a bottle of wine a week and cancer risk

A recent article calculated the lifetime risk of cancer from alcohol and compared it to the risk from smoking (see alcohol equiv to cigs for cancer bmjpubhlth2019 in dropbox, or https://bmcpublichealth.biomedcentral.com/track/pdf/10.1186/s12889-019-6576-9 ).

Details:

-- the study involved comparing the attributable cancer risk from alcohol consumption to that from smoking, based on epidemiologic data from the UK

-- in men, they looked at an array of cancers including oropharyngeal, esophageal, colorectal, and liver cancer

-- in women, the above as well as breast cancer

Results:

-- drinking one bottle of wine per week increases the absolute lifetime risk of cancer:

    -- in men, by 1.0%

    -- in women, by 1.4%. 55% of these were from breast cancer

-- in comparison to low levels of smoking, drinking one bottle of wine a week is equivalent to:

   -- in men, smoking 5 cigarettes per week

   -- in women, smoking 10 cigarettes per week

-- drinking 3 bottles of wine per week (i.e. half bottle per day) is associated with an absolute lifetime cancer risk increase of 1.9% for men and 3.6% for women (2.4% of that increase in women is from breast cancer)

    -- as per the above numbers, increasing alcohol consumption is associated with disproportionate increases in cancers in women

    -- drinking the 3 bottles per week is equivalent to 8 cigarettes per week for men and 23 cigarettes for women

Commentary:

-- from their calculations, the current levels of alcohol consumption in the UK is associated with 339,000 extra cancers

 -- risks of smoking:

    -- older studies have suggested that tobacco use is associated with 7 million deaths per year globally, and two thirds of smokers are expected to die from tobacco-related causes

    -- 22% of cancer deaths worldwide are related to smoking: smoking is still the single largest preventable cause of cancer worldwide

    -- 70% of the population understand that smoking is a major cause of cancer

-- risks of alcohol:

    -- 3.3 million deaths per year related to alcohol use, 5.9% of all deaths globally

    -- alcohol was the leading cause of death in those 15-49 yo worldwide in 2016: see http://gmodestmedblogs.blogspot.com/2018/10/alcohol-as-leading-risk-facor-for-death.html

    -- but a recent survey found that only 13% considered cancer as a health risk of alcohol

-- more recent analyses have suggested that there are no protective health benefits from alcohol, and a 2016 UK governmental assessment noted: “any level of alcohol consumption can be associated with a range of cancers and there is no justification for drinking for health reasons”

    --see http://gmodestmedblogs.blogspot.com/2015/02/moderate-alcohol-and-cardioprotection.html  for the studies/argument against alcohol having any cardioprotective effect

-- other cancers are also associated with alcohol with a dose-response curve, including melanoma, gallbladder, pancreas, lung, and prostate.

-- There are large epidemiologic differences between those who smoke and those who drink:

    -- though the average cigarette consumption by smokers is 80 per week in the UK and 100 per week in the US, only about 20% of people smoke

    -- alcohol is much more common, affecting about 72% of women and 83% of men in resource-rich countries

-- one observation is that the rising level of alcohol consumption over the past decade may be a significant factor in the 30% rise in breast cancer found in the UK (there is been a steady increase in alcohol consumption among women)

-- it is important to note that this study only looked at cancer, though overall mortality is much higher from the other health effects of smoking or drinking

    -- smoking even one cigarette a day is likely associated with significant coronary artery disease, at about half the rate of smoking a whole pack a day, see http://gmodestmedblogs.blogspot.com/2018/01/smoking-just-one-cigarette-one-too-many.html

    -- and there certainly are other smoking-related morbidities and mortality, including COPD, peripheral artery disease, etc.

    -- drinking also has an array of non-cancer bad health outcomes, including accidents, cirrhosis, etc.

-- also, not all bad cancers carry the same weight. For example, lung cancer tends to happen in older people, whereas breast cancer tends to affect women at a relatively younger age

-- some limitations of the study:

    -- these are clearly large-scale community data, and these 2 exposures may have quite variable cancer risk for individual patients

    -- the data reflects reports of smoking or drinking at one point in time, with subsequent development of cancer. These habits may well have changed over time: for example, those drinking alcohol may be more likely to stop in the future than those smoking cigarettes

    -- there may be important synergies between drinking and smoking, and this study looked at the attributable cancer risk of non-drinking smokers and non-smoking drinkers. These synergies include:

        -- the high overlap of people who both drink alcohol and smoke (a higher incidence of smoking among social drinkers compared to those who abstain from alcohol)

        -- and several diseases themselves may have a higher incidence with the combination of smoking and drinking, such as oropharyngeal cancer

   -- and, this study looked at people drinking relatively small amounts of wine, noting that increasing to 3 bottles/week created disproportionately more cancer in women. and the likelihood of that drinking even more alcohol would lead to relatively much higher cancer rates in women

So, this study projected cancer risk from low levels of drinking or smoking (not both), finding that for1000 non-smoking men or women who each drink one bottle of wine per week there would be 10 men and 14 women who would develop cancer. this was equivalent to smoking 5 cigarettes per week for men and 10 cigarettes for women.

To me, this brings up the actionable public health message for us clinicians: drinking even small amounts of alcohol is potentially very dangerous. This is an important message, especially given the widespread feeling that small amounts of alcohol are okay, even cardioprotective. I have found it helpful for cigarette smokers who have cut back to just a couple of cigarettes a day to hear that even one cigarette a day has half the cardiac risk of a pack a day, and then use motivational interviewing to help the patients achieve complete cessation. So, overall I think people in general should understand that it is great to decrease their consumption of these carcinogens to the lowest level possible, but that there still is a substantial risk from even small amounts of both cigarettes and alcohol....

geoff

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