AIR POLLUTION exposure was associated with poorer functional recovery among stroke survivors in a longitudinal cohort study, with higher levels of several common pollutants linked to declines in activities of daily living (ADL).
Researchers analysed data from 1,755 patients with incident ischaemic or haemorrhagic stroke who underwent at least two assessments of functional status between 2019 and 2025.
The study included 6,334 follow up visits and examined long term residential exposure to fine particulate matter (PM2.5), inhalable particles (PM10), nitrogen dioxide, sulphur dioxide, carbon monoxide, and ozone.
Functional recovery was assessed using the Modified Barthel Index (MBI), a measure of independence in activities of daily living.
The primary analysis showed that a 10 µg/m³ increase in PM2.5 exposure was associated with a significant reduction in MBI score (-11.11 points).
Higher PM2.5 exposure was also linked to a greater likelihood of ADL dependence and MBI score decline.
Beyond PM2.5, increases in nitrogen dioxide, sulphur dioxide, and carbon monoxide were also associated with worsening functional outcomes.
Interquartile range increases in nitrogen dioxide, sulphur dioxide, and carbon monoxide were linked to reductions in MBI scores of -7.44 points, -6.06 points, and -0.39 points, respectively.
Nonlinear modelling suggested inverse relationships between PM2.5, nitrogen dioxide, and sulphur dioxide exposure and the probability of maintaining ADL independence.
These effects became more pronounced at higher pollutant concentrations. Ozone showed a more complex association and was interpreted cautiously by the researchers because of its relationship with other pollutants.
Subgroup analyses indicated that patients with ischaemic stroke were particularly vulnerable to the effects of PM2.5 and carbon monoxide exposure. The association between PM2.5 and declining MBI scores differed significantly by stroke subtype.
Carbon monoxide exposure also had a substantially greater negative association among patients with ischaemic stroke than among patients with haemorrhagic stroke.
The researchers concluded that long-term exposure to PM2.5, nitrogen dioxide, sulphur dioxide, and carbon monoxide may impede post-stroke recovery and increase ADL dependence.
The findings suggest that air quality interventions and environmental risk assessment could become important components of stroke rehabilitation and secondary prevention strategies.
Reference
Liu J et al. Air pollution and longitudinal functional recovery in stroke survivors – a longitudinal cohort study from central China. BMC Public Health. 2026;DOI:10.1186/s12889-026-29241-9.
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