Anorexia nervosa, athletics, and amenorrhea

Activity anorexia: An interplay between basic and applied behavior analysis

The relationship between basic research with nonhumans and applied behavior analysis is illustrated by our work on activity anorexia. When rats are fed one meal a day and allowed to run on an activity wheel, they run excessively, stop eating, and die of starvation. Convergent evidence, from several different research areas, indicates that the behavior of these animals and humans who self-starve is functionally similar. A biobehavioral theory of activity anorexia is presented that details the cultural contingencies, behavioral processes, and physiology of anorexia. Diagnostic criteria and a three-stage treatment program for activity-based anorexia are outlined. The animal model permits basic research on anorexia that for practical and ethical reasons cannot be conducted with humans. Thus, basic research can have applied importance.

Prospective study of physical activity and risk of developing a stress fracture among preadolescent and adolescent girls

OBJECTIVE

To identify predictors of developing a stress fracture among adolescent girls during a 7-year period.

DESIGN

Prospective cohort study.

SETTING

Adolescent girls living throughout the United States.

PARTICIPANTS

A total of 6831 girls aged 9 to 15 years at baseline in the Growing Up Today Study, an ongoing prospective cohort study.

MAIN EXPOSURES

Exposures were assessed by self-report questionnaires completed by adolescent girls in 1996, 1997, 1998, 1999, 2000, 2001, and 2003. The adolescent girls' history of stress fracture, including age when fracture occurred and site, were reported by their mothers, who are registered nurses, in 2004. Cox proportional hazards models were used in the analysis. Main Outcome Measure Incident stress fracture that occurred between 1997 and 2004.

RESULTS

During 7 years of follow-up, 267 girls (3.9%) developed a stress fracture. Independent of age, age at menarche, family history of fracture, and hours per week of low- and moderate-impact activity, hours per week of running (hazard ratio = 1.13; 95% confidence interval, 1.04-1.23), basketball (hazard ratio = 1.12; 95% confidence interval, 1.03-1.23), and cheerleading/gymnastics (hazard ratio = 1.12; 95% confidence interval, 1.02-1.22) were significant predictors of developing a stress fracture. No other type of high-impact activity was associated with an increased risk.

CONCLUSION

Girls who engage in running, basketball, cheerleading, or gymnastics should be encouraged to include varied training in lower-impact activities to decrease the cumulative amount of impact in order to minimize their risk of stress fractures.

Family history predicts stress fracture in active female adolescents

OBJECTIVE

Increased physical activity and menstrual irregularity have been associated with increased risk for stress fracture among adult women active in athletics. The purposes of this study were to determine whether menstrual irregularity is also a risk factor for stress fracture in active female adolescents and to estimate the quantity of exercise associated with an increased risk for this injury.

PATIENTS AND METHODS

A case-control study was conducted of 13- to 22-year-old females diagnosed with their first stress fracture, each matched prospectively on age and self-reported ethnicity with 2 controls. Patients with chronic illnesses or use of medications known to affect bone mineral density were excluded, including use of hormonal preparations that could alter menstrual cycles. The primary outcome, stress fracture in any extremity or the spine, was confirmed radiographically. Girls with stress fracture had bone mineral density measured at the lumbar spine by dual-energy x-ray absorptiometry.

RESULTS

The mean +/- SD age of the 168 participants was 15.9 +/- 2.1 years; 91.7% were postmenarchal, with a mean age at menarche of 13.1 +/- 1.1 years. The prevalence of menstrual irregularity was similar among cases and controls. There was no significant difference in the mean hours per week of total physical activity between girls in this sample with stress fracture (8.2 hours/week) and those without (7.4 hours/week). In multivariate models, case subjects had nearly 3 times the odds of having a family member with osteoporosis or osteopenia. In secondary analyses, participants with stress fracture had a low mean spinal bone mineral density for their age.

CONCLUSIONS

Among highly active female adolescents, only family history was independently associated with stress fracture. The magnitude of this association suggests that further investigations of inheritable skeletal factors are warranted in this population, along with evaluation of bone mineral density in girls with stress fracture.

Usefulness of monitoring fertility from menarche

The concept of the ovarian cycle as a continuum considers that all types of ovarian activity encountered during the reproductive life are responses to different environmental conditions in order to ensure the health of the woman. During the normal ovulatory cycle, a series of sequential events have to occur in a highly synchronized manner. Fertility awareness is useful in helping women to identify the different stages of their reproductive life cycle. Fertility awareness is also a valuable tool in helping women to identify gynecological disorders. Persistence of irregularities within the mucus patterns and the menstrual cycle should be of concern to women presenting with these problems. These irregularities may be due to obstetrical, endocrine, gynecological or iatrogenic disorders. Insight into early pregnancy complications, ovulatory dysfunction and pelvic inflammatory disease can be ascertained from abnormalities within the menstrual cycle and mucus pattern. Thus, fertility awareness will also enable the recognition and early treatment of several metabolic, endocrine and infectious diseases.

Correlates of stress fractures among preadolescent and adolescent girls

OBJECTIVE

Although stress fractures are a source of significant morbidity in active populations, particularly among young female athletes, the causes of stress fractures have not been explored among females <17 years of age or in the general population. The purpose of this study was to examine correlates of stress fractures in a large, population-based, national, cohort study of preadolescent and adolescent girls.

METHODS

A cross-sectional analysis of data from 5461 girls, 11 to 17 years of age, in the Growing Up Today Study, an ongoing longitudinal study of the children of registered female nurses participating in Nurses' Health Study II, was performed. Mothers self-reported information regarding their children's histories of stress fractures on their 1998 annual questionnaire. Growing Up Today Study participants self-reported their weight and height, menarcheal status, physical activity, dietary intake, and disordered eating habits on annual surveys.

RESULTS

In 1998, the mean age of the participants was 13.9 years. Approximately 2.7% of the girls had a history of stress fracture, 3% engaged in disordered eating (using fasting, diet pills, laxatives, or vomiting to control weight), and 16% participated in > or =16 hours per week of moderate to vigorous activity. Age at menarche, z score of BMI in 1998, calcium intake, vitamin D intake, and daily dairy intake were all unrelated to stress fractures after controlling for age. Independent of age and BMI, girls who participated in > or =16 hours per week of activity in 1998 had 1.88 greater odds of a history of stress fracture than did girls who participated in <4 hours per week (95% confidence interval [CI]: 1.18-3.30). Girls who participated in > or =16 hours per week of activity were also more likely than their peers to engage in disordered eating (4.6% vs 2.8%); however, disordered eating did not have an independent association with stress fractures (odds ratio [OR]: 1.33; 95% CI: 0.61-2.89). Independent of age and BMI, each hour per week of high-impact activity significantly increased the risk of stress fracture (OR: 1.05; 95% CI: 1.02-1.09). Among the high-impact physical activities, only running (OR: 1.13; 95% CI: 1.05-1.22) and cheerleading/gymnastics (OR: 1.10; 95% CI: 1.01-1.21) were independently associated with greater odds of stress fracture.

CONCLUSIONS

These findings suggest that, although activity can be beneficial for bone health, there is a threshold over which the risk of stress fracture increases significantly among adolescent girls. High-impact activities, particularly running, cheerleading, and gymnastics, appear to be higher risk than other activities. Prospective studies are needed to explore the directionality of these relationships, as well as the role of menstrual history. In the meantime, clinicians should remain vigilant in identifying and treating disordered eating and menstrual irregularities among their highly active, young, female patients.

Eating disorders

Anorexia nervosa, bulimia nervosa, and eating disorders not otherwise specified remain a significant cause of morbidity and mortality in girls and young women. Management of eating disorders typically requires a multidisciplinary team approach, often spear-headed by the clinician initially detecting the illness. This article addresses the definitions and prevalence of eating disorders, tips on recognition and management of medical complications, and reproductive health concerns for these young women. Issues surrounding care of the patient with the female athlete triad, or amenorrhea, osteopenia, and eating disorders, are also discussed.

Normal bone accretion and effects of nutritional disorders in childhood

Although osteoporosis is usually considered to be a health concern of the elderly, increased attention is being paid to children and adolescents who are at risk for developing this devastating disease. As osteoporosis is a preventable condition with no identified cure, focus has been placed on modifiable areas in a young person's life that may prevent the development of the disease. A child or adolescent's nutrition is an example of such an area. This review examines factors influencing normal bone development and emphasizes the importance of the adolescent years as a time for peak bone accretion. Current methods to evaluate skeletal status are examined, including the challenges that arise in interpreting bone densities in children who have growing bones. Children and adolescents who are at high risk for osteoporosis are discussed, with an emphasis on groups in whom poor nutrition likely mediates bone loss. Two models of malnutrition, anorexia nervosa and the female athlete triad, are discussed, with emphasis on the way in which each has deleterious effects on the adolescent skeleton. The promotion of skeletal health is ultimately the encouragement of good general health principles for all young people. Approaches for working with children and adolescents are reviewed, including literature supporting each strategy.

Bone density issues in the adolescent gynecology patient

Because adolescence is a critical period for acquisition of peak bone mass, adolescent gynecology clinicians can play an important role in promoting and reinforcing skeletal health. Efforts should be focused on maximizing nutrition, exercise, and a normal sex steroid status during these formative years. Close attention should also be given to factors that jeopardize the attainment of peak bone mass: amenorrhea, malnutrition (e.g., anorexia nervosa), use of medications with deleterious effects on bone, and underlying medical conditions that may predispose a young woman to early bone loss. This review places special emphasis on a patient commonly seen in the adolescent and gynecology practice, the female athlete.

Estrogen agonist (zeranol) treatment in a castrated male lamb model: effects on growth and bone mineral accretion

The mechanism of estrogen's action on bone mineralization in children has received little attention. Our objective was to determine the effect of time (developmentally) and duration of exposure to an estrogen agonist (zeranol) on bone growth and mineralization using a castrated male lamb model. At birth, 40 male lambs were castrated and within 14 days of birth (day = 0) they were assigned (n = 10 per group) to age-matched control lambs (C-AGE) or to receive a 12.5-mg zeranol implant as follows: E-0, implanted on days 0, 45, 90, and 135; E-90, implanted on days 90 and 135; and E-0, 90, implanted on days 0, 90, and 135. Lambs were studied for 163 days. Serum was collected on days 28, 73, 118, 135, and 163 and analyzed for minerals (Ca, P, and Mg), markers of bone remodeling (bone alkaline phosphatase [ALP] and tartrate resistant acid phosphatase [TRAP]), 1,25-dihydroxyvitamin D [1,25(OH)2D], growth hormone (GH), and insulin-like growth factor I (IGF-I). Whole-body bone mineral content (BMC), bone mineral density (BMD), fat mass, and lean mass were determined by dual energy X-ray absorptiometry (DEXA) on days 28, 73, 118, and 163. There was a linear increase in growth at all time points. Whole-body BMC, weight, and lean mass of C-AGE and E-90 lambs were less than E-0, and E-0, 90 lambs at all time points. Whole-body BMD of C-AGE and E-90 lambs was less than E-0 and E-0, 90 lambs at 28 days and 73 days; however, after implantation at day 90 whole-body BMD of E-90 lambs was similar to E-0 and E-0, 90 lambs at day 118 and day 163 and all three were greater than C-AGE lambs. There was no effect of treatment on calcium absorption, serum minerals, hormones, or markers of bone remodeling. We conclude from these data that treatment of growing castrated lambs with an estrogen agonist from birth augments growth, whereas delaying estrogen agonist treatment does not facilitate growth but appears to augment bone mineral accretion. We suggest these observations may have clinical relevance, and deserve consideration when treating children with delays in growth and bone mineral accretion.

Exercise and reproductive dysfunction

OBJECTIVE

To provide an overview of our current understanding of exercise-induced reproductive dysfunction and an approach to its evaluation and management.

DESIGN

A MEDLINE search was performed to review all articles with title words related to menstrual dysfunction, amenorrhea, oligomenorrhea, exercise, and athletic activities from 1966 to 1998. The pathophysiology, proposed mechanisms, clinical manifestations, evaluation, and management of exercise-associated reproductive dysfunction were compiled.

CONCLUSION(S)

Exercise-induced menstrual irregularity appears to be multifactorial in origin and remains a diagnosis of exclusion. The underlying mechanisms are mainly speculative. Clinical manifestations range from luteal phase deficiency to anovulation, amenorrhea, and even delayed menarche. Evaluation should include a thorough history and a complete physical plus pelvic examination. Most cases are reversible with dietary and exercise modifications. Hormonal replacement in cases of a prolonged hypoestrogenic state with evidence of increased bone loss is recommended, although the long-term consequences of prolonged hormonal deficiency are ill-defined.

The female athlete triad

The opportunities for girls and women to play soccer has rapidly grown and gained acceptance in recent years. The benefits of involvement in soccer, both physically and psychologically, are overwhelmingly positive. Despite the benefits, girls and women involved in soccer are also at risk for medical problems as a result of their sports participation. Amenorrhea, disordered eating, and premature osteoporosis are entities known together as The Female Athlete Triad. The triad occurs in all sports and is associated with significant short- and long-term health consequences, and thus remains a concern for all involved in the care of the soccer athlete.

Sex steroid metabolism and menstrual irregularities in the exercising female. A review

This article aims to clarify why, and by which mechanisms, exercise may influence the normal menstrual cycle. Therefore, the vast amount of literature on this subject is reviewed and a critical appraisal of the most widespread hypotheses if offered. The strikingly low body mass which frequently accompanies exercise-related menstrual irregularities (ERMI) has led some authors to develop a hypothesis which postulates that a critical percentage of body fat is essential to trigger normal menstruation. The relevance of any reference to anorexia nervosa to support this view lacks consistency: female athletes differ in many ways from patients with anorexia nervosa, not least in their excellent physical status which is essential to deliver first-class performances. ERMI is not identical to the so-called female athlete triad, a complicated pathology that involves ERMI, premature osteoporosis and disordered eating. ERMI itself does not seem to have any substantial pathological effects as long as attention is paid to preventing osteoporosis or stress fractures which may result from prolonged hypo-estrogenaemia. In the female athlete with ERMI who wishes to conceive, the accompanying subfertility may necessitate a response other than a prompt reduction in training intensity, as this is hardly a first choice for any top athlete. During recent years, a number of prospective studies have greatly contributed to our understanding of the complexity of the mechanisms involved in ERMI. Older hypotheses, such as those considering hyperprolactinaemia as the cornerstone of ERMI, have now been firmly rejected. The present hypotheses emphasise the importance of caloric deficiency and limited energy availability, although they still fail to identify the actual mechanism that causes ERMI. There is, however, evidence that ERMI is produced by a disturbance of the hypothalamic gonadotrophin-releasing hormone oscillator. This disturbance is caused by either an insufficient estrogen or progesterone feedback or by an imbalance of local opioid peptide and catecholamine activities mediated by gamma-aminobutyric acid (GABA), corticotrophin-releasing hormone and insulin-like growth factor-1. More recent experiments have also linked ERMI with changes in steroid metabolism, in particular, an increasing activity of catecholestrogens possibly leading to enhanced intracerebral noradrenaline (norepinephrine) levels that may interfere with normal gonadotrophin release. This article demonstrates that the outcome of the many studies of ERMI is characterised by much controversy and numerous methodological flaws. The importance and complexity of some recent findings necessitate a comprehensive study which links older and newer findings within a critical perspective.

A nutrition study in juvenile elite gymnasts

Twenty-two female teenagers engaged in elite gymnast training and 22 healthy girls of comparable age were studied with regard to nutritional intake. The mean daily intakes of most nutrients in both groups were in accordance with the Swedish Nutritional Recommendations; exceptions were iron and dietary fibre which were too low in both groups. The individual variation was large in both groups and many subjects had an intake below the nutritional recommendations. Both the gymnasts and the reference group had an energy intake significantly below the estimated energy need. The mean daily energy intake was 725 kcal less than the energy need in the gymnast group and 450 kcal less in the reference group. The clinical investigation revealed that several gymnasts had delayed menarche or irregular menstruation as well as less body fat than the reference group. Among the gymnasts, girls with a regular menstrual pattern had more body fat than those who had not started to menstruate. The higher energy expenditure of the gymnasts could partly explain their smaller amounts of body fat, late pubertal development and menstrual patterns.

Stress fractures in ballet dancers

We surveyed 54 female dancers in two professional ballet companies. A total of 27 fractures were reported in 17 dancers. Metatarsal fractures were the most common (63%), followed by fractures of the tibia (22%) and spine (7%). Dancers who danced greater than 5 hours per day were significantly more likely to have a stress fracture than those dancing less than 5 hours per day. Dancers in the stress fracture group also had a significantly longer duration of amenorrhea than those in the group with no stress fractures. No significant difference was found between the dancers who had stress fractures and those who did not with regard to any of the other variables examined. These data suggest that prolonged amenorrheic intervals and heavy training schedules may predispose ballet dancers to stress fractures. Of the 17 dancers with stress fractures, only 1 had neither of these risk factors.

Late adolescent outcome of early onset anorexia nervosa

Forty-three young female patients admitted consecutively to hospital with anorexia nervosa (AN) were re-evaluated in late adolescence an average of 4.3 years following initial presentation. Follow-up interviews were conducted individually by a paediatrician and a psychiatrist on 32 of the original 43 patients (mean age 18.3 years) with outcome assessed by multidimensional physical, menstrual, eating behaviour, psychosocial and global outcome criteria. Physical outcome, as assessed by validated indices of body adiposity, was within the normal range (3-97th percentiles) in 94% of the 32 patients seen at follow-up, although only 56% reported regular cyclical menstrual function. Good physical outcome, however, was not necessarily predictive of successful adjustment in other areas. Eating behaviour was unequivocally normal in only 25% of patients, with a majority still dieting, binging or vomiting with meals, Psychosocial adjustment was satisfactory in the majority of cases but varied widely. Univariate and multivariate statistical analysis identified higher premorbid and admission body mass index (BMI) percentiles, a family history of obesity and shorter duration of illness on admission as significant prognostic indicators of favourable physical outcome. Although girls who develop AN in early adolescence are generally thought to have a favourable long-term prognosis, health professionals need to be aware that these patients form a heterogeneous group and may have considerable ongoing physiologic and psychologic disturbance despite normalization of body mass.

Medical needs of performing arts students

A questionnaire was administered to 71 college students enrolled in dance, drama, and musical theater programs to assess health care problems, injuries, risk-taking behaviors, and sources of care. Many desired help with depression, fatigue, and chronic bone or joint pain, although 37% identified no regular physician. Thirty-nine students reported 87 injuries involving the back, foot, ankle, and knee; 12% sustained injuries at least monthly; and 72% of injuries occurred in class. The incidence of eating disorders appears to be low, as assessed by indirect measures such as body weight, oligomenorrhea, diet pill or laxative use, and scores on a body image index. The 30-day prevalence of tobacco use was 26%; marijuana, 11%; and alcohol, 71%. This survey suggests that performing arts students have important unmet health care needs.