A British study has drawn a link between giving up alcohol in middle age and a heightened risk of dementia.
The study, published in The British Medical Journal, found those who drank over the recommended limits and those who became teetotallers in midlife were at an increased dementia risk.
The study looked at 9,000 public servants in London aged between 35 and 55 and began in the mid 1980s.
Researchers measured alcohol consumption for participants between 1985 and 1993, when they had an average age of 50 years.
This was then followed up for an average of 23 years, with cases of dementia identified through hospital, mental health services, and mortality records. A total of 397 cases of dementia were recorded.
Abstinence in midlife was associated with a 45 per cent higher risk of dementia compared with people who consumed between one and 14 units of alcohol per week.
The team of French and British researchers suggested that part of the excess risk of dementia in abstainers could be attributable to the greater risk of cardiometabolic disease reported in this group.
Among excessive drinkers - those who consumed more than 14 units per week - experts found a heightened risk of dementia which increased the more a person drank - they noted that with every seven units per week increase there was a 17 per cent increase in dementia risk.
"These results suggest that abstention and excessive alcohol consumption are associated with an increased risk of dementia, although the underlying mechanisms are likely to be different in the two groups," the authors wrote.
Dr Tony Rao, an expert at the Royal College of Psychiatrists, warned the study's results should be interpreted with a "high degree of caution".
"The study tells us little about how drinking above low risk guidance beyond the of age of 55 affects the development of dementia," Dr Rao said.
"We know that a third of older people with alcohol misuse develop this for the first time in later life.
"People with a history of heavy drinking who abstain for health reasons and those who under-report their drinking also makes it difficult to draw any firm conclusions."
Guidance from the UK chief medical officer states that men and women should drink no more than 14 units of alcohol each week - the equivalent of six pints of average strength beer.
Commenting on the study, Dr Sara Imarisio, head of research at Alzheimer's Research UK, said: "As this study only looked at people's drinking in midlife, we don't know about their drinking habits earlier in adulthood, and it is possible that this may contribute to their later life dementia risk".
Australian Associated Press