Bone Health in Athletes: The Role of Exercise, Nutrition, and Hormones

“Because of these concerns and the availability of other osteoporosis medications, estrogen has a role but is no longer a first-line agent for postmenopausal osteoporosis.(14,16,24,88)”

“Vitamin D insufficiency is defined as a level of 20 to 31 ng/mL, and a level of ≥32 ng/mL demonstrates sufficient levels.(45,46) The prevalence of vitamin D insufficiency and deficiency in athletes is about 56% overall with a higher incidence in the winter and spring, indoor sports, and mixed sports.”

“Cortical bone is dense, solid, and surrounds the marrow space, whereas trabecular bone consists of a honeycomb-like network of trabecular plates and rods distributed throughout the bone marrow compartment.(29) Mechanotransduction refers to bone’s recognition of and response to loading, with mechanoreceptors primarily…”

“It inhibits bone turnover and maintains balance between bone resorption and formation.(86) Estrogen acts on osteoblasts and osteoclasts in a receptor-mediated fashion and has indirect effects on other hormones, including calcitonin, parathyroid hormone, cytokines, and growth factors.”

“Finite element analysis applied to HR-pQCT images allows estimation of bone strength and mechanical properties, including stiffness and failure load, which are associated with fracture risk, but independent of bone density.(23) For example, in 1 study looking at postmenopausal women, those with fractures had 13% to 17…”

“Consuming calcium in diet, such as dairy products, however, does not seem to pose risks for kidney stones or cardiovascular events as seen with artificial forms of calcium supplementation.(19,32) On the other hand, both calcium and vitamin D supplementation can decrease the incidence of stress fractures, as seen among…”

“There still exists controversy over the benefit of vitamin D and calcium supplementation in reducing the risk of fractures.(15,18,42) The role of calcium in strengthening bones is unclear.”

“The advantage of TBS is that it may predict fracture risk in postmenopausal women and is associated with fracture risk in individuals with conditions related to reduced bone mass or bone quality.(91)”

“Maintenance of bone mass can reduce fracture risk by 50% to 80%.(48,51,79,80) In older adults, the goals for exercise are fall prevention and ensuring safe exercise with modifications for those with osteoporosis.”

“In older populations (age ≥65 years), high-dose vitamin D supplementation (>800 IU daily) prevented hip and nonvertebral fractures.(15) A recent study of professional football players also showed a higher incidence of fractures in vitamin D-deficient players and, perhaps, decreased performance.”

“Consuming calcium in diet, such as dairy products, however, does not seem to pose risks for kidney stones or cardiovascular events as seen with artificial forms of calcium supplementation.(19,32) On the other hand, both calcium and vitamin D supplementation can decrease the incidence of stress fractures, as seen among…”

“5 SDs below the young adult mean value (t score) with or without fractures.(58) Athletes participating in weightbearing sports should have an approximately 10% higher BMD than nonathletes, and athletes in high-impact sports have a higher BMD compared with medium- or low-impact sports.”

“4% increase in BMD is equal to a 64% increase in ultimate force and 94% increase in energy to failure.(87) Weightbearing activity was found to have a profound impact on BMD in female athletes, with site-specific mechanical loading significantly affecting bone accrual.”

“Stresses that cause osteogenesis must be variable, dynamic, and progressive; static loading does not cause osteogenesis.(25) A key principle of bone formation and adaptation is that physical deformation of the bone directly stimulates bone formation.”

“The Triad was originally described in 1992 as 3 interrelated components: disordered eating, amenorrhea, and osteoporosis.(82,105) This definition has expanded to now describe a spectrum of pathology that includes less severe forms of these 3 factors.”

“Surgery is rarely indicated but may be necessary in high-risk fracture sites such as the tension side of the femoral neck or anterior tibia.(10,17,36,38,90) Supplementation of calcium and vitamin D in a diet that is deficient in these reduces the incidence of stress fractures by as much as 20%.”

“While BMD is more frequently measured using DXA in the clinical setting, high-resolution peripheral quantitative computed tomography (HR-pQCT) can better distinguish healthy microarchitecture of bone from suboptimal bone, using 3-dimensional information to provide estimates of bone geometry.(54,64) Finite element anal…”

“Insulin-like growth factor 1 is a bone trophic hormone and oral estrogen decreases its systemic concentration but transdermal estrogen does not, thus leading researchers to investigate the effects of transdermal estrogen on BMD.(50,70,103) When low BMD is from low energy availability and a hypoestrogenic state as seen…”

“The risk of incurring a stress injury increases as the number of Triad-related risk factors increases.(6) Although the Triad is specifically describing the syndrome seen in women, a parallel syndrome is seen in men with low energy availability, hypogonadism, and low BMD, with further research needed in this area.”

“Athletes with amenorrhea are 2 to 4 times more likely to suffer a stress fracture than eumenorrheic subjects.(11) In a study of college athletes, the lower the BMD the longer the recovery from a stress injury.”

“7% to 21% in athletes.(12) Stress injuries of the foot and lower leg are most common,(3,68) but they can occur in any bone that is subjected to repetitive stress.”

“The active metabolite, 1,25(OH)D3, promotes gene transcription, increasing cell protein synthesis and growth.(28) Muscle biopsies of adults with low vitamin D levels have shown fatty infiltration and fibrosis, but changes appear reversible with vitamin D supplementation.”

“Up to 15.9% of athletes have all 3 most severe components of the Triad.”

“The prevalence of vitamin D insufficiency and deficiency in athletes is about 56% overall with a higher incidence in the winter and spring, indoor sports, and mixed sports.(37) In a study of NCAA (National Collegiate Athletic Association) athletes, the prevalence was 33.”

“TBS values tend to be lower in postmenopausal women and in men with previous fractures compared with their nonfractured peers.(57,83) The advantage of TBS is that it may predict fracture risk in postmenopausal women and is associated with fracture risk in individuals with conditions related to reduced bone mass or bon…”

“Although the Triad is specifically describing the syndrome seen in women, a parallel syndrome is seen in men with low energy availability, hypogonadism, and low BMD, with further research needed in this area.(95) The fact that the Triad is a spectrum of disease makes determining prevalence challenging.”

“Low energy availability often causes menstrual dysfunction and hypoestrogenism, leading to negative effects on bone health and endothelial cell dysfunction.(34,85) Bone stress injuries, which include stress reactions and fractures, are more often seen in athletes with menstrual irregularities and/or low BMD.”

“Both amenorrheic and eumenorrheic athletes were found to have greater total cross-sectional area, trabecular area, and cortical perimeter compared with nonathletes at the distal tibia.(1)”

“Adolescence and young adulthood are the most beneficial times for longterm bone density gains, with nearly 90% of peak bone mass gained by age 18 years.(104) However, it is also the most susceptible time, when negative consequences can occur from eating disorders, poor nutrition, hypoestrogenism, and inadequate calciu…”

“8%.(39) Early detection is critical to prevent the negative consequences of the Triad.”

“Low energy availability often causes menstrual dysfunction and hypoestrogenism, leading to negative effects on bone health and endothelial cell dysfunction.(34,85) Bone stress injuries, which include stress reactions and fractures, are more often seen in athletes with menstrual irregularities and/or low BMD.”

“Consuming calcium in diet, such as dairy products, however, does not seem to pose risks for kidney stones or cardiovascular events as seen with artificial forms of calcium supplementation.19,32 On the other hand, both calcium and vitamin D supplementation can decrease the incidence of stress fractures, as seen among f…”

“Consuming calcium in diet, such as dairy products, however, does not seem to pose risks for kidney stones or cardiovascular events as seen with artificial forms of calcium supplementation.19,32 On the other hand, both calcium and vitamin D supplementation can decrease the incidence of stress fractures, as seen among f…”

“Runners with oligomenorrhea were 6 times more likely to sustain a stress injury.(13) Stress injuries can be diagnosed clinically but imaging is often used to assist with the diagnosis of certain stress injuries.”

“Energy availability is defined as energy intake (kcal) minus exercise energy expenditure (kcal) divided by kilograms of fat-free mass or lean body mass.(63) These components can be difficult to measure outside the research setting but estimates and less precise measurements can be done and an energy availability calcu…”

“Restoration of weight and resumption of normal menses are the main goals of treatment and are important in preventing further bone loss.(33,71) The majority of athletes can be treated successfully with a nonpharmacologic approach, but in those with osteoporosis and/or history of multiple fractures who do not respond t…”

“Maintenance of bone mass can reduce fracture risk by 50% to 80%.(48,51,79,80) In older adults, the goals for exercise are fall prevention and ensuring safe exercise with modifications for those with osteoporosis.”

“Estrogen acts on osteoblasts and osteoclasts in a receptor-mediated fashion and has indirect effects on other hormones, including calcitonin, parathyroid hormone, cytokines, and growth factors.(5,60) Adolescence is a particularly crucial period for skeletal development.”

“In the athletic population, use of hormones in treatment of amenorrhea, oligomenorrhea, and low bone density has been controversial or inconclusive.(30,33,35,78) The impact of oral hormones on insulin-like growth factor 1 in the liver may negate the benefit of estrogen on bone.”

“External bone stimulators have also been used, although human evidence is lacking for their effectiveness in stress fractures and data are primarily found in studies of traumatic fractures.(27,59,99)”

“Surgery is rarely indicated but may be necessary in high-risk fracture sites such as the tension side of the femoral neck or anterior tibia.(10,17,36,38,90) Supplementation of calcium and vitamin D in a diet that is deficient in these reduces the incidence of stress fractures by as much as 20%.”

“Because of the significant impact puberty has on bone growth, there is up to a 50% increase in total body bone mass between the ages of 12 and 18 years.(89) Increases in growth hormone, insulin-like growth factor 1, and estrogen that occur between Tanner stages 2 and 4 coincide with maximal rates of bone mineral gains.”

“Estrogen acts on osteoblasts and osteoclasts in a receptor-mediated fashion and has indirect effects on other hormones, including calcitonin, parathyroid hormone, cytokines, and growth factors.(5,60) Adolescence is a particularly crucial period for skeletal development.”

“Muscle biopsies of adults with low vitamin D levels have shown fatty infiltration and fibrosis, but changes appear reversible with vitamin D supplementation.(9) In girls aged 12 to 14 years, there is a direct correlation between 25(OH)D3 levels and muscle power, force, velocity, and jump height measured by jump mechan…”

“Athletes participating in weightbearing sports should have an approximately 10% higher BMD than nonathletes, and athletes in high-impact sports have a higher BMD compared with medium- or low-impact sports.(98) Children, adolescents, and premenopausal women require different definitions that take into account age, spor…”

“The impact of oral hormones on insulin-like growth factor 1 in the liver may negate the benefit of estrogen on bone.(33,35,78) Insulin-like growth factor 1 is a bone trophic hormone and oral estrogen decreases its systemic concentration but transdermal estrogen does not, thus leading researchers to investigate the eff…”

“Many studies have identified a direct relationship between serum vitamin D levels and BMD in adults of all races.(2) When vitamin D levels fall below 30 ng/mL, parathyroid hormone levels are increased, which triggers an increase in osteoclastic activity in bone.”

“Not all stress fractures are the same; cancellous bone stress fractures occur more often in patients with osteopenia, compared with cortical stress fractures.(67,76) More severe stress fractures by magnetic resonance grading are correlated with lower BMD.”

“Maintenance of bone mass can reduce fracture risk by 50% to 80%.(48,51,79,80) In older adults, the goals for exercise are fall prevention and ensuring safe exercise with modifications for those with osteoporosis.”

“Surgery is rarely indicated but may be necessary in high-risk fracture sites such as the tension side of the femoral neck or anterior tibia.(10,17,36,38,90) Supplementation of calcium and vitamin D in a diet that is deficient in these reduces the incidence of stress fractures by as much as 20%.”

“A recent study of professional football players also showed a higher incidence of fractures in vitamin D-deficient players and, perhaps, decreased performance.(66)”

“Surgery is rarely indicated but may be necessary in high-risk fracture sites such as the tension side of the femoral neck or anterior tibia.(10,17,36,38,90) Supplementation of calcium and vitamin D in a diet that is deficient in these reduces the incidence of stress fractures by as much as 20%.”

“There has been some promising evidence for recombinant parathyroid hormone improving BMD, bone mineral content, and stress fracture healing in animal studies but further research is needed in humans.(92) External bone stimulators have also been used, although human evidence is lacking for their effectiveness in stress…”

“For example, in 1 study looking at postmenopausal women, those with fractures had 13% to 17% lower stiffness at the tibia and radius than those without fractures, despite similar BMDs measured via DXA scans.(93) An additional objective tool to assess bone integrity is the trabecular bone score (TBS), a gray-level text…”

“5 without exogenous estrogen replacement.(26) A higher body weight correlates with higher BMD, regardless of treatment with hormonal contraception, suggesting that body weight and body fat may override potential detrimental effects of Depo-Provera.”

“TBS values tend to be lower in postmenopausal women and in men with previous fractures compared with their nonfractured peers.(57,83) The advantage of TBS is that it may predict fracture risk in postmenopausal women and is associated with fracture risk in individuals with conditions related to reduced bone mass or bon…”

“6%, despite taking place in southern California during the summer months.(100) The causes of vitamin D deficiency can be multifactorial, including reduced skin synthesis, absorption of dietary vitamin D, and acquired and heritable disorders of vitamin D metabolism.”

“Combined oral contraceptive pills do not improve bone density in young women.(30,102) For athletes in whom the Triad has been diagnosed, clearance and return to play can be challenging, and clinicians want to ensure participation is safe for the athlete.”

“Consuming calcium in diet, such as dairy products, however, does not seem to pose risks for kidney stones or cardiovascular events as seen with artificial forms of calcium supplementation.19,32 On the other hand, both calcium and vitamin D supplementation can decrease the incidence of stress fractures, as seen among f…”

“Because of these concerns and the availability of other osteoporosis medications, estrogen has a role but is no longer a first-line agent for postmenopausal osteoporosis.(14,16,24,88)”

“When vitamin D levels fall below 30 ng/mL, parathyroid hormone levels are increased, which triggers an increase in osteoclastic activity in bone.(84) Concomitantly, 1,25(OH)D3 directly stimulates osteoblasts to produce receptor activator nuclear factor-κB, which increases osteoclastogenesis and mobilization of calcium…”

“External bone stimulators have also been used, although human evidence is lacking for their effectiveness in stress fractures and data are primarily found in studies of traumatic fractures.(27,59,99)”

“Consuming calcium in diet, such as dairy products, however, does not seem to pose risks for kidney stones or cardiovascular events as seen with artificial forms of calcium supplementation.19,32 On the other hand, both calcium and vitamin D supplementation can decrease the incidence of stress fractures, as seen among f…”

“The mechanism for loss in BMD among Depo-Provera users is estrogen deficiency because of suppression of the hypothalamic-pituitary-ovarian axis Mar • Apr 2017Goolsby and Boniquit without exogenous estrogen replacement.26 A higher body weight correlates with higher BMD, regardless of treatment with hormonal contracepti…”

“Among high school athletes, those taking hormonal contraceptive pills were more likely to have disordered eating despite the same injury and menstrual patterns as those not taking hormonal contraceptive pills.(97) If there are any concerns about the responses to the questions, further in-depth evaluation using a team…”

“Further, strong evidence suggests that exercise benefits bone health at all ages and is a critical factor in osteoporosis prevention and treatment in both sexes [33].”

“Adequate intakes of calcium, which plays a vital role in bone health and injury risk [34,35], and iron, essential to carry oxygen and maintaining energy release [36], are important for females, in particular when performing high-intensity contact sport.”