Research questions ‘iron deficiency’ as key cause of anaemia in India

Study challenges iron deficiency as primary cause of anaemia in India, highlighting various factors influencing the condition.

The conventional wisdom, that iron deficiency is the primary cause of anaemia in India, may be outdated, with a host of other factors, ranging from a Vitamin B12 deficiency to air pollution, influencing anaemia, says a study involving researchers from multiple institutions that was published earlier this week. Moreover, the manner in which blood is drawn for testing anaemia in public health programmes can dramatically alter estimates of the condition.

The study has appeared in the peer-reviewed European Journal of Clinical Nutrition.

Anaemia, characterised by weakness and fatigue, and paleness among other symptoms, is due to a lack of enough red blood cells (RBC) or haemoglobin, the carriers of oxygen to cells. The common wisdom is that insufficient iron – necessary for the liver to produce RBC – is the culprit and is the driving force behind public policy interventions such as iron supplementation or mixing iron into staple foods (bio-fortification).

The latest official assessment of anaemia in the fifth round of the National Family Health Survey (NFHS), in 2019-2021, suggests that despite decades of policy intervention, anaemia had only gotten worse. The prevalence in India had risen from 53.2% to 57.2% in women of reproductive age, and from 58.6% to 67.1% in children, compared to the previous NFHS-4 conducted in 2015–2016.

The latest study, funded by the Department of Biotechnology, measured venous blood haemoglobin (Hb) concentrations from about 4,500 people in eight States. Overall, 34.9% of those tested were anaemic. However, only 9% of them had what could be medically characterised as iron-deficiency anaemia; 22% of them were characterised as having anaemia from ‘unknown’ causes.

“The major proportion of anaemia in all groups studied, was due to... unknown (and unmeasured) causes of anaemia. This could be due to deficiencies in other erythropoietic (blood-producing) nutrients like B12 or folate, or due to hemoglobinopathies, undetected blood loss, an unhygienic environment [20] or other causes like air pollution,” the authors said in their report. The team of scientists and doctors spanned institutions such as St. John’s Medical College, Bengaluru; the National Institute of Nutrition (ICMR), Centre for Cellular and Molecular Biology, and Institute of Genomics and Integrative Biology, among others.

For women aged between 15 and 49, anaemia prevalence in the eight States was 41.1% in comparison with 60.8% in the NFHS-5. The prevalence of anaemia in adolescent girls (15-19 years) – as a group that is the most anaemic – in the eight States was 44.3% compared to 62.6% in NFHS-5. The same trend persisted in adult men (20.7% vs 26.0%) and adolescent boys (24.3% vs 31.8%) between the comparable age groups in NFHS-5. Assam had a very high prevalence of anaemia (between 50%-60%) and relatively low iron deficiency (18%), suggesting that other factors may be responsible.