Stunting among children under five is more common in Bangladeshi slums than in both urban and rural areas in the country.
Previous studies have reported that inadequate nutrition, low socio-economic status, sub-standard hygiene and sanitation, and a lack of maternal education are "substantial predictors" of childhood stunting, all of which are seen in Bangladeshi slums.
However, what actually determines stunting among slum-dwelling populations has not been prospectively examined.
Growth and stunting
As such, researchers at Bangladesh's International Centre for Diarrhoeal Disease Research, and Australia's Menzies School of Health Research, conducted a cohort study to investigate micronutrient status among slum-dwelling children and its possible link to stunting, alongside other determinants.
They enrolled 265 newborn children (130 boys and 135 girls) and tracked them until they were two years old, collecting dietary intake, morbidity and anthropometric data every month.
They also assessed the children's micronutrient status using the mean adequacy ratio (MAR), calculated from the average intake of four minerals (calcium, iron, zinc, and copper) and nine vitamins (vitamins A, B6, B12, C and E, and thiamine, riboflavin, niacin and folate).
They later observed that the prevalence of low birth weight was approximately 28.7%, and about 50% of the children were stunted by the time they reached two years of age.
Their average micronutrient consumption was significantly lower than the recommended dietary intake, and the MAR was only 0.48 at two years of age, lower than the optimum value of 1.
Weight a minute
However, the researchers found that MAR was not related to stunting between one and two years of age. Instead, low birth weight was the "significant determinant", even after adjusting for age and sex.
They wrote: "Children with a history of low birth weight had three-fold greater odds of being stunted compared to children with a normal birth weight. With increasing age, the odds of being stunted almost increased by two folds at both 18 and 24 months of age compared to 12 months of age."
They added that in developing countries, low birth weight is usually lined to intrauterine growth restriction (IUGR) and stunting; IUGR is essentially the failure of a foetus to achieve actual genetic growth potential, because of nutritional deprivation during gestation, or other environmental factors.
Newborns with low birth weight often continue to experience growth failure in early childhood, and this might persist into adolescence. This is exacerbated by environmental factors in slums.
The researchers added, "Certain diseases have been suggested to originate through adaptations of the foetus when it is undernourished.
"Such adaptations may cause permanent structural and / or functional changes to the body to facilitate survival over growth and thus, may explain the strong association between low birth weight and stunting in low- and middle-income countries like Bangladesh."
They then concluded: "Improving the nutritional quality of the complementary food is imperative for optimum growth. However, this may not be enough to mitigate the burden of stunting in impoverished slums.
"Further research should focus on identifying multiple strategies that could work synergistically to diminish the burden of stunting in such underprivileged and resource depleted settings."
Source: PLOS ONE
"Micronutrient adequacy is poor, but not associated with stunting between 12-24 months of age: A cohort study findings from a slum area of Bangladesh"
Authors: Kazi Istiaque Sanin, et al.