Comparison of haematological indices between women of four ethnic groups and the effect of oral contraceptives.

Six-hundred-and-eighty-two women volunteers from four ethnic groups--Black, Indian, Oriental and White took part in a study to assess differences in haematological indices between the groups. This study was part of a broad investigation into the metabolic effects of oral contraceptives. The effect of the oral contraceptive (OC) on haematological indices was analysed but not found to be significant. The haemoglobin concentrations were lower than normal laboratory reference values for White subjects in 12.5% of Indian, 16.5% of Black and 4.3% of Oriental control groups respectively. All the White control group were within the normal range. These findings were considered in relation to age, weight, pregnancies, smoking, alcohol consumption, nutritional status, and disorders of haemoglobin synthesis. A deficient iron intake accounted for the high incidence of low haemoglobin in the Indian group in whom low transferrin saturation and serum ferritin were observed. With the possible exception of inherited disorders of haemoglobin synthesis, none of the factors we considered could account for the low haemoglobins found in the Black group. Separate reference values for haematological indices in different ethnic populations are considered.