Disordered eating,menstrual irregularity,and bone mineral density in female runners

PURPOSE: To examine the relationships between disordered eating, menstrual irregularity, and low bone mineral density (BMD) in young female runners. METHODS: Subjects were 91 competitive female distance runners aged 18-26 yr. Disordered eating was measured by the Eating Disorder Inventory (EDI). Menstrual irregularity was defined as oligo/amenorrhea (0-9 menses per year). BMD was measured by dual x-ray absorptiometry. RESULTS: An elevated score on the EDI (highest quartile) was associated with oligo/amenorrhea, after adjusting for percent body fat, age, miles run per week, age at menarche, and dietary fat, (OR [95% CI]: 4.6 [1.1-18.6]). Oligo/amenorrheic runners had lower BMD than eumenorrheic runners at the spine (-5%), hip (-6%), and whole body (-3%), even after accounting for weight, percent body fat, EDI score, and age at menarche. Eumenorrheic runners with elevated EDI scores had lower BMD than eumenorrheic runners with normal EDI scores at the spine (-11%), with trends at the hip (-5%), and whole body (-5%), after adjusting for differences in weight and percent body fat. Runners with both an elevated EDI score and oligo/amenorrhea had no further reduction in BMD than runners with only one of these risk factors. CONCLUSION: In young competitive female distance runners, (i) disordered eating is strongly related to menstrual irregularity, (ii) menstrual irregularity is associated with low BMD, and (iii) disordered eating is associated with low BMD in the absence of menstrual irregularity.     

The effect of oral contraceptives on bone mass and stress fractures in female runners

PURPOSE: To determine the effect of oral contraceptives (OC) on bone mass and stress fracture incidence in young female distance runners. METHODS: One hundred fifty competitive female runners ages 18-26 yr were randomly assigned to OC (30 microg of ethinyl estradiol and 0.3 mg of norgestrel) or control (no intervention) for 2 yr. Bone mineral density (BMD) and content (BMC) were measured yearly by dual x-ray absorptiometry. Stress fractures were confirmed by x-ray, magnetic resonance imaging, or bone scan. RESULTS: Randomization to OC was unrelated to changes in BMD or BMC in oligo/amenorrheic (N=50) or eumenorrheic runners (N=100). However, treatment-received analyses (which considered actual OC use) showed that oligo/amenorrheic runners who used OC gained about 1% per year in spine BMD (P<0.005) and whole-body BMC (P<0.005), amounts similar to those for runners who regained periods spontaneously and significantly greater than those for runners who remained oligo/amenorrheic (P<0.05). Dietary calcium intake and weight gain independently predicted bone mass gains in oligo/amenorrheic runners. Randomization to OC was not significantly related to stress fracture incidence, but the direction of the effect was protective in both menstrual groups (hazard ratio [95% CI]: 0.57 [0.18, 1.83]), and the effect became stronger in treatment-received analyses. The trial's statistical power was reduced by higher-than-anticipated noncompliance. CONCLUSION: OC may reduce the risk for stress fractures in female runners, but our data are inconclusive. Oligo/amenorrheic athletes with low bone mass should be advised to increase dietary calcium and take steps to resume normal menses, including weight gain; they may benefit from OC, but the evidence is inconclusive.     

Effects of ball sports on future risk of stress fracture in runners.

OBJECTIVE: To evaluate whether playing ball sports during childhood and adolescence is associated with the risk of stress fractures in runners later in life. DESIGN: Retrospective cohort study. SETTING: National track and field championships, held at Stanford University. PARTICIPANTS: One hundred fifty-six elite female and 118 elite male distance runners, age 18 to 44 years. INTERVENTIONS: A 1-page questionnaire was used to collect data regarding ages during which athletes played basketball and soccer, as well as other important covariates and outcomes. OUTCOME MEASUREMENTS: Athletes reported the ages when stress fractures occurred. Time to event was defined as the number of years from beginning competitive running to the first stress fracture or to current age, if no fracture had occurred. RESULTS: In both men and women, playing ball sports in youth correlated with reduced stress fracture incidence later in life by almost half, controlling for possible confounders. In men, each additional year of playing ball sports conferred a 13% decreased incidence of stress fracture (adjusted hazard ratio [HR] and 95% confidence interval, 0.87 [0.79-0.95]. Among women with regular menses, the HR for each additional year of playing ball sports was similar: 0.87 (0.75-1.00); however, there was no effect of length of time played among women with irregular menses (HR, 1.03 [0.92-1.16]). In men, younger ages of playing ball sports conferred more protection against stress fractures (HR for each 1-year-older age at first exposure, 1.29 [1.14, 1.45]). CONCLUSIONS: Runners who participate during childhood and adolescence in ball sports may develop bone with greater and more symmetrically distributed bone mass, and with enhanced protection from future stress fractures.     

Prevalence of menstrual dysfunction in Norwegian long-distance runners participating in the Oslo Marathon games

The objective of this study was to estimate the prevalence of athletic amenorrhea in a wide range of long-distance runners and the relation to possible risk factors. The study group consisted of 187 long-distance runners between 16 and 46 years of age. Information was obtained through a mailed questionnaire consisting of 32 different entries, including questions on age, leanness, training history, menstrual history, performance level, stress, as well as some sociological and nutritional aspects. Seventy-six per cent of the responding runners had normal menstrual function, 9.5% had minor irregularities (O), and 14.6% were amenorrheic (A), which is defined as absence of menstrual bleeding for more than 3 consecutive months the previous year. Half of the amenorrheic group had not had menstrual bleeding at all that year. The runners with menstrual disorders (O+A) had a significantly higher incidence of stress fractures. The most important factors associated with menstrual disorders were a feeling of conflict associated with food; age; and the age of menarche. There was no evidence that age of menarche was associated with an early training debut per se , the frequency and intensity of prepubertal training was not taken into account. All subgroups (E, O, and A) had low body mass index scores, and body composition did not seem to vary with menstrual status within the study group. Thus a high prevalence of menstrual disorders was observed in Norwegian long-distance runners, a condition associated with increased training loads, but even more with age, menarchal age and a feeling of nutritional conflict.     

Menstrual irregularity and stress fractures in collegiate female distance runners

From 240 questionnaires, we investigated the prevalence of stress fractures in competitive collegiate female long distance runners and its relationship to menstrual history. The runners were divided into three groups according to their menstrual history: very irregular 69/240 (0 to 5 menses/year), irregular 51/240 (6 to 9 menses/year), and regular 120/240 (10 to 13 menses/year). Stress fractures occurred in 49% of the very irregular runners, 39% of the irregular runners, and 29% of the regular runners. The majority of the stress fractures occurred in the tibia. Runners who had never used oral contraceptives were over twice as likely to have had a stress fracture when compared with runners who had used oral contraceptives for more than 1 year. These data suggest that female distance runners who have a history of irregular or absent menses and who have never used oral contraceptives may be at an increased risk for developing a stress fracture. When amenorrheal runners were separated from the very irregular group, an alarming trend was noted in eating behavior disorders. Forty-seven percent of the amenorrheal group, 20% of the one to five menses/year group, 10% of the irregular group, and 7% of the regular group admitted to an eating behavior disorder.     

Stress fractures and bone health in track and field athletes

The effect of exercise on bone health has received much attention in recent years. The problems of the female athlete triad: disordered eating, amenorrhea and osteoporosis have helped us to better understand and appreciate the important interaction of mechanical, hormonal, nutritional as well as genetic factors on bone health in the young female athlete. The relatively high stress fracture incidence of young track and field athletes can be quite disabling for the athlete's present and future running career. A number of risk factors including low bone mineral density (BMD), menstrual irregularities, dietary factors and prior history of stress fractures have been associated with an increased risk for stress fractures in the female athlete. Few studies have found risk factors for stress fractures in the male athlete. Female gender has been found to be a risk factor for stress fractures in the military population, but this finding is less apparent in athlete studies. Caucasians have been found to have a higher risk for stress fractures than African-American military recruits, but there is very limited data assessing stress fracture risk in athletes of varying ethnicity. Prevention of stress injury to bone involves maximizing peak bone mass in the pediatric and young adult age groups. Maintaining adequate calcium nutrition, caloric intake as well as hormonal and energy balance are important preventive measures, as are ensuring appropriate amounts of weight bearing exercise for optimizing bone health and preventing fractures. More research is needed to determine factors leading to improvements in bone density and fracture reduction in athletes at risk.     

Pelvic stress fracture in female runners

Stress fractures are a common injury in long-distance runners, and typically involve the lower extremities. Although relatively rare, pubic ramus stress fractures also occur, primarily in female runners. Bone imaging visualized a pubic stress fracture and a tibial stress fracture in a female long-distance runner with groin pain. Pubic stress fractures should be considered in female runners who present with groin pain. Radionuclide bone imaging is useful in diagnosing these lesions.     

Low vertebral bone density values in young non-elite female runners

Thirty-five female runners (26.6 +/- 0.9 years, range 17-35) were scheduled for bone mineral density evaluation, using quantitative computed tomography of the lumbar spine. In 17 women with oligo-amenorrhea, vertebral bone mineral density was under the normal range (defined from a control group of 46 sedentary healthy females in the same age range), while it was within the normal range in all runners with regular menses (n = 18). When age classes were considered, all runners aged 17-21 (11/11) were found to have oligo-amenorrhea and low bone mineral density values, the difference in mineral density with the controls of the same age quartile being highly significant (p less than 0.001). Runners from the two youngest age classes (17-21 and 22-26) had started training early after menarche (0.9 +/- 0.6 and 2.5 +/- 1.6 years, respectively). These results show that very young female runners with oligo-amenorrhea may have impressively low bone mineral density values. The possibility that early onset of training, close to menarcheal age, might be a risk factor for low mineral density, deserves further investigation.     

Stress fractures in the female athlete

Stress fractures are common among female athletes, especially runners. Although both intrinsic and extrinsic factors can contribute to stress injury etiology, the female athlete triad—negative energy balance leading to menstrual irregularity, and reduced bone mineral mass—is a significant contributor to the incidence of stress fractures in the female athlete. When combined with impact weight-bearing activity, this triad puts these women at increased risk for stress fractures. Treatment must focus on reversing identified risk factors, in addition to relative rest, and maintenance of fitness. Most stress fractures heal without complication. High-risk stress fractures should be evaluated and treated by a practitioner with expertise in the care of these injuries.     

Ground reaction forces and bone parameters in females with tibial stress fracture

PURPOSE: Tibial stress fracture is a common overuse running injury that results from the interplay of repetitive mechanical loading and bone strength. This research project aimed to determine whether female runners with a history of tibial stress fracture (TSF) differ in ground reaction force (GRF) parameters during running, regional bone density, and tibial bone geometry from those who have never sustained a stress fracture (NSF). METHODS: Thirty-six female running athletes (13 TSF; 23 NSF) ranging in age from 18 to 44 yr were recruited for this cross-sectional study. The groups were well matched for demographic, training, and menstrual parameters. A force platform measured selected GRF parameters (peak and time to peak for vertical impact and active forces, and horizontal braking and propulsive forces) during overground running at 4.0 m.s.(-1). Lumbar spine, proximal femur, and distal tibial bone mineral density were assessed by dual energy x-ray absorptiometry. Tibial bone geometry (cross-sectional dimensions and areas, and second moments of area) was calculated from a computerized tomography scan at the junction of the middle and distal thirds. RESULTS: There were no significant differences between the groups for any of the GRF, bone density, or tibial bone geometric parameters (P > 0.05). Both TSF and NSF subjects had bone density levels that were average or above average compared with a young adult reference range. Factor analysis followed by discriminant function analysis did not find any combinations of variables that differentiated between TSF and NSF groups. CONCLUSION: These findings do not support a role for GRF, bone density, or tibial bone geometry in the development of tibial stress fractures, suggesting that other risk factors were more important in this cohort of female runners.     

Effect of oral contraceptives on weight and body composition in young female runners

PURPOSE: To examine the effect of oral contraceptives (OC) on body weight, fat mass, percent body fat, and lean mass in young female distance runners. METHODS: The study population consisted of 150 female competitive distance runners aged 18-26 yr who had participated in a 2-yr randomized trial of the effect of the OC Lo/Ovral (30 microg of ethinyl estradiol and 0.3 mg of norgestrel) on bone health. Weight and body composition were measured approximately yearly by balance beam scales and dual-energy x-ray absorptiometry, respectively. RESULTS: Women randomized to the OC group tended to gain slightly less weight (adjusted mean difference (AMD) = -0.54 +/- 0.31 kg.yr, P = 0.09) and less fat (AMD = -0.35 +/- 0.25 kg.yr, P = 0.16) than those randomized to the control group. OC assignment was associated with a significant gain in lean mass relative to controls among eumenorrheic women (those who had 10 or more menstrual cycles in the year before baseline; AMD = 0.77 +/- 0.17 kg.yr, P < 0.0001) but not among women with fewer than 10 menstrual cycles in that year (AMD = 0.02 +/- 0.35 kg.yr, P = 0.96). Treatment-received analyses yielded similar results. CONCLUSION: This randomized trial confirms previous findings that OC use does not cause weight or fat mass gain, at least among young female runners. Our finding that this OC is associated with lean mass gain in eumenorrheic runners, but not in those with irregular menses, warrants examination in other studies.     

Bone mineral content and menstrual regularity in female runners

The relationship between bone mineral content and menstrual regularity in 10 amenorrheic runners (0-3 menses during the past year), 12 runners with regular menstrual cycles (10-12 menses during the past year), and 15 non-athletic women with regular menstrual cycles was investigated. Comparisons of the two groups of runners indicated no significant differences in body fatness, average weekly running distance, or average daily intake of calcium (Ca), phosphorus (P), and Ca/P ratios. Mean bone mineral content for the three groups, measured by photon absorptiometry, was 0.508, 0.529, and 0.544 g X cm-2, respectively, at 3 cm distal radius, and 0.707, 0.700, and 0.707 g X cm-2, respectively, at one-third distal radius, indicating no significant differences among the groups (P less than 0.05). However, a significant relationship (r = 0.77) was noted between bone mineral content and body fatness only in the amenorrheic runners. Within the amenorrheic population, the five thinnest runners had significantly lower mean bone mineral content values at 3 cm distal radius (0.457 g X cm-2) than the five runners with higher relative body fatness (0.559 g X cm-2). We conclude, therefore, that amenorrhea, independent of body composition, was not related to reduced bone mineral content in female runners. However, the combination of excessive thinness and amenorrhea may, in fact, predispose female athletes to reduced bone mass.     

Stress fractures of the sacrum. An atypical cause of low back pain in the female athlete

Low back pain is a common finding in an athletically active premenopausal female population. We describe an unusual cause of persistent low back/sacroiliac pain: a fatigue-type sacral stress fracture. Plain radiographs, bone scans, computed tomography, and magnetic resonance imaging studies were obtained in the female athletes to determine the nature of the pathologic abnormality. The most significant risk factor for fatigue-type sacral stress fractures was an increase in impact activity due to a more vigorous exercise program. Potential risk factors such as abnormal menstrual history, dietary deficiencies, and low bone mineral density were examined. The clinical course was protracted, with an average 6.6 months of prolonged low back pain before resolution of symptoms. Sacral fatigue-type stress fractures did not preclude the athletes from returning to their previous level of participation once healing had occurred.     

Stress fractures in runners

Stress fractures are a relatively common entity in athletes, in particular, runners. Physicians and health care providers should maintain a high index of suspicion for stress fractures in runners presenting with insidious onset of focal bone tenderness associated with recent changes in training intensity or regimen. It is particularly important to recognize “high-risk” fractures, as these are associated with an increased risk of complication. A patient with confirmed radiographic evidence of a high-risk stress fracture should be evaluated by an orthopedic surgeon. Runners may benefit from orthotics, cushioned sneakers, interval training, and vitamin/calcium supplementation as a means of stress fracture prevention.     

Postmenopausal bone density referral decision rules: correlation with clinical fractures

OBJECTIVE: To test decision rules for bone mineral density (BMD) against fractures. METHODS: We surveyed postmenopausal women in a military primary care clinic and tested three national clinical decision rules (Osteoporosis Risk Assessment Instrument; age, body size, no estrogen; weight) for correlation with fracture history. Outcome measures included relative risk (RR), area under the receiver operating characteristics curve (aROC), sensitivity, and specificity. RESULTS: Patients were 69 years old on average, 53% were Caucasian, 38% were African American, and 15% had a history of fractures. Caucasian women (RR, 1.8; 95% confidence interval [CI], 1.1-3.1) and those older than 65 years (RR, 2.0; 95% CI, 1.2-3.5) had higher prevalence of fractures. The Osteoporosis Risk Assessment Instrument decision rule had the highest aROC (0.65; 95% CI, 0.57-0.731 and sensitivity (sensitivity, 0.83; specificity, 0.31). Age, Body Size, No Estrogen had the next highest aROC (0.63; 95% CI, 0.54-0.71) and sensitivity (sensitivity, 0.74; specificity, 0.46). Weight criterion was the most specific (aROC, 0.60; 95% CI, 0.52-0.68; sensitivity, 0.64; specificity, 0.56). CONCLUSIONS: Current postmenopausal bone density referral decision rules only modestly correlate with clinical fractures.     

Risk factors for recurrent stress fractures in athletes

Our aim was to identify factors predisposing athletes to multiple stress fractures, with the emphasis on biomechanical factors. Our hypothesis was that certain anatomic factors of the ankle are associated with risk of multiple stress fractures of the lower extremities in athletes. Thirty-one athletes (19 men and 12 women) with at least three separate stress fractures each, and a control group of 15 athletes without fractures completed a questionnaire focusing on putative risk factors for stress fractures, such as nutrition, training history, and hormonal history in women. Bone mineral density was measured by dual-energy x-ray absorptiometry in the lumbar spine and proximal femur. Biomechanical features such as foot structure, pronation and supination of the ankle, dorsiflexion of the ankle, forefoot varus and valgus, leg-length inequality, range of hip rotation, simple and choice reaction times, and balance in standing were measured. There was an average of 3.7 (range, 3 to 6) fractures in each athlete, totaling 114 fractures. The fracture site was the tibia or fibula in 70% of the fractures in men and the foot and ankle in 50% of the fractures in women. Most of the patients were runners (61%); the mean weekly running mileage was 117 km. Biomechanical factors associated with multiple stress fractures were high longitudinal arch of the foot, leg-length inequality, and excessive forefoot varus. Nearly half of the female patients (40%) reported menstrual irregularities. Runners with high weekly training mileage were found to be at risk of recurrent stress fractures of the lower extremities.     

Low energy availability in the marathon and other endurance sports

Energy availability is the amount of dietary energy remaining after exercise training for all other metabolic processes. Excessively low energy availability impairs reproductive and skeletal health, although genetics and age may alter an individual's initial conditions and sensitivity when low energy availability is imposed. Many marathon runners and other endurance athletes reduce energy availability either (i) intentionally to modify body size and composition for improving performance; (ii) compulsively in a psychopathological pattern of disordered eating; or (iii) inadvertently because there is no strong biological drive to match energy intake to activity-induced energy expenditure. Inadvertent low energy availability is more extreme when consuming a low fat, high carbohydrate diet. Low energy availability, reproductive disorders, low bone mineral density and stress fractures are more common in female than male athletes. Functional menstrual disorders caused by low energy availability should be diagnosed by excluding diseases that also disrupt menstrual cycles. To determine energy availability (in units of kilocalories or kilojoules per kilogram of fat-free mass), athletes can record their diets and use diet analysis software to calculate energy intake, measure energy expenditure during exercise using a heart monitor and measure fat-free mass using a bioelectrical impedance body composition scale. All are commercially available at consumer prices.     

Fracture Risk (FRISK) Score: Geelong Osteoporosis Study

PURPOSE: To develop and evaluate a fracture risk (FRISK) score based on multiple-site bone mineral density (BMD) measurements and other risk factors, to enable prediction of future fracture occurrence. MATERIALS AND METHODS: All participants gave written informed consent, and the study was approved by the Barwon Health Research and Ethics Advisory Committee. BMD was measured at the femoral neck and spine in two concurrently recruited groups: women 60 years of age or older who had sustained a low-trauma fracture of the hip, spine, humerus or distal forearm during a 2-year ascertainment period (n = 231; mean age, 74 years +/- 7 [standard deviation]) and a population-based random sample of women who had not sustained a fracture during the recruitment period (n = 448; mean age, 72 years +/- 8). Falls in the previous year and the number of self-reported fractures in adult life were recorded. Coefficients of a multiple logistic regression model were used as weightings for a combined model. A longitudinal population-based sample was used to assess the fracture risk equation (n = 600; median age, 74 years; interquartile range, 67-82 years). RESULTS: The FRISK score was obtained from the following equation: 9.304 - 4.735BMD(SP) - 4.530BMD(FN) + 1.127FS + 0.344NPF + 0.037W, where BMD(SP) is spinal BMD (in grams per square centimeter), BMD(FN) is femoral neck BMD, FS is falls score, NPF is number of previous fractures, and W is weight (in kilograms). The FRISK score successfully predicted 75% of fractures 2 years after baseline measurements in subjects in the longitudinal study with 68% specificity. CONCLUSION: This study resulted in the derivation of a fracture risk score that successfully predicted 75% of fractures 2 years after baseline.     

Factors associated with menstrual dysfunction and self-reported bone stress injuries in female runners in the ultra- and half-marathons of the Two Oceans

Objective

To investigate factors associated with menstrual dysfunction, self‐reported bone stress injuries and energy balance in women runners.

Methods

613 runners were randomly sampled during the registration period for an endurance event. Demographic information, including self‐reported height and weight, training and injury history and menstrual history, was collected by questionnaire.

Results

Ultra‐marathon (ULTRA) participants (n = 276) were significantly older (mean (SD) 39 (8.2) vs 34 (10.5) years; p<0.001), lighter (58.2 (6.6) vs 59.6 (8.3) kg; p<0.05) and reported a higher training volume (p<0.001) than half‐marathon (HALF) participants (n = 337). Significantly more ULTRA subjects than HALF subjects reported a previous bone stress injury (21% vs 14%; p<0.05). There was no difference between the groups for menstrual status, but age at menarche was later (p<0.01) in the ULTRA group. Data were combined according to the absence (REG; n = 368/602 (61%)) or presence (IRREG; n = 234/602 (39%)) of a history of menstrual irregularity. Subject morphology was similar between groups, but the IRREG group had a higher self‐reported measure on the self‐loathing subscale (SLSS; p<0.01). The whole group was then classified according to current menstrual status, with 165 women being classified as currently irregular. (OLIGO/AMEN; 11.6%) and 445 women as currently regular (EUMEN; 88.4%). There were no morphological differences between the groups, however the OLIGO/AMEN group had a later age of menarche (p<0.01) than the EUMEN group. Further, women who reported a previous bone stress injury had higher SLSS scores than those who did not (2.91 (0.98) vs 2.68 (0.84); p<0.05).

Conclusions

There may be two independent mechanisms associated with energy balance, which are related to bone stress injuries, but may not necessarily be related to menstrual dysfunction.