Wicki Benedikt, Flückiger Benjamin, Vienneau Danielle, de Hoogh Kees, Röösli Martin, Ragettli Martina S
Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland; University of Basel, Basel, Switzerland.
Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland; University of Basel, Basel, Switzerland.
Environ Res. 2024 Apr 1;246:118116. doi: 10.1016/j.envres.2024.118116. Epub 2024 Jan 5.
In the light of growing urbanization and projected temperature increases due to climate change, heat-related mortality in urban areas is a pressing public health concern. Heat exposure and vulnerability to heat may vary within cities depending on structural features and socioeconomic factors. This study examined the effect modification of the temperature-mortality association of three socio-environmental factors in eight Swiss cities and population subgroups (<75 and ≥ 75 years, males, females): urban heat islands (UHI) based on within-city temperature contrasts, residential greenness measured as normalized difference vegetation index (NDVI) and neighborhood socioeconomic position (SEP). We used individual death records from the Swiss National Cohort occurring during the warm season (May to September) in the years 2003-2016. We performed a case time series analysis using conditional quasi-Poisson and distributed lag non-linear models with a lag of 0-3 days. As exposure variables, we used daily maximum temperatures (Tmax) and a binary indicator for warm nights (Tmin ≥20 °C). In total, 53,593 deaths occurred during the study period. Overall across the eight cities, the mortality risk increased by 31% (1.31 relative risk (95% confidence interval: 1.20-1.42)) between 22.5 °C (the minimum mortality temperature) and 35 °C (the 99th percentile) for warm-season Tmax. Stratified analysis suggested that the heat-related risk at 35 °C is 26% (95%CI: -4%, 67%) higher in UHI compared to non-UHI areas. Indications of smaller risk differences were observed between the low vs. high greenness strata (Relative risk difference = 13% (95%CI: -11%; 44%)). Living in low SEP neighborhoods was associated with an increased heat related risk in the non-elderly population (<75 years). Our results indicate that UHI are associated with increased heat-related mortality risk within Swiss cities, and that features beyond greenness are responsible for such spatial risk differences.
鉴于城市化进程不断加快以及气候变化导致气温预计上升，城市地区与高温相关的死亡率成为一个紧迫的公共卫生问题。由于城市的结构特征和社会经济因素不同，城市内部的高温暴露情况和对高温的脆弱性也可能存在差异。本研究考察了瑞士八个城市的三个社会环境因素以及人口亚组（<75岁和≥75岁、男性、女性）对温度与死亡率关联的效应修正：基于城市内部温度差异的城市热岛效应（UHI）、以归一化植被指数（NDVI）衡量的住宅绿化程度以及邻里社会经济地位（SEP）。我们使用了瑞士国民队列在2003年至2016年暖季（5月至9月）期间的个体死亡记录。我们使用条件准泊松模型和分布滞后非线性模型进行了病例时间序列分析，滞后时间为0至3天。作为暴露变量，我们使用了每日最高气温（Tmax）和暖夜（最低气温≥20°C）的二元指标。在研究期间共发生了53,593例死亡。在八个城市总体来看，暖季Tmax在22.5°C（最低死亡率温度）至35°C（第99百分位数）之间时，死亡率风险增加了31%（相对风险1.31（95%置信区间：1.20 - 1.42））。分层分析表明，与非城市热岛地区相比，城市热岛效应地区在35°C时与高温相关的风险高出26%（95%CI：-4%，67%）。在绿化程度低与高的阶层之间观察到风险差异较小的迹象（相对风险差异 = 13%（95%CI：-11%；44%））。生活在社会经济地位低的社区与非老年人群（<75岁）中与高温相关的风险增加有关。我们的结果表明，城市热岛效应与瑞士城市内与高温相关的死亡风险增加有关，并且绿化程度以外的特征导致了这种空间风险差异。
