Bone Metabolism in Adolescent Athletes With Amenorrhea, Athletes With Eumenorrhea, and Control Subjects

Abstract

OBJECTIVE-We hypothesized that, despite increased activity, bone density would be low in athletes with amenorrhea, compared with athletes with eumenorrhea and control subjects, because of associated hypogonadism and would be associated with a decrease in bone formation and increases in bone-resorption markers.METHODS-In a cross-sectional study, we examined bone-density measures (spine, hip, and whole body) and body composition by using dual-energy radiograph absorptiometry and assessed fasting levels of insulin-like growth factor I and bone-turnover markers (N-terminal propeptied of type 1 procollagen and N-telopeptide) in 21 athletes with amenorrhea, 18 athletes with eumenorrhea, and 18 control subjects. Subjects were 12 to 18 years of age and of comparable chronologic and bone age.RESULTS-Athletes with amenorrhea had lower bone-density z scores at the spine and whole body, compared with athletes with eumenorrhea and control subjects, and lower hip z scores, compared with athletes with eumenorrhea. Lean mass did not differ between groups. However, athletes with amenorrhea had lower BMI z scores than did athletes with eumenorrhea and lower insulin-like growth factor I levels than did control subjects. Levels of both markers of bone turnover were lower in athletes with amenorrhea than in control subjects. BMI z scores, lean mass, insulin-like growth factor I levels, and diagnostic category were important independent predictors of bone mineral density z scores.CONCLUSIONS-Although they showed no significant differences in lean mass, compared with athletes with eumenorrhea and control subjects, athletes with amenorrhea had lower bone density at the spine and whole body. Insulin-like growth factor I levels, body-composition parameters, and menstrual status were important predictors of bone density. Follow-up studies are necessary to Copyright © 2008 by the American Academy of Pediatrics. All rights reserved.Address correspondence to Madhusmita Misra, MD, MPH, Massachusetts General Hospital, Neuroendocrine Unit, BUL 457, 55 Fruit St, Boston, MA 02114. mmisra@partners.org. The authors have indicated they have no financial relationships relevant to this article to disclose.Drs Christo and Prabhakaran contributed equally to this work. NIH Public Access Author ManuscriptPediatrics. Author manuscript; available in PMC 2011 November 4. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript determine whether amenorrhea in athletes adversely affects the rate of bone mass accrual and therefore peak bone mass. Keywordsadolescents; athletes; bone density; bone-turnover markers; insulin-like growth factor I Amenorrhea has been reported to occur in 23.5% of high school athletes, 1 although the prevalence may vary depending on the type, intensity, and duration of exercise, as well as the athlete's nutritional status. [1][2][3][4] In particular, activities such as gymnastics, running track, ballet, diving, swimming, and cheerleading are common among high school girls, require a thin physique, and are as...

Bone Geometry According to Menstrual Function in Female Endurance Athletes

“…Previous studies have reported lower lumbar spine BMD in amenorrheic than eumenorrheic athletes (13,(34)(35)(36).…”

Current and past menstrual status is an important determinant of femoral neck geometry in exercising women

“…In fact, doubling the radius of the bone increases bone strength by a factor of 16 [34]. As such, a smaller femoral neck CSA and CSMI among female athletes with past and/or current menstrual disturbances when compared with athletes who have always had regular menstrual cycles may be detrimental to bone health by compromising bone strength and by adding to the negative effects that low BMD [4,11,12,15] has on bone strength. Interestingly, the C/P-RIR group demonstrated the smallest proportion of women with low neck diameter compared with both the C + P-IR group and the C + P-R group, which had similar proportions of women with low-neck diameter.…”

“…high as 60% [11], and the co-existence of menstrual irregularity and compromised BMD has been repeatedly observed [4,5,[12][13][14][15]. Functional hypothalamic amenorrhea, defined as the absence of menses for greater than 90 days (secondary amenorrhea) [16] or the failure to attain menarche by age 15 (primary amenorrhea) [17] which cannot be explained by other underlying pathology [17], and oligomenorrhea, defined as irregular and inconsistent menses at intervals of 36 to 90 days [16], are the most severe presentations of menstrual cycle disturbances and are linked to poor skeletal health [3,5,8].…”

“…Substantial evidence demonstrates that female athletes presenting with amenorrhea have significantly lower BMD at the lumbar spine in comparison to their eumenorrheic counterparts [2][3][4][5][12][13][14][15]22]. Less consistently, lower BMD at the femoral neck and/or total hip has also been observed [4,5,14,15].…”

Optimizing Bone Health in Children and Adolescents

“…When female athletes become amenorrheic, the protective effect of exercise on BMD is lost. 65 Children who are immobilized have rapid declines in bone mass.…”