Alcohol consumption has been found to be linked with increased risks of 61 diseases in Chinese men, according to a new study. These include 33 diseases that had previously not been established as alcohol-related, such as gout, fractures, cataract and gastric ulcer, the study, published June 8 in the journal Nature Medicine, said. The new study is significant because it assesses the impact of alcohol consumption on an extensive range of diseases within the same population, and does not only look at the diseases caused by heavy drinking, such as cirrhosis, stroke and some cancers, but also at diseases previously not linked to alcohol consumption.


Every year, about three million deaths occur worldwide due to alcohol consumption. The number of alcohol-related deaths is increasing in low- and middle-income countries such as China. 


How the study was conducted


As part of the study, researchers from Oxford Population Health and Peking University used data from the China Kadoorie Biobank (CKB), a collaborative study of over 5,12,000 adults recruited between 2004 and 2008 from ten diverse urban and rural areas across China. The study interviewed participants about their lifestyle and behaviours, including detailed alcohol drinking patterns. The researchers found that about a third of men, but only two per cent of women, drank alcohol at least once a week. After identifying over 200 different diseases in men influenced by alcohol use, the researchers made a comprehensive assessment of the health effects of alcohol consumption on these illnesses. In order to understand whether alcohol intake was responsible for causing a particular disease, the researchers undertook a genetic analysis. 


ALSO READ | The Science Of Health: How Stem Cell Transplants For Blood Cancers Work, And What The Challenges Are


Diseases affecting regular drinkers


The researchers analysed a total of 207 diseases. Self-reported alcohol intake was associated with higher risks of 61 diseases, and of these, 28 diseases had previously been established by the World Health Organization (WHO) as alcohol-related, and 33 were previously not established as alcohol-related. Liver cirrhosis, stroke and several gastrointestinal cancers are alcohol-related diseases, and gout, gastric ulcer and cataract are some of the diseases previously not established as alcohol-related. 


The study recorded more than 1.1 million hospitalisations, and found that men who had ever drunk alcohol regularly, which means they had a pattern of drinking alcohol at least once a week, had significantly higher risk of developing any disease, and experienced more frequent stays in hospitals, compared with men who had drunk alcohol only occasionally. 


Drinking daily, drinking alcohol in heavy binge episodes, and drinking outside meals are certain drinking patterns linked with increased risks of diseases such as liver cirrhosis, the study said. 


The genetic analysis found that higher alcohol intake was significantly linked with a higher risk of stroke in a dose-dependent manner, and this finding was consistent with previous findings in the collaborative study. However, no increased risk with ischaemic heart diseases was found. According to the new study, moderate drinking, which refers to consuming one to two alcoholic drinks everyday, did not have any protective effects against ischaemic heart disease.


How are genetic variants linked to alcohol tolerability?


Since less than two per cent of women in the study drank regularly, the women served as a useful control group in the genetic analyses. This helped the researchers confirm that the excess disease risks in men were caused by drinking alcohol, and were not other mechanisms related to genetic variants.


Some genetic variants that greatly reduce alcohol tolerability are common in East Asian populations. These variants result in an extremely unpleasant flushing reaction after drinking alcohol. Therefore, people with these variants drink less alcohol. Since the genetic variants are not related to other lifestyle factors such as smoking or socio-economic status, they can be used to analyse the cause-and-effect relationships of alcohol with a wide range of diseases.


Previous studies on the health impacts of alcohol consumption


A study published March 21 in The Lancet said that the implementation of minimum unit pricing legislation for alcohol is linked with a 13 per cent reduction in deaths from alcohol consumption in Scotland, a trend observed in the most socio-economically deprived areas of the country. The 13 per cent reduction in alcohol-specific deaths is equivalent to avoiding around 150 deaths per year. 


A study published in September 2022 in the journal Proceedings of the National Academy of Sciences found that even the single administration of alcohol can permanently alter the brain, and affect energy supply in the body, because alcohol influences the morphology of neurons, the structure of synapses, and the dynamics of mitochondria, which are the powerhouses of the cell. 


A study published July 2022 in The Lancet said that alcohol consumption poses higher health risks for young people than older adults, and that males aged 15 to 39 years were the largest segment of the population drinking unsafe amounts of alcohol in every region in 2020. 


According to the study, 59.1 per cent of individuals consuming harmful amounts of alcohol in 2020 were aged 15 to 39 years, and 76.7 per cent were male.