Below are abstracts and links to the full-text of articles in the August 2014 issue of Tropical Medicine and International Health.
Focus on the Global Burden of Disease from Water
While the methods of Global Burden of Disease (GBD) study continue to evolve, recent changes raise questions about the basis of new estimates of the risk associated with water, sanitation and hygiene and warrant consideration of alternative approaches.
- Inadequate water, sanitation and hygiene are estimated to have caused 842,000 deaths from diarrhoea in 2012, i.e., 1.5% of deaths worldwide. These include 361,000 deaths of children under five years.
- A systematic review of the global prevalence of handwashing with soap and its effect on diarrhoeal diseases estimates that only 19% of the world’s population washes hands with soap after contact with excreta and that handwashing reduces the risk of diarrhoeal disease by 23%–40%.
- Based on over 300 studies from a systematic review, an estimated 1.1 billion people are exposed to a drinking water source of moderate to high risk.
- A meta-regression shows that risks of diarrhoea from inadequate drinking water and sanitation could be reduced considerably through targeted interventions. Risk differences depend on type of intervention.
1 – Authors: Clasen, Thomas, Pruss-Ustun, Annette, Mathers, Colin D., et al.
TI – Estimating the impact of unsafe water, sanitation and hygiene on the global burden of disease: evolving and alternative methods
Abstract – http://onlinelibrary.wiley.com/doi/10.1111/tmi.12330/abstract
AB – The 2010 global burden of disease (GBD) study represents the latest effort to estimate the global burden of disease and injuries and the associated risk factors. Like previous GBD studies, this latest iteration reflects a continuing evolution in methods, scope and evidence base. Since the first GBD Study in 1990, the burden of diarrhoeal disease and the burden attributable to inadequate water and sanitation have fallen dramatically. While this is consistent with trends in communicable disease and child mortality, the change in attributable risk is also due to new interpretations of the epidemiological evidence from studies of interventions to improve water quality. To provide context for a series of companion papers proposing alternative assumptions and methods concerning the disease burden and risks from inadequate water, sanitation and hygiene, we summarise evolving methods over previous GBD studies. We also describe an alternative approach using population intervention modelling. We conclude by emphasising the important role of GBD studies and the need to ensure that policy on interventions such as water and sanitation be grounded on methods that are transparent, peer-reviewed and widely accepted.
2 – Authors: Prüss-Ustün, Annette, Bartram, Jamie, Clasen, Thomas, et al.
TI – Burden of disease from inadequate water, sanitation and hygiene in low- and middle-income settings: a retrospective analysis of data from 145 countries
Objective – To estimate the burden of diarrhoeal diseases from exposure to inadequate water, sanitation and hand hygiene in low- and middle-income settings and provide an overview of the impact on other diseases.
Methods – For estimating the impact of water, sanitation and hygiene on diarrhoea, we selected exposure levels with both sufficient global exposure data and a matching exposure-risk relationship. Global exposure data were estimated for the year 2012, and risk estimates were taken from the most recent systematic analyses. We estimated attributable deaths and disability-adjusted life years (DALYs) by country, age and sex for inadequate water, sanitation and hand hygiene separately, and as a cluster of risk factors. Uncertainty estimates were computed on the basis of uncertainty surrounding exposure estimates and relative risks.
Results – In 2012, 502 000 diarrhoea deaths were estimated to be caused by inadequate drinking water and 280 000 deaths by inadequate sanitation. The most likely estimate of disease burden from inadequate hand hygiene amounts to 297 000 deaths. In total, 842 000 diarrhoea deaths are estimated to be caused by this cluster of risk factors, which amounts to 1.5% of the total disease burden and 58% of diarrhoeal diseases. In children under 5 years old, 361 000 deaths could be prevented, representing 5.5% of deaths in that age group.
Conclusions – This estimate confirms the importance of improving water and sanitation in low- and middle-income settings for the prevention of diarrhoeal disease burden. It also underscores the need for better data on exposure and risk reductions that can be achieved with provision of reliable piped water, community sewage with treatment and hand hygiene.