RELIABILITY OF A QUESTIONNAIRE ON SICKNESS ABSENCE WITH SPECIFIC ATTENTION TO ABSENCE DUE TO BACK PAIN AND RESPIRATORY COMPLAINTS

Objective-To evaluate the performance of a questionnaire on sickness a bsence due to back pain and respiratory disorders with the view of usi ng sickness absence as a measure of morbidity. Methods-A cross section al survey was conducted among 511 male workers aged 20-65, drawn from the personnel register of an animal feed mill. The response was 404 (7 9%) participants. Data on sickness absence in the six months before th e survey were collected by a self administered questionnaire and by si ckness absence records. Correlation between both methods was examined for prevalence, duration, and frequency of overall sickness absence, b ack pain absence, and absence due to respiratory complaints. Results-T he questions about the prevalence of sickness absence from all causes, back pain, and respiratory complaints showed a high specificity of 91 %, 97%, and 98%, respectively. The sensitivities of these questions we re 79%, 88%, and 13%, respectively. The survey found a moderate agreem ent between the questionnaire and the medical register for duration an d frequency of overall sickness absence with kappa values of 0.54 and 0.50. A good agreement was found for back pain absence with kappa valu es of 0.65 and 0.61. Respiratory absence showed a poor agreement of 0. 16 and 0.13. Conclusion-In epidemiological studies questionnaires migh t be considered a valuable source of information on overall sickness a bsence or absence due to back pain which lasted for at least two weeks in the past six months. Whether a questionnaire survey is a reliable source of data on sickness absence due to respiratory complaints remai ns to be seen.