Night shift workers at heightened risk of asthma, study finds

Report draws focus on ‘emerging area concerning ill-effects of shift working on health’

Permanent night shift workers are at heightened risk of moderate to severe asthma,the study found.

Permanent night shift workers are at heightened risk of moderate to severe asthma,the study found.


Permanent night shift workers are at heightened risk of moderate to severe asthma, with “far reaching” public health implications given the prevalence of asthma and shift work, according to a new study.

The study published in the medical journal Throrax said about 20 per cent of employees in the developed world work permanent or rotating night shifts, which can causes a person’s internal body clock - or circadian rhythm - to be out of step with the external light and dark cycle.

It found that after taking account of age and sex, and a wide range of other potentially influential risk factors, there was a 36 per cent increase in the odds of having moderate to severe asthma in permanent night shift workers compared to those working normal office hours.

According to Prof Marcus Butler, medical director of the Asthma Society of Ireland and a respiratory consultant physician at St Vincent’s University Hospital, the study highlights an emerging area involving the ill-effects of shift working on health.

Compared with those working office hours, the study found shift workers were more likely to be men, smokers and to live in urban areas and in more deprived neighbourhoods.

Night shift workers were more likely to have poorer health and were more likely to work in service jobs or as process, plant and machine operatives.

According to Prof Butler, the study, while undertaken by researchers in the University of Manchester in the UK, was “a cause of concern” for people here, given that asthma issues in the UK mirror those in Ireland “to a large extent”.

He said the study “can serve to draw focus on the emerging area concerning ill-effects of shift working on health”.

Quality of life

“ As the study points out, many of the permanent night shift workers are more likely to be living in deprived neighbourhoods and may have other disparities in health care access. The Asthma Society aims to improve asthma quality of life for all, and to leave no one behind,” he said.

He said the implications for Ireland were that findings in this large scale study, “predominantly among individuals of European ancestry, are likely to be also attributable to Irish asthma patients.”

“We share a very close genetic ancestry with the UK, and asthma has a complex genetic relationship in its causation, interacting with environmental factors. This important study is highlighting one such environmental factor that has complex associated lifestyle, exposure implications and emotional well-being factors relating to shift work, which seems likely to be relevant to contributing to asthma” he said.

Further studies in this area are needed to help inform decision-making for policy makers and employers” Prof Butler said.

Study author Dr Hannah Durrington of the School of Biological Sciences at the University of Manchester said the “misalignment” of an individual’s circadian rhythm with the external day and night cycle was associated with “a heightened risk of various metabolic disorders, cardiovascular disease, and cancer”.

The Asthma Society’s Asthma and COPD Adviceline is available on 1800 44 54 64 and a WhatsApp service on on 086 059 0132. Both services are free and allow users to communicate directly with an asthma/COPD nurse specialist.