Critique 055: Alcohol intake and “successful ageing” – 8 September 2011

Sun Q, Townsend MK, Okereke OI, Rimm EB, Hu FB, Stampfer MJ, Grodstein F.  Alcohol consumption at midlife and successful ageing in women: A prospective cohort analysis in the Nurses’ Health Study.  PLoS Med 8(9): e1001090. doi:10.1371/journal.pmed.1001090

Authors’ Abstract

Background: Observational studies have documented inverse associations between moderate alcohol consumption and risk of premature death. It is largely unknown whether moderate alcohol intake is also associated with overall health and well-being among populations who have survived to older age. In this study, we prospectively examined alcohol use assessed at midlife in relation to successful ageing in a cohort of US women.

Methods:  Alcohol consumption at midlife was assessed using a validated food frequency questionnaire.  Subsequently, successful ageing was defined in 13,894 Nurses’ Health Study participants who survived to age 70 or older, and whose health status was continuously updated.  ‘‘Successful ageing’’ was considered as being free of 11 major chronic diseases and having no major cognitive impairment, physical impairment, or mental health limitations.  Analyses were restricted to the 98.1% of participants who were not heavier drinkers (> 45 g/day) at midlife.  

Results:  Of all eligible study participants, 1,491 (10.7%) achieved successful ageing. After multivariable adjustment of potential confounders, light-to-moderate alcohol consumption at midlife was associated with modestly increased odds of successful ageing.  The odds ratios (95% confidence interval) were 1.0 (referent) for nondrinkers, 1.11 (0.96–1.29) for ≤ 5.0 g/d, 1.19 (1.01–1.40) for 5.1–15.0 g/d, 1.28 (1.03–1.58) for 15.1–30.0 g/d, and 1.24 (0.87–1.76) for 30.1–45.0 g/d.  Meanwhile, independent of total alcohol intake, participants who drank alcohol at regular patterns throughout the week, rather than on a single occasion, had somewhat better odds of successful ageing; for example, the odds ratios (95% confidence interval) were 1.29 (1.01–1.64) and 1.47 (1.14–1.90) for those drinking 3–4 days and 5–7 days per week in comparison with nondrinkers, respectively, whereas the odds ratio was 1.10 (0.94–1.30) for those drinking only 1–2 days per week.

Conclusions: These data suggest that regular, moderate consumption of alcohol at midlife may be related to a modest increase in overall health status among women who survive to older ages.

Forum Comments

Background:  Numerous studies have indicated that moderately drinking adults are a considerably lower risk of cardiovascular diseases, are at lower risk of dementia, and have lower risk of total mortality.  This study developed a definition of “successful ageing” that consisted of survival to age 70 years, not having a major chronic disease (such as coronary disease, cancer, stroke, diabetes), and having no major cognitive impairment, physical impairment, or mental health problems.  Their results indicate that moderate drinkers, especially those consuming wine and drinking regularly (especially those drinking on 5 or more days per week) were more likely to exhibit such successful ageing. 

Comments on this paper:  In this cohort of American female nurses, there were almost 14,000 women with data in middle age who were alive and furnishing further data an average of 16 years later.  (More than 5,000 women had died before reaching age 70.)  Excluded from the analyses were 130 women who had a previous diagnosis of alcohol dependence or chronic liver disease, 674 who stated that they had substantially reduced their intake, and 268 subjects reporting more than 45 g/day of alcohol.  Hence, the results relate to moderate drinkers.

The investigators used the amount of alcohol reported on two separate occasions (at an average age of 58 years) for estimating alcohol use, and carried out appropriate analyses, including sensitivity analyses.  Sub-analyses included evaluations when subjects dying before the age of 70 were included and when analyses were limited to non-smokers. 

There were few differences between results when analyses were adjusted only for age and for a large number of lifestyle variables.  To avoid reverse causation (women stopping drinking due to the development of illness), there was a lag period averaging 16 years between the assessments of alcohol intake and the evaluation of the components of successful living.

The key findings of the study indicate that, in comparison with nondrinkers, consumers of 5.1-15.0 (up to a little over 1 typical drink/day) and 15.1-30 g of alcohol per day (between 1 and 2 ½ drinks per day) had 19% and 28%, respectively, greater chance of exhibiting successful ageing.  In sub-analyses, the findings of successful ageing were particularly seen for those consuming alcohol on 3-4 days per week (OR = 1.29) and 5-7 days per week (OR = 1.47).  Women reporting drinking on only 1 to 2 days per week showed an OR of 1.10 (not statistically significant) for successful ageing, in comparison with nondrinkers.  Further, the favorable effects on successful ageing were primarily among consumers of wine (but the authors state that the large majority of subjects consumed wine, so there may not have been adequate numbers of consumers of other beverages to provide reliable results). 

One Forum reviewer commented: “The paper is well written, and strengths and limitations are described.  Despite the necessary adjustments for confounding factors in the multivariate models, confounding remains a possibility, as ‘successful agers’ tend to be healthy in many ways – are leaner, have less hypertension, and lower cholesterol values.   However, the study supports what has been shown repeatedly: regular, moderate drinking, especially of wine, is associated with beneficial health outcomes among women.”

Another reviewer stated:  “This is a good and interesting study with valuable information for women in middle age: regular and moderate drinking is associated with overall benefits in spite of possible increased risks from alcohol of cancers such as breast cancer.”

Comments on definition of “successful ageing”  One Forum reviewer took issue with the definition used in this paper of “successful ageing.”  “Only 10 percent of the study group met the requirements of successful aging.  I know I am quibbling about semantics, but it would be more accurate, not to mention diplomatic, to use other words.”  He continued: “Many great minds of this world and leaders (including Einstein, Churchill, Presidents John Adams and Abraham Lincoln) prospered despite life-long disabilities that would disqualify them from being deemed successful agers.  A more important mark of success, however defined, might include achievement despite obstacles.”

Forum Summary

Among 13,894 women in the Nurses’ Health Study, investigators prospectively examined alcohol use assessed at midlife in relation to “successful ageing,” which was defined as survival to age 70 years, not having a major chronic disease (such as coronary disease, cancer, stroke, diabetes), and having no major cognitive impairment, physical impairment, or mental health problems.  Only 11% of the women met these criteria. 

The results indicate that moderate drinkers, especially those consuming wine and drinking regularly, were more likely to exhibit successful ageing.  For average amount consumed, the largest benefit (an increase of 28%) was among women who reported 15.1 – 30 g of alcohol per day (an average of just over 1 to 2 ½ drinks per day), when compared with non-drinkers.  The frequency of drinking was especially important: in comparison with nondrinkers, women who drank only on 1 to 2 days per week had little increase in their risk of successful ageing, but those drinking on at least 5 days per week had almost a 50% greater chance of successful ageing.

Forum reviewers had some questions about the definition of “successful ageing” used in this study.  It is believed that a much greater percentage of people who may not meet these criteria make huge contributions to society and should be considered “successful.” 

In summary, these results support the findings of earlier studies showing that many aspects of successful ageing, in addition to just survival, are favorably affected by regular, moderate consumption of alcohol. 

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Contributions to this critique by the International Scientific Forum on Alcohol Research were made by the following members:

Gordon Troup, MSc, DSc, School of Physics, Monash University, Victoria, Australia

Arne Svilaas, MD, PhD, general practice and lipidology, Oslo University Hospital, Oslo, Norway

Harvey Finkel, MD, Hematology/Oncology, Boston University Medical Center, Boston, MA, USA

Erik Skovenborg, MD, Scandinavian Medical Alcohol Board, Practitioner, Aarhus, Denmark

R. Curtis Ellison, MD, Section of Preventive Medicine & Epidemiology, Boston University School of Medicine, Boston, MA, USA