Do subject characteristics modify the effects of particulate air pollution on daily mortality among the elderly?

OBJECTIVE: Studies have reported associations between mortality and air pollution, but questions subsist on the identification of susceptible subgroups in the population. We studied individual characteristics that modify the relationship between particulate air pollution and mortality among elderly. METHOD: We examined 527 nonaccidental deaths (197 cardiorespiratory deaths) among the 1469 subjects from the Personnes Agees QUID cohort in Bordeaux between 1988 and 1997. Air pollution was measured as black smoke by urban monitoring background stations. We used a case crossover approach and calculated odds ratio by conditional logistic regression models. RESULTS: We observed associations between the third lag day and cardiorespiratory mortality for an increase of 10 microg/m3 of black smoke (odds ratio = 1.30, 95% confidence interval: 1.01-1.68). CONCLUSIONS: Our results provide insight into factors possibly conferring susceptibility to the acute effect of urban air pollution.