A conference abstract has reported summary data on preschool children (aged 6–59 months, 24 surveys, n=35 088) among selected healthy participants who had no iron or vitamin A deficiency, inflammation (CRP or α1-acid glycoprotein biomarkers), or malaria (if measured).9 This resulted in 17–88% data loss, and the age-adjusted and country-adjusted mean of haemoglobin concentration was 11·7 g/dL (SE 0·14), with substantial country heterogeneity (p<0·001). The gene discussed is CRP; the disease is vitamin A deficiency.