Daily smoking and drinking 'linked to modest increase in brain age'
By Nilima Marshall
Smoking and drinking on a daily basis may lead to a "modest increase" in brain age, new research suggests.
Scientists have found that regular drinkers and smokers appear to have slightly older brains than people who do not, or only occasionally, smoke or drink.
The findings also show the brain age of moderate drinkers to be "indistinguishable" from those who abstain from drinking.
A team led by Arthur W Toga, from the Keck School of Medicine of University of Southern California, looked at data from the UK Biobank project, an online database of 500,000 people and their medical conditions.
They used machine learning technologies and a type of brain scan known as structural MRI to calculate the relative brain age of 17,308 people aged 45 to 81.
The authors found that those who smoked or drank alcohol on most or all days had older-looking brains than those who smoked or drank less frequently or not at all.
Each additional pack-year of smoking, defined as smoking a pack of cigarettes per day for a whole year, was associated with 0.03 years of increased relative brain age, the researchers said.
And each additional gram of alcohol consumption per day was associated with 0.02 years of increased relative brain age, the team added.
Writing in the journal Scientific Reports, the authors noted: "We found that daily or almost daily consumption of tobacco and alcohol were both significantly associated with increased RBA (relative brain age).
"Our results suggest that both environmental and genetic factors are associated with structural brain ageing."
Commenting on the research, Derek Hill, a professor of medical imaging at University College London who was not involved in the study, said the research does not fully answer the question as to whether regular smoking and drinking damages the brain.
He added: "But it does suggest smoking and drinking may not be good for the brain, as a higher relative brain age is associated with a brain that functions less well.
"Perhaps the more interesting result is that people who drink three or four times per week have a brain age indistinguishable from those who abstain, whereas those who drink daily have a measurably higher brain age.
"So this might provide further evidence that drinking in moderation is perfectly healthy, but drinking every day has health risks."