We generally assume moderate drinking (two standard drinks per day) is good for our health.
This idea comes from studies over the past three decades showing moderate drinkers are healthier and less likely to die prematurely than those who drink more, less, or don't drink at all. I would be glad if this were true.
When we control for the influence of wealth, then alcohol's apparent health benefit is much reduced in women aged 50 years or older, and disappears completely in men of similar age.
Health, wealth and alcohol intake
Limited research shows moderate drinking is linked to better health in older adults aged between 55 to 65. But this work failed to account for one of the main factors influencing both health and alcohol use: wealth.
To address this question, we explored whether older moderate drinkers are healthier because of their drinking, or because their wealth affords them healthier lifestyles.
We used data from 2,908 older New Zealanders (average age 65) in the government-funded Health, Work and Retirement Study at Massey University. This is New Zealand's foremost longitudinal ageing study, spanning ten years, including a representative sample of the population aged 50 and over.
We split the adults aged 50 or older into groups reflecting their average level of drinking, from non-drinkers through to those drinking three or more drinks a day. We also made sure to clearly differentiate "sick quitters" (those who stopped drinking due to poor health) from "lifetime abstainers" (those who have never drunk alcohol).
We first compared the health of these groups and confirmed the trend in previous research: moderate drinkers of both sexes were much healthier than heavier drinkers or non-drinkers. This analysis relied on study participants rating their own health in terms of perceived levels of physical health and limitations in physical activity.
But we also found moderate drinkers of both sexes to be wealthier than heavier drinkers or non-drinkers. And, when we took wealth out of the equation, moderate alcohol use was not linked with better health in men.
In women, moderate alcohol use was still linked with a health benefit, but given the few women drinking moderately (4%) this effect was questionable.
Our findings offer little support for a health-protective effect of moderate drinking. Instead, they suggest that older adults' health and the amount they drink mainly reflect wealth and socioeconomic status.
Perhaps the relationship between alcohol intake and health in older drinkers reflects who is drinking not how much they drink.
Re-examining moderate alcohol intake
Thousands of studies spanning multiple decades show that alcohol use is linked with more than 200 health conditions and is responsible for 6% of deaths worldwide. Scientists are still looking for a plausible mechanism that would allow alcohol - a carcinogen and a key predictor of sickness and early death - to have a health-protective effect.
Researchers are also increasingly concerned about the validity of previous claims on the health benefits of moderate drinking. Reviews of studies supporting a relationship between alcohol and health show many grouped "sick quitters" (previous drinkers who stopped due to poor health) with those who have never regularly drunk alcohol.
The presence of these sick ex-drinkers in analyses makes the health of non-drinkers seem much poorer than that of moderate drinkers.
Many studies also failed to account for differences between moderate drinkers and other groups on factors known to predict health; moderate drinkers tend to have better wealth, education, physical activity levels and diet.
After controlling for such differences as we recently did, there is little evidence that moderate alcohol consumption has a health benefit compared with lifetime abstention or occasional drinking.
Older adults beware
Older adults are now a rapidly growing population for whom alcohol use can have serious ramifications and we must consider any claims of health benefits cautiously.
Compared to younger adults, older adults are at greater risk of poor health outcomes from drinking alcohol. Older adults process alcohol less effectively, are more likely to have health conditions that alcohol can worsen and to use medications that alcohol interferes with.
Yet, recent research indicates newly retiring baby boomers are drinking more alcohol, more often, than previous generations of retirees. And many older adults still assume moderate drinking is beneficial, some actively drinking for "medicinal purposes".
Older drinkers are one of the most at-risk populations from alcohol-related harm, yet they are also one of our least understood drinking groups.
If drinking has no benefits for older adults' health and they are at increased risk of alcohol-related harm, then how much is too much for older adults to drink? My international colleagues and I are trying to answer this question.