Classification of Work Ability Index among young employees.

Background: The reference values of the Work Ability Index (WAI) are best known for people aged over 45 years. However, the WAI score is highly dependent on age and population-based reference values for young employees are needed.

Aim: To present WAI scores calculated for a population-based sample of employees in their early 30s.

Methods: A self-administered questionnaire including the items of the WAI was used. The study included 3725 employees (2021 men and 1704 women) aged 31 from part of the Northern Finland Birth Cohort 1966 Study (NFBC-66) and who were working in a wide range of occupations in northern Finland or in the Helsinki region during 1997-1998.

Results: The WAI scores among young employees varied from 15 to 49 with a mean of 40.7 points (SD 4.2). The 15th percentile, median and 85th percentile of the WAI scores were 37, 41 and 45 points, respectively. The WAI scores were relatively high for both men and women.

Conclusions: When classification of WAI scores into four work ability categories is used, the scores of employees in their early 30s should be evaluated separately from those of older age groups. For young employees work ability categories poor (7-36 points), moderate (37-40 points), good (41-44 points) and excellent (45-49 points) are suggested.