The following correction was printed in the Observer's For the record column, Sunday 24 May 2009.
Below we quoted Dr Jane Marshall of London's Maudsley Hospital as saying alcohol is more likely to help induce dementia in women than men because "women have more body water and less body fat" than men. It is the other way round; the ratio of water to fat is lower in the female than the male. Ethanol (alcohol) is distributed in water so for a given body weight its concentration in water (thus the blood stream) tends to be higher in the female than the male.
Heavy drinking may be to blame for one in four cases of dementia. Doctors have linked alcohol intake to the development of the brain-wasting condition in between 10 and 24% of the estimated 700,000 people in the UK with the disease.
They warn that binge drinking and increased consumption are likely to produce an epidemic of alcohol-related brain damage in the future, which could see drinkers starting to experience serious memory problems in their 40s.
Women who drink a lot are at much greater risk than men of suffering problems with their cognitive functions, because they are physiologically less well able to cope with alcohol's effects. Drink is known to kill brain cells, but the estimate of its impact on neurological health, contained in the journal Alcohol and Alcoholism, indicates that the problem may be much more widespread than previously thought.
The rise in the amounts that people drink means "it is therefore likely that prevalence rates of alcohol-related brain damage are currently underestimated and may rise in future generations", say the authors.
Dr Jane Marshall, one of the co-authors and consultant psychiatrist at the Maudsley Hospital in south London, said: "People think that dementia is something that happens to people over 65. But a lot of those under 65 have got cognitive problems and a large proportion of the problems in that group are related to alcohol. Alcohol-related brain damage may account for 10-24% of all cases of all forms of dementia. We know that alcohol is associated with serious cognitive impairment. It reduces memory and general cognition," she added.
These findings follow research in America last year indicating that consuming more than two drinks a day can bring forward the onset of Alzheimer's by as much as 4.8 years. Two thirds of all the 700,000 people in the UK with dementia have Alzheimer's.
"Drink is more likely to help induce dementia in women than men because women have more body water and less body fat, which means that they metabolise alcohol differently and so are more vulnerable," said Marshall.
Women who drink the same as men have a higher risk of cognitive impairment for that reason, in the same way that they are at higher risk of getting alcohol-related liver disease.
However, a heavy drinker of either sex who abstains from alcohol can expect to see brain cells regenerate and improvements in key areas of brain activity. Gayle Willis of the Alzheimer's Society said: "We know that the prolonged use of alcohol can lead to memory deficiencies. Only one third of the people with Alzheimer's are diagnosed, but the problem of under-diagnosis of people with alcohol-related memory impairment could be even greater." But the society believes that only a handful of all cases of dementia, perhaps as few as 3%, are directly attributable to alcohol.
Marshall and her colleagues examined Korsakoff's syndrome, a little-known form of dementia linked to alcohol intake, characterised by short-term memory loss, changes in behaviour and confusion. It is increasingly common in Scotland and the Netherlands, especially among poorer people with poor diets. One study of sufferers found that half were under 50.
Professor Ian Gilmore, president of the Royal College of Physicians, said: "It is really concerning that awareness among clinical staff of this important link between alcohol and dementia remains poor, yet detection of early signs often gives a real chance of successfully heading off the condition. It is vital that we improve understanding among doctors and nurses about the links between heavy drinkers and neurological damage. Equally important is that people understand that alcohol-related brain damage can strike at any time of life."
Other research has shown that moderate drinking, of up to two drinks a day, can help protect against the onset of dementia.
Dr Allan Thomson, the guest editor of Alcohol and Alcoholism and spokesman for the Medical Council on Alcohol, has written to Dawn Primarolo, the public health minister, warning that the NHS must give alcohol-related brain damage the same priority it has put into liver problems linked to heavy drinking.
