This study examines the association of the levels of different airborne pollutants on the incidence of osteoporotic hip fracture in a southern European region. Association was detected between SO2 and NO2 and hospital admissions due to hip fracture.
Introduction: To examine the short-term effects of outdoor air pollution on the incidence of osteoporotic hip fracture in a southern European region.
Methods: This is an ecological retrospective cohort study based on data obtained from three databases. In a time-series analysis, we examined the association between hip fracture incidence and different outdoor air pollutants (sulfur dioxide (SO2), monoxide (NO), nitrogen dioxide (NO2), ozone (O3), and particulate matter in suspension < 2.5 (PM2.5) and < 10-μm (PM10) conditions by using general additive models (Poisson distribution). The incidence rate ratio (IRR), crude and adjusted by season and different weather conditions, was estimated for all parameters. Hip incidence was later analyzed by sex and age (under or over age 75) subgroups. The main outcome measure was daily hospital admissions due to fracture.
Results: Hip fracture incidence showed association with SO2 (IRR 1.11 (95% CI 1.04-1.18)), NO (IRR 1.01 (95% CI 1.01-1.02)), and NO2 (IRR 1.02 (95% CI 1.01-1.04)). For O3 levels, this association was negative (IRR 0.97 (95% CI 0.95-0.99)). The association persisted for SO2 and NO2 when the models were adjusted by season. After adjusting by season and weather conditions, the association persisted for NO2. When participants were stratified by age and sex, associations persisted only in women older than 75 years.
Conclusions: A short-term association was observed with several indicators of air pollution on hip fracture incidence. This is the first study that shows these associations.
Keywords: Air pollution; Climate variables; Hip fracture; Osteoporosis; Seasonality; Spain; Weather.