Background Information on the validity of self-reported cases of stroke and acute myocardial infarction (AMI) is varied. The aim of this study was to assess the validity and agreement of self-reported prevalent cases of stroke and AMI in the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC).

Methods At recruitment, 1992–1996, and in the follow-up (3 years after recruitment), each participant in the Spanish EPIC cohort (15 630 men and 25 808 women) was asked if a doctor had ever said that they had had a stroke or AMI, and the results were compared with information available in medical records. Validity of self-reported prevalent cases of stroke and AMI was examined by calculating sensitivity, specificity, positive predictive values and κ statistics.

Results The sensitivity of self-reported prevalent cases of stroke was 81.3% and that for AMI was 97.7%. The positive predictive value was 22.2% and 60.7% for stroke and AMI, respectively, whereas specificity was very high (>99%) for both diseases. The agreement between self-report questionnaire results and medical records was substantial (κ=0.75) for AMI but not for stroke (κ=0.35).

Conclusion Self-reported information on stroke and AMI included in the EPIC questionnaire is a valid instrument for the assessment of AMI disease but should be used with caution in stroke.