Hematocrit: Maturity Relationship in Adolescence

Wa, Daniel

doi:10.1542/peds.52.3.388

Cited by 52 publications

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“…Furthermore, muscular development after the start of testosterone secretion causes proportional elevation of blood volume, which is even more evident in boys undergoing active training. These changes and the additional rise in the blood concentration of hemoglobin (3,4) either occur simultaneously or follow one another within a few years. Thus, they considerably increase the need for iron during a relatively short period.…”

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Development of Iron Status and Response to Iron Medication in Pubertal Boys

Anttila,

Siimes

1996

J. pediatr. gastroenterol. nutr.

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SummaryDuring male puberty, rapid growth of body mass and the rise in hemoglobin concentration require much iron. The increasing need for iron may carry a risk of iron deficiency. Criteria for iron deficiency in adolescence are difficult to assess, as indicated by prevalences ranging from 0.5 to 30% in five recent studies from developed countries. We followed 60 prepubertal or early pubertal boys, testing them at 6‐month intervals for 24 months and relating hemoglobin levels and other iron parameters to age, pubertal development, and response to iron medication. A significant increase in mean hemoglobin was first seen at genital stage G4. In early puberty, in contrast, between stages G1 and G3, ferritin decreased. Mean transferrin increased slightly during the study. The prevalence of iron deficiency increased both with age and with advancing puberty. However, the early decline in ferritin may be a physiologic response to guarantee increasing intestinal absorption. After iron medication, we observed improvements in the levels of our parameters of iron status, which showed that hemoglobin levels had been limited by iron deficiency. In pubertal boys, evaluation of iron deficiency should not be based on laboratory parameters alone; age, pubertal development, and growth should also be taken into account.

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confidence: 99%

Development of Iron Status and Response to Iron Medication in Pubertal Boys

Anttila,

Siimes

1996

J. pediatr. gastroenterol. nutr.

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The Female Adolescent Athlete and Iron

Brown¹

1993

Arch Pediatr Adolesc Med

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Reliability of Tanner stage assessments in a multi‐center study

Espeland

Gallagher

Tell

et al. 1990

American J Hum Biol

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Tanner stage indices have been frequently used in research studies to characterize the level of sexual maturation among adolescents. The Cooperative Study of Sickle Cell Disease (CSSCD) is a large multi-center study in which the assessment of Tanner stage indices has been performed to describe delays in sexual maturation and correlates of delays. Rigorous training, however, in rating Tanner stages was not provided for the clinicians in the study. Data from the CSSCD were analyzed to characterize the reliability of the assessment of sexual maturation in this study, and demonstrate the potential for increasing the reliability by more careful training. In lieu of a gold standard, a maximum likelihood algorithm was employed to examine the longitudinal consistency of Tanner stage assessments. Based on the assumption that the underlying process of sexual maturation is progressive, models were developed that allowed one to estimate jointly the incidence distribution for the attainment of Tanner stages and the error rates of assessment. Estimated false-positive rates for assessing the attainment of Tanner stages from the CSSCD ranged from 2% to 19%. Estimated false-negative rates ranged from 1% to 18%. The occurrence of these errors was found not to vary markedly with the subject's age. Error rates of this magnitude can introduce considerable bias to the estimation of the distribution of Tanner stages and result in serious losses in relative efficiency. While the validity of Tanner stage indices can be demonstrated from study data, the loss in statistical efficiency and power associated with the study error rates was severe. This underscores the utility of careful training in pubertal rating for research studies.

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Hematocrit: Maturity Relationship in Adolescence

Cited by 52 publications

References 0 publications

Development of Iron Status and Response to Iron Medication in Pubertal Boys

Development of Iron Status and Response to Iron Medication in Pubertal Boys

The Female Adolescent Athlete and Iron

Reliability of Tanner stage assessments in a multi‐center study

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