Blood pressure and stroke risk rise steadily the more alcohol people drink, and previous claims that one or two drinks a day might protect against stroke are not true, according to the results of a major genetic study.
The research, which used data from a 160,000-strong cohort of Chinese adults, many of whom are unable to drink alcohol due to genetic intolerance, found that people who drink moderately - consuming 10 to 20 grams of alcohol a day - raise their risk of stroke by 10 to 15 percent.
For heavy drinkers, consuming four or more drinks a day, blood pressure rises significantly and the risk of stroke increases by around 35 percent, the study found.
"The key message here is that, at least for stroke, there is no protective effect of moderate drinking," said Zhengming Chen, a professor at Oxford University's Nuffield Department of Population Health who co-led the research. "The genetic evidence shows the protective effect is not real."
"Using genetics is a novel way ... to sort out whether moderate drinking really is protective, or whether it's slightly harmful," said Iona Millwood, an epidemiologist at Oxford who co-led the study. "Our genetic analyses have helped us understand the cause-and-effect relationships."
… the biological effects of alcohol should be the same for all people worldwide.