School of Population and Public Health, University of British Columbia, 2206 East Mall, Vancouver, BC, V6T 1Z3, Canada.
Air Pollution Exposure Lab, Department of Medicine, University of British Columbia, 2775 Laurel Street 7th Floor, Vancouver, BC, V5Z 1M9, Canada.
Environ Health. 2018 Nov 14;17(1):78. doi: 10.1186/s12940-018-0424-8.
Cycling and other forms of active transportation provide health benefits via increased physical activity. However, direct evidence of the extent to which these benefits may be offset by exposure and intake of traffic-related air pollution is limited. The purpose of this study is to measure changes in endothelial function, measures of oxidative stress and inflammation, and lung function in healthy participants before and after cycling along a high- and low- traffic route.
Participants (n = 38) bicycled for 1 h along a Downtown and a Residential designated bicycle route in a randomized crossover trial. Heart rate, power output, particulate matter air pollution (PM, PM, and PM) and particle number concentration (PNC) were measured. Lung function, endothelial function (reactive hyperemia index, RHI), C-reactive protein, interleukin-6, and 8-hydroxy-2'-deoxyguanosine were assessed within one hour pre- and post-trial.
Geometric mean PNC exposures and intakes were higher along the Downtown (exposure = 16,226 particles/cm; intake = 4.54 × 10 particles) compared to the Residential route (exposure = 9367 particles/cm; intake = 3.13 × 10 particles). RHI decreased following cycling along the Downtown route and increased on the Residential route; in mixed linear regression models, the (post-pre) change in RHI was 21% lower following cycling on the Downtown versus the Residential route (-0.43, 95% CI: -0.79, -0.079) but RHI decreases were not associated with measured exposure or intake of air pollutants. The differences in RHI by route were larger amongst females and older participants. No consistent associations were observed for any of the other outcome measures.
Although PNC exposures and intakes were higher along the Downtown route, the lack of association between air pollutant exposure or intake with RHI and other measures suggests other exposures related to cycling on the Downtown route may have been influential in the observed differences between routes in RHI.
ClinicalTrials.gov, NCT01708356 . Registered 16 October 2012.
骑行和其他形式的主动交通通过增加身体活动来带来健康益处。然而，关于这些益处可能在多大程度上被与交通相关的空气污染的暴露和摄入所抵消的直接证据有限。本研究的目的是测量健康参与者在沿着高交通和低交通路线骑行前后内皮功能、氧化应激和炎症标志物以及肺功能的变化。
参与者（n=38）在一项随机交叉试验中沿着市区和住宅指定自行车道各骑行 1 小时。测量心率、功率输出、颗粒物空气污染（PM、PM 和 PM）和颗粒数浓度（PNC）。在试验前和后 1 小时内评估肺功能、内皮功能（反应性充血指数，RHI）、C 反应蛋白、白细胞介素-6 和 8-羟基-2'-脱氧鸟苷。
与住宅路线相比，市区路线的 PNC 暴露和摄入量的几何平均值更高（暴露=16226 个/立方厘米；摄入=4.54×10 个）（暴露=9367 个/立方厘米；摄入=3.13×10 个）。RHI 在沿着市区路线骑行后下降，在沿着住宅路线骑行后增加；在混合线性回归模型中，与在住宅路线相比，在市区路线骑行后 RHI 的（后-前）变化低 21%（-0.43，95%置信区间：-0.79，-0.079），但 RHI 下降与测量的空气污染物暴露或摄入无关。RHI 路线间的差异在女性和年龄较大的参与者中更大。其他测量指标没有观察到一致的关联。
尽管市区路线的 PNC 暴露和摄入量较高，但空气污染物暴露或摄入与 RHI 和其他指标之间缺乏关联表明，与在市区路线骑行相关的其他暴露可能对 RHI 路线间的差异有影响。
ClinicalTrials.gov，NCT01708356。于 2012 年 10 月 16 日注册。
