The Male-Female Health-Survival Paradox: A Survey and Register Study of the Impact of Sex-Specific Selection and Information Bias

PURPOSE: This study examined whether the health-survival paradox could be due partially to sex-specific selection and information bias in surveys. METHODS: The study is based on the linkage of three population-based surveys of 15,330 Danes aged 46102 years with health registers covering the total Danish population regarding hospitalizations within the last 2 years and prescription medicine within 6 months before the baseline surveys. RESULTS: Men had higher participation rates than women at all ages. Hospitalized women and women taking medications had higher participation rate compared with nonhospitalized women (difference = 0.7%-3.0%) and female nonusers (difference = 0.8%-7.6%), respectively, whereas no consistent pattern was found among men according to hospitalization or medication use status. Men used fewer medications than women, but they underreported medication use to a similar degree as did women. CONCLUSIONS: Hospitalized women, as well as women using prescription medicine, were slightly over-represented in the surveys. Hence, the Study found some evidence that selection bias in surveys may contribute to the explanation of the health-survival paradox, but its contribution is likely to be small. However, there was no evidence for sex-specific reporting of medication use among Study participants. Ann Epidemiol 2009; 19:504-511. (C) 2009 Elsevier Inc. All rights reserved.