Drinking a bottle of wine per week increases the lifetime risk of cancer by the equivalent of smoking five to 10 cigarettes, research suggests.
For women, drinking one bottle of wine per week increases the absolute lifetime risk of cancer to the same extent as smoking 10 cigarettes a week, mostly due to an increased risk of breast cancer caused by drinking, according to the study.
For men, drinking a bottle of wine a week increases the absolute lifetime risk of cancer equivalent to smoking five cigarettes.
This is due to the risk of cancer in parts of the body such as the bowel, liver and oesophagus, according to the team of researchers from the University Hospital Southampton NHS Foundation Trust, Bangor University and University of Southampton.
The team estimated that if 1,000 non-smoking men and 1,000 non-smoking women each drank one bottle of wine per week across their lifetime, around 10 men and 14 women would develop cancer as a result.
And if 1,000 men and 1,000 women drank three bottles of wine per week throughout their lives, around 19 men and 36 women could develop cancer as a result.
The team said three bottles a week is equivalent to smoking roughly eight cigarettes per week for men and 23 cigarettes per week for women.
Writing in the journal BMC Public Health, the team said alcohol is generally perceived by the public as being far less harmful than smoking, despite being directly linked to several different types of cancer.
In terms of absolute risk, the researchers said one bottle of wine per week is associated with an increased absolute lifetime cancer risk for non-smokers of 1% (men) and 1.4% (women).
They concluded: “One bottle of wine per week is associated with an increased absolute lifetime risk of alcohol-related cancers in women, driven by breast cancer, equivalent to the increased absolute cancer risk associated with 10 cigarettes per week.”
The risks for men were equivalent to five cigarettes per week, they added.
Dr Theresa Hydes, who worked on the study, said: “It is well established that heavy drinking is linked to cancer of the mouth, throat, voice box, gullet, bowel, liver and breast.
“Yet, in contrast to smoking, this is not widely understood by the public. We hope that by using cigarettes as the comparator we could communicate this message more effectively to help individuals make more informed lifestyle choices.”
She added: “We must be absolutely clear that this study is not saying that drinking alcohol in moderation is in any way equivalent to smoking. Our finds relate to lifetime risk across the population.
“At an individual level, cancer risk represented by drinking or smoking will vary and, for many individuals, the impact of 10 units of alcohol (one bottle of wine) or five to 10 cigarettes may be very different.”
Professor Sir Ian Gilmore, chairman of the Alcohol Health Alliance, said: “Even at relatively low levels, alcohol can have serious consequences for our health.
“The Chief Medical Officers recommend drinking no more than 14 units a week to keep the risks low but, worryingly, few people are aware of the guidelines.”
Jane Green, professor of epidemiology and co-director of the cancer epidemiology unit at the University of Oxford, said: “It is important to view these results in context.
“For both men and women in the UK, the lifetime risk of cancer is around 50%.
“The authors estimate that lifetime risk is around 1% higher for men and women who drink a bottle of wine a week, or who smoke five to 10 cigarettes a week, than for those who neither smoke nor drink.
“The average UK drinker reports drinking the equivalent of about a bottle-and-a-half of wine a week, and the average smoker smokes about 10 cigarettes a day, or 70 a week.
“This work confirms that, for most smokers, their smoking carries much greater risks for cancer than does alcohol for most drinkers.
“Moderate levels of drinking are in absolute terms particularly important for cancer risk in women, because they are associated with increased risk of breast cancer, which is very common (lifetime risk of 14%).”
Sophia Lowes, from Cancer Research UK, said: “Smoking remains the biggest cause of cancer, so this comparison can be useful to raise awareness of less well-known risk factors like alcohol. It highlights that even low levels of drinking can increase the risk of cancer.
“Research is clear – the less a person drinks, the lower the risk of cancer. Small changes like having more alcohol-free days can make a big difference to how much you drink.
“But smoking causes over four times as many cases of cancer in the UK compared to alcohol. If you’re a smoker, the best thing you can do for your health is stop completely, and you’re most likely to be successful using support from your local free stop-smoking service.”
A spokeswoman from the Alcohol Information Partnership, which is funded by the drinks industry, said: “The conclusions drawn from this study are both unhelpful and confusing at a time when the public is being bombarded by contradictory warnings of risk.”
She added: “There are a wide variety of genetic and lifestyle factors that can contribute to an increased risk of cancer and the study itself is clear that drinking in moderation is not equivalent to smoking.”
A spokesman for Diageo, which makes Guinness, Smirnoff and Johnnie Walker, said: “Drinking is not the same as smoking, nor does it carry the same health risks.
“To make that comparison is misleading and will confuse people who want to enjoy alcohol in moderation.”
Susannah Brown, acting head of research interpretation at the World Cancer Research Fund, said: “This is a very interesting paper.
“By using a ‘cigarette equivalent’ to show how alcohol affects cancer risk, it conveys the findings in a way well understood by the public and could do a lot to increase public awareness of the link between drinking alcohol and cancer.”