People who live in areas with high levels of air pollution are up to 60 per cent more likely to suffer a bad night’s sleep, a new study warns. “The study indicates the possibility that commonly experienced levels of air pollution not only affect heart and lung disease, but also sleep quality,” said Martha E Billings, assistant professor at the University of Washington in the US. Researchers analysed data from about 1,863 participants with an average age of 68 years. They looked at two of the most common air pollutants: nitrogen dioxide (NO2), a traffic-related pollutant gas, and PM2.5 – fine-particle pollution.
Researchers used air pollution measurements, local environment features and sophisticated statistical tools to estimate air pollution exposures at each participant’s home at two time points: one year and five years. They calculated “sleep efficiency” – a measure of the percentage of time in bed spent asleep vs awake with the help of wrist actigraphy. Wrist actigraphy, which measures small movements, provided detailed estimates of sleep and wake patterns over seven consecutive days.
Participants were divided into “fourths” according to levels of pollution. The quarter of those who experienced the highest levels of pollution was compared to the quarter with the lowest levels. Researchers found that the group with the highest levels of NO2 over five years had an almost 60 per cent increased likelihood of having low sleep efficiency compared to those with the lowest NO2 levels.
The group with the highest exposures to small particulates (PM2.5) had a nearly 50 per cent increased likelihood of having low sleep efficiency, researchers said. “These new findings indicate the possibility that commonly experienced levels of air pollution not only affect heart and lung disease, but also sleep quality. Improving air quality may be one way to enhance sleep health and perhaps reduce health disparities,” said Billings.