Prognostic factors for respiratory sickness absence and return to work among blue collar workers and office personnel

To analyze factors that determine the occurrence of sickness absence due to respiratory disorders and the time it takes to return to work.

A longitudinal study with 2 year follow up was conducted among 326 male blue collar and white collar workers. The survey started with an interview on respiratory complaints and spirometry. Sixty six (21%) workers were lost to follow up. Complete data on sickness absence among 251 workers during the follow up were collected from absence records and self reports. Regression analysis based on a proportional hazards model was applied to identify risk factors for the occurrence and duration of sickness absence due to respiratory disorders.

During the follow up 35% workers attributed at least one period of sickness absence to respiratory complaints, which accounted for 14.2% of all days lost. A history of chronic obstructive pulmonary disease (COPD) did not predict sickness absence for COPD; the same was true for chronic non-specific lung disease (CNSLD). Complaints about asthma contributed significantly to absence due to asthma (relative risk (RR) 3.96; 95% confidence interval (95% CI) 1.99 to 7.90). Job title was a significant predictor of sickness absence due to respiratory complaints. Decrease in forced vital capacity (FVC, <80% of the reference value) was also a significant predictor of absence due to asthma (RR 4.03; 95% CI 1.41 to 11.54) and of respiratory absence (RR 2.49; 95% CI 1.07 to 5.79). Absence with respiratory complaints was not associated with age, height, body mass index, or smoking. Duration of employment was a weak almost significant predictor against respiratory absenteeism (RR 0.94; 95% CI 0.91 to 0.97). Return to work after respiratory absence was worse for blue collar workers than office personnel (RR 5.74; 95% CI 1.90 to 17.4 for welders, and RR 6.43; 95% CI 2.08 to 19.85 for metal workers).

Asthmatic complaints in the 12 months before the study were associated with sickness absence for these complaints during the follow up. An abnormal level of FVC also influenced respiratory absenteeism. Blue collar workers had more often and more prolonged absences due to respiratory disorders than white collar workers. Workers with absence due to respiratory complaints were at higher risk of subsequent sickness absence in the next year.