EAL

DLM: Alcohol and Coronary Heart Disease (2007-2010)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

In regard to risk of cardiovascular disease, to clarify the relative roles of the quantity and frequency of alcohol consumption or consumption with meals

Inclusion Criteria:

enrolled in Health Professionals Follow-up Study
male
40-75 years of age at baseline
returned initial mail questionnaire

Exclusion Criteria:

history of myocardial infarction, angina, stroke, transient ischemic attack, claudication or cancer other than nonmelanoma skin cancer.
missing data on alcohol consumption
other technical problems with questionnaire
currently consumming no alcohol but reported having consummed alcohol in the preceding 10 years

Description of Study Protocol:

Recruitment

presumably volunteers from health careers: dentists, vets, optometrists, osteopathic physicians, and podiatrists

Design

Participations completed base-line diet and medical history and follow-up questionnaires every two years for 12 years. Deaths during the 12 years confirmed and associated with alcohol consumption patterns.

Blinding used (if applicable)

Intervention (if applicable)

Statistical Analysis

Calculated person-years from baseline to date of first CHD event or end of observation (12 yrs). Estimated relative risks with cumulative incidence ratios, adjusted for age and smoking. In multivariate analysis used pooled logistic regression to control for age, smoking status, BMI, aspirin use, hypertension, diabetes, parental history of premature myocardial infarction, enery intake, and energy-adjsuted intakes of Vit E, folate, saturated fat, trans fatty acids, and dietary fiber.

Data Collection Summary:

Timing of Measurements

Measurements obtained at baseline (1986) and every two years thereafter until coronary event or 12 years (1998). Not all variables were assessed at every observation.

Dependent Variables

Myocardial infarction (MI):
- 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 if participant required hospitalization and supplementary correspondence corroborated diagnosis.
- Deaths reported by kin, work associates, or postal workers.
  - Fatal CHD confirmed from med records or autopsy reports
  - Sudden death within 1 hr symptom onset in man without known disease that would explain death considered fatal MI

Independent Variables

Alcohol use determined from semi-quantitative food frequency questionnaires

Beer, wine, & spirits included
Portion sizes specified: can/bottle beer, 4 oz wine, & 1 drink or shot spirits; converted to ethanol consumption by multiplying consumption by ethanol content.
Asked how often, on average, consumed per week during past year.
Validated earlier by correlation with food records (r=0.79)

Control Variables

age, smoking, dietary intake, hypertension, diabetes, family history of premature MI, physical exertion, asprin use, and BMI assessed on various of the self-reported mailed questionnaires over the 12 years.

Description of Actual Data Sample:

Initial N: (e.g., 731 (298 males, 433 females)): 51,529 in Health Professionals Follow-up Study

Attrition (final N): 38,077 after application of exclusion criteria

Age: 40-75 years at baseline

Ethnicity: not reported

Other relevant demographics: all male, all highly educated professionals

Anthropometrics (e.g., were groups same or different on important measures) NA

Location: across USA

Summary of Results:

Relative risk of any MI predicted from updated alcohol consumption

Alcohol consumption	N	RR	95% Confidence intervals
0 g/day	255	1.00
0.1-4.9 g/day	430	0.97	0.83-1.13
5.0-9.9 g/day	206	0.80	0.66-0.96
10.0-14.9 g/ day (approx 1 serving)	167	0.65	0.54-0.80
15.0-29.9 g/day	189	0.71	0.58-0.86
30.0-49.9 g/day	133	0.67	0.53-0.83
> 50 g/day	38	0.55	0.39-0.78

Other Findings

Consistently similar risks with categories of frequency of alcohol use, regardless of amount consummed per drinking day.
the inverse association between frequency of alcohol consumption and MI was similar across age groups
Neither aspirin use or BMI modify the association of alcohol use and MI risk
Relative risks did not differ with type of alcohol consummed.
Drinking alcoholic beverages with meals was associated with similar risk as drinking outside of meals.
Increasing alcohol intake over the 12 yr of observation was associated with decreased risk (RR=0.55) when the increase was 10.0 g/day or more. Decreased alcohol consumption had insig effect on MI risk.

Author Conclusion:

Among men, consumption of alcohol at least 3-4 days/wk was inversely associated with MI risk. Neither type of beverage nor proportion consummed with meals substantially altered this association. Men who increased their alcohol consumption by a mod amt during follow-up had a decreased MI risk.

Funding Source:

Government:	NIH
University/Hospital:	Beth Israel Deaconess Medical Center, University of Sydney (Australia), Harvard School of Public Health, Brigham and Women's Hospital Harvard Medical School, Massachusetts General Hospital

Reviewer Comments:

Both this investigation and Tanasecu et al '01 use data from the Health Professionals Follow-up Study. The Tanasecu report uses only diabetics whereas this study includes both diabetics and nondiabetics.

This study is strengthened by the use of updated alcohol consumption data as opposed to relying on baseline reports. The availability of the updated data permits observation of the impact of changes in intake.

Care was taken in validating the data collection systems.

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?		N/A
	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?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	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?	???
	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?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	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?		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?	Yes
	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?	???
	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