Distribution of Haemoglobin Level in a Group of School Children and Its Relation to Height, Weight, and Other Variables.

It is generally accepted that differences in the mean haemoglobin level in the two sexes become apparent after puberty, and this is thought to be due mainly to a gradual rise in the mean level in boys, which continues until about the age of 16 or 17 years (Sunderman, MacFate, MacFayden, Stevenson, and Copeland, 1953). However, in addition to age and (after puberty) to sex, many other factors are likely to be associated with haemoglobin level. These probably include family size, though this may be merely a reflection of differences in diet. It also seems likely that body mass may be a further associated factor and, if this is true, some, if not all, of the difference in mean haemoglobin between the two sexes may simply reflect differences in body mass. This possibility does not appear to have been examined. The report which follows presents the results of a survey of haemoglobin levels in school children aged 14 years in eleven Cardiff schools, undertaken to determine the distribution of haemoglobin levels and to examine the associations between those levels and sex, family size, height and weight, and (in girls) menstruation.