Bone health In adolescent female athletes: The influence of menstrual and oral contraceptive status on bone mineral density and content of the lumbar spine and proximal femur
Date
2002
Authors
DeNeef Ooms, Shana L.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The purpose of this research was to investigate the influence of menstrual status and oral contraceptive status on areal bone mineral density (aBMD) and bone mineral content (BMC) of the lumbar spine and proximal femur in 31 adolescent, athletic Caucasian, non-smoking females, aged 14 to 21 years (mean 18.8 ± 1.3 years). Participants were grouped by menstrual and oral contraceptive status: eumenorrheic, non-oral contraceptive users (ENOC, n=15), eumenorrheic, oral contraceptive users (EOC, n=11), and irregularly menstruating (amenorrheic and oligomenorrheic), non-oraJ contraceptive users (INOC, n=5). A secondary purpose was to determine if the ENOC, EOC and INOC groups were distinguishable by other factors which have been associated with aBMD and BMC, such as anthropometrics, age at menarche, physical activity, calorie and calcium intake, and eating attitudes. Subjects participated in a regular program of vigorous weight bearing activity that involved a minimum of 3 times per week for at least 45 minutes each time. Measures of aBMD and BMC of the lumbar spine (LS, L1-4), proximal femur (PF) and its sub regions, the femoral neck (FN) and trochanter (FT), were taken using a Hologic QDR 2000 dual energy x-ray absorptiometer (DXA) in array mode. Descriptive information regarding menstrual and oral contraceptive history, familial history of osteoporosis, medical history and current physical activity levels was gathered with a general health questionnaire. A three-day dietary record was used to assess calorie and calcium intake, and the Eating Attitudes Test (EAT-26) was used to evaluate restrictive eating tendencies. Anthropometrics including stature, weight, body mass index (BMJ), and sum of five skin folds (So5S) were also assessed.
ENOC, EOC and INOC groups were similar in terms of chronological age, age at menarche, anthropometrics, current physical activity and resistance training (hours per week), and all dietary measures. Height and weight correlated significantly with measures of BMC and bone mineral area (BMA) (p<0.05), but not with measures of aBMD. Weight bearing activity and resistance training correlated significantly with aBMD of the FT and FN, respectively (p<0.05). Age at menarche, calorie and calcium intake, EAT-26 scores, and So5S did not correlate significantly with any of the bone mineral measures.
A one-way ANOVA revealed that in non-oral contraceptive users (ENOC and INOC), menstrual status did not influence aBMD and BMC at the LS and PF. Conversely, in the eumenorrheic groups, oral contraceptive users (EOC) had significantly higher BMC at the PF (p=0.028) and FT (p=0.020) compared to non-oral contraceptive users (ENOC). Oral contraceptive use did not influence BMC at the LS or aBMD at any site. BMC at the PF may be influenced by initiation of oral contraceptive use prior to 20 years of age and before adult peak bone mass is achieved. Skeletal growth during puberty reflects increases in BMC more so than in aBMD because of increases in bone size. A longer period of bone mineral accrual after longitudinal growth has ceased, therefore, might be necessary before any influence of oral contraceptive use on aBMD is observed.