Low, moderate alcohol intake elevates women’s risk of alcohol-related cancers

By Shreeya Nanda, Senior medwireNews Reporter

Low to moderate alcohol consumption is linked to an increased risk of alcohol-related cancers in women, but not men, who have never smoked, research suggests.

Male ever smokers who are light to moderate drinkers also have an elevated risk of alcohol-attributable cancers, but the overall risk of total cancer is only “minimally increased” compared with non-drinkers in both women and men, report Edward Giovannucci (Harvard T H Chan School of Public Health, Boston, Massachusetts, USA) and study co-authors.

Among 88,084 female participants of the US Nurses’ Health Study and 47,881 male participants of the US Health Professionals Follow-up Study, a total of 19,269 and 7571 malignancies, respectively, were diagnosed during a follow-up period of up to 30 years. Of these, 9016 cancers in women and 1611 in men had a known link to alcohol consumption, including tumours of the colorectum, female breast, oral cavity, pharynx, larynx, liver and oesophagus.

After adjusting for age, ethnicity, obesity and other confounders, light to moderate alcohol consumption (5.0–14.9 g/day) in women was associated with a 1.13-fold increase in the risk of alcohol-related cancers relative to non-drinkers. This association was driven primarily by an increased risk of breast cancer and was irrespective of smoking status.

By contrast, light to moderate drinking in men, defined as an alcohol intake of 5.0 g/day to 29.9 g/day, led to an elevated risk of developing alcohol-related cancers in ever smokers, but not in never smokers.

Giovannucci et al report a “small but non-significant” increase in overall cancer risk in women and men compared with non-drinkers. The relative risks of total cancer were 1.02 and 1.04 in women with an alcohol intake of 0.1 g/day to 4.9 g/day and 5.0 g/day to 14.9 g/day, respectively. And in men, alcohol consumption of 0.1 g/day to 5.0 g/day, 5.0 g/day to 14.9 g/day, and 15.0 g/day to 29.9 g/day was associated with relative risks of total cancer of 1.03, 1.05 and 1.06, respectively.

The findings were comparable in ever and never smokers, but above moderate consumption of alcohol (≥30 g/day) “was more strongly associated with risk of cancer among ever than among never smokers”, they write in The BMJ.

In an accompanying editorial, Jürgen Rehm (Centre for Addiction and Mental Health, Toronto, Ontario, Canada) notes that the upper thresholds for light to moderate drinking used by the researchers are “roughly in line with the upper limits of many national guidelines”, and thus he does not anticipate any major consequences for current guidelines.

But he adds that “people with a family history of cancer, especially women with a family history of breast cancer, should consider reducing their alcohol intake to below recommended limits, or even abstaining altogether, given the now well established link between moderate drinking and alcohol related cancers.”

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