Investigation of factors which might indicate susceptibility to particulate air pollution

Objectives-To determine whether previous symptoms or recognised risk factor s of cardiovascular hi health, are associated with an increased likelihood of adverse health effects related to particulate air pollution. Methods-Cardiovascular event rates were studied relative to urban concentra tions of particulate air pollution and baseline risk factors. The Edinburgh artery study consisted of a cohort of 1592 subjects aged 55-74 and was fol lowed up to the end of March 1998 for a median of 10 years resulting in abo ut 5 million person-days of observation. Baseline measurements included pla sma fibrinogen and blood and plasma viscosity. A nested case-control approa ch was used to investigate a possible interaction between effects of these selected baseline risk factors and particulate air pollution, on subsequent event rates. Results-During the follow up period there were 343 fatal and non-fatal myoc ardial infarctions or strokes. Trends in adverse cardiovascular outcomes re lated to pollution were identified among subjects belonging to the highest baseline quintile of plasma fibrinogen. Evidence for interactions between c oncentrations of particulate pollution and fibrinogen was not established a t conventional levels of significance. Conclusions-People with high concentrations of plasma fibrinogen might be m ore susceptible to adverse cardiovascular effects of particulate air pollut ion, but limitations of power mean that evidence relating to such an intera ction is not conclusive. A range of cardiopulmonary risk factors warrant in vestigation in relation to possible susceptibility to air pollution.