Women who work nightshifts are more likely to suffer asthma than women who work during the day and all men, regardless of when they work.
A new study from the University of Manchester, which involved more than 270,000 people, is the first to evaluate sex differences in the relationship between shift work and asthma.
Dr Robert Maidstone said asthma disproportionately affected women.
“Women generally have more severe asthma, and higher rate of hospitalisation and death from asthma compared to men,” Dr Maidstone said.
“In our previous research we found a higher risk of moderate or severe asthma in nightshift workers, so we wanted to see whether there were further differences between the sexes.”
He said their analysis revealed that, overall, women who performed shift work were more likely to have asthma.
“Women who only work nightshifts are around 50 percent more likely to suffer with moderate or severe asthma compared to women who only work in the daytime.
“This type of research cannot explain why shift work and asthma are linked, however, it could be because shift work disrupts the body clock, including the levels of male and female sex hormones.”
Dr Maidstone said high testosterone had previously been shown to be protective against asthma, and so lower testosterone in women could play a role.
“Alternatively, men and women work different types of shift jobs, and this could be a factor.”
He said in postmenopausal women, the risk of moderate or severe asthma was almost doubled in night workers, compared to day workers, in those not taking hormone replacement therapy (HRT).
“Our results suggest that HRT might be protective against asthma for nightshift workers, however further research is needed to test this hypothesis in prospective studies and randomised controlled trials.”
Read the full study: Increased risk of asthma in female night shift workers.
