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Original research
Temporal trends of the association between extreme temperatures and hospitalisations for schizophrenia in Hefei, China from 2005 to 2014
  1. Rubing Pan1,
  2. Qizhi Wang2,
  3. Weizhuo Yi1,
  4. Qiannan Wei1,
  5. Jian Cheng1,
  6. Hong Su1
  1. 1 Epidemiology and Health Statistics, Anhui Medical University, Hefei, Anhui, China
  2. 2 Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China
  1. Correspondence to Professor Hong Su, Epidemiology and Health Statistics, Anhui Medical University, Hefei, China; 271244914{at}; Mr Jian Cheng; 809712000{at}


Objective We aimed to examine the temporal trends of the association between extreme temperature and schizophrenia (SCZ) hospitalisations in Hefei, China.

Methods We collected time-series data on SCZ hospitalisations for 10 years (2005–2014), with a total of 36 607 cases registered. We used quasi-Poisson regression and distributed lag non-linear model (DLNM) to assess the association between extreme temperature (cold and heat) and SCZ hospitalisations. A time-varying DLNM was then used to explore the temporal trends of the association between extreme temperature and SCZ hospitalisations in different periods. Subgroup analyses were conducted by age (0–39 and 40+ years) and gender, respectively.

Results We found that extreme cold and heat significantly increased the risk of SCZ hospitalisations (cold: 1st percentile of temperature 1.19 (95% CI 1.04 to 1.37) and 2.5th percentile of temperature 1.16 (95% CI 1.03 to 1.31); heat: 97.5th percentile of temperature 1.37 (95% CI 1.13 to 1.66) and 99th percentile of temperature 1.38 (95% CI 1.13 to 1.69)). We found a slightly decreasing trend in heat-related SCZ hospitalisations and a sharp increasing trend in cold effects from 2005 to 2014. However, the risk of heat-related hospitalisation has been rising since 2008. Stratified analyses showed that age and gender had different modification effects on temporal trends.

Conclusions The findings highlight that as temperatures rise the body’s adaptability to high temperatures may be accompanied by more threats from extreme cold. The burden of cold-related SCZ hospitalisations may increase in the future.

  • climate
  • environmental exposure
  • risk assessment

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  • Contributors RP: conceptualisation, software, writing of original draft, investigation. QW, WY: software. QW: validation, data curation. JC: writing-review and editing, methodology. HS: project administration, funding acquisition, writing-review and editing.

  • Funding This work was supported by the National Natural Science Foundation of China (grant number: 81773518).

  • Competing interests None declared.

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

  • 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.