Healthcare (Commonwealth Union) – According to a new study conducted at the University of Manchester, women who have night shifts are more likely to experience moderate to severe asthma in comparison to those who work during the day. The findings were published recently in ERJ Open Research.
The study, which analysed data from over 270,000 individuals, found no similar association between night shift work and asthma in men.
The research was led by Dr Robert Maidstone of the University of Manchester who pointed out that asthma tends to affect women more severely. Compared to men, women are more likely to suffer serious symptoms, require hospital care, and face a higher risk of death from the condition.
He also noted that in their previous studies they found a higher risk of moderate or severe asthma in nightshift workers, so they wanted to find out if there were further differences between the sexes.
The study drew on data from the UK Biobank, involving 274,541 employed individuals. Among them, 5.3% were found to have asthma, with 1.9% classified as having moderate to severe forms of the condition—defined as using a preventive inhaler alongside at least one additional treatment, such as oral corticosteroids. Participants were grouped based on their work schedules: daytime only, exclusively night shifts, or a mix of both.
The researchers’ findings showed that, overall, women working shifts were more prone to asthma. In particular, women who consistently worked night shifts were approximately 50% more likely to experience moderate or severe asthma than those who worked only during the day.
In contrast, men’s asthma risk did not appear to be affected by whether they worked during the day or at night.
Dr. Robert Maidstone stated that this is the first research to explore how the link between shift work and asthma differs between sexes. They discovered that individuals working permanent night shifts had increased odds of developing moderate to severe asthma compared to their daytime counterparts.
“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. High testosterone has 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.”
Researchers of the study indicated that in postmenopausal women who were not using hormone replacement therapy (HRT), those working night shifts faced nearly twice the risk of developing moderate to severe asthma compared to their counterparts working daytime hours.
Dr. Maidstone indicated that their findings show that HRT could potentially offer some protection against asthma in women working night shifts. However, more research is necessary to confirm this through future prospective studies and randomized controlled trials.
The team now intends to explore the possible influence of sex hormones on the link between shift work and asthma, using data from both the UK Biobank and the UK’s new health research initiative, Our Future Health.
Professor Florence Schleich, a member of the European Respiratory Society’s expert group on airway diseases, asthma, COPD, and chronic cough at the University of Liège in Belgium, was not part of the study. She indicated that asthma is a widespread, chronic condition that impacts millions globally. While it’s clear that women are more prone to developing asthma, tend to experience more severe symptoms, and face a higher risk of dying from the disease, the reasons behind these gender differences remain unclear.
“This research suggests that working nightshifts could be a risk factor for asthma in women, but not in men. The majority of workers will not have an easy option of switching their shift pattern, so we need further research to verify and understand this link and find out what could be done to reduce the risk for women who work shifts.”
