A study across eight States in India involving 4,613 participants that included adolescents (647 girls and 674 boys), adults (931 women and 927 men) and elderly (714 women and 720 men) has found that the prevalence of anaemia has been overestimated by previous surveys. While the NFHS surveys measured haemoglobin using finger prick-based capillary blood, the latest multi-institutional study carried out by a team led by Dr. Anura Kurpad from St. John’s Medical College, Bengaluru, used venous blood to measure haemoglobin and iron status through ferritin. The other institutions involved in the study include ICMR-NIN, Hyderabad, Sitaram Bhartia Institute of Science and Research, New Delhi, CSIR-IGIB, New Delhi, CSIR-CCMB, Hyderabad, Banaras Hindu University, and KEM Hospital, Pune. The results have been posted as a preprint; preprints are not peer-reviewed.
Capillary blood haemoglobin will be an underestimate of the true value as the red blood cell count in the capillary blood will be a little lower than venous blood due to a phenomenon called plasma-skimming. Also, tissue fluid gets mixed with capillary blood while drawing the blood sample leading to dilution and thus a reduction in haemoglobin value. The WHO has also recently recommended that anaemia be diagnosed from venous blood estimations of haemoglobin.
The study found that anaemia prevalence was predominantly of the mild variety. Overall, 18.4% of the entire sample were mildly anaemic, 14.7% were moderately and 1.8% were severely anaemic. As expected, the overall prevalence of anaemia was higher in women compared with men. The prevalence of moderate anaemia was significantly higher in women (22%) compared with men (7.6%). Anaemia prevalence was 44%, 41% and 45% in adolescent girls, adults and elderly women, respectively. In the case of adolescent boys, adults, and elderly men, anaemia prevalence was 24%, 21% and 37%, respectively.
