This appears to be a well-done analysis of the relation of moderate drinking with depression among adult subjects at high-risk of cardiovascular disease. There were appropriate restrictions to entry into the study cohort and important sensitivity analyses were carried out. The analyses are based almost exclusively on “moderate” drinkers, as people exceeding certain amounts of alcohol or testing positive on the CAGE questionnaire (a measure of alcohol misuse) were excluded.
It was a large prospective study, based on data from more than 5,000 55-80 years old subjects who were followed for up to 7 years for the initial development of depression. A total of 443 subjects had a clinical diagnosis of depression made or began to use anti-depressive medications during follow up. The subjects in this study were at increased risk of cardiovascular disease due to diabetes (about one-half of participants) or other risk factors. Essentially all were primarily wine drinkers.
There were repeated assessments of alcohol consumption, every two years, with the development of depression only within the second year after each alcohol assessment counted (to prevent reverse causation). A rather complete list of potentially confounding variables was available. In sensitivity analyses, the authors evaluated lifetime non-drinkers vs current non-drinkers, men vs women, subjects by age groups, excluding diabetics, etc. Only the latter (diabetes) changed the estimates of effect. The key findings were that subjects reporting >5-15 grams/day of total alcohol intake, and wine drinkers of 2-7 drinks/week, were at a lower risk of developing depression than were non-drinkers.
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