Nav: Home

Widely used public health surveys may underestimate global burden of childhood diarrhea

April 03, 2019

Public health surveys used in as many as 90 countries may be missing the number of recent diarrhea episodes among children by asking parents and caregivers to recall events two weeks versus one week out, suggests a study from researchers at Johns Hopkins Bloomberg School of Public Health.

The researchers, whose findings were published March 25 in the International Journal of Epidemiology, compared the responses to two large public health surveys that were worded almost identically, and concluded that the survey with a two-week recall period, which has been the standard in the field, is less accurate than the survey with a one-week recall period.

"People asked to recall events over a two-week period may remember significantly less than they would if the recall period were just one week," says study principal investigator Natalie G. Exum, PhD, an assistant scientist in the Department of Environmental Health and Engineering at the Bloomberg School. "Understanding the global burden of diarrheal diseases in young children is critical to identifying tools to treat and prevent diarrhea in this vulnerable population."

Diarrhea is a significant global health concern because there are between 1 and 2 billion cases of it every year among children under 5, including about 500,000 fatal cases. In many low- and middle-income countries diarrheal illness is a leading cause of death among young children.

Researchers commonly estimate the burden of diarrheal illness in countries where it is endemic using large-scale, house-to-house surveys of mothers and other caregivers. The most widely used set of surveys, the Demographic and Health Surveys (DHS) sponsored by the U.S. Agency for International Development, ask respondents to recall cases among children in their care in the previous two weeks. The number of recalled cases in this period, as a proportion of the sampled population, is an estimate of "two-week prevalence:" a snapshot of the overall diarrhea burden that researchers can compare to similar two-week snapshots taken at other times or in other populations.

Human recall is subject to error, however, and prior, smaller studies have hinted that a two-week recall period for diarrhea prevalence surveys may yield less accurate results than shorter recall periods.

A newer set of public health surveys, conducted under the Performance Monitoring and Accountability 2020 (PMA2020) project, are almost identical to DHS surveys but use a one-week recall period instead. Launched in 2013, PMA2020 is sponsored by the Bill & Melinda Gates Foundation with direction and support provided by the Bill & Melinda Gates Institute for Population and Reproductive Health and the Johns Hopkins University Water Insti­tute at the Johns Hopkins Bloomberg School of Public Health.

For this study, Exum and her colleagues compared results from PMA2020 and DHS surveys of similar communities in the same five African countries (Democratic Republic of the Congo, Ethiopia, Ghana, Kenya, and Uganda) from 2013 to 2016. The PMA2020 surveys covered 14,603 households and the DHS surveys 66,717 households.

On average, there should be more diarrhea cases in any two-week period compared to any one-week period. Thus the two-week prevalence--the percentage of the sampled population that had a bout of diarrhea in the two weeks prior to the survey--should be greater than the one-week prevalence. Yet the researchers found that the DHS surveys yielded a two-week diarrhea prevalence estimate of 16.0 percent, whereas the PMA2020 surveys yielded a one-week diarrhea prevalence estimate that was higher, at 21.4 percent. Moreover, the PMA2020 surveys consistently yielded higher estimates than DHS when compared on a country-by-country basis.

The scales of the surveys and the similarities of their questions and covered populations were such that the difference in outcome was unlikely due to statistical "noise," the researchers note.

The authors are recommending that future versions of the DHS use a one-week recall period instead of the traditional two-week period.

"Comparison of 1-week and 2-week recall periods for caregiver-reported diarrhoeal illness in children, using nationally representative household surveys" was written by Katie Overbey, Kellogg Schwab and Natalie Exum.
-end-
Support for the research was provided by the Osprey Foundation of Maryland and the National Institutes of Health (T32 ES007141).

Johns Hopkins University Bloomberg School of Public Health

Related Public Health Articles:

Public health guidelines aim to lower health risks of cannabis use
Canada's Lower-Risk Cannabis Use Guidelines, released today with the endorsement of key medical and public health organizations, provide 10 science-based recommendations to enable cannabis users to reduce their health risks.
Study clusters health behavior groups to broaden public health interventions
A new study led by a University of Kansas researcher has used national health statistics and identified how to cluster seven health behavior groups based on smoking status, alcohol use, physical activity, physician visits and flu vaccination are associated with mortality.
Public health experts celebrate 30 years of CDC's prevention research solutions for communities with health disparities
It has been 30 years since CDC created the Prevention Research Centers (PRC) Program, currently a network of 26 academic institutions across the US dedicated to moving new discoveries into the communities that need them.
Public health experts support federally mandated smoke-free public housing
In response to a new federal rule mandating smoke-free policies in federally funded public housing authorities, three public health experts applaud the efforts of the US Department of Housing and Urban Development to protect nonsmoking residents from the harmful effects of tobacco exposure.
The Lancet Public Health: UK soft drinks industry levy estimated to have significant health benefits, especially among children
The UK soft drinks industry levy, due to be introduced in April 2018, is estimated to have significant health benefits, especially among children, according to the first study to estimate its health impact, published in The Lancet Public Health.
Social sciences & health innovations: Making health public
The international conference 'Social Sciences & Health Innovations: Making Health Public' is the third event organized as a collaborative endeavor between Maastricht University, the Netherlands, and Tomsk State University, the Russian Federation, with participation from Siberian State Medical University (the Russian Federation).
Columbia Mailman School Awards Public Health Prize to NYC Health Commissioner Dr. Mary T.
Dr. Mary T. Bassett, Commissioner of the New York City Department of Health and Mental Hygiene, was awarded the Frank A.
Poor health literacy a public health issue
America's poor record on health literacy is a public health issue, but one that can be fixed -- not by logging onto the internet but by increased interaction with your fellow human beings, a Michigan State University researcher argues.
Despite health law's bow to prevention, US public health funding is dropping: AJPH study
Although the language of the Affordable Care Act emphasizes disease prevention -- for example, mandating insurance coverage of clinical preventive services such as mammograms -- funding for public health programs to prevent disease have actually been declining in recent years.
'Chemsex' needs to become a public health priority
Chemsex -- sex under the influence of illegal drugs -- needs to become a public health priority, argue experts in The BMJ this week.

Related Public Health Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Moving Forward
When the life you've built slips out of your grasp, you're often told it's best to move on. But is that true? Instead of forgetting the past, TED speakers describe how we can move forward with it. Guests include writers Nora McInerny and Suleika Jaouad, and human rights advocate Lindy Lou Isonhood.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...