Results chime with earlier review indicating almost every cell in the body may be affected by dirty air
Nicola DavisWed 27 Nov 2019 23.30 GMT
The number of health problems linked to air pollution could be far higher than previously thought, according to research suggesting hospital admissions for conditions ranging from heart failure to urinary tract infections increase as air becomes dirtier.
However, the research suggests the impact could be far wider, despite looking at only one component of air pollution, chiming with a global review published earlier this year that indicated almost every cell in the body may be affected by dirty air.
“The drive behind [the new research] was to do the most comprehensive study ever conducted at looking at all possible causes of hospitalisation that could be [linked] to exposure to fine particulate matter,” said Prof Francesca Dominici, ofHarvard University and co-author of the study.
Writing in the BMJ, Dominici and colleagues report how they analysed more than 95m insurance claims made between 2000 and 2012 by hospital inpatients in the US aged 65 or older enrolled in the Medicare programme.
They then looked at air pollution, focusing on levels of a type of fine particulate matter, known as PM2.5, which is produced by sources including vehicles and power stations. By harnessing air quality data from a range of sources, they were able to estimate PM2.5 levels for each patient based on their home zip code.
The team then compared air pollution levels for each patient during the two days around their hospital visit with levels from other points in time.
This approach essentially takes into account factors such as age, socioeconomic status and even obesity, since it uses each patient as their own reference. Fluctuations in air temperature and other factors were taken into account separately.
The results back up previous studies showing a link between short-term exposure to dirty air and conditions such as heart failure, pneumonia and heart attack.
Indeed, the analysis suggests even a small average rise in PM2.5 of 1 micrograms per cubic metre over a two-day period is linked to an increase of 68 older people per billion being taken to hospital with heart failure the next day.
Put another way, that increase in air pollution raises the risk of such people being hospitalised with heart failure by 0.14% .
However, the team also found diseases including septicaemia, Parkinson’s disease and urinary tract infections were associated with poorer air quality. For the latter, the team estimate the short-term rise in PM2.5 is linked to a further 39 older people per billion being taken to hospital the next day.
While the increases in risk might look small, the team say a 1micrograms per cubic metrerise in PM2.5 levels occurred on more than 122 days in each year within each zip code.
The team’s analysis further reveals air pollution is linked to more than just hospital visits: the data shows short-term increases in PM2.5 were linked to an average annual increase of 634 deaths, and about $100m in costs for inpatients and post-acute care.
Even when the team looked at days when the air quality was within the limits set by the WHO, they found the trends remained.
Yaguang Wei, first author of the study, said the research suggested the health effects of PM2.5 were not restricted within individual organs. “It has a more systemic effect on multiple pathophysiological processes such as inflammation, infection, and water electrolyte balance,” he said, although the details remain unclear.
While the study cannot prove that air pollution causes the diseases, the team say it adds weight to calls for air pollution guidelines to be reviewed.
Impact of air pollution on health may be far worse than thought, study suggests | The Guardian
Results chime with earlier review indicating almost every cell in the body may be affected by dirty air Nicola DavisWed 27 Nov 2019 23.30 GMT The number of health problems linked to air pollution could be far higher than previously thought, according to research suggesting hospital admissions for conditions ranging from heart failure to urinary… [Read More]