New study suggests female night shift workers are at higher risk of asthma

Background 

Asthma affects more women than men around the world and has been linked with night shift work. As more women now work in roles that include night shifts, it is important to understand whether these working patterns are related to the chance of developing asthma.  

What did the study look at? 

Researchers from the University of Manchester, United Kingdom, analysed data from more than 280,000 working adults, aged 40–69 years, in the UK Biobank, which is a large health research project that collects medical and lifestyle information from volunteers across the UK. They looked at a collection of data gathered at the same time to explore: 

• whether the number of people with asthma differed between people who worked only during the day, people who working on permanent night shifts, and those who worked on rotating or mixed shifts. 

• other factors linked with asthma such as age, lifestyle and weight 

• possible explanations for the higher risk of asthma seen in people who work night shifts. 

The researchers also looked at whether people were naturally more active in the morning or evening, which can be known as being a morning or evening person. They also examined whether menopause and the use of hormone replacement therapy (HRT) were linked with asthma risk in women who worked night shifts.  

What do the results show? 

Women who worked permanent night shifts were more likely to have moderate-to-severe asthma than women who worked day shifts. This pattern was not seen in men. 

The highest risk was seen in postmenopausal women who were not taking HRT. Women in this group who worked permanent night shifts were more likely to have moderate to severe asthma. Postmenopausal women taking HRT did not show this increased risk. 

Women who worked permanent night shifts were also more likely to report symptoms such as wheezing or whistling in the chest. These symptoms followed a similar pattern to the asthma findings. 

Why is this important? 

This study is the first to look closely at differences between women and men in the link between shift work and asthma. Many people around the world work night shifts, so understanding these differences may help to identify groups who could be more affected. 

The findings suggest that hormones and menopause may play a role in the relationship between night shift work and lung health. More research is needed to understand the reasons for this and to find out whether changes in working patterns or the use of HRT could help reduce the risk. 

Read the full research: Increased risk of asthma in female night shift workers