In India, issues related to child malnutrition have long been a cause for grave concern. According to the National Family Health Survey (NFHS) 5 conducted in 2019-2020, 35.5 per cent of children under the age of five in India are stunted, 19.3 per cent wasted, and 32.1 per cent underweight.

The question here is how malnutrition should be measured. Globally, child malnutrition is measured through the ‘growth charts’. They are a powerful visual tool to assess a child’s growth based on various readings such as height, weight, age or body mass index.

India currently uses the growth charts recommended by WHO (2006) based on the Multicentre Growth Reference Study (MGRS) for children from zero to five years. WHO collected the data of 8.440 children from populations with unconstrained growth in six countries, namely, India, Brazil, the US, Oman, Ghana, and Norway. In India, the samples were drawn from 58 affluent neighbourhoods of South Delhi, where relatively large groups of affluent, educated individuals reside. The standard growth curves were constructed using this data. The children who lie below the third percentile of these charts are defined as undernourished. Similarly, children above the 97 percentile are considered overweight.

The WHO growth charts are the  growth standards which consider the optimal condition to determine normal growth. Instead of taking random children, their selection criteria were strict, making them more reasonable than other available growth charts at that time (between 1997 & 2003). For instance, the WHO charts exclude formula-fed babies that tend to be heavier than breast-fed ones. Consequently, many countries adopted these charts as a means to assess malnutrition in children.

However,  they consider that other factors, such as genetics and other geographically specific factors, do not matter. Therefore, an average of six countries was considered a standard for the entire world. But different studies have proven otherwise .

Therefore, it leads to both overestimation and underestimation in different population groups. For example, a recent study published in Lancet showed the overestimation of stunting while using the WHO standards compared to the Indian “Indian Urban Middle Class” (IUMC) reference.

MGRS was a great starting point in developing global growth charts. It played an important role in standardising the assessment of malnutrition in India and provided a globally recognised reference for comparison. However, growth patterns can vary significantly depending on factors such as genetics, environment and socio-demographic characteristics. These growth charts assume that the growth pattern of infants and toddlers is fairly comparable all over the world.

However, substantial differences in growth patterns have been observed in studies carried out in various countries, including India.

For example, if the WHO growth charts were used in France, most children would be considered to have slow growth during the first three months of life. In cases like West Java in Indonesia, the difference in estimating the under-nutrition between the WHO and indigenously developed Indonesian standards is an enormous 40 per cent.

A paper published in the February 2023 issue of  The Lancet examined the extent to which the prevalence of stunting, wasting, and underweight differed when derived using the 2006 WHO growth standard to the published India-specific growth chart. Indian Urban Middle Class (IUMC) reference, as it is called, is based on a sample of children from urban middle and upper-middle class households from the five geographically dispersed zones. The disaggregation has the advantage of allowing for State-wise measurement of stunting based on more localised benchmarks.

Using the IUMC reference, the stunting prevalence for India was 24 per cent, compared to the MGRS-based prevalence of 33 per cent, and the prevalence of wasting was 9 per cent (IUMC) and 19 per cent (MGRS). There was variation amongst the States as well. For example, stunting in Chhattisgarh went from 32 per cent based on the WHO benchmark to 23 per cent using the local upper-middle class standard, and in Sikkim, from 18 per cent to 15 per cent.

Such misestimation can have grave consequences. It has the potential to undermine breastfeeding and introduce formula feeding, which is contrary to the recommendation of exclusive breastfeeding for the first six months.

Re-examine criteria

Therefore, it is important to re-examine the growth measurement criteria in India. Firstly, it is crucial to conduct further studies to evaluate the consequences of using the WHO growth charts. By considering the role of diversity and environmental forces in human growth, such studies can provide reliable estimates for defining malnutrition standards in different population groups across the nation.

Secondly, the policy should adopt standards customised to specific situations. For instance, the US recommended the WHO standards for children aged less than 24 months, while the UK adopted it for children between two weeks and 48 months based on studies.

Thirdly, continuous evaluation of growth charts is essential for further improvement due to rapid socio-economic changes, such as in Korea, where national growth charts are revised nearly every ten years.

The main challenges include collecting representative data from diverse geographical regions, socio-economic groups, and ethnic backgrounds, standardising methods for data collection, processing and analysis, building capacity in data collection and analysis and the costs involved in the exercise.

The updated tools of measurement can ensure the targeted identification of the outliers, alleviating the anxiety among the falsely diagnosed while tracking the missed ones due to the underestimation. The success of achieving SDG 2.2, which is to end all forms of malnutrition by 2030, including achieving, by 2025, the internationally agreed targets on stunting and wasting in children under five years of age, depends on these critical metrics.

Mittal is Collector, Jashpur, Chhattisgarh; Nathani is peer mentor at the WHO Collaborating Centre for Research in surgical care delivery in LMICs; and Jain is a DM Resident in Neurology at NIMHANS, Bengaluru. Views are personal

Growth charts are a powerful visual tool to assess a child’s growth based on various readings such as height, weight, age or body mass index.