Background: Downsizing has in previous studies, as well as in public debate, been associated with increased sickness absence. No studies have, however, looked at the long-term relation between workplace expansion and morbidity.
Methods: We investigated exposure to personnel change during 1991-96 in relation to long-term (90 days or longer) medically certified sickness absence and hospital admission for specified diagnoses during 1997-99 in 24?036 participants with a complete employment record in the biennial national Swedish Work Environment Surveys from 1989 to the end of 1999.
Findings: Accumulated exposure to large expansion (> or =18% per year) was related to an increased risk of long-term sickness absence (odds ratio 1.07 [95% CI 1.01-1.13], p=0.013) and hospital admission (1.09 [1.02-1.16], p=0.017). In this context, odds ratio signifies the change in odds for each additional year of exposure, varying from 0 to 6. Moderate expansion (> or =8% and <18% per year), was associated with a decreased risk of admission (0.91 [0.84-0.98], p=0.012). Moderate downsizing (> or =8% and <18% per year) was associated with an increased risk of sickness absence (1.07 [1.02-1.12], p=0.003). The strongest association between large expansion and sickness absence was in women in the public sector (1.18 [1.08-1.30], p=0.0002), corresponding to an odds ratio of 2.77 [1.62-4.74] between full exposure (all 6 years) and no exposure.
Interpretation: This study confirms earlier findings that downsizing is associated with health risks. It also shows that repeated exposure to rapid personnel expansion, possibly connected with centralisation of functions, statistically predicts long-term sickness absence and hospital admission. Although no conclusions about causal pathways can be drawn from our results, this exposure should be considered in future studies, policy making, and occupational health care practice.