Outdoor Air Pollution and Hip Fracture in UK

Background: Until now, only a few studies have evaluated the impact of air pollution on BMD and associated fractures, and their results are controversial. Methods: We constructed a cohort of all NFHD beneficiaries (513,540 patients) in the UK from 2013 to 2018. Averages of particulate matter in suspension < 2.5μm (PM2.5), particulate matter in suspension < 10μm (PM10), ozone (O3), nitrogen dioxide (NO2), and sulphur dioxide (SO2) were estimated according to the person's residence. The incidence rate ratio, and all-cause mortality within 30 days post-fracture (ACM30D) rate ratios were estimated using generalized additive models. Results: The incidence of hip fracture (IHF) and ACM30D showed a positive association with PM2.5, PM10, and NO2. This association was negative for O3 levels. Each increase of 1 μg/m3 in PM2.5, PM10, and NO2 will cause a 1.83%, 1.77%, and 0.81% higher rate, respectively, of the IHF, and also a 1.79%, 1.61%, and 0.57% higher rate, respectively, of the ACM30D. When we restricted the analysis to low-level exposure of air pollutants, we continued to see the same results. Conclusions: Our study proved a moderate, direct association between IHF, ACM30D and the levels of specific air pollutants in the entire NHFD population. A reduction of levels of PM2.5, PM10, and NO2 may contribute to decrease the incidence, and associated mortality of hip fracture in elderly people. Our study highlights the influence of air pollution on hip fractures, which is one of the main causes of death in the elderly population. Funding Statement: Financial support for this study is from the National Natural Science Foundation of China (81871789, 81772358, 81702214); the Natural Science Foundation of Jiangsu Province (BK20180052). Declaration of Interests: All the authors declare that the research was conducted in the absence of any commercial or financial relationships which could be construed as a potential conflict of interest. Ethical Approval Statement: The institutional review board at Soochow University approved this study.