Shift work may increase the risk of enforced early retirement among women, indicates research published ahead of print in Occupational and Environmental Medicine.
The findings are based on just under 8000 male and female employees, who were part of a large health and work study (Danish Work Environment Cohort Study), which began in 1990, and data from the national welfare register.
Successive waves of participants in the Cohort Study were formally interviewed about their workplace, work patterns, health, and lifestyle.
Participants were monitored until the age of 60, death, emigration, or the end of the study in June 2006, whichever came first.
Of the 3980 women included in the study, 253 had been forced to retire early on account of ill health and had been granted a disability pension by June 2006.
Of the 4025 men, 173 had similarly been granted a disability pension by this time.
After adjusting for factors likely to influence the results, such as lifestyle, including smoking, the workplace environment, and socioeconomic status, women were more likely than men to require a disability pension.
And they were 34% more likely to do if they had been shift workers, whereas male shift workers were no more likely to have to retire early than other employees.
This study did not look at the reasons for enforced early retirement. But shift work has been associated with an increased risk of heart disease, breast cancer, peptic ulcer, sleep disturbance, complications of pregnancy and accidents.
But it is not clear why women should be more vulnerable, say the authors.