A new study demonstrates that reducing alcohol consumption in China could be an important cancer prevention strategy. Full story on the NDPH website.
For Western populations, there is a well-established association between regular alcohol consumption and a greater risk of various types of cancer. However, it was unknown whether these increased risks were the same for Eastern populations, which have very different drinking patterns and alcohol tolerance. Cancer rates are rising rapidly in China, and this may be partly due to more frequent alcohol consumption as citizens become more affluent. A new study led by NDPH on the large China Kadoorie Biobank has investigated this, with the findings published today in the International Journal of Cancer.
The study assessed over half a million adults recruited across ten diverse regions in China between 2004 and 2008. Each participant was questioned about their drinking habits, then followed up for a median period of 10 years. By the end of the study, almost 27,000 individuals had developed cancer (13,342 men, 13,619 women).
About a third of the men in the study drank regularly (at least once every week). Compared with those who abstained from alcohol, regular drinkers had a 26% higher risk for cancers previously associated with alcohol (ie, mouth/throat, oesophagus, colon-rectum and liver) and a 7% higher risk for all types of cancer. The risks were greater in those who drank daily or drank outside of meals.
For most of the cancers investigated, there was a clear dose-response relationship. Each 280 g/week higher alcohol intake was associated with an increased risk of 98% for oesophageal cancer; 74% for mouth/throat cancer; 52% for liver cancer and 19% for colon-rectum cancer. The study also found that each 280 g/week higher alcohol intake increased the risk of lung cancer (25%) and gallbladder cancer (60%), even though these cancers had not previously been clearly linked with alcohol.
In East Asia, many people cannot metabolise alcohol effectively due to an inherited deficiency in the enzyme aldehyde dehydrogenase 2. This causes the carcinogenic compound acetaldehyde to accumulate, which can lead to facial flushing. In this study, those who experienced flushing after drinking had stronger associations between alcohol intake and cancer risk, particularly for oesophageal and lung cancer. This suggests that the risk of developing cancer is greater for those with low alcohol tolerability.
The associations remained strong when the researchers controlled for potential confounding variables including age, region, education, income, body mass index, physical activity, and fresh fruit intake. The association between alcohol and lung cancer was similar for regular smokers and those who had never smoked regularly. Nevertheless, large-scale genetic studies are needed to determine if the associations between alcohol and cancer are likely to be causal.
Very few women in the study drank alcohol regularly, hence the study was unable to assess whether the association between alcohol and cancer risk was the same for women.
Lead author Dr Pek Kei Im said: ‘Our study has clearly shown that among Chinese men, alcohol consumption is associated with increased risks of several types of cancer, including some that were less clearly established to be alcohol-related previously. This suggests that lowering population levels of alcohol consumption is an important strategy for cancer prevention in China.’