During the study, the researchers used data from three large prospective cohort studies in which 210,252 participants were followed for a mean of 18.3 years, using food-frequency questionnaires to determine their alcohol consumption. According to the authors, a standard drink was defined as 12.8 grams of alcohol.
Findings suggested that alcohol intake was associated with a 14% higher risk of melanoma per drink per day. In particular, each drink per day of white wine was associated with a 13% increased risk of melanoma. Other forms of alcohol—beer, red wine, and liquor—did not significantly affect melanoma risk.
“It was surprising that white wine was the only drink independently associated with increased risk of melanoma. The reason for the association is unknown. However, research has shown that some wine has somewhat higher levels of pre-existing acetaldehyde than beer or spirits,” said the lead author, Eunyoung Cho, an associate professor of dermatology and epidemiology at the Warren Alpert Medical School of Brown University in Providence, R.I.
“While red and white wine may have similar amounts of pre-existing acetaldehyde, the antioxidants in red wine may offset the risks,” added Cho, who was quoted in a press release.
The association between alcohol and melanoma was strongest for parts of the body that typically receive less sun exposure. Cho said that compared with non-drinkers, those who consumed 20 grams or more of alcohol per day were 2% more likely to be diagnosed with melanomas of the head, neck, or extremities, but 73% more likely to be diagnosed with melanomas of the trunk.
“Previous research has suggested that alcohol can cause carcinogenesis as the ethanol in alcohol metabolizes into acetaldehyde, which damages DNA and prevents DNA repair,” said Cho.
Cho indicated that the study’s chief limitation was the homogeneity of the study population. Non-whites were excluded, as there were too few non-white participants to draw statistically valid conclusions. Therefore, the study’s findings cannot be generalized for other racial or ethnic groups.
Also, few study participants reported heavy drinking, and the study did not account for some potential risk factors of melanoma, such as sun-protection behaviours. Participants were excluded if they reported a personal history of cancer at baseline in order to avoid bias due to closer physician follow-up of cancer patients.
“The clinical and biological significance of these findings remains to be determined, but for motivated individuals with other strong risk factors for melanoma, counselling regarding alcohol use may be an appropriate risk-reduction strategy to reduce risks of melanoma as well as other cancers,” Cho said.
However, Cho pointed out that modest alcohol intake has been connected with reduced risk of cardiovascular disease.
“For drinkers, risks and benefits of alcohol consumption have to be considered individually, including the risk related to skin cancer,” she said.
This study was supported by grants from the National Institutes of Health. Cho declares no conflicts of interest.