Global diarrhoea morbidity, weather and climate

Abstract

Diarrhoea rates are influenced by weather and climate; transmission can be affected by temperature and rainfall extremes, although few studies have quantified this effect. We undertook a global cross-sectional study of diarrhoea incidence in children under 5, drawing on studies published in the last 50 yr, and assessed the association with climate variables. Log-linear regression was used to quantify any association, controlling for the effects of age, socio-economic conditions and access to improved water and sanitation. We found a negative association between rainfall and diarrhoea rates, with a 4% increase in diarrhoea incidence (95% confidence interval, CI: 1-7%, p = 0.02) for each 10 mm mo -1 decrease in rainfall. Little evidence for association with temperature or climate type was found. Our result for rainfall is consistent with a similar study covering a smaller geographic region. Though biases cannot be excluded, the most likely mechanism is that low rainfall leads to water scarcity, which in turn leads to the use of unprotected water sources and reduces hygiene practices. In the future, greater numbers are expected to experience water scarcity, which may lead to more diarrhoea cases in some locations. This study lends support to programmes for hygiene and water and sanitation coverage, as well as lending support to actions to adapt to and mitigate climate change.

Association between climate factors and diarrhoea in a Mekong Delta area

“…Nevertheless, in contrast to the findings regarding the relationship between heavy rainfall and diarrhoea, which have been demonstrated in the majority of studies, the relationship between temperature and diarrhoea is not fully understood. A recent study conducted on a global scale (Lloyd et al 2007) found no association between average temperature and diarrhoea morbidity. Three influencing factors for this finding were considered by the author: (i) the study used the allcause diarrhoea in a broad range of sites, resulting in quite different pathogen profiles; (ii) the range of temperatures in the study sites, which did not have cool weather, was too narrow to allow differences to be detected and (iii) uncontrolled biases might have obscured an association.…”

Roundtable on Urban Living Environment Research (RULER)

“…86,87 Heat waves: A growing literature focuses on the health problems arising from heat waves in urban areas, with recent work considering the implications in lowincome urban settings. 82,[88][89][90][91] One study examined the history of heat wave-related deaths in three cites of contrasting wealth (gross national income per capita)-Delhi, India; London, England; and São Paulo, Brazil-based on daily counts of all-cause mortality (excluding violent deaths) using counts of deaths by age and cause derived from mortality registries for the four-year period of January 1991 to December 1994. Setting these data against time series data of daily ambient temperature, they found that for each of these cities, an increase in all-cause mortality was observed for same day and previous day temperatures 920°C, with the excess mortality being greatest in Delhi and smallest in London.…”

The Impacts of Air Temperature on Accidental Casualties in Beijing, China

“…A multitude of studies have assessed the influence of weather conditions on human mortality or morbidity for chronic or infectious diseases [1,2,3,4,5]. However, few weather-health-related studies were found that have a focus on weather-related accidental casualties, which seem to happen unintentionally or from certain direct causes, such as traffic injury, assaults, or trauma.…”