Exploring the broader consequences of diarrhoeal diseases on child health
Authors: Thomas F Wierzba, Farzana Muhib
Journal: The Lancet Global Health (2018)

Fewer parents in low-resource nations are living with the fear or tragedy of a child's death from acute diarrhoea as the frequency of these deaths decreases globally each year. In 2015, there were an estimated 526 000 deaths due to diarrhoea in children younger than 5 years, which was a 57% drop from the 1 213 000 estimated deaths in 2000.1Liu L Oza S Hogan D et al.Global, regional, and national causes of under-5 mortality in 2000-15: an updated systematic analysis with implications for the Sustainable Development Goals.Lancet. 2016; 388: 3027-3035Summary Full Text Full Text PDF PubMed Scopus (1723) Google Scholar While we celebrate the dramatic reduction in paediatric deaths, diarrhoea episodes in children are not showing the same vivid decrease. In 1990, in low-income and middle-income nations, there were an estimated 1·9 million diarrhoea episodes compared with an estimated 1·7 million in 20102Fischer Walker CL Perin J Aryee MJ Boschi-Pinto C Black RE Diarrhea incidence in low- and middle-income countries in 1990 and 2010: a systematic review.BMC Public Health. 2012; 12: 220Crossref PubMed Scopus (319) Google Scholar—a very modest decrease relative to the reduction in diarrhoea deaths. The decrease in deaths, without commensurate changes in cases, should refocus the attention of the public health community on the implication of these frequent disease events for child health. Studies indicate that repeated diarrhoea infections in preschool children in the absence of catch-up growth leads to growth faltering resulting in stunting, which is associated with a decrease in cognitive development and increased risk of mortality from other infectious diseases such as malaria, measles, pneumonia, and diarrhoea.3Guerrant RL DeBoer MD Moore SR Scharf RJ Lima AA The impoverished gut—a triple burden of diarrhoea, stunting and chronic disease.Nat Rev Gastroenterol Hepatol. 2013; 10: 220-229Crossref PubMed Scopus (362) Google Scholar, 4Black RE Allen LH Bhutta ZA et al.Maternal and child undernutrition: global and regional exposures and health consequences.Lancet. 2008; 371: 243-260Summary Full Text Full Text PDF PubMed Scopus (3854) Google Scholar There is evidence that diarrhoea can affect cognitive development independent of stunting.5Pinkerton R Oria RB Lima AA et al.Early childhood diarrhea predicts cognitive delays in later childhood independently of malnutrition.Am J Trop Med Hyg. 2016; 95: 1004-1010Crossref PubMed Scopus (37) Google Scholar Clearly, poor cognitive development has lifelong implications for health and wellbeing. To the best of our knowledge, the study by Christopher Troeger and colleagues in The Lancet Global Health is the first to quantify the global impact of diarrhoea and diarrhoea-induced sequelae on child health.6Troeger C Colombara DV Rao PC et al.Global disability-adjusted life-year estimates of long-term health burden and undernutrition attributable to diarrhoeal diseases in children younger than 5 years.Lancet Glob Health. 2018; 6: e255-e269Summary Full Text Full Text PDF PubMed Scopus (86) Google Scholar Using disability-adjusted life-years (DALYs), a measure of disease impact, the investigators calculate both acute and long-term DALYs for each step in the chain of diarrhoea events that lead from fatal and non-fatal cases to growth faltering and to risk of morbidity and mortality from infectious diseases and protein-energy malnutrition. In a single year, the authors estimate that diarrhoea cases and deaths in children younger than 5 years was responsible for more than 40 million DALYs, but the expanded effects of diarrhoea were responsible for almost 16 million additional DALYs; a 39% increase from baseline. Over 84% of long-term DALYs were due to the increased risk of infectious diseases due diarrhoea-induced undernutrition. Globally, the authors note the heterogeneity of DALYS among nations and continents, with the larger burden noted in sub-Saharan Africa and South Asia. The conclusion of research should spark the interest of policy makers and stimulate the global health community beyond thinking about diarrhoea disease incidence and case fatality alone. While the current manuscript vastly expands our understanding of diarrhoeal diseases and their broader consequences, other issues need addressing. Diarrhoea episodes and deaths are not exclusive to preschool children, but strike also older children, adolescents, and adults. In a systematic literature review,7Lamberti LM Fischer Walker CL Black RE Systematic review of diarrhea duration and severity in children and adults in low- and middle-income countries.BMC Public Health. 2012; 12: 276Crossref PubMed Scopus (90) Google Scholar among people aged 5 years and older, there were about 45 million episodes and 62 500 deaths associated with just two diarrhoeal pathogens, enterotoxigenic Escherichia coli (ETEC) and Shigella.7Lamberti LM Fischer Walker CL Black RE Systematic review of diarrhea duration and severity in children and adults in low- and middle-income countries.BMC Public Health. 2012; 12: 276Crossref PubMed Scopus (90) Google Scholar The economic and educational consequences of diarrhoea for these ages are clear with, for example, missed school days and workdays affecting cognitive development and family resources that in turn influence health outcomes. The increased DALYs attributed to diarrhoea-associated malnutrition could be substantial. With adults, it has been suggested that diarrhoea in childhood is linked to adult chronic disease including cardiovascular disease, diabetes, obesity, and hypertension.3Guerrant RL DeBoer MD Moore SR Scharf RJ Lima AA The impoverished gut—a triple burden of diarrhoea, stunting and chronic disease.Nat Rev Gastroenterol Hepatol. 2013; 10: 220-229Crossref PubMed Scopus (362) Google Scholar If this link between diarrhoea-induced malnutrition and adult chronic disease can be strengthened, the number of DALYs attributed to childhood diarrhoea would be greatly increased. The authors have explored all-cause diarrhoea, but pathogen-specific data would be of importance to policy makers. It is highly plausible that some pathogens (eg, ETEC, Cryptosporidium, Shigella, Campylobacter) have greater impact on DALYs than others do, and a similar study exploring pathogen-specific events would bring further clarity to our understanding of the diverse consequences of diarrhoea. Toward this end, investigators have already suggested that rotavirus, Cryptosporidium, ETEC, and Shigella are the four leading causes of years lived with disability.8Colombara DV Khalil IA-M Rao PC et al.Chronic health consequences of acute enteric infections in the developing world.Am J Gastroenterol Suppl. 2016; 3: 4-11Crossref Google Scholar As the authors note, the inclusion of the short-term and long-term effects of diarrhoea provide evidence that globally, diarrhoea is the third leading cause of DALYs in this age group, surpassing malaria and neonatal encephalopathy. These results imply that policy makers need to move beyond diarrhoeal deaths as a measure for prioritising interventions and look at the broader consequences of diarrhoea on the health and wellbeing of children residing in the poorest nations. We declare no competing interests. Global disability-adjusted life-year estimates of long-term health burden and undernutrition attributable to diarrhoeal diseases in children younger than 5 yearsDiarrhoea represents an even larger burden of disease than was estimated in the Global Burden of Disease Study. In order to adequately address the burden of its long-term sequelae, a renewed emphasis on controlling the risk of diarrhoea incidence may be required. This renewed effort can help further prevent the potential lifelong cost on child health, growth, and overall potential. Full-Text PDF Open Access