Increased absenteeism from work among aware and treated hypertensive and hypercholesterolaemic patients

The 'labelling hypothesis' was introduced on the basis of the observation that labelling subjects with blood pressure elevation as hypertensive was associated with an increase in sickness absence. In the Belstress I study this hypothesis was analysed in the same way for the possible influence on sick leave of labelling persons with elevated cholesterol as hypercholesterolaemic.

The Belstress I cohort concerns a sample of more than 16,000 men and 5,000 women at work in 24 Belgian industries in various sectors. Baseline data were collected by questionnaire and clinical examination. Awareness was defined as answering positively to the question 'did a physician ever tell you that your blood pressure/serum cholesterol was too high?' Sick leave data were independently and objectively recorded during 1 year following the screening. Sick leave was treated in a dichotomous way whereby the event was defined as being in the highest quartile of the annual number of days of sick leave (10 days or more for men and 15 days or more for women) or as being in the highest quartile of the annual number of spells of sick leave (two spells or more for both sexes). Gender-specific logistic regression analyses were performed, with adjustment for a large set of covariates. A positive association was observed between both awareness of hypertension and awareness of hypercholesterolaemia and the various definitions of sick leave, in both sexes and after adjustment for different covariates. When dividing up aware subjects into treated versus untreated, we observed in men the highest sick leave incidence in aware and treated hypertensive patients as well as in aware and treated hypercholesterolaemic patients. In women findings were less consistent, probably due to the smaller sample size. When looking at cumulative effects by examining participants with both hypertension and hypercholesterolaemia and their level of awareness for one or both risk factors, a statistically significant gradient was noticed in men, with the highest sick leave incidence, whatever the definition, in men aware for both risk factors, followed by men aware for one. In women the same trends were observed, but no level of statistical significance was reached.

Without being able to test the effect of 'labelling' as such, our study provides support for the association between awareness of two different coronary risk factors and incidence of sick leave. Probably a common mechanism is at the base of these findings. Further research is needed, in order to reduce potential negative effects of screening on human wellbeing as well as on productivity.