Night Shifts May Pose a Higher Risk of Asthma for Women

Who Is at Risk

Scientists have previously studied the link between night shifts and the development of asthma. One study found that people who work at night have a higher risk of developing the condition than those who work during the day.

The highest risk of moderate to severe asthma was observed in people with a morning chronotype who work irregular shifts, including nights. According to researchers, shift work is also associated with more frequent wheezing and reduced lung function.

Another study focused on how asthma incidence and severity differ by sex and age. It found that asthma is more common in boys during childhood, but more frequent and more severe in women during adulthood. Researchers highlight the role of sex hormones, genetic and epigenetic factors, and environmental influences. In women, asthma is also affected by hormonal changes during puberty, menstruation, and pregnancy.

A Dangerous Combination

In a study recently published in ERJ Open Research, experts focused specifically on asthma risk linked to night shift work in women, as more and more of them are working shifts. The study used data from the UK Biobank biomedical database.

An initial analysis of data from over 274,500 working individuals revealed that 5.3% had asthma, with 1.9% suffering from moderate or severe forms of the disease.

Researchers then examined whether these individuals—particularly women—worked during the day, at night, or on rotating shifts. They found that women working shifts in general were more likely to have asthma. Those working exclusively at night had a 50% higher likelihood of developing moderate or severe asthma than women working during the day. The risk increased with both the number of night shifts and the duration of employment in such roles.

The Unclear Role of Hormones

The researchers further discovered that among women not using hormone replacement therapy, postmenopausal women working only night shifts had nearly double the risk of developing moderate asthma compared to women working daytime hours. This suggests that hormone therapy might offer some protection against asthma for night shift workers—though the researchers caution that more studies are needed to confirm this.

Somewhat surprisingly, the study found no significant difference in asthma prevalence among men based on work schedules. Study co-author Robert Maidstone noted that women generally experience more severe forms of asthma and have higher rates of hospitalization and mortality from the condition than men.

He emphasized that this is the first study to assess sex-based differences in the relationship between shift work and asthma. However, it does not explain why the link exists. He added that the connection may lie in how shift work disrupts levels of male and female sex hormones. Previous research has shown that high testosterone levels offer protection against asthma—so lower levels in women may play a role.

The researchers plan to further investigate whether sex hormones influence the relationship between shift work and asthma, and how significant that influence might be.

Editorial Team, Medscope.pro

Sources:

1. Maidstone R. J., Ray D. W., Liu J. et al. Increased risk of asthma in female night shift workers. ERJ Open Research, 2025, 00137-2025, doi: org/10.1183/23120541.00137-2025.

2. Martinez F. D. Genes, environments, development and asthma: a reappraisal. Eur Respir J, 2007 Jan; 29 (1): 179–84, doi: 10.1183/09031936.00087906.

3. Maidstone R. J., Turner J., Vetter C. et al. Night shift work is associated with an increased risk of asthma. Thorax, 2021 Jan; 76 (1): 53–60, doi: 10.1136/thoraxjnl-2020-215218.

4. Chowdhury N. U., Guntur V. P., Newcomb D. C. et al. Sex and gender in asthma. European Respiratory Review, 2021 30 (162): 210067, doi: org/10.1183/16000617.0067-2021.