Living on a busy road aggravates heart failure, according to new research. Exposure to air pollution has been linked to a rise in hospital procedures for stress, diabetes and blood clotting.
It adds to evidence regulatory standards are not sufficiently protective - and need further tightening. The results come from an analysis of almost 21,000 American patients.
Lead author Dr Samantha Catalano, from the University of North Carolina, said: "We observed increased performance of diagnostic procedures with increased PM2.5 (fine particulate matter) exposure - which fit with the known mechanisms of PM2.5 exposure."
PM2.5 are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated. The toxic particles are the leading environmental risk factor for disease. Less than a fiftieth the width of a human hair, they get into the blood through the lungs, making it more sticky and triggering inflammation.
Sources include diesel fumes, wood smoke, brake pads, tyres and road dust. The Environmental Protection Agency's current annual regulatory standard is 12 micrograms per cubic metre (µg/m3). They have been linked to illness and death worldwide. The study in PLOS ONE is the first to quantify the risk using hospital procedures.
It analysed the effect of long-term exposure by examining electronic health records for 20,920 individuals diagnosed with heart failure. Around three-quarters (15,979) subsequently received at least one of 53 common procedures within the University of North Carolina Healthcare System from 2004-2016.
Researchers used each patient's address alongside the date of their heart failure diagnosis to map and analyse environmental exposure data alongside their health records. Three specific procedures were significantly more likely to be performed on patients with increased PM2.5 exposure.
They included stress tests (6.84% increase per 1 μg/m3 increase in PM2.5), glycosylated haemoglobin tests which screen for diabetes (10.8% increase), and prothrombin time tests, which evaluate blood clotting (15.8% increase) Prothrombin time tests remained significantly linked to this exposure even after adjusting for access to healthcare and healthy food based on county.
Since all three of these tests relate to diagnostic testing for cardiorespiratory health, the authors posit that their results provide evidence of patients with high PM2.5 exposure experiencing more cardiovascular morbidity, prompting healthcare professionals to perform more diagnostic tests. The results will assist future researchers in better estimating the burden of PM2.5 exposure on patients and hospital systems.
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Dr Catalano said: "Associations between PM2.5 and hospital procedures can give us unique insight into the impacts of PM2.5 exposure on both patients and the healthcare system. This research provides evidence that hospital procedures can be a unique lens through which to view the health effects of air pollution exposure."
Last month another US study of more than 16 million adults identified an alarming 42 per cent greater risk of dementia for every 2 µg/m3 increase in average concentrations of PM2.5s. Air pollution has been linked to all major life-threatening illnesses including cardiovascular disease, cancer and diabetes. More than 900,000 Britons are currently living with heart failure, according to the British Heart Foundation.
