The relationship between body composition and onset of menarche.
BACKGROUND
A late age of menarche in elite adolescent athletes is frequently attributed to low body fat/weight. If a critical body weight/fat is necessary for menarche, a reduction in the variability of these parameters would be observed at menarche compared to times before and after this event.


OBJECTIVE
The study determined the variability in body mass (BM), per cent body fat (%BF) and total body fat (TBF) of girls between -2 and +2 years from menarche.


METHODS
Participants were part of the Saskatchewan Pediatric Bone Mineral Accrual Study (1991-1998). Body composition was assessed using dual X-ray absorptiometry (DXA). An individual's data was retained for analysis if they had at least four DXA scans between -3 and +3 years from menarche. Values were interpolated from the cubic spline at whole years between -2 and +2 years from menarche. Coefficient of variation (CV) was used to assess variability.


CONCLUSIONS
Data on 61 girls were retained for analysis. The range in BM, TBF and %BF at menarche was 50.10 kg, 35050.06 g and 31.61%, respectively. Reductions in variability of body fat and weight were not apparent at menarche, which does not provide support for the hypothesis that a critical body weight/fat is required for menarche.
Sherar
L B
LB
College of Minesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, Saskatchewan, Canada. lauren.sherar@usask.ca
Baxter-Jones
A D G
AD
Mirwald
R L
RL
D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000293:Adolescent; D000375:Aging / Q000502:physiology; D001823:Body Composition; D002648:Child; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008572:Menarche