DLM: Alcohol (2001)

Study Design:
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Quality Rating:
Research Purpose:

To examine the association between intake of different types of alcoholic beverages and mortality.

Inclusion Criteria:

Subjects were a subsample of the Copenhagen city heart study, aged 20 or more, living in the Osterbro-area of Copenhagen in 1976.

Exclusion Criteria:
  • Subjects who reported having more than five drinks per day of beer, wine or spirits
  • Subjects who abstained from drinking due to medical treatment or dipsomania.
Description of Study Protocol:
  • 6,051 women and 7,234 women, 30 to 70 years of age taken from a random, age-stratified sample of 19,698 from 87,172 living in Copenhagen, Denmark
  • Subjects completed self-administered questionnaires related to health characteristics including: Alcohol intake, smoking, education and household income
  • Alcohol consumption divided into categories of beer, wine and spirits with frequency of each
  • Population sample followed until January 1988 and outcomes analyzed.
Data Collection Summary:
  • Self-administered questionnaire on health, education, income, alcohol use and smoking collected 1976 to 1978
  • Coded follow-up on medical outcomes of subsample population through January 1988 including death certificates from the National Board of Health
  • Height and weight used to calculate BMI
  • Alcohol intake determined by asking if beer, wine or spirits was taken hardly ever/never, monthly, weekly or daily
  • Smoking amounts measured as non-smoker, former smoker (number of years) and amount of tobacco per day
  • Outcome measures: Number and time of cause-specific deaths from 1976 to 1988.
Description of Actual Data Sample:
  • Alcohol consumption:
    • 5,858 drank both wine and beer
    • 5,408 drank both wine and spirit
    • 4,629 drank spirit and beer
    • 77 drank wine, beer and spirit daily
    • 2,745 (2,120 females, 625 males) never drank alcohol
  • Mortality: 
    • 2,229 total deaths (831 females, 1,398 males)
    • 1,119 deaths (354 females, 765 males) from cardiovascular and cerebrovascular disease.



Summary of Results:
  • Relative risk (RR) of alcohol consumption on mortality compared to non drinkers:
    • Wine (three to five glasses per day) 0.51 (95% CI, 0.32 to 0.81)
    • Spirits (three to five per day) 1.34 (95% CI, 1.05 to 1.71) 
    • Beer (three to five per day) 0.72 (95% CI, 0.61 to 0.88) 
  • Wine drinking showed the same relation to risk of death from cardiovascular and cerebrovascular disease as to risk of death from all causes
  • Low to moderate intake of wine is associated with lower mortality from cardiovascular and cerebrovascular disease and other causes
  • Similar intake of spirits implied an increased risk, while beer drinking did not affect mortality.
Author Conclusion:

Light and moderate wine drinking, in contrast with beer and spirits drinking, is associated with a strong dose-dependent decrease in all cause mortality. This is attributable to a decrease in mortality from cardiovascular and cerebrovascular disease, as well as from other causes.

Funding Source:
Government: Danish National Board of Health
Reviewer Comments:
  • Very large sample, but no dietary intake information 
  • Unclear if height and weight reported or measured and if BMI changed over time.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.6. Were extra or unplanned treatments described? No
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes