Bone Abstracts

Background: Prolonged hypothalamic amenorrhoea with anovulation has been associated with hypo-oestrogenism in adolescents and has been shown to be associated with lower bone mineral density (BMD) values.

Objective: To determine whether differences in BMD between oligo/amenorrhoeic adolescents at risk of low BMD and normal eumenorrhoeic controls can be detectable by quantitative ultrasound (QUS) of the os calcis.

Methods: Adolescents with oligo/amenorrhoea (defined as having amenorrhoea for 3 months or more in past 1 year) and a control group of eumenorrhoeic adolescents were recruited from the Adolescent Gynaecology clinic. All underwent basic anthropometric measurements, body fat composition estimation, hormonal profile assay, DXA of the lumbar spine and hip, peripheral quantitative computerized tomography (pQCT) measurement of distal radius/ tibia volumetric BMD, as well as QUS of the os calcis.

Results: 45 eumenorrhoeic and 30 oligo/amenorrhoeic adolescents aged 15–19 (mean age 16.8) were recruited. The oligo/amenorrhoeic group had lower BMD at the lumber spine (0.88 vs 0.96 g/cm², P=0.002) and hip sites (neck of femur 0.82 vs 0.86 g/cm², P=0.05; trochanter 0.65 vs 0.71 g/cm², P=0.007). pQCT showed the oligo/amenorrheic group had lower total BMD in the distal tibia (510 vs 550 mg/cm³; P=0.013). QUS measurements showed that the oligo/amenorrhoeic group also had lower stiffness values (96 vs 103, P=0.035) and lower derived BMD values (0.49 vs 0.58 g/cm²; P=0.04).

Conclusion: In a high risk group of adolescents with menstrual dysfunction, the significantly lower BMD values as demonstrated by DXA and pQCT were also reflected in lower estimated BMD values in QUS measurements. The findings supported the use of quantitative USG as a screening tool.