Working for a company that expands rapidly increases an employee's risk of long-term sickness, say researchers.

The Lancet study by experts from the Swedish National Institute for Psychosocial Medicine also found hospital admission rates increased.

The team found women working in the public sector¹ were worst affected².

Experts suggest while expansion may be thought to be beneficial, growing firms may have too few qualified³ staff and feel generally unstable⁴.

Previous research looked at the negative health effects of downsizing, but the Swedish team believe theirs is the first to look at the opposite phenomenon.

They studied the employment records of 24,000 healthy workers aged⁵ under 65 in 1999.

They looked at long-term sick leave (of over 90 days) and hospital admission rates.

Significant company expansion, classed as an increase in the number of employees of 18% or more in a year, was found to be linked to an increased risk of long-term sickness absence and hospital admission.

Women in the public sector who were exposed to large expansion every year over the six years of the study had a two to three times higher risk of long-term sickness absence than those who were never exposed to large expansion.

Researchers suggest this could be because public sector jobs such as healthcare and education, commonly dominated by women, have been linked to increased demands and hazards.

Being exposed to moderate expansion (between 8 and 18% increase in staff in a year) resulted in a decreased risk of hospital admission.