Reduced exposure to PM10 and atten ... | Article | H1 Connect

The outstanding merit of this study is not in the type of outcome examined (lung function) but rather in showing for the first time that, in adults, reducing the level of particulate matter (PM)10 leads to the reduction of its health effect, thus adding a substantial argument to the causality of this association. A variety of health outcomes (from all-cause mortality to molecular markers) have been found to be associated with air pollution. Respirable PM10 is one of the most relevant components of the polluting mixture. A large population, nearly 5000 subjects, aged 18 to 60 years, were prospectively followed over a period of 11 years between 1991 and 2002. Their lung function was examined at the starting and closing dates of follow-up. Each subject was assigned an annual PM10 concentration every year, based on measurements of PM10 concentration outside individual homes. Moving to less polluted areas attenuated the age-related decline in lung function. The net effect of a decline of 10mcg/cubic meter in PM10 over the follow-up period was a reduction of the annual rate of decline in the forced expiratory volume in 1 second (FEV1) by 9%. The study confirms a previous observation in a smaller group of children (aged 10-15 years): those who moved to areas with lower PM10 levels showed an increased growth in lung function and those who moved to communities with a higher PM10 level showed a decrease in lung function growth (Avol et al., Am J Respir Crit Care Med 2001, 164:2067-2072 [PMID:11739136]). The study also represents a nice illustration of one of the criteria for causality suggested by A. Bradford Hill in 1965 to evaluate the possible causal nature of an exposure-effect epidemiological association (Hill, Proc R Soc Med 1965, 58:295-300 [PMID:14283879]) and it provides evidence that controlling air pollution has positive consequences for public health.