Consuming alcohol directly accelerates ageing by damaging DNA in telomeres, a new study shows today.
Researchers from Oxford Population Health have completed a genetic-based analysis, investigating the association between alcohol intake and telomere length in more than 245,000 participants in the UK Biobank.
Mendelian Randomisation (MR) was used for the first time to investigate the effects of alcohol on ageing, using ‘genetic proxies’ to predict the level of exposure for each participant.
They used genetic variants that have previously been associated with alcohol consumption and alcohol use disorders in large-scale genome-wide association studies and to complement the MR analysis, they also performed an observational assessment, based on the participants’ self-reported weekly alcohol intake at recruitment.
The findings, published today in *Molecular Psychiatry*, found a significant association between high alcohol intake and shorter telomere length.
Compared with drinking less than six units of alcohol a week, drinking more than 29 units weekly was associated with between one and two years of age-related change on telomere length.
The research also found that individuals with a diagnosed alcohol-use disorder had significantly shorter telomere lengths compared with controls, equivalent to between three and six years of age-related change.
Dose important
In the MR analysis, higher genetically predicted alcohol consumption was associated with shorter telomere length, with an increase from 10 units to 32 units per week associated with the equivalent of three years of ageing.
However, the association between genetically predicted alcohol consumption and telomere length was only significant for those drinking more than 17 units per week.
Most of the participants, of whom 51% were men and 49% women, were current drinkers, with only 3% having never drunk alcohol and 4% describing themselves as previous drinkers. Their average age was 57 years.
Study lead Dr Anya Topiwala from Oxford Population Health said: “These findings support the suggestion that alcohol, particularly at excessive levels, directly affects telomere length.
“Shortened telomeres have been proposed as risk factors which may cause a number of severe age-related diseases, such as Alzheimer’s disease. Our results provide another piece of information for clinicians and patients seeking to reduce the harmful effects of excess alcohol. Furthermore, the dose of alcohol is important – even reducing drinking could have benefits.”
For the observational and MR analysis, leucocytes from the participants’ DNA samples collected when participants were first recruited to the UK Biobank were used to measure telomere lengths.
In the MR analysis, alcohol intake was estimated by screening DNA samples for 93 genetic variants that have previously been associated with weekly alcohol consumption, as well as 24 variants that have previously been linked to a diagnosis of an alcohol use disorder.
Although these results do not conclusively prove that alcohol directly affects telomere length, two findings from the study support this being the case: effects were only found in current drinkers, and not previous or never-drinkers; and the most influential genetic variant in the MR analysis was AD1HB, an alcohol metabolism gene.
*Molecular Psychiatry* 26 July 2022
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