumption and functional outcome after ischemic stroke. Neurology. Published online September 21, 2022. doi: 10.1212/WNL.0000000000201291

Is recovery from stroke worse if you have genes linked to increased risk of smoking? News release. American Academy of Neurology; September 16, 2022. Accessed September 26, 2022.