Study of Chinese Finds Smoking Strongly Related to Stroke

(This report was updated on April 17, 2008.)

The first large-scale study of its kind in China has found that cigarette smoking significantly and independently increases the risk of stroke in Chinese adults.

The study's public health messages - to provide smoking prevention and quitting programs, and to stop smoking - could apply to Chinese immigrants in the USA as well as other populations.

"[T]he message is the same to individuals living in China and for Chinese in the USA," said Tanika N. Kelly, the study's lead author, in an e-mail to EthnicNewz.org. "I think there is a growing body of evidence showing a relationship between smoking and certain cancers, other cardiovascular diseases, and [deaths] in populations all over the world."

China, whose population is 1.3 billion, is the world's largest producer and consumer of tobacco, according to the World Health Organization. About 60 percent of the men and 3 percent of the women in China smoke.

Many studies have examined the relationship between smoking and stroke in the West. However, the relationship has not been established in Asian populations, reported Kelly and her co-researchers.

The research team studied some 150,000 men and women in China from 17 provinces, for an average time period of 8.3 years.

During that time, the researchers documented 6,780 strokes, including 3,979 that resulted death.

"We found that participants who smoked had an increased risk of stroke...and mortality [death] compared to those who did not smoke," said Kelly, in an e-mailed response to questions from EthnicNewz.org.

Kelly emphasized that she and her co-investigators did not study death due to smoking. Instead, they studied only death due to stroke, for which they found an increased risk of death due to stroke that was attributed to smoking.

The risk of stroke increased significantly in response to two factors: the more cigarettes smoked per day as well as the greater the number of years during which the person smoked.

Compared to never-smokers, smokers' risk of stroke increased:
• 21 percent for those who smoke 1–19 cigarettes per day and
• 36 percent for those who smoke 20 or more cigarettes per day.

The researchers also analyzed “pack-years” to quantify the number of 20-cigarette packs smoked daily, multiplied by the number of years smoked.

Smoking half a pack, or 10 cigarettes, daily for 20 years or one pack daily for 10 years would both be calculated as 10 pack-years.

Compared to never-smokers, smokers' risk of stroke increased:
• 18 percent for smokers with 1–11 pack-years
• 25 percent for smokers with 12–26 pack-years
• 34 percent for smokers with more than 26 pack-years.

In stroke, parts of the brain have been deprived of blood. The resulting damage to the body varies since different parts of the brain control specific physical and mental functions.

Also, prompt treatment of stroke victims can dramatically lessen the damage.

Effects of stroke may be mild to severe. The effects may be paralysis on the right or left side of the body; trouble using the hands to hold eating utensils and get dressed; inability to speak or understand others who are speaking; difficulty with reading or writing; problems with memory or intellect; inaccurate judgement of distance, size and speed, such as when walking or driving; or other consequences of varying severity.

Two main kinds of stroke exist, hemorrhagic and ischemic, though the brain is deprived of blood in each kind.

In an ischemic stroke, a clot forms in a blood vessel in the brain. In a hemorrhagic stroke, a blood vessel ruptures and bleeds into the brain.

The researchers found a positive relationship between smoking and both types of stroke. However, the link was stronger for ischemic stroke.

"The more these [study] participants smoked, the more likely they were to suffer or die from ischemic stroke," said Kelly, who is also a a researcher at Tulane University's School of Public Health and Tropical Medicine.

"The results of our study really highlight the public health importance of smoking prevention and cessation programs as a vital component for reducing stroke...and [stroke-related death]," she said.

Kelly and her co-investigators were affiliated with three institutions: Tulane University in New Orleans, the Chinese Academy of Medical Sciences, and Peking Union Medical College in Beijing, China.

The principal investigator was Jiang He, who is a professor and the chair of the department of epidemiology at Tulane University School of Public Health and Tropical Medicine.

Their study was published last month in Stroke.

Click on the attachment link below to see the entire published study.

Source: EthnicNewz.org

Copyright 2008 New England Ethnic News, EthnicNewz.org. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without the express permission of the news source. Contact Newz for more information.

SEE ALSO:

中风 Stroke Risk Factors, in Chinese
(courtesy of The Ohio State University Medical Center, Mount Carmel Health and OhioHealth in Columbus)

中风 疾病常识
www.caregiver.org/caregiver/jsp/content/pdfs/fs_cs_stroke.pdf
(Family Caregiver Alliance, San Francisco, CA)

¿Qué es un "ataque cerebral"?
(Información en Español)