Stockfelt Leo, Andersson Eva M, Molnár Peter, Gidhagen Lars, Segersson David, Rosengren Annika, Barregard Lars, Sallsten Gerd
Department of Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden.
Department of Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden.
Environ Res. 2017 Oct;158:61-71. doi: 10.1016/j.envres.2017.05.036. Epub 2017 Jun 8.
Long-term exposure to air pollution increases cardiopulmonary morbidity and mortality, but it is not clear which components of air pollution are the most harmful, nor which time window of exposure is most relevant. Further studies at low exposure levels have also been called for. We analyzed two Swedish cohorts to investigate the effects of total and source-specific particulate matter (PM) on incident cardiovascular disease for different time windows of exposure.
Two cohorts initially recruited to study predictors of cardiovascular disease (the PPS cohort and the GOT-MONICA cohort) were followed from 1990 to 2011. We collected data on residential addresses and assigned each individual yearly total and source-specific PM and Nitrogen Oxides (NO) exposures based on dispersion models. Using multivariable Cox regression models with time-dependent exposure, we studied the association between three different time windows (lag 0, lag 1-5, and exposure at study start) of residential PM and NO exposure, and incidence of ischemic heart disease, stroke, heart failure and atrial fibrillation.
During the study period, there were 2266 new-onset cases of ischemic heart disease, 1391 of stroke, 925 of heart failure and 1712 of atrial fibrillation. The majority of cases were in the PPS cohort, where participants were older. Exposure levels during the study period were moderate (median: 13µg/m for PM and 9µg/m for PM), and similar in both cohorts. Road traffic and residential heating were the largest local sources of PM air pollution, and long distance transportation the largest PM source in total. In the PPS cohort, there were positive associations between PM in the last five years and both ischemic heart disease (HR: 1.24 [95% CI: 0.98-1.59] per 10µg/m of PM, and HR: 1.38 [95% CI: 1.08-1.77] per 5µg/m of PM) and heart failure. In the GOT-MONICA cohort, there were positive but generally non-significant associations between PM and stroke (HR: 1.48 [95% CI: 0.88-2.49] per 10µg/m of PM, and HR: 1.50 [95% CI: 0.90-2.51] per 5µg/m of PM, in the last five years). Effect estimates were stronger for women, non-smokers, and higher socioeconomic classes. Exposure in the last five years seemed to be more strongly associated with outcomes than other exposure time windows. Associations between source-specific PM air pollution and outcomes were mixed and generally weak. High correlations between the main pollutants limited the use of multi-pollutant models.
The main PM air pollutants were associated with ischemic heart disease and stroke (in women) at the relatively low exposure levels in Gothenburg, Sweden. The associations tended to be stronger for women than for men, for non-smokers than for smokers, and for higher socioeconomic classes than for lower. The associations could not be attributed to a specific PM source or type, and differed somewhat between the two cohorts. The results of this study confirm that further efforts to reduce air pollution exposure should be undertaken in Sweden to reduce the negative health effects in the general population.
长期暴露于空气污染中会增加心肺疾病的发病率和死亡率，但尚不清楚空气污染的哪些成分危害最大，也不清楚哪个暴露时间窗最为关键。此外，也需要在低暴露水平下开展进一步研究。我们分析了两个瑞典队列，以研究总颗粒物和特定来源颗粒物（PM）在不同暴露时间窗对心血管疾病发病的影响。
两个最初为研究心血管疾病预测因素而招募的队列（PPS队列和哥德堡市莫妮卡项目队列）于1990年至2011年期间接受随访。我们收集了居住地址数据，并根据扩散模型为每个人分配每年的总PM、特定来源PM和氮氧化物（NO）暴露量。使用带有时间依存性暴露的多变量Cox回归模型，我们研究了居住PM和NO暴露的三个不同时间窗（滞后0天、滞后1 - 5天以及研究开始时的暴露）与缺血性心脏病、中风、心力衰竭和房颤发病率之间的关联。
在研究期间，有2266例新发缺血性心脏病病例、1391例中风病例、925例心力衰竭病例和1712例房颤病例。大多数病例在PPS队列中，该队列中的参与者年龄较大。研究期间的暴露水平适中（PM中位数为13μg/m³，PM中位数为9μg/m³），且两个队列相似。道路交通和住宅供暖是本地PM空气污染的最大来源，长途运输是总的最大PM来源。在PPS队列中，过去五年的PM与缺血性心脏病（每10μg/m³的PM，HR：1.24 [95%CI：0.98 - 1.59]；每5μg/m³的PM，HR：1.38 [95%CI：1.08 - 1.77]）和心力衰竭均呈正相关。在哥德堡市莫妮卡项目队列中，过去五年的PM与中风呈正相关但一般无统计学意义（每10μg/m³的PM，HR：1.48 [95%CI：0.88 - 2.49]；每5μg/m³的PM，HR：1.50 [95%CI：0.90 - 2.51]）。女性、非吸烟者和社会经济阶层较高者的效应估计更强。过去五年的暴露似乎比其他暴露时间窗与结局的关联更强。特定来源PM空气污染与结局之间的关联不一且总体较弱。主要污染物之间的高相关性限制了多污染物模型的应用。
在瑞典哥德堡，主要的PM空气污染物在相对较低的暴露水平下与缺血性心脏病和中风（女性）相关。女性的关联往往比男性更强，非吸烟者比吸烟者更强，社会经济阶层较高者比社会经济阶层较低者更强。这些关联不能归因于特定的PM来源或类型，并在两个队列之间略有不同。本研究结果证实，瑞典应进一步努力减少空气污染暴露，以降低普通人群的负面健康影响。
