By Eric Crampton 02/09/2016


In a recent Dominion Post editorial Doug Sellman’s right about one thing: alcohol consumption does increase your risk of cancer.

But unless your family history of cancer gives you a lot more to worry about than your family history of heart disease, you should be looking at the stats on all-source mortality rather than the stats for any particular disorder.

The latest American Journal of Public Health has a pile of articles looking at results from the Nurses’ Heath Study. That study’s followed 120,000 nurses over decades. I’ve previously noted findings from that study showing that moderate alcohol consumption is associated with more successful ageing.

In this month’s edition, Mostofsky, Mukamal, et al look over alcohol consumption and a wide range of disorders, along with all-source mortality. The findings (keeping in mind that a standard drink is 10 grams):

  • All-cause mortality:
    • light drinking, of 1.5-4.9 grams per day, gives a relative risk of 0.83 as compared to abstainers;
    • moderate drinking, of 5-29.9 grams per day, gives a relative risk of 0.88;
    • heavier drinking, >30 grams per day, gives a relative risk of 1.19

That’s the big one. Unless you have particular family histories to worry about, drinking about a standard drink per day reduces your risk of dying to 88% of that of a non-drinker. A glass of wine or beer every other day reduces it to 83%. These numbers are very close to the ones I usually report from DiCastelnuovo and Donati.

Here are all the subcategories of risk listed. I hadn’t realised the protective effects against diabetes were so strong. Alcohol is associated with higher risk of cancer, but lower risk of a lot of other things. That’s why I like the all-cause mortality figure. I also like the prior work on more successful ageing, because morbidity matters too.

Let’s jump to their conclusion before listing all the things.

As noted earlier, most of our work has focused on moderate alcohol consumption. The adverse effects of heavy consumption are well known. Although moderate drinking appears to increase the risk of colon and breast cancer, these risks are more than counterbalanced by the boost in cardiovascular health—especially in middle age and older, when CVD accounts for an increasingly large share of disease and deaths. We still do not have strong enough evidence to suggest that women who are nondrinkers start drinking later in life to reduce their risk of CVD or total mortality, although this would appear to be a reasonable option in the absence of any contraindication. However, there are many other lifestyle choices documented in the Nurses’ Health Study that can substantially reduce a woman’s risk of chronic disease without the potential downsides of alcohol.

Yeah, but are those other lifestyle choices as fun? And it isn’t like having healthy lifestyle choices across the board makes alcohol less helpful – it shows up as helpful even in studies restricted to people with healthy behaviours.

Bit different from the nonsense New Zealand ‘no safe level’ talk. Now here are the gory details on all kinds of illnesses and their associations with alcohol consumption.

  • Hypertension
    • light drinking (0.1-5 grams): relative risk of 0.88
    • light/moderate (5-10 grams): relative risk of 0.84
    • Elevated risk for >30 grams per day: relative risk of 1.61
  • Diabetes
    • Lowest Type 2 diabetes risk for those consuming 1-2 drinks per day: 40% lower risk than for lifetime abstainers. Smaller benefits for heavier drinkers.
  • Coronary Heart Disease
    • light to moderate drinking (0.1-14.9 grams) gives relative risk of 0.77; “12.6% of all confirmed CHD events could have been prevented if they had all adhered to this optimal level of alcohol intake.”
  • Stroke
    • Moderate consumption (5-15 grams/day) lowers stroke relative risk to 0.85.
    • Heavy consumption increases risk, but figures not provided.
  • Colon Polyps and Cancer
    • Heavier drinking (>30 grams per day) has:
      • 1.84 relative risk of colorectal adenoma.
      • 1.79 higher risk of hyperplastic polyp of the distal colon and rectum, which indicates high risk of colorectal carcinoma
  • Breast Cancer
    • There’s about a 10% higher risk per 10 grams per day alcohol intake.
  • Total Cancer
    • Cancer risk increases linearly in consumption, with highest risk among those drinking more than 45 grams per day: relative risk of 1.30.
  • Bone density and fractures
    • Moderate drinking increases bone density, but can lead to poor balance and falls; chronic heavy drinking can reduce bone density and lead to poor balance and falls. They report a relative risk of 1.73 for fractures for women of BMI less than 21 drinking more than 15 grams per day, but I start getting nervous when the data gets sliced that finely – I don’t know whether they were adjusting their confidence intervals for multiple testing.
  • Gallstones
    • Reduced risk of gallstones. Every 15 grams per day reduces risk of gallstones leading to cholecystectomy by 14%, with the lowest risk for daily drinking.
  • Cognitive function
    • At age 70, light drinking women had better cognitive functioning scores than non-drinkers.
  • Moderate drinking after diagnosis of chronic disease
    • Drinking in moderation among women with diabetes reduced risk of subsequent CHD;
    • Drinking did not affect prognosis after a diagnosis of colorectal cancer.

I really hate the obsession with “links to X” studies. There are all kinds of effects going either way from alcohol consumption, including that people enjoy the experience.

Update: I’d missed Sellman’s last line in that DomPost op-ed, where he talks about drinking’s negative effects on coronary health. Moderate drinking massively reduces your risk of CHD. People see what they want to see.

Featured image: Flickr / Quinn Dombrowski