Article Text

Original research
Effects of diurnal temperature range on first-ever strokes in different seasons: a time-series study in Shenzhen, China
  1. Lin Lei1,
  2. Junzhe Bao2,3,
  3. Yanfang Guo4,
  4. Qiong Wang3,5,
  5. Ji Peng1,
  6. Cunrui Huang2,3,5,6
  1. 1 Department of Non-Communicable Disease Control and Prevention, Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong, China
  2. 2 College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
  3. 3 School of Public Health, Sun Yat-Sen University, Guangzhou, Guangdong, China
  4. 4 Department of Non-Communicable Disease Control and Prevention, Bao'an District Hospital for Chronic Diseases Prevention and Cure, Shenzhen, Guangdong, China
  5. 5 Shanghai Typhoon Institute, China Meteorological Administration, Shanghai, China
  6. 6 Shanghai Key Laboratory of Meteorology and Health, Shanghai Meteorological Service, Shanghai, China
  1. Correspondence to Professor Cunrui Huang; huangcr{at}; Mr Ji Peng; pengji126{at}


Objective Diurnal temperature range (DTR) is an important meteorological indicator of global climate change; high values of DTR may induce stroke morbidity, while the related high-risk periods and sensitive populations are not clear. This study aims to evaluate the effects of DTR on first-ever strokes in different seasons and in relation to sensitive populations.

Methods We collected data on 142 569 first-ever strokes during 2005–2016 in Shenzhen. We fitted a time-series Poisson model in our study, estimating the associations between DTR and first-ever strokes, with a distributed lag non-linear model. Then, we calculated strokes attributable to high DTR in different genders, age groups, education levels and stroke subtypes.

Results High DTR had a significant association with first-ever strokes, and the risk of stroke increased with the rise of DTR in the summer and winter. In total, 3.65% (95% empirical CI (eCI) 1.81% to 5.53%) of first-ever strokes were attributable to high DTR (5.5°C and higher) in the summer, while 2.42% (95% eCI 0.05% to 4.42%) were attributable to high DTR (8°C and higher) in the winter. In the summer, attributable fraction (AF) was significant in both genders, middle-aged and old patients, patients with different levels of education, as well as patients with cerebral infarction (CBI); in the winter, AF was significant in middle-aged patients, patients with primary and lower education level, as well as patients with CBI.

Conclusions High DTR may trigger first-ever strokes in the summer and winter, and CBI is more sensitive than intracerebral haemorrhage to DTR. Most people are sensitive to high DTR in the summer, while middle-aged and low-education populations are sensitive in the winter. It is recommended that the DTR values be reported and emphasised in weather forecast services, together with the forecasts of heat and cold.

  • diurnal temperature range
  • first-ever strokes
  • season
  • time-series study

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  • LL and JB contributed equally.

  • Contributors The study was conceived and designed by JB and CH; LL and JB conducted statistical analysis and drafted the manuscript; JP, LL and YG contributed to data collection and processing; JB and QW helped in study management and the interpretation of the results; JP and CH reviewed the manuscript for important intellectual content; all authors read and approved the final version.

  • Funding This study was supported by the grants from the National Key R&D Program of China (Grant No. 2018YFA0606201), China Postdoctoral Science Foundation (Grant No. 2017M612827), Nature Science Foundation of Guangdong Province (Grant No. 2016A030313216), and Shenzhen Science and Technology Project (Grant No. JCYJ20170303104937484).

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  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The institutional review board at the School of Public Health, Sun Yat-sen University, approved the study protocol (number 2019-029) with a waiver of informed consent. Data were analysed at the aggregate level. All patients were anonymous, and no patient's privacy was revealed.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No data are available. Due to confidentiality requirements, the data involved in this study are currently not publicly available.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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