Standards and guidelines for performing central dual X-ray densitometry from the Canadian panel of International Society for Clinical Densitometry

The Female Athlete Triad

The female athlete triad (Triad) refers to the interrelationships among energy availability, menstrual function, and bone mineral density, which may have clinical manifestations including eating disorders, functional hypothalamic amenorrhea, and osteoporosis. With proper nutrition, these same relationships promote robust health. Athletes are distributed along a spectrum between health and disease, and those at the pathological end may not exhibit all these clinical conditions simultaneously. Energy availability is defined as dietary energy intake minus exercise energy expenditure. Low energy availability appears to be the factor that impairs reproductive and skeletal health in the Triad, and it may be inadvertent, intentional, or psychopathological. Most effects appear to occur below an energy availability of 30 kcal.kg(-1) of fat-free mass per day. Restrictive eating behaviors practiced by girls and women in sports or physical activities that emphasize leanness are of special concern. For prevention and early intervention, education of athletes, parents, coaches, trainers, judges, and administrators is a priority. Athletes should be assessed for the Triad at the preparticipation physical and/or annual health screening exam, and whenever an athlete presents with any of the Triad's clinical conditions. Sport administrators should also consider rule changes to discourage unhealthy weight loss practices. A multidisciplinary treatment team should include a physician or other health-care professional, a registered dietitian, and, for athletes with eating disorders, a mental health practitioner. Additional valuable team members may include a certified athletic trainer, an exercise physiologist, and the athlete's coach, parents and other family members. The first aim of treatment for any Triad component is to increase energy availability by increasing energy intake and/or reducing exercise energy expenditure. Nutrition counseling and monitoring are sufficient interventions for many athletes, but eating disorders warrant psychotherapy. Athletes with eating disorders should be required to meet established criteria to continue exercising, and their training and competition may need to be modified. No pharmacological agent adequately restores bone loss or corrects metabolic abnormalities that impair health and performance in athletes with functional hypothalamic amenorrhea.

Absorptiometrie

This article is an introduction to dual X-ray absorptiometry (DXA), the most widely used method today for diagnosis of osteoporosis. DXA can be used to assess projective bone mineral density at the lumbar spine, the proximal hip, and the whole body as well as the skeletal periphery at the forearm, the hand, and the heel. The prominent area of application of DXA is the diagnosis and monitoring of osteoporosis and its treatment. Because of its high accuracy, precision, and ability to predict osteoporotic fracture as well as its relatively low cost, DXA has prevailed over alternative methods. This article discusses the underlying X-ray physics and technological aspects, acquisition protocols, quality characteristics, and sources of error and their relevance. It also describes the various skeletal regions accessible to measurement, details on precision, nominal results, usability to predict fracture risk, and results of influential clinical trials.

Effect of diagnostic radioisotopes and radiographic contrast media on measurements of lumbar spine bone mineral density and body composition by dual-energy x-ray absorptiometry

Since there is almost no information on whether the concomitant use of diagnostic radioisotopes and radiographic contrast media interferes with dual-energy X-ray absorptiometry (DXA), we investigated these potentially confounding effects. At routine scheduled radiographic follow-up, 40 patients previously treated for malignant lymphomas or solid tumors in Hamilton and Ottawa, Canada were evaluated, 10 in each of the following 4 categories of diagnostic procedure: (1) computed tomography (CT) with intravenous, iodine-based contrast (+/-oral contrast), (2) magnetic resonance imaging (MRI) with gadolinium-based contrast, (3) gallium scan (GS), and (4) technetium bone scan (TBS). Whole body bone mineral content (WB-BMC) and lumbar spine bone mineral density (LS-BMD), total fat mass (TFM), and lean body mass (LBM) were measured by DXA immediately before and after the other radiological studies (on the same day) and then 7 days later. No statistically significant differences were found among WB-BMC, LS-BMD, TFM, and LBM Z-scores immediately before and after MRI, GS, TBS, and 7 days later. The DXA measurements performed immediately before and after CT showed statistically significant differences in WB-BMC (100% vs 124.5%, p<0.001), TFM (100% vs 75.4%, p<0.001), and LBM (100% vs 110%, p<0.001), resulting from the CT contrast agents compromising the precision of the DXA. The DXA results after 7 days were not statistically different from those at baseline. Dual-energy X-ray absorptiometry can be performed in association with other radiological techniques, with the exception of CT conducted with contrast within 1 week. This study provides information that applies not only to patients with cancer but to the general population undergoing diagnostic procedures.

Review of guidelines for testing and treatment of osteoporosis

Our knowledge on diagnosis and treatment of osteoporosis has steadily increased during the past decade. Several guidelines on treatment of osteoporosis are now available. Although there is heterogeneity in these recommendations, there are several common suggestions found. Case finding is advocated in all; however, it is generally acknowledged that further research is necessary to evaluate the effectiveness of case-finding strategies. Dual-energy x-ray absorptiometry is considered the gold standard for diagnosis of osteoporosis. The use of the T score is different for diagnostic purposes and for treatment decisions. Other bone measurement techniques are proposed as risk evaluation or as alternatives when dual-energy x-ray absorptiometry is not available. Bone markers are not considered for evaluation in clinical practice. Treatment options include general measures on lifestyle, fall prevention, calcium and vitamin D supplements, hormone therapy, raloxifene, and bisphosphonates. Consistent recommendations are found mostly for raloxifene in the prevention of vertebral fractures and for alendronate and risedronate in the prevention of vertebral and nonvertebral fractures, including hip fractures.