Work ability index (WAI) and its association with psychosocial factors in one of the petrochemical industries in Iran.

Objectives: In recent decades, work ability index (WAI) has been a common practical tool to measure individuals' work ability in many European, Asian and South American countries. However, there is no study concerning work ability in Iran. The aim of this study was to determine the work ability index in an Iranian petrochemical job setting and to examine its relationship with psychosocial factors.

Methods: A cross-sectional study was conducted among 420 male workers in various occupations. Work ability was evaluated using the WAI questionnaire developed by FIOH; the Job content questionnaire (JCQ) was used to assess psychosocial factors.

Results: The mean WAI score was 39.1 (SD=5.7) among workers in the studied petrochemical industry. Multiple linear regression analysis revealed a significant association between mean WAI score and age, job tenure, educational level, rest and sleep status and vocational education. Moreover, the results showed that skill discretion, coworker support and supervisor support were positively associated with the mean WAI score. On the other hand, it was inversely associated with job demands, job strain and job insecurity.

Conclusions: This study was the first research to determine WAI in an important industry in Iran. Overall, work ability was in the "Good" category among the workers in the studied field. On the basis of the WAI guidelines, this level should be maintained and promoted to excellent level by providing supportive countermeasures. The WAI score was significantly associated with psychosocial factors. The results showed that even in heavy physical work, factors such as job insecurity, skill discretion, job strain and social support play an important role in maintaining work ability. A positive combination of "psychosocial characteristics" of the job with "individual resources" can promote work ability in such occupations.