Working Nights Increases Asthma Risk for Women: Study

New Delhi: A recent study has revealed that women who work night shifts face a significantly higher risk of developing moderate to severe asthma compared to their counterparts who work during the daytime. The research, published in ERJ Open Research, involved a comprehensive analysis of data from more than 270,000 working individuals and uncovered a striking sex-based difference in how shift work affects respiratory health.

The study found that women working permanent night shifts were approximately 50% more likely to suffer from moderate or severe asthma than those who only worked during the day. Moderate or severe asthma was defined in the study as requiring an asthma-preventer inhaler in addition to at least one other asthma medication, such as oral steroids.

Interestingly, this association between night shifts and asthma was not observed in men. The risk of asthma in male participants did not appear to vary based on their work schedule. According to lead researcher Dr. Robert Maidstone from the University of Manchester, UK, this is the first study to explore sex differences in the relationship between shift work and asthma.

“Asthma disproportionately affects women, who also tend to experience more severe symptoms and higher rates of hospitalization and death related to asthma,” explained Dr. Maidstone. “We found that permanent night shift workers had higher odds of moderate-severe asthma when compared to corresponding day workers.”

The study included a total of 274,541 participants, among whom 5.3% were diagnosed with asthma, and 1.9% had moderate or severe forms of the condition. Overall, shift-working women were more likely to be affected by asthma, although the underlying causes are not yet fully understood.

Researchers speculate that the disruption of the body’s circadian rhythm caused by night shift work may influence hormone levels, which could play a role in asthma risk. Lower testosterone levels, which have been shown to be less protective against asthma, may contribute to the increased vulnerability in women. Differences in the types of jobs typically held by men and women might also be a contributing factor.

The study also highlighted a particularly elevated risk among postmenopausal women working night shifts who were not on hormone replacement therapy (HRT). In this group, the risk of developing moderate or severe asthma was nearly double compared to day workers.

The findings suggest that HRT may offer some protective benefits against asthma for women working night shifts. However, researchers emphasize the need for further studies, including prospective and randomized controlled trials, to better understand the role of sex hormones in the relationship between shift work and asthma.