Journal Club Alcohol, Other Drugs, and Health: Current Evidence May-June 2008

Featured Article Alcoholic beverages and incidence of dementia: 34-year follow-up of the prospective population study of women in Göteborg Mehlig K, et al. Am J Epidemiol. 2008;167(6):

Study Objective To determine whether an association exists between the use of different types of alcoholic beverages (wine, distilled spirits, beer) and the risk for dementia.

Study Design A random sample of 1462 Swedish women aged years at baseline were followed in this prospective population-based study. –Subjects were followed over 34 years. –Alcohol consumption, smoking, and other lifestyle habits were recorded at baseline and on 4 subsequent occasions. –Analyses were adjusted for education and socioeconomic status.

Assessing Validity of an Article about Prognosis Are the results valid? What are the results? How can I apply the results to patient care?

Are the Results Valid? Was the sample representative? Were the subjects sufficiently homogeneous with respect to prognostic risk? Was follow-up sufficiently complete? Were objective and unbiased outcome criteria used?

Was the sample representative? Subjects were selected randomly from a national registry in Sweden. The sample was large (N=1462). All subjects were women, and all ranged in age from years at baseline.

Were the subjects sufficiently homogeneous with respect to prognostic risk? Subjects were selected randomly based on age and gender from a single city in Sweden. At baseline: –none of the patients met criteria for dementia –46% smoked tobacco, 39% had hypertension, 1% had diabetes, 0.1% had suffered a stroke

Was follow-up sufficiently complete? Subjects were assessed at baseline and on 4 subsequent occasions over 34 years ( ). Participation in the 4 follow-up interviews was 91%, 83%, 70%, and 71%, respectively, among those still alive.

Were objective and unbiased outcome criteria used? Diagnoses of dementia, according to formal diagnostic criteria, were based on physical and neuropsychiatric examinations by psychiatrists or psychiatric nurses and corroborated by interviews with personal contacts (e.g., family). For those lost to follow-up, diagnoses were based on medical record review. Blinding was not reported.

What Are the Results? How likely are the outcomes over time? How precise are the estimates of likelihood?

What are the results? 162 women had a diagnosis of dementia during the 34-year follow-up. –Wine consumption was shown to have a protective effect (hazard ratio [HR]=0.6). –This association was strongest in women whose only alcohol consumption was wine (HR=0.3). –Spirit consumption was associated with a slightly increased risk of dementia (HR=1.5). –Beer consumption had no effect on dementia risk.

How likely are the outcomes over time? Analyses were adjusted for hypertension, body mass index, triglycerides, cholesterol, smoking, physical activity, diabetes, myocardial infarction, stroke, education, social class, and lifestyle. Adjustments were made for change in drinking status over time. The observations period, 34 years, was appropriate for the outcome of interest, dementia, in this cohort, who were age years at baseline.

How precise are the estimates of likelihood? 95% Confidence Intervals (CI) in the updated multivariate model: –Protective effect of wine consumption: HR=0.6; 95% CI, 0.4, 0.8 –Protective effect in women who consumed wine only: HR=0.3; 95% CI, 0.1, 0.8 –Consumption of spirits at baseline and increased risk of dementia: HR=1.5; 95% CI, 1.0, 2.2

How Can I Apply the Results to Patient Care? Were the study patients and their management similar to those in my practice? Was follow-up sufficiently long? Can I use the results in the management of patients in my practice?

Were the study patients similar to those in my practice? All patients were women aged and living in Göteborg, Sweden, at baseline. Applying the results to male populations and those with differing levels of baseline risk should be done with caution.

Was follow-up sufficiently long? Patients were followed for 34 years.

Can I use the results in the management of patients in my practice? Although findings of this population-based study suggest that wine decreases dementia risk, and consumption of spirits may increase it, other lifestyle factors may have influenced results. Further studies including randomized controlled trials with both men and women, and based on a more heterogeneous sample, are needed before recommending moderate wine consumption to patients at risk for dementia.