The analysis is based on data from the National Health Interview Survey in the US, assessing more than 300,000 subjects who encountered 8,000 deaths from cancer. The research focused on total cancer deaths and deaths from colorectal, lung, breast, and prostate cancers.
The overall message derived from this analysis is that light to moderate alcohol consumption does not appear to raise the risk of all-site cancer. Light drinking was even found to be associated with a reduced risk in cancer risk. Light to moderate alcohol intake was also found to have no association with specific cancers like colorectal, lung, breast or prostate.
As consumption of alcohol increased from 1 drink on drinking days to 3 or more drinks on drinking days (US drinks are 14g), risk of all-site cancer mortality increased by 22% among all participants. For data regarding total alcohol consumption (frequency x quantity), the data found a significant decrease in the risk of all forms of cancers.
Moderate alcohol consumption consistently had no effect in the analysis. Only heavier alcohol intake was associated with an increase in all-site cancer risk. For site-specific cancers, heavier drinkers faced a higher risk of lung cancer, with patterns of less cancer for light drinkers. There was no evidence of impact from total alcohol consumption on colorectal, prostate, or breast cancer.
The authors then conducted a second analysis that excluded non-drinkers and categorized daily quantity and frequency of alcohol consumption in order to investigate their separate effects. For all-site cancer and lung cancer, these results again show that there was only an increase in cancer risk for those who were heavy drinkers.
The data also displayed an increase in cancer risk from drinking more frequently among women but not among men. For colorectal, prostate, and breast cancer, the investigators found no clear pattern of an increase in relation to the quantity of alcohol consumed. In regards to drinking frequency, there is a suggestion of a heightened risk of cancer death with more frequent drinking, although the trends are not statistically significant.
Drinking three or more drinks per occasion is known to have a number of negative health effects, including certain cancers, as was demonstrated in this study. When considering cancer, alcohol consumption should not be examined in isolation but in conjunction with other lifestyle habits (especially smoking when considering lung cancer). Both quantity and frequency of intake need to be considered when examining the connection between alcohol and cancer.