Department of Occupational and Environmental Health Sciences, Peking University, School of Public Health, Beijing, China.
Environ Res. 2013 Jan;120:82-9. doi: 10.1016/j.envres.2012.08.008. Epub 2012 Sep 18.
Both ambient temperature and air pollution have been associated with alterations in cardiac autonomic function, but the responsive patterns associated with temperature exposure and the interactive effects of temperature and air pollution remain largely unclear.
We investigated the associations between personal temperature exposure and cardiac autonomic function as reflected by heart rate variability (HRV) in a panel of 14 healthy taxi drivers in the context of traffic-related air pollution.
We collected real-time data on study subjects' in-car exposures to temperature and traffic-related air pollutants including particulate matter with an aerodynamic diameter ≤2.5 μm (PM(2.5)) and carbon monoxide (CO) and HRV indices during work time (8:30-21:00) on 48 sampling days in the warm season (May-September) and cold season (October-March). We applied mixed-effects models and loess models adjusting for potential confounders to examine the associations between temperature and HRV indices.
We found nonlinear relationships between temperature and HRV indices in both the warm and cold seasons. Linear regression stratified by temperature levels showed that increasing temperature levels were associated with declines in standard deviation of normal-to-normal intervals over different temperature strata and increases in low-frequency power and low-frequency:high-frequency ratio in higher temperature range (>25 °C). PM(2.5) and CO modified these associations to various extents.
Temperature was associated with alterations in cardiac autonomic function in healthy adults in the context of traffic-related air pollution.
环境温度和空气污染均与心脏自主神经功能的改变有关，但温度暴露相关的反应模式以及温度与空气污染的交互作用在很大程度上仍不清楚。
在与交通相关的空气污染背景下，我们调查了 14 名健康出租车司机个体温度暴露与心率变异性（HRV）所反映的心脏自主神经功能之间的关系。
我们在暖季（5 月至 9 月）和冷季（10 月至 3 月）的 48 个采样日工作时间（8:30-21:00）内，实时收集了研究对象车内的温度和交通相关空气污染物（包括空气动力学直径≤2.5 μm 的颗粒物[PM（2.5）]和一氧化碳[CO]）暴露数据以及 HRV 指数。我们应用混合效应模型和局部加权散点平滑回归模型（loess models）调整潜在混杂因素，以检验温度与 HRV 指数之间的关系。
我们在暖季和冷季均发现温度与 HRV 指数之间存在非线性关系。按温度水平分层的线性回归显示，随着温度水平的升高，不同温度水平的正常-正常间期标准差逐渐下降，而在较高温度范围（>25°C）的低频功率和低频：高频比值逐渐升高。PM（2.5）和 CO 在不同程度上改变了这些关联。
在交通相关空气污染背景下，温度与健康成年人心脏自主神经功能的改变有关。
