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Association between Rainfall and Mortality Due to Diarrhoeal Diseases by Climate Classification: A Multi-Country Modelling Study
25 Pages Posted: 13 Sep 2023
More...Abstract
Background: Various rainfall conditions could promote the transmission of diarrhoeal diseases by affecting the pathogen concentration in the environment. Given the diversity of rainfall patterns across different climates, this study explored the associations between rainfall and diarrhoeal mortality in tropical, temperate, and arid regions.
Methods: Daily counts of diarrhoeal mortality and 28-day cumulative rainfall from 1997 to 2019 were analysed across 29 within-country climatic regions in eight middle-income countries (Argentina, Brazil, Costa Rica, India, Peru, Philippines, South Africa, and Thailand). A two-stage approach was employed, using conditional Poisson regression models for each location and meta-analysis for pooling location-specific coefficients by climate.
Findings: In tropical climate, higher rainfall increased the risk of diarrhoeal mortality. Under extremely wet conditions (95th percentile of 28-day cumulative rainfall), diarrhoeal mortality increased by 18·1% [95% confidence interval (CI): 9·7–27·2%] compared to minimum risk rainfall. For temperate and arid climates, diarrhoeal mortality increased in both dry and wet conditions. In extremely dry conditions (5th percentile of 28-day cumulative rainfall), diarrhoeal mortality risk increased by 2·2% (95%CI: 0·6–4·0%) for temperate and 4·1% (95%CI: 0·7–7·7%) for arid climates. Similarly, under extremely wet conditions, diarrhoeal mortality risk increased by 2·6% (95%CI: 0·2–5·1%) for temperate and 5·3% (95%CI: 1·0–9·9%) for arid climates.
Interpretation: Associations between rainfall and diarrhoeal mortality exhibit variations across different climates. These findings emphasise the importance of considering such climate-specific differences in global projections of future rainfall-related diarrhoeal mortality.
Funding: This research was performed by Japan Science and Technology Agency as part of SICORP (Grant Number JPMJSC20E4) and the Environment Research and Technology Development Fund (Grant Numbers JPMEERF23S21120 and JPMEERF20231007) of the Environmental Restoration and Conservation Agency provided by the Ministry of Environment of Japan.
Declaration of Interest: We declare no competing interests.
Keywords: diarrhoea, gastroenteritis, rainfall, precipitation, climate, weather
Suggested Citation: Suggested Citation