Temperature and Cardiovascular Mortality Associations in Four Southern Chinese Cities: A Time-Series Study Using a Distributed Lag Non-Linear Model

Jixia Huang,Weiwei Yu,Jing Tan

doi:10.3390/su9030321

Jixia Huang, Weiwei Yu + Show 1 more

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https://doi.org/10.3390/su9030321

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Abstract

Few studies on population-specific health effects of extreme temperature on cardiovascular diseases (CVDs) deaths have been conducted in the subtropical and tropical climates of China. We examined the association between extreme temperature and CVD across four cities in China. We performed a two-stage analysis; we generated city-specific estimates using a distributed lag non-linear model (DLNM) and estimated the overall effects by conducting a meta-analysis. Heat thresholds of 29 °C, 29 °C, 29 °C, and 30 °C and cold thresholds of 6 °C, 10 °C, 14 °C, and 15 °C were observed in Hefei, Changsha, Nanning, and Haikou, respectively. The lag periods for heat-related CVD mortality were observed only for 0–2 days, while those of cold-related CVD mortality were observed for 10–15 days. The meta-analysis showed that a 1 °C increase above the city-specific heat threshold was associated with average overall CVD mortality increases of 4.6% (3.0%–6.2%), 6.4% (3.4%–9.4%), and 0.2% (−4.8%–5.2%) for all ages, ≥65 years, and <65 years over a lag period of 0–2 days, respectively. Similarly, a 1 °C decrease below the city-specific cold threshold was associated with average overall CVD mortality increases of 4.2% (3.0%–5.4%), 4.9% (3.5%–6.3%), and 3.1% (1.7%–4.5%), for all ages, ≥65 years, and <65 years over a lag period of 0–15 days, respectively. This work will help to take appropriate measures to reduce temperature-mortality risk in different populations in the subtropical and tropical climates of China.

Highlights

Determining the potential health impacts of climate change is an important but complex issue [1]
We found an interesting phenomenon; the cold-related cardiovascular diseases (CVDs) mortality for females in Haikou was very high, wherein 1 ◦C decrease below the cold threshold was associated with an increase in CVD mortality of 10.0%
The research conditions were different for these studies, we clearly found that the heat thresholds were close to each other, while the discrepancy in cold thresholds was huge

Summary

Introduction

Determining the potential health impacts of climate change is an important but complex issue [1]. The frequency of warm days and nights has increased, which increases the relative risk of extreme temperature exposure [5]. Because of these dramatic global temperature changes, temperature-related mortality studies have become increasingly important, especially for cardiovascular disease (CVD) [6,7]. Many studies have shown that extreme temperatures seriously impact CVD [8,9,10,11,12,13] Both heat waves and cold snaps significantly increase CVD mortality [14,15]. A meta-analysis was used to stratify these results by age and gender [27]

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