Lagged association between climate variables and hospital admissions for pneumonia admissions in South Africa

Hugo Pedder*, Thandi Kapwata, Guy Howard, Rajen Naidoo, South Medical, Richard W Morris, Angela Mathee, Caradee Y. Wright

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

6 Citations (Scopus)
66 Downloads (Pure)


Pneumonia is a leading cause of hospitalization in South Africa. Climate change could potentially affect its incidence via changes in meteorological conditions. We investigated the delayed effects of temperature and relative humidity on pneumonia hospital admissions at two large public hospitals in Limpopo province, South Africa. Using 4062 pneumonia hospital admission records from 2007 to 2015, a time-varying distributed lag non-linear model was used to estimate temperature-lag and relative humidity-lag pneumonia relationships. Mean temperature, relative humidity and diurnal temperature range were all significantly associated with pneumonia admissions. Cumulatively across the 21-day period, higher mean daily temperature (30 C relative to 21 C) was most strongly associated with a decreased rate of hospital admissions (relative rate ratios (RR): 0.34, 95% confidence interval (CI): 0.14–0.82), whereas results were suggestive of lower mean daily temperature (12 C relative to 21 C) being associated with an increased rate of admissions (RR: 1.27, 95%CI: 0.75–2.16). Higher relative humidity (>80%) was associated with fewer hospital admissions while low relative humidity (<30%) was associated with increased admissions. A proportion of pneumonia admissions were attributable to changes in meteorological variables, and our results indicate that even small shifts in their distributions (e.g., due to climate change) could lead to substantial changes in their burden. These findings can inform a better understanding of the health implications of climate change and the burden of hospital admissions for pneumonia now and in the future.
Original languageEnglish
Article number6191
Number of pages17
JournalInternational Journal of Environmental Research and Public Health
Issue number12
Publication statusPublished - 8 Jun 2021

Bibliographical note

Funding Information:
Funding: This research was carried out for the iDEWS (infectious Diseases Early-Warning System) project supported by SATREPS (Science and Technology Research Partnership for Sustainable Development) Program of JICA (JAPAN International Cooperation Agency)/AMED (Japan Agency for Medical Research and Development) in Japan, the ACCESS (Applied Centre for Climate and Earth Systems Science) program of NRF (National Research Foundation) and DST (Department of Science and Technology in South Africa) and from the Quality Related Global Challenges Research Fund of the University of Bristol. TK, AM, ZK and CYW receive research funding from the South African Medical Research Council.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Structured keywords

  • Water and Environmental Engineering


  • climate change
  • distributed non-linear lag model
  • environmental health
  • public health
  • respiratory disease
  • pneumonia
  • South Africa
  • meteorology


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