Primary versus proxy respondents: comparability of questionnaire data on alcohol consumption

Area of Science:

• Epidemiology
• Cardiovascular Disease Research
• Public Health

Background:

• Assessing alcohol consumption is crucial for understanding its impact on cardiovascular health.
• Previous studies have questioned the reliability of self-reported alcohol data, especially when collected via proxy.

Purpose of the Study:

• To evaluate the accuracy of alcohol consumption data reported by next of kin compared to primary respondents in a case-control study.
• To determine if proxy reporting introduces bias in alcohol consumption estimates for coronary heart disease research.

Main Methods:

• A community-based case-control study of coronary heart disease (CHD) was conducted in Auckland, New Zealand (1986-1988).
• Questionnaire data on alcohol consumption from primary respondents (myocardial infarction cases and controls) were compared with data from their next of kin.
• Statistical analysis included exact agreement, agreement within one category, and tests of marginal homogeneity.

Main Results:

• Exact agreement between primary respondents and next of kin was 62-64% for drinking frequency.
• Agreement within one category (plus or minus) reached 89% for both cases and controls.
• Mean differences in daily alcohol intake between respondents and next of kin were small, though individual variability existed.

Conclusions:

• Next of kin provide reliable estimates of alcohol consumption frequency at an aggregate level.
• Proxy data is unlikely to cause significant bias in population-level alcohol consumption assessments.
• These findings support the use of proxy respondents in epidemiological studies when direct data collection is challenging.