Previous research regarding the association between alcohol consumption and dementia or cognitive impairment in later life suggests that mild to moderate alcohol consumption might be protective of dementia. However, most of the research has been conducted on subjects already rather elderly at the start of the follow-up. A new study published in the December issue of the Journal of Alzheimer's Disease addresses this problem with a follow-up of more than two decades.
The study, conducted at the University of Turku, University of Helsinki and National Institute for Health and Welfare in Finland based on subjects from the Finnish Twin Cohort, shows that midlife alcohol consumption is related to the risk of dementia assessed some 20 years later. The study indicates that both abstainers and subjects consuming large amounts of alcohol have a greater risk for cognitive impairment than light drinkers.
"Our finding is significant as the changes typical of Alzheimer's disease – the most common dementia syndrome – are thought to start appearing two to three decades before clinical manifestation and therefore identification of early risk factors is imperative", states Jyri Virta, researcher at University of Turku, Finland.
In addition to total alcohol consumption, the authors were able to assess the effects of different drinking patterns. The study suggests that drinking large amounts of alcohol (defined as a bottle of wine or the equivalent) at a single occasion at least monthly is an independent risk factor for cognitive impairment. Such binge drinking doubles the risk of cognitive impairment even when total alcohol consumption was statistically controlled for.
Similarly, passing out because of heavy drinking on one occasion was also found to increase the development of subsequent cognitive impairment. Thus, it is not only the amount of alcohol, but also the pattern by which alcohol is consumed that affects the risk of cognitive impairment. The published study is among the first to report these effects.
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