Clinical Studies in Humans Exploring the Link Between Air Pollution and Stroke
Unlike in cardiac pathologies [40, 41], controlled exposure studies in patients with stroke remain sparse. However a few longitudinal studies do reveal potential mechanisms linking exposure to air pollution and stroke. Wellenius et al. showed that sub-acute exposure to PM25 over a few weeks was associated with alteration in cerebral haemodynamics including increased cerebrovascular resistance and reduced cerebral blood flow [42]. In a further cross-sectional analysis Newman et al. showed a positive association between presence of carotid artery stenosis and exposure to PM25, with a twofold increased risk of stenosis per 10 pg/m3 of PM25. This association was persistent despite adjustment for known risk factors for atherosclerosis including age, sex, ethnicity, body mass index, cholesterol levels and hypertension [43]. Biological mechanisms which could account for these observations are discussed in [44] and below.
