Prevalence of suspected anemia in Japanese young children determined using noninvasive hemoglobin measurements: an observational study

Recently, noninvasive spot hemoglobin measurement (SpHb) using Pulse CO-Oximeter Rad-67™ Spot-check (Rad-67) has been validated, although anemia diagnosis typically relies on blood hemoglobin concentration measurement. In this large-scale survey of Japanese children aged 1-5 years, we evaluated SpHb distribution to understand the prevalence of suspected anemia, and further examined the relationship between SpHb and background factors. Children were recruited from large retail stores in Japan between November 2022 and August 2023. SpHb was measured by nutritionists or registered dietitians using Rad-67. Four thousand one hundred thirty-three participants were included and stratified by age and sex. The prevalence of children below the World Health Organization threshold value for anemia was found to be 5.2% in total (ranging between 2.6% and 7.8% in subgroups). Mean SpHb values increased with age, and were higher in boys. Age and sex were independently related to SpHb. Overall, this study shows that approximately 3%-8% of young children in Japan are suspected to be anemic.