Coarse particles (PM2.5-10) and cause-specific hospitalizations in southwestern China: Association, attributable risk and economic costs.

ABSTRACT

The short-term morbidity effects of the coarse particle (diameter in 2.5-10 µm, PM2.5-10), as well as the corresponding morbidity burden and economic costs, remain understudied, especially in developing countries. This study aimed to examine the associations of PM2.5-10 with cause-specific hospitalizations in a multi-city setting in southwestern China and assess the attributable risk and economic costs. City-specific associations were firstly estimated using generalized additive models with quasi-poisson distribution to handle over-dispersion, and then combined to obtain the regional average association. City-specific and pooled concentration-response (C-R) associations of PM2.5-10 with cause-specific hospitalizations were also modeled. Subgroup analyses were performed by age, sex, season and region. The health and economic burden of hospitalizations for multiple outcomes due to PM2.5-10 were further evaluated. A total of 4,407,601 non-accidental hospitalizations were collected from 678 hospitals. The estimates of percentage change in hospitalizations per 10 µg/m³ increase in PM2.5-10 at lag01 was 0.68% (95%CI 0.33%-1.03%) for non-accidental causes, 0.86% (95% CI 0.36%-1.37%) for circulatory diseases, 1.52% (95% CI 1.00%-2.05%) for respiratory diseases, 1.08% (95% CI 0.47%-1.69%) for endocrine diseases, 0.66% (95% CI 0.12%-1.21%) for nervous system diseases, and 0.84% (95% CI 0.42%-1.25%) for genitourinary diseases, respectively. The C-R associations of PM2.5-10 with cause-specific hospitalizations suggested some evidence of nonlinearity, except for endocrine diseases. Meanwhile, the adverse effects were modified by age and season. Overall, about 0.70% (95% CI 0.35%-1.06%) of non-accidental hospitalizations and 0.78% (95% CI 0.38%-1.17%) of total hospitalization expenses could be attributed to PM2.5-10. The largest morbidity burden and economic costs were observed in respiratory diseases. Our findings indicate that PM2.5-10 exposure may increase the risk of hospitalizations for multiple outcomes, and account for considerable morbidity and economic burden.