Could Night Shifts Raise Asthma Risk?

TUESDAY, Nov. 17, 2020 (HealthDay News) -- Night-shift workers are about one-third more likely to develop moderate to severe asthma compared to folks working daylight hours, a new study finds.

Researchers in Britain explained that working a night shift can play havoc with the body's internal clock, and has been tied to an increased risk for various metabolic disorders, cardiovascular disease and cancer. So, in the new study, they collected data on nearly 287,000 people listed in the U.K. Biobank between 2007 and 2010.

Compared with people who worked regular office hours, shift workers were more likely to be men, smokers, and live in urban areas and poorer neighborhoods. They also drank less alcohol, slept fewer hours and worked longer hours.

About 5% of all the participants had asthma and nearly 2% had symptoms that were moderate to severe, said researchers led by Dr. Hannah Durrington of the University of Manchester, in England.

After accounting for age, sex and a range of other risk factors, night-shift workers had a 36% rise in the odds of having moderate to severe asthma, compared with those working normal office hours, the researchers found.

Also, the odds of "wheeze" or airway whistling were 11% to 18% higher among night-shift workers, and the odds of poorer lung function were about 20% higher in people working permanent night shifts.

Durrington's group stressed that the study can't establish cause and effect, and only points to an association.

"However, it is plausible that circadian misalignment leads to asthma development," the authors theorized. "The public health implications of our findings are potentially far-reaching, since both shift work and asthma are common in the industrialized world."

The report was published online Nov. 16 in the journal Thorax.

About one in five people in the developed world work either permanent or rotating night shifts, most often in service industries or factories, the study authors noted in a journal news release.

Dr. Len Horovitz is a pulmonary specialist at Lenox Hill Hospital in New York City. He wasn't involved in the study, but said its findings were "confounded by the fact that there were many smokers in this group," and smoking can greatly raise the risk for asthma.

More information

For more on asthma, head to the U.S. National Heart, Lung, and Blood Institute.

SOURCE: BMJ, news release, Nov. 16, 2020