High alcohol consumption increases stroke risk among Chinese men

August 20, 2007

Heavy drinking may increase the risk of stroke in Chinese men and should be targeted for prevention strategies, according to a new study to be published online in the Annals of Neurology, a journal published by John Wiley & Sons.

In China, stroke is the leading cause of death for men; it kills more than 20 percent of the male population. It is also the top reason for long-term disability. High alcohol consumption is a known risk factor for stroke and alcohol use in China has increased in recent years alongside the country’s economic development. Researchers, led by Lydia Bazzano of Tulane University School of Public Health and Tropical Medicine, recently examined the relationship between alcohol consumption and stroke in a large nationally representative sample of Chinese men.

They conducted a prospective cohort study of 64,338 men who participated in the 1991 China National Hypertension Survey. At baseline, all of the men were over 40 years old and free of stroke. They provided information about their demographic characteristics, medical history and lifestyle risk factors, including alcohol consumption. Those who said they consumed more than 12 drinks per year were defined as drinkers, and then quantified the number of drinks they had each month. Between 1999 and 2000, the researchers followed up with the study participants and determined all incidents of stroke. For every such incident and for each death, medical records and death certificates were obtained to verify the diagnosis. The researchers then analyzed the data to assess any relationship between alcohol consumption and stroke.

At the time of follow-up, the participants had suffered 3,434 incident strokes and 1,848 fatal strokes. After adjusting for factors such as age, body mass index and geographic variation, the researchers found that the risk of stroke was higher among those who drank more alcohol. For participants who had 1 to 6 drinks per week, the relative stroke risk was .92. It was 1.02 for those who consumed 7 to 20 drinks per week, and 1.22 for those consuming more than 21 drinks per week. Heavier drinking also correlated to higher risk of death by stroke.

“Alcohol consumption was significantly related to increased stroke incidence and mortality,” the authors report. “At the top level of alcohol consumption (at least 35 drinks per week), risk of stroke incidence was 22 percent higher and risk of mortality was 30 percent higher than among nondrinkers.”

The researchers did not have information about binge drinking, leisure-time physical activity and other potential confounding factors, however they suggested such information would have not have greatly impacted their results, given the large sample size, high follow-up rate, and strong association identified.

“Our findings are likely to be applicable to men of other ethnicities because they are based on proven physiological mechanisms,” the authors conclude. “Preventing heavy alcohol consumption (more than 21 drinks per week) among men may be one element of multi-faceted public health strategies to reduce stroke burden in the world.”

Source: John Wiley & Sons