Alcohol Intake and Risk of Incident Melanoma: A Pooled Analysis of Three Prospective Studies in the United States
Alcohol consumption is associated with increased risk of numerous cancers, but existing evidence for an association with melanoma is equivocal. No study has evaluated the association with different anatomic locations of melanoma.
The World Cancer Report 2014 shows that alcohol accounts for 3.5% of all cancers (about 1 in 30 cancer deaths) globally. Recent data indicate that the proportion of cancers attributable to alcohol worldwide has increased.
Most typically alcohol causes cancers of the aerodigestive tract, liver, pancreas, colon, rectum, and breast. Previous research has suggested that alcohol can cause carcinogenesis as the ethanol in alcohol metabolizes into acetaldehyde, which damages DNA and prevents DNA repair.
The researchers used data from three large prospective cohort studies to investigate whether alcohol intake was associated with risk of melanoma. Alcohol intake was assessed repeatedly by food-frequency questionnaires. A Cox proportional hazards model was used to calculate multivariate-adjusted hazard ratios (HRs).
A total of 1,374 cases of invasive melanoma were documented during 3,855,706 person-years of follow-up. There was an association between higher alcohol intake and incidence of invasive melanoma. Overall alcohol intake was associated with a 14% higher risk of melanoma per alcoholic drink per day. Each alcoholic drink per day of white wine was associated with a 13% increased risk of melanoma.
Among alcoholic beverages, white wine consumption was associated with an increased risk of melanoma after adjusting for other alcoholic beverages. White wine was the only type of alcohol independently associated with increased risk of melanoma. The reason for the association is unknown.
The association between alcohol consumption and melanoma risk was stronger for melanoma in relatively UV-spared sites (trunk) versus more UV-exposed sites (head, neck, or extremities).
Compared with non-alcohol users, the pooled multivariate-adjusted HRs for ≥20 g/day of alcohol were 1.02 (95% CI, 0.64–1.62; Ptrend = 0.25) for melanomas of the head, neck, and extremities and 1.73 (95% CI, 1.25–2.38; Ptrend = 0.02) for melanomas of the trunk.
According to the researchers, the study’s main 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.
Another limitation was that a few study participants reported heavy alcohol use, and the study did not account for some potential risk factors of melanoma, such as sun-protection behaviors. Participants were excluded if they reported a personal history of cancer at baseline of the follow-up in order to avoid bias due to closer physician follow-up of cancer patients.
Conclusions and significance
The study adds melanoma to the list of cancers associated with alcohol. Alcohol intake was associated with a modest increase in the risk of melanoma, particularly in UV-protected sites.
These findings further support American Cancer Society Guidelines for Cancer Prevention to limit alcohol intake.