Reliability of a retrospective decade-based life-course alcohol consumption questionnaire administered in later life.

Abstract

Retrospective measures of alcohol intake are becoming increasingly popular; however, the reliability of such measures remains uncertain. This study assessed the reliability of a retrospective decade-based life-course alcohol consumption questionnaire, based on the standardized Alcohol Use Disorder Identification Test-Consumption (AUDIT-C) administered in older age in a well-characterized cohort study. A retrospective alcohol life-grid was administered to 5980 participants (72% male, mean age 70 years) in the Whitehall II study covering frequency of drinking, number of drinks in a typical drinking day and frequency of consuming six or more drinks in a single drinking occasion in the teens (16-19 years) through to the 80s. A subsample of 385 individuals completed a repeat survey to determine test-retest reliability. Retrospective measures were also compared with prospectively ascertained information and used to predict objectively measured systolic blood pressure to test their predictive validity. Across all decades of life, test-retest reliability was generally good (κ range = 0.62-0.78 for frequency, 0.55-0.62 for usual number of drinks and 0.57-0.65 for frequency of consuming six or more drinks in a single occasion). The concordance between prospective and retrospective measures was consistently moderate to high. The life-grid method performed better than a single question in identifying life-time abstainers. Retrospective measures were also related to systolic blood pressure in the manner anticipated. A retrospective decade-based AUDIT-C grid administered in older age provides a relatively reliable measure of alcohol consumption across the life-course.