A team of researchers fromOxford Population Health has developed research involving a new genetic analysis that has shown that alcohol directly accelerates aging by damaging DNA in the telomeres. Before today, being able to identify the effects of excessive alcohol intake was difficult because there were no reliable means.
The results of the study have been published in the scientific journal Molecular Psychiatry.
Alcohol accelerates biological aging: here’s why
Telomeres are repetitive DNA sequences that cover the ends of chromosomes, protecting them from damage. Telomere length is considered an indicator of biological aging, as 50-100 strands of DNA are lost each time a cell replicates. Once telomeres become too short, cells can no longer divide and may even die.Previous research has linked shorter telomere lengths with several aging-related diseases including Alzheimer’sthe cancer and the coronary heart disease.
While developing the new research, the team of scientists carefully examined the association between alcohol intake and telomere length in over 245,000 British biobank volunteers. The researchers exploited a genetic approach called Mendelian randomization (MR), the first time it was applied to study the effects of alcohol on biological aging. This method uses “genetic proxies”To predict the level of exposure for each volunteer recruited for the study.
For this research, the team employed genetic variants that have previously been associated with alcohol use and alcohol use disorders in large-scale genome-wide association studies. To complete the MR analysis, the researchers also performed an observational assessment, based on self-reported weekly alcohol intake by the volunteers recruited for the research in question.
In the observational analysis, a significant association was observed between high alcohol intake and shorter telomere length. Compared to consuming less than 6 units of alcohol per week (approximately two large 250ml glasses of wine), consuming more than 29 units per week (approximately ten 250ml glasses of wine at 14% by volume of wine) it has been associated with an age between one and two years, a related change in telomere length.
Individuals diagnosed with alcohol use disorder had significantly shorter telomere lengths than controls, equivalent to an age-related change between 3 and 6 years.
Similarly, in the MR analysis, higher genetically predicted alcohol consumption was associated with shorter telomere length. An increase from 10 units to 32 units per week was associated with the equivalent of 3 years of biological aging. However, the association between genetically predicted alcohol consumption and telomere length only proved relevant for those who consumed more than 17 units of alcohol per week. This indicates that a minimal amount of alcohol consumption may be required to damage telomeres.
MR analysis also found a significant association between genetically predicted alcohol consumption disorder and telomere length, equivalent to approximately 3 years of biological aging. Most of the volunteers recruited are currently drinkers, with only 3% never drinking and 4% having previously drank. 51% were men, 49% were women and the average age was around 57.
The research was coordinated by Dr. la Anya Topiwala of Oxford Population Health, who said: “These results support the suggestion that alcohol, particularly at excessive levels, directly affects telomere length. Shortened telomeres have been proposed as risk factors that can cause a number of serious age-related diseases, such as Alzheimer’s disease. Our findings provide yet another piece of information for physicians and patients seeking to reduce the harmful effects of excess alcohol. In addition, the dose of alcohol is important, even reducing alcohol consumption could have benefits ”.
For both observational and MR analysis, telomere lengths were measured using leukocytes (immune system cells) from participants’ DNA samples collected when participants were first recruited into the UK biobank.
In MR analysis, alcohol intake was estimated by examining DNA samples for 93 genetic variants that were previously associated with weekly alcohol consumption, as well as 24 variants that had previously been linked to a diagnosis of alcohol use disorder . Because these genetic variants are randomly assigned and fixed prior to birth, the results give more confidence that alcohol directly affects telomere length, rather than some other responsible factor.
Although these results do not conclusively demonstrate that alcohol directly affects telomere length, two study results support this hypothesis: 1) The effects were only seen in current drinkers, and not in previous or non-drinkers; 2) The most influential genetic variant in the MR analysis was AD1HB, an alcohol metabolism gene.
According to the team of researchers, a potential biological mechanism to explain the influence of alcohol on telomere length is oxidative increase and inflammation. The process that breaks down ethanol in the body can both produce reactive oxidative species that damage DNA and reduce the levels of antioxidant compounds that protect against oxidative stress.
Doctor Richard Pipermanaging director of Alcohol Change UK, concluded that he welcomes all research on the effects of alcohol on the human body: “This particular study shows clear links between alcohol consumption and biological aging and points to a possible link between alcohol and Alzheimer’s. The researchers are clear that this study does not demonstrate a causal link, but they also make a well-argued case about the probable biological mechanism. In general, there is a growing body of science that shows how, exactly, alcohol causes so many health problems and so many premature deaths ”.
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