Influence of short term and long-term sickness absence on work ability index

Background and aims: Sickness absence is a major socio-economic problem imposing a huge amount of cost to societies. Absence from work entails complex conditions and multifactorial etiology. There are various occupational and personal factors contributing to the incidence of sickness absence. Long-term sickness absence compels the employer to reassign the tasks to other workers or replace the absent worker. In this light, it is essential to identify the workers at risk of sickness absence, particularly long-term sickness absence. The work ability index (WAI) can serve research purposes and clinical assessments in occupational health, aimed at evaluating the ability to work during occupational health examinations and environmental monitoring. Given the importance of sickness absence and identification of workers at risk of absence from work, this study attempted to evaluate influence of short-term and long-term sickness absence on work ability index. Methods: This cross-sectional study was conducted on 806 car accessories production company workers. The questionnaires were handed to workers with, at a minimum, one year of employment volunteering in the research project. Certain occupational data concerning date of employment, working location and shift work status were obtained from the Personnel Selection Department. Informed consent was obtained from all individual participants included in the study. The sickness absence data were extracted from the HSE of the factory, containing the number of days and episodes of sickness absence. Absence from work was divided into two categories: short-term (<3day) and long-term (≥3days) sickness absence. A questionnaire completed by the workers was employed to collect data on demographic information including age, marital status, education level, smoker/non-smoker and BMI. In terms of age, the subjects were divided into two categories of less than 35 years old and equal or greater than 35 years old. The work ability among the workers was measured through the Work Ability Index questionnaire comprising 7 items: 1) current work ability compared with the lifetime best, 2) work ability in relation to the demands of the job 3) number of current diseases diagnosed by physician, 4) estimated work impairment due to diseases, 5) sick leave during the past year (12 months), 6) work ability in the forthcoming two years, and 7, and 7) mental resources. In all items, the highest scores of WAI represent the best work ability. The Chi- square test was used to compare the qualitative variables and the logistic regression analysis to determine the relationship between WAI and sickness absence. In all tests, the significance level was considered 0.05. Results: Of 956 workers, 850 responded to the questionnaire (response rate of 88.91%). Having applied the exclusions criteria, a total of 806 subjects were analyzed. All the subjects were male ranging from 21 to 63 years old with an average age of 35.04±6.84 years. Moreover, 75.7% of the subjects had shift work, and 76.4% were blue collar. Analysis of r on revealed that 55.3% of subjects had a record of absence from work, of 61.9% were short-term (<3 days) and 38.1% long-term (≥3 days). The mean WAI score was 42.19±4.37. In comparison of the two groups with and without sickness absence in terms of demographic characteristics, the mean age was 35.65±7.32 for the non-absence group and 34.55±6.40 for the absence group, indicating a statistically significant difference (p=0.025). Furthermore, the mean BMI was 25.90±2.78 in the non-absence group, higher than 25.35±2.62 in the absence group (p=0.004). The Chi-square test suggested that shift workers and blue collars had more frequent absence from work with (OR=1.651 and p=0.002) and (OR=2.256 and p<0.001), respectively. Short-term sickness absence was higher among shift workers (OR=1.84 and p=0.011). Moreover, the long-term absence was more frequent among smokers while short-term absence was more frequent among non-smokers (OR=2.12 and p=0.002). The two groups with short and long-term absences, however, indicated no significant differences in terms of age and BMI. The mean WAI was 41.0 ±4.8 in smokers and 42.4±4.2 in non-smokers, indicating a statistically significant difference (p<0.001). The mean (SD) of WAI scores in workers with short-term, long-term and total sickness absence were 41.97(3.97) 40.62(5.30) and 41.45(4.56), respectively; and in workers without any sickness absence was 43.09(3.93). The WAI of workers without sickness absence was higher than that of workers with sickness absence (OR=2.79; 95% CI=1.63-4.76 and P-value<0.001); finding can be explained by the fact that sick or non-healthy individuals are more likely to prefer jobs not requiring work shift. The lower WAI scores increased the episodes and lengths of sickness absence. The findings suggested that WAI can be correlated with short-term and long-term Sickness absence and can be employed as a simple and useful tool to identify workers at risk of sickness absence.