The authors state that they did this study to assess the prospective association between alcohol consumption and self-rated health: in particular whether there is a relationship between stable alcohol intake and health; whether health is affected by changes in alcohol consumption; whether having a chronic condition alters the relationships between stable and changing alcohol intake and health; and whether the health of longer-term abstainers is different from more recent and intermittent abstainers.
The researchers carried out a longitudinal analysis of a prospective, population-based study in Australia. There were a total of 13,585 randomly selected 4550-year-old women surveyed in 1996, of whom 9,396 (69%) were resurveyed in 1998, 2001 and 2004. They related alcohol use to estimates for the General Health subscale of the SF-36 for different levels of alcohol intake adjusted for having a chronic condition, depression, smoking and other factors.
Results of longitudinal models of consistent alcohol intake showed mean scores for general health of moderate drinkers were significantly better than that of non-drinkers [mean difference = 4.3, standard error (SE) = 0.61], occasional drinkers (mean difference = 3.1, SE = 0.52) and heavy drinkers (mean difference = 2.1, SE = 1.00). Among moderate drinkers, a decrease or variation in alcohol consumption was associated with a significant decline of three to four points in general health. Similar results were obtained when women with an existing chronic condition were excluded from these models. The health of recent abstainers and intermittent drinkers was the same as longer-term abstainers. The authors conclude that consistent moderate drinkers had the best health even after adjustment for having a chronic condition, depression and life-style factors. Poorer health was associated with decreased alcohol intake among occasional and moderate drinkers.
Comments by professor R. Curtis Ellison: ‘This paper is based on a rather complex and extensive analysis of data from a study of approximately 10,000 women in Australia, initially age 45-50 at a baseline examination in 1996. The study was large enough to have adequate numbers at baseline of both abstainers (> 2,000) and heavy drinkers (n=716), with the latter reporting > l40 g of alcohol per week (more than 14 units of 10g/unit, or the equivalent of about 10 typical US drinks (l2g of alcohol) each week. During follow up over 8 years, 4 assessments of self-reported general health were obtained using a standard instrument. The analysis compared alcohol intake with health assessments of women, with separate analyses for stable drinkers (similar intakes over time) and those who changed their intake during follow up. Alcohol consumption prior to the baseline assessment (at age 45-50) was not known.
The overall results show that stable moderate drinkers had better overall health than non-drinkers, occasional drinkers, or heavy drinkers. Further, moderate drinkers who decreased their alcohol intake showed a decrease in health status and the occasional drinkers who increased their intake tended to show improvement in health scores. These results were robust when adjustments were made for depression, having a chronic condition (e.g., cancer, heart disease, hypertension, diabetes), and other life-style factors.
It is always difficult to know how to judge changes in alcohol intake in observational studies, as the reason for a change in intake is generally not known. In this study, the investigators state that such changes in alcohol intake were apparently not related to the occurrence of a new chronic medical condition. Further, in this study at least, information on depression and many other factors were also adjusted for, and the results still show that subjects who stopped moderate drinking had poorer health outcomes’.
Source: Powers JR, Young AF. Longitudinal analysis of alcohol consumpation and health of middle-aged women in Australia. Addiction 2008;103:424-432.