GSTM1 and hyperinsulinemic hypoglycemia, familial, 4: In five studies examining Fe and Fe-deficiency anaemia, two (one American and one Korean) reported no deficiency or anaemia(28,31), while a study from India reported 30 % anaemia prevalence, based on Hb concentrations, without assessing ferritin concentrations or other markers that differentiate Fe-deficiency anaemia from other forms(29).