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Bone density at weight-bearing and nonweight-bearing sites in ballet dancers: the effects of exercise, hypogonadism, and body weight.
J Clin Endocrinol Metab. 1994 Feb; 78(2):449-54.JC

Abstract

Exercise is recommended as a means of preventing osteoporosis. When intensive, weight-bearing exercise is often associated with hypogonadism. As weight-bearing exercise is likely to be more beneficial at weight-bearing than nonweight-bearing sites, and hypogonadism is likely to be more detrimental to trabecular than cortical bone, we tested the hypothesis that exercise and hypogonadism result in differing regional effects: net benefits at weight-bearing, predominantly cortical sites, and net deficits at nonweight-bearing trabecular-rich sites. Bone density (grams per cm2), body fat, and fat-free mass (kilograms) were measured using dual x-ray absorptiometry in 44 ballet dancers, aged 17.0 +/- 0.2 yr (mean +/- SEM), 18 sedentary amenorrheic girls with anorexia nervosa, and 23 girls of comparable age with regular menstrual cycles. Bone density, expressed as a percentage above or below the mean in the girls with regular menstrual cycles, was normal or elevated at weight-bearing sites in dancers [femoral neck, 3.1 +/- 1.7% (P = NS); Wards triangle, 4.1 +/- 2.3% (P = NS); trochanter, 5.9 +/- 1.9% (P < 0.05)] and normal or reduced at these sites in girls with anorexia nervosa [-10.5 +/- 3.8% (P < 0.05), -7.8 +/- 4.3% (P = NS), and -8.7 +/- 4.0% (P < 0.05), respectively]. By contrast, deficits similar to those in girls with anorexia nervosa were found in dancers at nonweight-bearing sites [ribs, -5.7 +/- 0.8% (P < 0.01); arms, -4.6 +/- 1.1% (P < 0.01); skull, -5.9 +/- 1.3% (P < 0.01)] before, but not after, correcting for fat mass. Fat mass was 7.8 +/- 0.4 kg in dancers, similar to that in girls with anorexia nervosa (6.3 +/- 0.7 kg) and lower than that in girls with regular menstrual cycles (16.8 +/- 1.6 kg; P < 0.01). The net result of vigorous exercise, hypogonadism, and leanness in athletic amenorrhea may not be generalized osteoporosis. Weight-bearing exercise may offset the effects of hypogonadism at predominantly cortical weight-bearing sites, such as the proximal femur. Non-weight-bearing sites and weight-bearing sites containing substantial amounts of trabecular bone, such as the lumbar spine, may be adversely affected by hypogonadism while benefiting little from weight-bearing exercise. Deficits at nonweight-bearing sites may be attenuated by maintenance of body weight.

Authors+Show Affiliations

Department of Endocrinology, Austin Hospital, Heidelberg, Melbourne, Australia.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8106634

Citation

Young, N, et al. "Bone Density at Weight-bearing and Nonweight-bearing Sites in Ballet Dancers: the Effects of Exercise, Hypogonadism, and Body Weight." The Journal of Clinical Endocrinology and Metabolism, vol. 78, no. 2, 1994, pp. 449-54.
Young N, Formica C, Szmukler G, et al. Bone density at weight-bearing and nonweight-bearing sites in ballet dancers: the effects of exercise, hypogonadism, and body weight. J Clin Endocrinol Metab. 1994;78(2):449-54.
Young, N., Formica, C., Szmukler, G., & Seeman, E. (1994). Bone density at weight-bearing and nonweight-bearing sites in ballet dancers: the effects of exercise, hypogonadism, and body weight. The Journal of Clinical Endocrinology and Metabolism, 78(2), 449-54.
Young N, et al. Bone Density at Weight-bearing and Nonweight-bearing Sites in Ballet Dancers: the Effects of Exercise, Hypogonadism, and Body Weight. J Clin Endocrinol Metab. 1994;78(2):449-54. PubMed PMID: 8106634.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Bone density at weight-bearing and nonweight-bearing sites in ballet dancers: the effects of exercise, hypogonadism, and body weight. AU - Young,N, AU - Formica,C, AU - Szmukler,G, AU - Seeman,E, PY - 1994/2/1/pubmed PY - 1994/2/1/medline PY - 1994/2/1/entrez SP - 449 EP - 54 JF - The Journal of clinical endocrinology and metabolism JO - J Clin Endocrinol Metab VL - 78 IS - 2 N2 - Exercise is recommended as a means of preventing osteoporosis. When intensive, weight-bearing exercise is often associated with hypogonadism. As weight-bearing exercise is likely to be more beneficial at weight-bearing than nonweight-bearing sites, and hypogonadism is likely to be more detrimental to trabecular than cortical bone, we tested the hypothesis that exercise and hypogonadism result in differing regional effects: net benefits at weight-bearing, predominantly cortical sites, and net deficits at nonweight-bearing trabecular-rich sites. Bone density (grams per cm2), body fat, and fat-free mass (kilograms) were measured using dual x-ray absorptiometry in 44 ballet dancers, aged 17.0 +/- 0.2 yr (mean +/- SEM), 18 sedentary amenorrheic girls with anorexia nervosa, and 23 girls of comparable age with regular menstrual cycles. Bone density, expressed as a percentage above or below the mean in the girls with regular menstrual cycles, was normal or elevated at weight-bearing sites in dancers [femoral neck, 3.1 +/- 1.7% (P = NS); Wards triangle, 4.1 +/- 2.3% (P = NS); trochanter, 5.9 +/- 1.9% (P < 0.05)] and normal or reduced at these sites in girls with anorexia nervosa [-10.5 +/- 3.8% (P < 0.05), -7.8 +/- 4.3% (P = NS), and -8.7 +/- 4.0% (P < 0.05), respectively]. By contrast, deficits similar to those in girls with anorexia nervosa were found in dancers at nonweight-bearing sites [ribs, -5.7 +/- 0.8% (P < 0.01); arms, -4.6 +/- 1.1% (P < 0.01); skull, -5.9 +/- 1.3% (P < 0.01)] before, but not after, correcting for fat mass. Fat mass was 7.8 +/- 0.4 kg in dancers, similar to that in girls with anorexia nervosa (6.3 +/- 0.7 kg) and lower than that in girls with regular menstrual cycles (16.8 +/- 1.6 kg; P < 0.01). The net result of vigorous exercise, hypogonadism, and leanness in athletic amenorrhea may not be generalized osteoporosis. Weight-bearing exercise may offset the effects of hypogonadism at predominantly cortical weight-bearing sites, such as the proximal femur. Non-weight-bearing sites and weight-bearing sites containing substantial amounts of trabecular bone, such as the lumbar spine, may be adversely affected by hypogonadism while benefiting little from weight-bearing exercise. Deficits at nonweight-bearing sites may be attenuated by maintenance of body weight. SN - 0021-972X UR - https://www.unboundmedicine.com/medline/citation/8106634/Bone_density_at_weight_bearing_and_nonweight_bearing_sites_in_ballet_dancers:_the_effects_of_exercise_hypogonadism_and_body_weight_ L2 - https://academic.oup.com/jcem/article-lookup/doi/10.1210/jcem.78.2.8106634 DB - PRIME DP - Unbound Medicine ER -