Premature to conclude that there is a causal relationship

Reports from a number of observational studies have concluded that moderate drinking of alcohol is associated with a reduced risk of more than twenty different diseases and health problems. Is this a causal relationship or is it a statistical co-variation, the discussion goes. The Norwegian psychiatrist, Dr. Hans Olav Fekjær, has in the journal Addiction published a critical review of existing data.

Dr. Fekjær concludes that it would be premature to conclude that there is a causal relationship between moderate alcohol consumption and improved health. Furthermore, that there is evidence for the harmful effects of alcohol is undoubtedly stronger than the evidence for beneficial effects.

The Addiction article is openly accessible here.

“There is solid evidence that light or moderate drinkers have a reduced risk of several diseases which are influenced by life-style factors. Whether or not the lower risk is due to alcohol is a more complicated issue. Taken together, the existing evidence does not seem to meet the criteria for inferring causality, such as the classical Bradford Hill guidelines for causation in epidemiology”, concludes Dr. Fekjær in the Addiction article.

Dr Fekjær found three basic reasons for questioning the causal association of moderate drinking and a reduced health risk are: the lack of dose-response relationships; the characteristics and lifestyles of today’s abstainers and moderate drinkers; the lack of plausible biological mechanisms; the problems in the classification of drinking groups, and; the general limitations of observational studies.

In a popularized article in the Norwegian newspaper Aftenposten Dr Hans Olav Fekjær has claimed that it would be one of the greatest sensations in the history of modern medicine if the alcohol molecule should prove to prevent such a large number and wide variation of diseases as is often reported in newspapers.