Centre for Air Pollution, Energy and Health Research, Australia; The University of Sydney, University Centre for Rural Health, School of Public Health, Sydney, Australia; Centre for Research and Action in Public Health, University of Canberra, Canberra, Australia.
The University of Sydney, University Centre for Rural Health, School of Public Health, Sydney, Australia.
Environ Int. 2019 May;126:762-770. doi: 10.1016/j.envint.2019.02.044. Epub 2019 Mar 15.
Epidemiological studies show that long-term exposure to ambient air pollution reduces life expectancy. Most studies have been in environments with relatively high concentrations such as North America, Europe and Asia. Associations at the lower end of the concentration-response function are not well defined.
We assessed associations between all-cause mortality and exposure to annual average particulate matter <2.5 μm (PM) and nitrogen dioxide (NO) in Sydney, Australia, where concentrations are relatively low.
The '45 and Up Study' comprises a prospective longitudinal cohort from the state of New South Wales, Australia with 266,969 participants linked to death registry data. We analyzed data for the participants who resided in Sydney at baseline questionnaire (n = 75,268). Exposures to long-term pollution were estimated using annual averages from a chemical transport model (PM), and a satellite-based land-use regression model (NO). Socio-demographic information was extracted from the baseline questionnaire. Cox proportional hazard models were applied to estimate associations, while adjusting for covariates.
In our cohort mean annual PM was 4.5 μg/m and mean NO was 17.8 μg/m. The mortality rate was 4.4% over the 7 years of follow up. Models that adjusted for individual-level and area-level risk factors resulted in a detrimental non statistically significant hazard ratio (HR) of 1.05 (95% CI: 0.98-1.12) per 1 μg/m increase in PM, and 1.03 (95% CI: 0.98-1.07) per 5 μg/m increase in NO.
We found evidence that low-level air pollution exposure was associated with increased risk of mortality in this cohort of adults aged 45 years and over, even at the relatively low concentrations seen in Sydney. However, a clear determination of the association with mortality is difficult because the results were sensitive to some covariates. Our findings are supportive of emerging evidence that exposure to low levels of air pollution reduces life expectancy.
流行病学研究表明，长期暴露于环境空气污染会降低预期寿命。大多数研究都在北美、欧洲和亚洲等浓度相对较高的环境中进行。在浓度-反应函数的低端，关联尚未得到很好的定义。
我们评估了在澳大利亚悉尼，所有原因死亡率与暴露于年平均细颗粒物<2.5μm（PM）和二氧化氮（NO）之间的关系，那里的浓度相对较低。
“45 岁及以上研究”是一项来自澳大利亚新南威尔士州的前瞻性纵向队列研究，有 266969 名参与者与死亡登记数据相关联。我们分析了基线问卷调查时居住在悉尼的参与者的数据（n=75268）。使用化学输送模型（PM）和基于卫星的土地利用回归模型（NO）估算长期污染暴露。从基线问卷中提取社会人口统计学信息。应用 Cox 比例风险模型来估计关联，同时调整协变量。
在我们的队列中，年平均 PM 为 4.5μg/m，NO 平均为 17.8μg/m。在 7 年的随访中，死亡率为 4.4%。调整个体水平和区域水平危险因素的模型得出，PM 每增加 1μg/m，危害比（HR）为 1.05（95%CI：0.98-1.12），NO 每增加 5μg/m，HR 为 1.03（95%CI：0.98-1.07），均无统计学意义。
我们发现，即使在悉尼看到的相对较低浓度下，暴露于低水平空气污染与该队列中 45 岁及以上成年人的死亡风险增加有关。然而，由于结果对一些协变量敏感，因此很难确定与死亡率的关联。我们的研究结果支持了越来越多的证据，即暴露于低水平空气污染会降低预期寿命。
