Global hemoglobin cut-off to define anemia overestimates disease burden in Indian children

Anemia rates among children and teenagers in India may be 20 per cent lower than currently reported as diagnosis is based on ethnically inappropriate blood count thresholds, a study argues.

The study of hemoglobin concentrations in healthy Indian children aged zero to 19 found that the hemoglobin thresholds — or cut-offs — used to define anemia were lower for both sexes and all ages than those recommended by the World Health Organization (WHO).

Anemia is a deficiency in the number of red blood cells or the hemoglobin concentration inside the cells and is a serious global health problem. WHO estimated 42 per cent of children under five and 40 of pregnant women worldwide are anemic. Common causes are nutritional deficiencies, genetic diseases of hemoglobin and infectious diseases.

For more than 15 years, experts have been calling for a re-evaluation of the WHO criteria for anemia.

"WHO's hemoglobin cut-offs to define anemia were based on five studies of predominantly White adult populations, done over 50 years ago," say the researchers.

The findings suggest that a single, global hemoglobin cut-off to define anemia may not be appropriate for all regions and ethnic populations. The authors urge WHO to re-examine its cut-offs to define anemia and issue updated guidelines based on recent evidence.

Published this month in The Lancet Global Health, the study assessed age-specific and sex-specific hemoglobin percentiles among healthy children and adolescents based on India's first nationally representative nutrition survey conducted between 2016 and 2018.

Using the WHO cut-offs resulted in a prevalence of anemia of 30 per cent compared with only 10.8 per cent using the study's cut-offs. Differences in prevalence were higher among children aged 1 to 4 years and adolescents aged 15 to 19 years.

The current use of WHO cut-offs which are Caucasian-based higher hemoglobin cut-offs to define anemia substantially overestimates the burden in Indian children creating avoidable national stigma, lack of progress and emphasis on multiple routes to provide iron supplements and fortification apart from diet, and are unlikely to bridge the gap and have the potential to cause adverse effects."

Harshpal Singh Sachdev, Study Lead Author