Objective: To identify and validate a measure of disease prevalence in a town or other subpopulation for the purpose of estimating variations in morbidity and health care needs between groups.
Design: A national prospective study of cardiovascular disease based in 24 British towns.
Subjects: 7,735 men aged 40-59 years sampled from 24 general practice age-sex registers between 1978 and 1980.
Method: A questionnaire administered at recruitment and a postal questionnaire five years later (98% response) asked if the subject recalled ever having had a diagnosis by a doctor of any of 12 listed conditions. In addition, the men were asked about regular medication, occupation, lifestyle and perceived health status. All-cause mortality data were collected during 13.5 years of follow-up.
Results: Prevalence of recalled doctor diagnoses varied between the towns; for cardiovascular disease, it correlated significantly with other health indices and personal characteristics and with standardised mortality ratios for the town. Consistency of reporting over time and mortality outcome after 13.5 years also supported the validity of patient recall.
Conclusions: A simple standardised questionnaire using patient recall of common conditions diagnosed by a doctor provides a plausible, valid measure of variations in disease burden between communities.