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Abnormal temperature has important effects on the occurrence of ischemic stroke (IS). However, relatively less efforts have been taken to systematically unravel the association between various abnormal temperature and IS hospital admission. Focusing on three temperature indicators (i.e., mean temperature, maximum temperature, and minimum temperature), this study attempts to analyse how their abnormal values affect IS hospital admission. The dataset covers the period between September 17, 2012 and August 28, 2018, and includes a total of 1464 cases who were admitted to the hospital for the first onset of IS and lived in the main urban area of Guangzhou. The study adopts the time-stratified case-crossover analysis. Abnormal values of temperature were measured using the 2.5th and 97.5th quantile values of each temperature indicator, with the former refers to a low value whereas the latter a high one. The effects of abnormal temperature on IS hospital admission were assessed through calculating the relative risks induced by the low and high values (the median values of each temperature indicators were taken as the references). The results show that the risk window periods for IS hospital admission associated with the low values of the temperature indicators are the lags of 3–7 days and 18–19 days. The risks of high temperature values on IS admission, however, are insignificant with either one-day lag or cumulative lag. As to different population groups, females show higher risks of IS hospital admission at low temperature values than males; and elderly people, compared with young people, are more vulnerable to low temperature values. To cities with similar climate of Guangzhou, particular attention should be paid to the impact of low temperature values, especially the low value of minimum temperature, on IS admission, and to females and elderly people who are more sensitive to abnormal temperatures. • Low mean and minimum temperatures pose IS admissions at several lags, high maximum temperature only has the risk at a lag. • The risk window of IS admissions associated with the low mean and minimum temperatures are the lag 3–7 days and 18–19 days. • Particular attention should be paid to the low temperatures, especially the low minimum temperature, on IS admissions. • Females and elderly people show higher risks of IS admissions at low temperatures. [ABSTRACT FROM AUTHOR]

Extreme temperatures have an adverse effect on the occurrence of cardiovascular diseases (CVDs). Previous literatures tend to discuss the modification of CVDs occurrence by green space under high temperature. Relatively less attention is paid to the modification under low temperature. The variation of different attributes and spatial scales of green space in affecting CVDs occurrence are also overlooked. This study collected a total of 4364 first-time admission cases due to CVDs in a tertiary hospital in Guangzhou from 2012 to 2018, measured the scale of green space by greening rate (GR) and percentage of landscape (PLAND), the distribution of green space by patch density (PD), mean nearest neighbor distance (ENN_MN) and largest patch index (LPI), and the accessibility of green space by green patch accessibility index (GPAI). Using the time stratified case crossover design method, the modification of low temperature-related CVDs occurrence by the above green space indicators is evaluated in an area with a radius of 100–1000 m which is further divided at an interval of 100 m. We found high GR, high PLAND, high PD, low ENN_MN, high LPI, and low GPAI corresponds to low risk of CVDs occurrence, the optimal modification scale of each green space indicator, which is radius corresponding to the maximum risk difference between high and low indicator subgroups, is around 800 m (GR), 600 m (PLAND and PD), 500 m (GPAI), and 300 m (LPI and ENN_MN), respectively. As the temperature decreases further, the health benefit from low GPAI at the optimal scale is weakened, whereas the benefits from the others are strengthened. Low temperature related CVDs occurrence risk can be modified by multiple green space indicators, and these modifications have spatial scale effect. Our findings have important theoretical and practical significance for the formulation and implementation of local green space policies. [Display omitted] [ABSTRACT FROM AUTHOR]