Observational approaches in the study of the effects of Total Suspended Particulates (TSP) exposure

Literature contains mainly reports of observations based on time-series, or those of a case-crossover analysis design or, although less frequently, case control studies. However, data obtained by different approaches are difficult to compare based on different and non-homogenous population. The principal aim of this research was to compare the estimated risks obtained by differing approaches based on the same population study in the period 2006-2009. The data were based on a total of 44,200 residents in the city of Turin, hospitalised for respiratory diseases (ICD 460-519) in the period 2006-2009. Total suspended particulates (TSP), measured in µg/m(3), are the most commonly used predictors of urban pollution. The association between hospital admission for respiratory diseases and TSP exposure was investigated using at the same time the time-series, case-crossover and case-control approaches. The analyses show a general comparability of the case-crossover design stratified for time and the time-series approach, and the case control approach provided a more unstable estimation of risks. In conclusion, our results seem to indicate that the different approaches studied seem to offer comparable results.