Research Links Night Shift Work in Women to Increased Asthma Risk

A new study reveals that women working night shifts are at a significantly higher risk of developing moderate to severe asthma, highlighting the need for further research into hormonal and circadian influences.

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Recent research indicates a significant association between night shift work and a higher likelihood of developing moderate to severe asthma among women. The study, published in ERJ Open Research, analyzed data from over 270,000 individuals from the UK Biobank, revealing that women working exclusively night shifts are approximately 50% more likely to suffer from moderate or severe asthma compared to those working only daytime hours. Interestingly, this correlation was not observed in men, suggesting a sex-specific effect.

The research was led by Dr. Robert Maidstone from the University of Manchester, UK. He highlighted that asthma tends to disproportionately affect women, who often face higher rates of severe symptoms, hospitalizations, and mortality related to the condition. Previous studies also indicated a link between shift work and increased asthma risk, prompting the team to explore potential sex differences.

The findings showed that women who only worked night shifts had increased odds of experiencing more serious asthma symptoms. However, the risk remained unchanged for men regardless of their shift pattern. This suggests possible hormonal influences, such as variations in sex hormones like testosterone, which is known to be protective against asthma. The disruption of body clocks due to shift work might also play a role, particularly affecting hormone levels.

Moreover, the study found that postmenopausal women not on hormone replacement therapy (HRT) had almost doubled risk of moderate or severe asthma if they worked night shifts, implying that HRT could have a protective effect.

While the exact mechanisms remain unclear, the researchers suggest future studies focus on hormonal influences and the impact of shift work on the immune system. They plan to analyze additional data from UK Biobank and the Our Future Health program to better understand these relationships.

Expert opinions from the European Respiratory Society emphasize the importance of recognizing shift work as a potential risk factor for asthma in women. Given the challenges in changing shift schedules for many workers, further research is necessary to develop strategies to reduce this risk.

Source: https://medicalxpress.com/news/2025-06-women-nightshifts-asthma.html