EAL

Alcohol

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine the association between alcohol consumption and CHD among men with Type 2 diabetes.

Inclusion Criteria:

Male
Enrolled in Health Professionals Follow-up Study (HPFS)
Reported physician’s diagnosis of diabetes mellitus at age 30 years or older
Reported any of following:
- One or more classic symptoms of diabetes plus elevated plasma glucose: Fasting at least 7.8mmol per L, random at least 11.1mmol per L
- In absence of symptoms, two or more raised glucose levels (standards as above) on two separate occasions or 11.1mmol per L after two hours on glucose tolerance testing
Treatment with hypoglycemic drug or oral hypoglycemic agent.

Exclusion Criteria:

Subjects with a history of CHD (MI, angina or coronary revascularization), stroke or cancer reported at baseline
Patients with a prior MI and cancer were subsequently excluded from analyses.

Description of Study Protocol:

Design

Longitudinal study using self-reported data
Relative risk of fatal and nonfatal myocardial infarction (MI) determined relative to alcohol intake. Person-months of follow-up were accumulated for patients with diabetes starting with the date of return of the 1986 questionnaire for men diagnosed with diabetes at enrollment or with the return of the questionnaire on which Type 2 diabetes was first reported until the occurrence of a CHD end point, death or January 31, 1996.

Blinding Used

Not applicable.

Intervention

Alcohol consumption survey.

Statistical Analysis

Alcohol’s interaction with CHD risk factors (smoking, BMI, hypertension, family history of MI and hypercholesterolemia) were assessed by the likelihood ratio statistic (difference in deviance or in- 2 Log Likelihood) between the model containing the interaction of alcohol with each risk factor and the main effects model following a chi square distribution with two degrees of freedom.
Multivariate logistic regression was then used to estimate RRs of CHD over each two-year follow-up interval using the alcohol intake reported on the most recent questionnaire, adjusting for other potential confounders: physical activity (quintiles of metabolic equivalents spent weekly), body mass index (BMI) (less than 23kg per m², 23 to 24.9, 25 to 29.9, greater than 30kg per m²), smoking (never smoker, less than 10, 10 to 24, 25 to 44, 45 to 64, 65+ pack years), history of hypertension, high cholesterol, family history of MI, use of vitamin E supplements and dietary intake of trans fat, polyunsaturated fat (percent of total energy intake), fiber, folate and total calories.

Data Collection Summary:

Report of physician’s diagnosis of diabetes mellitus on any questionnaire 1986 to 1994
Supplementary questionnaire querying symptoms and clinical testing related to diagnosis
Validity of self-reported diagnosis verified in subsample, confirmed in 97%
Alcohol use determined from semi-quantitative food frequency questionnaires in 1986, 1990, and 1994
- Beer, wine, and spirits included
- Portion sizes specified: Can/bottle beer, 4oz wine and one drink or shot spirits
  - Asked how often, on average, consumed in past year.
    - Validated earlier by correlation with food records (r=0.86)
Nonfatal MI self-reported confirmed by reviewing med records for WHO criteria (characteristic symptoms plus typical electrographic changes or elevated cardiac enzymes)
Nonconfirmed MI included after ensuring that results similar to definite cases
Deaths reported by kin, work associates, or postal workers.
- Fatal CHD confirmed from med records or autopsy reports
- Sudden death within one hour symptom onset in man without known disease that would explain death considered fatal MI
For men with multiple end patients, follow-up ended with first event.

Description of Actual Data Sample:

N: 2,419 men; 11,411 person-years of follow-up after diagnosis
Other relevant demographics:
- 39% no alcohol use (no alcohol)
- 20% at least 0.5 drinks per day
- 20% 0.5 to two drinks per day
- 10% greater than two drinks per day, median 2.8 drinks.

Summary of Results:

150 new cases CHD documented
- 81 nonfatal
- 69 fatal
Age adjusted relative risks (total MI), P=0.06):
- At least 0.5 drinks per day: 0.76
- 0.5 to two drinks per day: 0.64
- More than two drinks per day, median 2.8 drinks: 0.59
Relative risks (total MI), adjusted for BMI, smoking, family history MI, hypertension, hypercholesterolemia, duration diabetes, physical activity, vitamin E supplementation and intakes of trans fat, PUFA, fiber and folate (P=0.03):
- At least 0.5 drinks per day: 0.78
- 0.5 to two drinks per day: 0.62
- More than two drinks per day, median 2.8 drinks: 0.48
No differences in relative risk found among beverage type
Compared to non-diabetes from the HPFS, the inverse relationship of alcohol intake and risk of MI was stronger.

Author Conclusion:

Moderate alcohol consumption is associated with lower risk of CHD men with Type 2 diabetes
The inverse association was not confounded by other independent risk factors for CHD
For most diabetics, the benefits of moderate alcohol use outweigh the risks.

Funding Source:

Government:

NIH

University/Hospital:

Brigham and Women's Hospital and Harvard School of Public Health,

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

Although the study relies on self-reported data, validation efforts indicated that there was little if any distortion in the reports. Findings are consistent with other epidemiologic studies with diabetics.
The sample was limited to male health professionals, presumably largely Caucasian. This is an important limitation given that patterns of alcohol use differ among males and females, various ethnic groups and persons varying in socio-economic status.
The strongest findings were found after the data was adjusted for differences in numerous factors. Although this process isolates the influence of alcohol consumption, it makes it difficult to apply conclusions to individuals.

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?	N/A
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	N/A
	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?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	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?	N/A
	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?		N/A
	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%.)	N/A
	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.)	???
	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?		N/A
	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?	Yes
	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?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	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?		N/A
	7.1.	Were primary and secondary endpoints described and relevant to the question?	N/A
	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?	Yes
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