Amenorrheic athletes have low axial bone-mineral density (BMD, g.cm-2). We compared 12 amenorrheic and 9 eumenorrheic women athletes to determine whether athletes with amenorrhea have lower BMD in other skeletal regions, including weight-bearing lower limbs. BMD was measured by dual energy x-ray and single photon absorptiometry. Both groups had similar age, body mass, and exercise quantity. Women with amenorrhea missed 86.3 +/- 58.3 menstrual periods since menarche. BMD was lower in the amenorrheic vs eumenorrheic subjects for the lumbar spine (0.928 +/- 0.056 vs 1.050 +/- 0.110, P < 0.005), whole body (1.032 +/- 0.05 vs 1.09 +/- 0.06, P < 0.05), most regions of the whole body (P < 0.05-0.001), all areas of the proximal femur (P < 0.005), and at the femoral mid-shaft (1.333 +/- 0.109 vs 1.491 +/- 0.088, P < 0.005). No significant differences were detected at the mid-radius and tibial shaft. The best predictors of BMD were years of regular menstruation for lumbar spine; and years of amenorrhea for hip, femoral mid-shaft, and whole body. We conclude that low BMD in athletes with amenorrhea is not limited to the axial skeleton but is also present in other regions including appendicular weight-bearing bones.
"Estrogen, a steroid with direct effects on bone remodeling , is another important contributor to bone health in women. Functional hypothalamic amenorrhea is a menstrual cycle disturbance characterized by complete suppression of estrogen and this suppression is often cited as a primary cause of reduced bone mass in amenorrheic women   resulting in low BMD, particularly at the spine       . "
[Show abstract][Hide abstract] ABSTRACT: The benefits of exercise are widely recognized, however physically active women can develop exercise associated menstrual cycle disturbances such as amenorrhea (i.e., estrogen deficiency) secondary to a chronic energy deficiency.
To assess the effects of exercise status and estrogen deficiency on osteoprotegerin (OPG) and its relationship to bone resorption in premenopausal exercising women.
Cross-sectional study of serum OPG, urinary c-telopeptides (uCTX), urinary estrone 3-glucuronide (E1G), urinary pregnanediol 3-glucuronide (PdG) and bone mineral density (BMD) measured on multiple occasions in 67 women. Volunteers were retrospectively grouped: 1) sedentary menstruating group (SedMen n=8), 2) exercising menstruating group (ExMen, n=36), and 3) exercising amenorrheic group (ExAmen, n=23). One-way ANOVAs were performed, and LSD post-hoc tests were performed when differences were detected.
Subjects were similar with respect to age (24.2+/-1.0 years), weight (57.8+/-1.7 kg), and height (164.3+/-1.3 cm) (p>0.05). ExMen and ExAmen groups were more aerobically fit (p=0.003) and had less body fat (p=0.002) than the SedMen group. Resting energy expenditure/fat free mass was lowest (p=0.001) in the ExAmen groups. Mean E1G across the measurement period (p<0.001) and overall E1G exposure as assessed by E1G area under the curve (AUC) (p<0.001) were lower in the ExAmen group vs. the SedMen and ExMen groups. U-CTX-I was elevated (p=0.033) in the ExAmen group (281.8+/-40.3 microg/L/mmCr), compared with the SedMen and ExMen groups (184.5+/-22.4, 197.2+/-14.7 microg/L/mmCr, respectively). OPG was suppressed (p=0.005) in the ExAmen group (4.6+/-0.2 pmol/L) vs. ExMen group (5.2+/-0.2 pmol/L), and OPG was lower in the SedMen group (4.1+/-0.3 pmol/L) compared with the ExMen group. Findings were translated to BMD; the ExAmen group had suppressed total body BMD (p=0.014) and L2-L4 BMD (p=0.015) vs. the ExMen group.
Our results suggest that OPG responds to the bone loading effect of exercise, and that suppressed OPG may play a role in the etiology of increased bone resorption observed in exercising women with chronic estrogen deficiency secondary to hypothalamic amenorrhea.
Bone 09/2008; 44(1):137-44. DOI:10.1016/j.bone.2008.09.008 · 3.97 Impact Factor
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