Social disparities in hazardous alcohol use: self-report bias may lead to incorrect estimates.

Background: Self-report bias in surveys of alcohol consumption is widely documented; however, less is known about the distribution of such bias by socioeconomic status (SES) and about the possible impact on social disparities. This study aims to assess social disparities in hazardous drinking (HD) and to analyze how correcting alcohol consumption data for self-report bias may affect estimates of disparities.

Methods: National survey data from 13 countries, Canada, England, Finland, France, Germany, Hungary, Ireland, Japan, Korea, New Zealand, Spain, Switzerland and USA, are used to examine social disparities in HD by SES and education level. Defining HD as drinking above 3 drinks/day for men and 2 for women, social disparities were assessed by calculating country-level concentration indexes. Aggregate consumption data were used to correct survey-based estimates for self-report bias.

Results: Survey data show that more-educated women are more likely than less-educated women to engage in HD, while the opposite is observed in men in most countries. Large discrepancies in alcohol consumption between survey-based and aggregate estimates were found. Correcting for self-report bias increased estimates of social disparities in women, and decreased them in men, to the point that gradients were reversed in several countries (from higher rates in low education/SES men to an opposite pattern).

Conclusion: This study provides evidence of a likely misestimation of social disparities in HD, in both men and women, due to self-report bias in alcohol consumption surveys. This study contributes to a better knowledge of the social dimensions of HD and to the targeting of alcohol policies.