A single drink a day unsafe? Not so simple.

I wanted this blog to be about the healthy role of wine in everyday life that I observed on my trip to Austria and Hungary last week, not the latest salvo against alcohol from another big study. It’s getting tiresome seeing an important issue being muddled in the search for clarity, and I don’t like the idea that a reasonable person viewing the same data but seeing something else might be seen as an apologist for the alcohol industry. Yet the same mistakes endure, both in the studies themselves and the reporting on them. They are technically correct and fundamentally wrong at the same time.

First the happy part: What I saw in Europe, as I have on previous trips, was a view of wine as a normal part of everyday life. Wineries are still often family businesses, with everyone contributing. At a winery in the Etyek region of Hungary we were served by the owners and their teenage daughter. In our wine tasting group was a 20-year old woman from Finland, on holiday with her mother and grandmother. The only one in our entourage who might have enjoyed the wine a tiny bit too much was a surgeon from Latvia. The memory of seeing him dancing on a barrel will endure, a reminder that wine can unquestionably bring happiness.

Now to the study, invariably reported as condemning any amount of alcohol from any source. Funded by the Bill & Melinda Gates Foundation here in Seattle, the study updates a survey of worldwide causes of death and “disability-adjusted life years” or DALYs.[i]In comparing aggregated data from 1990 and 2010, an increase in the role of alcohol was observed, so this recent report followed that trend through 2016. Tabulating 195 locations for both sexes and for 5-year age groups beginning at 15 years, the authors looked at hundreds of data sources and studies.

It was a massive effort. In the 1990-2010 article, just the list of contributing authors spans 4 pages, and some 194 references are cited. In that study, the authors concluded that “the contributions of risk factors to regional and global burden of diseases and injuries has shifted substantially between 1990 and 2010, from risk factors that mainly cause communicable diseases in children to risk factors that mainly cause non-communicable diseases in adults.” In 1990, the top 3 contributors were childhood malnutrition, household air pollution from solid fuels (e.g. wood, dung, coal), and tobacco use. By the end of the first decade of the 21st century, the primary offenders were high blood pressure, tobacco, and alcohol.

Before I get into a critique of the study, I think it’s important to point out what great work the Bill & Melinda Gates Foundation does for world health issues. The types of data that studies like this one produce are vital in order to determine how scarce resources should be allocated. With that said, the emphasis on the apparent ascent of alcohol as a public health concern undermines the encouraging news about progress in prevention of childhood illnesses. Worldwide, people are living longer due to “a combination of the ageing population, substantial achievements in lowering mortality of children aged younger than 5 years, and changes in risk factor exposure.”  The issues are morphing from malnutrition to obesity, and from poverty to the conditions of excess consumption. 

The return of the J-shaped curve

One thing that jumps out in looking at the 2016 article is that for both men and women, the plots for heart disease and diabetes actually show a J-shaped curve, for all types of alcohol. It disappears only when all causes of death and disability are lumped together. This is where the study starts to go awry, because correlation does imply causation; for example, the study also shows a reported association of alcohol and tuberculosis, which is an infectious disease. Counting that against a pattern of potentially healthy wine consumption is misleading and logically questionable. Are we to conclude that  alcoholics at risk for TB in developing countries cancel out the benefits of a glass of wine with dinner in Europe or North America? There is a similar problem with breast cancer: Though there is a correlation, alcohol consumption is a possible contributing factor rather than a sole cause, and the potential benefits of red wine would be easily obscured when the data is formatted in this way.

As with other large studies on alcohol and health, the question of whether wine has a privileged position is often nuanced. As I noted in my May 2018 post, habits of drinking have changed around the globe, with a shift away from the traditional model of wine with meals. Alcohol consumption around the globe was distinctly different in 1990, when populations with traditional habits could be statistically isolated. This makes comparisons for wine exceptionally challenging today. Even if it were possible to add drinking patterns (as opposed to total average daily consumption) into an already colossal data set would have only widened the margins of uncertainty.  In the search for granular detail with number crunching on this scale, nuggets of wisdom aren’t easily sifted out. The complexity of the math requires that certain things be oversimplified, and concluding that a single drink a day is risky overstates the case.

Yet the senior author of the project, Dr. Emmanuela Gakidou of the Institute for Health Metrics and Evaluation at the University of Washington was quick to point out that “the health risks associated with alcohol are massive. Our findings are consistent with other recent research, which found clear and convincing correlations between drinking and premature death, cancer, and cardiovascular problems. Zero alcohol consumption minimizes the overall risk of health loss.” Even if strictly true, there is no accounting for quality of life, a known correlate of wine consumption.[ii]When I see Dr. Gakidou dancing joyfully on a barrel, I may change my mind.

Despite the staggering number of references, there is one missing, and from the same journal. A 1979 article in The Lancet by St. Leger, Cochrane, and Moore[iii]found an indisputably clear inverse correlation of heart disease with wine consumption by country, setting the foundation for what became known as the French Paradox more than a decade later. That is where the final contradiction lies: Even as world health improves, we move away from the healthy way of drinking wine that sustained humanity for millennia.

[i]Lim SS et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2012 December 15; 380(9859): 2224–2260.
[ii] Alcoholic beverage preference, 29-year mortality, and quality of life in men in old age. Strandberg TE1, Strandberg AY, Salomaa VV, Pitkälä K, Tilvis RS, Miettinen TA. Gerontol A Biol Sci Med Sci. 2007 Feb;62(2):213-8.
[iii] St Leger AS, Cochrane AL, Moore F. Ischaemic heart-disease and wine. Lancet. 1979 Jun 16;1(8129):1294.

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