Bone Mineral Content of Amenorrheic and Eumenorrheic Athletes

Drinkwater, Barbara L.; Nilson, Karen; Chesnut, Charles H.; Bremner, W J; Shainholtz, Sydney; Southworth, Molly B.

doi:10.1056/nejm198408023110501

Cited by 885 publications

(162 citation statements)

References 18 publications

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“…Indeed, exercise can facilitate statural growth by stimulating growth hormone synthesis. In young female athletes, undertaking very intense aerobic exercise, oligomenorrhoea, amenorrhea, bone loss and stress fractures have been observed [31][32][33] . Approximately half of competitive female athletes experience oligomenorrhea or amenorrhea, compared to 5% in the general population.…”

Section: Can Excess or Wrong Exercise Be Dangerous For Bone?mentioning

confidence: 99%

Physical activity, diet and skeletal health

Branca

1999

Public Health Nutr.

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Diet and physical exercise concur in the determination of skeletal mass at the end of adolescence and in the conservation of it during adult life. The functional demand imposed on bone is a major determinant of its structural characteristics. Stress applied to a skeletal segment affects the geometry of the bone, the microarchitecture and the composition of the matrix. The stimulatory effect occurs when the skeleton is subjected to strains exceeding habitual skeletal loads, and the intensity of load is more important than the duration of the stimulus.Physical activity leads to greater bone density in children and adolescents and, to a minor extent, in adults. Weight bearing activities, such as walking, have a greater effect than non weight bearing activities, such as cycling and swimming. Reduction of loads as in bed resting or in space flights leads to bone loss. Intense training may cause damage, promptly repaired, as in stress fractures observed in army recruits. Female athletes may experience oligo-amenorrhea, though they still have a positive bone balance.There is an important interaction between the mechanical demands and the availability of nutrients to manufacture bone tissue. The increase in bone density in post-menopausal women is positively related to calcium intake when calcium supplementation is accompanied by exercise. When mechanical demands are low, such as during immobilisation, the intestinal calcium absorption is reduced. Calcium intake should also be analysed in the light of other dietary factors affecting the balance between absorption and excretion, and in combination with a number of other minerals, trace elements and bioactive substances with an impact on bone metabolism.

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Section: Can Excess or Wrong Exercise Be Dangerous For Bone?mentioning

confidence: 99%

Physical activity, diet and skeletal health

Branca

1999

Public Health Nutr.

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“…It is estimated that at least 50% of competitive female athletes experience oligomenorrhoea or amenorrhoea compared with 5 % in the normal population (Carbon, 1992). Despite their high levels of activity, these women can lose bone, particularly in the lumbar spine (Drinkwater et al 1984;Rutherford, 1993). A low bone density may put the athlete at increased risk of stress fractures in the short term (Myburgh et al 1990) and osteoporosis later in life.…”

Section: The 'Dangers' Of Exercisementioning

confidence: 99%

Bone density and physical activity

Rutherford

1997

Proc. Nutr. Soc.

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Osteoporosis is currently the major cause of fracture in older people. The most common fractures in the UK are hip fractures (60000 per year), closely followed by wrist (or Colle's) fractures (50000 per year) and vertebral fractures (40000 per year). Many osteoporotic fractures are associated with significant morbidity and mortality, with hip fractures being the most severe consequence. Of hip-fracture victims, 5-20 % will die within 1 year of the fracture and many more experience long-term disability which seriously reduces the quality of life. In 1994 the cost to the National Health Service was approximately 5750 million, and with the growing elderly population this figure is set to rise.The maximal load a bone can withstand without fracture is positively related to its bone mineral density (BMD). Bone mass peaks between the ages of 20 and 40 years, with men achieving a greater peak bone mass. After the age of 40 years, bone mass declines at a rate of 0.5-1 .O % per year, with an accelerated period of loss in women for 5-10 years after the menopause. In total, women lose about 25-30 % of the cortical bone and 35-50 % of the trabecular bone over a lifetime; men lose at about two-thirds this rate (Riggs et al. 1981). This leaves thin cortical bone and thin or interrupted trabecular plates. Once bone mass has declined to a critical threshold, fractures are likely to occur. Physical activity is one of the factors which can influence the attainment of peak bone mass and reduce the age-related loss. For this reason, there is considerable interest in identifying the most effective forms of exercise for increasing BMD with the assumption that, in the longer term, this will reduce fracture incidence. A large number of intervention and crosssectional studies have been conducted to try and identify the optimal form of activity for improving bone density. The present review aims to highlight those studies which have provided evidence that activity is good for bone and point to those forms of exercise which have been shown to improve BMD at the key fracture sites. In addition, attention will be drawn to possible detrimental effects of exercise on BMD and fracture incidence. FALLS AND FRACTURESThe majority of osteoporotic fractures, particularly those of the hip, occur as a result of a fall. It is important, therefore, to consider the factors which predispose the person to fall. These risk factors include: psychoactive drugs and other medications; dementia, depression and cognitive function; poor proprioception; poor gait and muscle strength; poor postural stability; dizziness and vestibular problems; poor functional ability; poor eyesight. Of these, muscle strength, postural stability and functional ability may be improved by the appropriate exercise. In the older person, therefore, exercise regimens should be designed to target these risk factors in addition to improving BMD.

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“…The third point of interest was that these authors documented two runners below the fracture threshold, a finding similar to that reported by Drinkwater et a1. (5).…”

Section: Review Of Literaturementioning

confidence: 99%

“…(5). Bone density was measured in the distal radius and lumbar vertebrae (L1 -L4) of 28 female athletes.…”

Section: Review Of Literaturementioning

confidence: 99%

Osteopenia: Its Relation to Menstrual Disorders in Female Athletes

Millar¹,

Hunter²

1990

J Orthop Sports Phys Ther

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Loss of bone density (osteopenia) is a problem which is usually associated with postmenopausal women; however, it is a problem which has recently been identified in some female athletes. It is well documented that changes in the hormonal cycle are responsible for the changes in bone density, although the exact etiology remains to be identified. Amenorrhea occurs with some female distance runners and is linked to abnormal hormonal cycles, notably, decreased estrogen levels, similar to those experienced by postmenopausal women. Recent research has identified significant bone density losses in these amenorrheic female runners, and some have identified an associated increase in stress fractures and other injuries. Knowledge regarding the potential problems of amenorrhea and appropriate physical therapy are essential for those working with young female distance runners.Loss of bone density (osteopenia) and related injuries are problems which one usually associates with postmenopausal women. However, physical therapists need to be aware of the potential for osteopenia in some female athletes. Increased bone loss has been linked to decreased estrogen levels, although the exact etiology of this relationship has not been identified (13,14). Typically, premenopausal women were not thought to be at risk for osteopenia unless they were hyperprolactinemic. In the last few decades, however, a group of women have been identified who suffer from secondary (hypothalamic) amenorrhea. Secondary amenorrhea does not stem from a diseased state, menopause, or surgery (6). Originally, research centered around documentation of the loss of menses with associated alteration of the normal hormonal cycle and its effect upon the reproductive system. Recently the research has focused on the side effects of decreased estrogen levels in amenorrheic athletes. Many researchers have not considered osteopenia as an area of concern, as exercise has previously been shown to increase bone density, thus providing a preventative mechanism for female athletes. In addition, the skeletal site and type of bone examined must be considered when assessing the validity of the research as specific ' Ass~stant Professor. Physlcal Therapy Program. Southwest Texas State Univers~ty. San Marcos. TX 78666-4616.

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Bone Mineral Content of Amenorrheic and Eumenorrheic Athletes

Cited by 885 publications

References 18 publications

Physical activity, diet and skeletal health

Physical activity, diet and skeletal health

Bone density and physical activity

Osteopenia: Its Relation to Menstrual Disorders in Female Athletes

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