> researchers followed 1824 people over a total of 20 years, as they aged between 55 and 65. Of those who abstained entirely, 69 percent died. Among those who drank in "moderate" amounts, 41 percent died—which was 23 percent less than the "light" drinkers. Even "heavy drinkers" fared better than abstainers, with just 61 percent passing away during the study period.
I believe that's the case when the correlation is similar to global warming and number of pirates [1]
Alcohol is really getting a beating these days. Just like anything, in moderation it actually is ok, and has some benefits. Studies on pubmed show light to moderate alcohol consumption helps with:
Not to sound trite but the problem isn't alcohol it is problem drinkers. Those who can drink moderately do so with any consequential benefits which accrue. Those who can't drink moderately always start out thinking they are drinking moderately but unthinkingly fall into "just one more".
A problem drinker (or a 'seasoned' smoker) cannot partake moderately, they don't know how to stop. For these people the moderate drinking message is misleading and harmful.
Haven't read the book the article is based on because it appears to be out of print in the UK (or at least very expensive) but another factor contributing to alcoholism is a person's capacity to take alcohol. The more tolerant you are the more you drink to get a buzz, and if you are in the habit of drinking heavily on a regular basis then the other health issues - such as habituation - have a greater chance to develop.
Please find the (apparently obvious) problem with the results. I keep seeing articles about how study after study confirms the alcohol/longevity link, so if you can find the common problem those studies all have, (very minor) fame awaits! :)
The one problem that I can see is the fact that these studies can only correlate people's behaviour and their longevity, as opposed to randomly assigning people into groups of drinkers/teetotallers. It is a fair assumption that people who don't drink differ from other people in other aspects, too. (e.g. they might be more religious, or not drink for health reasons, or have a less active social life etc). You obviously cannot do double-blind studies about long-term alcohol consumption, so correlation is the best we have, but one must still be careful when interpreting these kinds of results.
There are numerous experimental designs that, while they don't have the predictive value of double-blind experiments, are found to have significant predictive value. The simplest way is to control for the confounding factors such as you describe.
Full disclojure (hah): I don't drink though I don't consider myself a teetotaler. I really don't mind what others do to their bodies.
not drink for health reasons
Yes this sounds plausible. Even if the person isn't unhealthy maybe their family history is such that they still don't drink.
have a less active social life etc
As a semi-introvert[1] I always wonder how true this is for the minority of us that much prefer this so called social isolation. I'd take a night alone or with a small group of friends over a bar or conference absolutely every time always. Of course that is assuming there are no other external influences - which is rarely (I'd say never but we're on HN...) the case. All that really matters is whether you are suffering from anxiety rather than loneliness[2].
[2] I can't remember the last time I was lonely or bored. Hmmm, is this really that unusual amongst similar introverts? I just consider myself somewhat curious and self-motivated.
I think the argument may exist that if you didn't die from alcohol abuse early enough, then your body might have higher than average resistance towards various harmful substances. Therefore, alcohol usage is just correlation, while the real reason for increased longevity is the said resistance.
This would require evidence of many young deaths from alcohol abuse. As far as I know, even heavy drinkers are pretty unlikely to die from their habit before age 50. Moderate drinkers, reflected as the healthiest in the study, are tremendously unlikely to die from alcohol abuse early in their lives.
And again, maybe the reason non-drinkers show as much longevity as they do is because those are the ones who have an increased resistance to the negative effects of abstinence. Maybe most of them die much younger. Since non-drinkers are such a minority in most places, this is actually more likely, since the die-off would be less noticeable than if everybody who drank an occasional beer dropped dead at age 40. (I still don't think this is likely either, incidentally.)
> This would require evidence of many young deaths from alcohol abuse. As far as I know, even heavy drinkers are pretty unlikely to die from their habit before age 50.
Don't forget people who have died as a result of accidents while intoxicated (driving drunk, etc.) or have been incarcerated for drunken infractions. They may be excluded from those statistics, adding a kind of bias. Not sure if the total is high enough to impact the study's results, but it's worth checking.
If there were no causation then you'd expect to see the same J-curve for all causes of mortality, but that's not what you see. For example the more you drink the lower your risk of heart attack, regardless of how much you drink. There's actually very clear causation for certain causes of mortality and morbidity, it's just that the picture is a little bit murky when looking at total mortality and morbidity.
I believe that's the case when the correlation is similar to global warming and number of pirates [1]
[1] http://www.tonguetiedandtwisted.com/wp-content/uploads/2009/...
[add]: i.e. no correlation.