A longitudinal study of serum ferritin concentration during the female adolescent growth spurt

An 8-year longitudinal study of changes in serum ferritin concentration has been carried out with additional measurements of haemoglobin and serum iron in 39 schoolgirls aged 10 years at entry to the study. This laboratory data was analysed in relation to menarche and stature. The mean serum ferritin concentration declined significantly due to the occurrence of menarch, rather than to a growth spurt and showed the lowest level at the third year after menarche. Thereafter, it increased again. The prevalence of schoolgirls with latent iron deficiency, defined by a low serum ferritin concentration, normal haemoglobin and normal serum iron concentration, also increased after menarche, and reached its highest level (71.8%) at the third year after menarche. Although haemoglobin and iron concentration declined after menarche, these changes were not statistically significant except for haemoglobin at the second year after menarche. These findings show that serum ferritin concentration is a sensitive variable, and indicates that latent iron deficiency follows menarche rather than an increase in height velocity in adolescence.