A new study has found a genetic connection of alcohol consumption being a direct cause of cancer, according to Oxford Population Health.
The study set out to confirm whether alcohol consumption contributed to cancer cases or is the direct cause, researchers from Oxford, Peking University, and the Chinese Academy of Medical Sciences used a genetic approach in studying 150,000 subjects in China.
"These findings indicate that alcohol directly causes several types of cancer, and that these risks may be increased further in people with inherited low alcohol tolerability who cannot properly metabolise alcohol," according to Oxford Population Health's Dr. Pek Kei (Becky) Im, who was the lead researcher.
Alcohol consumption is estimated to cause around three million deaths a year, including more than 400,000 from cancer, according to the report.
"Our study reinforces the need to lower population levels of alcohol consumption for cancer prevention, especially in China where alcohol consumption is increasing despite the low alcohol tolerability among a large subset of the population," Oxford Population Health senior researcher Dr. Iona Millwood said.
The study homed in on two common genetic variants (alleles) that "reduce alcohol tolerability and are strongly associated with lower alcohol intake, because they cause an unpleasant 'flushing' effect."
Researchers found Chinese individuals with the genes for low alcohol tolerability had "between 13-25% lower risks of overall cancer and alcohol-related cancers, particularly head and neck cancer, and oesophageal cancer."
The genetic alleles allocated at birth can remove other lifestyle factors, allowing researchers to link alcohol to greater risk of cancers commonly linked to alcohol consumption, including cancers of the head and neck; oesophagus, colon, rectum, and liver, according to the study.
Those with those genes for low alcohol tolerability that drank alcohol regularly had significant higher risk for those cancers, while those with those alleles and were non-drinkers or occasional drinkers showed no association of an increased cancer risk.
The study was published in the International Journal of Cancer.