A systematic review of the effects of climate change on childhood diarrhoeal disease burden in low and middle income countries

Background and objective: Climate change significantly impacts human health, particularly worsening diarrhoeal disease burden in low- and middle-income countries (LMICs). While children under five experience the highest disease burden, climate-health relationships affect all age groups. This systematic review examined how climate change variables (temperature, precipitation, extreme weather events) impact diarrhoeal disease burden in LMICs. Methods: We conducted a comprehensive literature search from January 2010 to December 2024, using Medical Subject Headings (MeSH) terms and keywords related to climate change, diarrhoeal diseases, and geographical locations in middle- and low-income countries. We descriptively synthesized the extracted data. Key findings: The systematic search identified 39 studies meeting inclusion criteria, of which 34 studies (87.2%) reported statistically significant positive associations between climate variables and diarrhoeal disease outcomes. Temperature effects were examined in 28 studies (71.8%), with 25 studies (89.3%) finding significant positive associations and consistent effect sizes of 3–5% increased diarrhoea risk per 1 °C temperature rise across diverse settings. Rainfall showed bidirectional patterns: 14 studies (63.6%) found increased disease with heavy rainfall in monsoon regions, while 8 studies (36.4%) found increased disease during rainfall shortage in semi-arid settings. Regional vulnerabilities included Nepal showing 4.4% increased diarrhoea per 1 °C in mountain regions, and South/Southeast Asia experiencing 39% increased probability at 30–40 °C. Infrastructure analysis (12 studies) revealed household water improvements reduced climate-associated risk by 15–35%, while community-level interventions showed 40–85% protection. Conclusions: The review demonstrates clear evidence of climate-disease relationships mediated by environmental, social, and infrastructural factors. Consistent temperature-disease relationships exist across regions, with quantifiable disease burden increases corresponding to rising temperatures and rainfall patterns. The findings highlight the importance of limiting global warming below 2 °C, preferably 1.5 °C above pre-industrial levels, as outlined in the Paris Climate Agreement, to minimize future diarrhoeal disease burden.