En-net update
By Tamsin Walters, en-net moderator
Over the past four months, 57 questions have been posted on en-net,1 generating 200 responses. Seventy vacancy announcements have been posted, which have accumulated over 9,000 views.
There has been an increase in the number of questions around stunting, including discussions on the relationship between wasting and stunting, potential interventions to reverse stunting in children under 2 years and the timeframe within which both individual and population level stunting might be reduced.
A question asking whether the WHO Growth Standards are appropriate for assessing stunting in populations of South East Asia generated significant debate:
A response from WHO outlined the process of construction of the WHO Growth Standards and the evidence-base behind their application: The WHO Standards are based on data collected in six countries (Brazil, Ghana, India, Norway, Oman, USA) following a prescriptive approach that excluded children with growth constraints due to environmental factors (as opposed to selecting elite segments of the population)…. Linear growth among children in the six sites was strikingly similar confirming previous evidence from Martorell, Habicht and other researchers showing that, on average, children from different world regions have similar growth potential when raised in environments that minimised constraints to growth such as poor diets and infection. After the standards were released, countries like China or India conducted thorough evaluations of them prior to their adoption.
More than 10 years after the WHO Growth Standards were developed, the Intergrowth21st consortium conducted a study on foetal growth and newborn size in urban areas of eight countries2 using a methodology similar to that used to construct the WHO standards. The results of this study are in strong agreement with the WHO results.3
Further input from the INTERGROWTH-21st Consortium confirmed that… International standards based on the WHO MGRS and INTERGROWTH-21st studies compare the longitudinal skeletal growth in diverse populations around the world free from overtly adverse influences. This allows us to determine how much of the variation in human size is due to differences between countries. The answer has been shown consistently to be only around 3%; hence the vast majority of the differences in human size and early growth observed around the world are due to factors independent of ethnicity….and raised the concern that the use of growth references specific to the local population risks normalising abnormal growth, perpetuating a cycle of low growth expectations in many parts of the world.
Despite these helpful clarifications, several participants remain concerned that, although there is agreement that the majority of the growth variation is environmentally mediated (by the social, economic and natural environment), why should we aim to have every child growing the same way? Given that environmental conditions in which children live are not similar, growth patterns can be expected to differ: Certain growth patterns are likely to confer short and long-term advantages in certain environments as well as penalties. These advantages and penalties are likely to be different in different environmental settings.
While this debate remains unresolved, participants unanimously agreed on the value of having a common yardstick to facilitate understanding of how much growth varies across the world and the reasons behind this variability, and further note the value of the WHO Growth Standards in giving shape to growth curves and providing information on timing and velocity of child growth.
Advocacy for researching the causes of deviance from the standards where it exists was proposed in order to institute appropriate high impact measures where necessary.
Follow the discussion at http://www.en-net.org/question/1755.aspx
To join any discussion on en-net, share your experience or post a question, visit www.en-net.org
Contributions from Aisling, Melaku Begashaw, Blessing, Carlos Grijalva-Eternod, Jane Hirst, Mark Myatt, Mercedes de Onis, Rosemary, Brad Woodruff.
1From 1st April 2015 to the reporting date of 17th July 201
2The cities of Pelotas (Brazil), Turin (Italy), Muscat (Oman), Oxford (UK), and Seattle (USA); Shunyi County, Beijing (China); the central area of Nagpur (India); and the Parklands suburb of Nairobi (Kenya)
3Villar J, et al. The likeness of fetal growth and newborn size across non-isolated populations in the INTERGROWTH-21st Project. Lancet Diabetes Endocrinol 2014, https://intergrowth21.tghn.org/site_media/media/articles/Villar_published_LancetDE_article.pdf