Article Abstract:
Often, technical methods introduced for research purposes start being adopted for general clinical practice. This transition from research technique to clinical procedure is sometimes awkward. This is the case with bone densitometry. Bone densitometry uses gamma rays of X-rays to estimate the density of bone mineral, and this method has been instrumental in establishing reduced bone mass as a risk factor for fractures. Reduced bone mass is a common contributor to fractures in the elderly, especially among menopausal white women. However, it is far from clear that physicians treating such patients should begin relying heavily upon bone densitometry for diagnostic purposes. The Scientific Advisory Board of the National Osteoporosis Foundation has prepared a set of guidelines indicating the four situations in which the use of bone densitometry is justified by the scientific evidence. Menopausal women are at high risk for osteoporosis, but screening all menopausal women with bone densitometry is not recommended. Women should be counselled on the risks and benefits of estrogen replacement therapy; not all will choose replacement therapy. For women who express concern about osteoporosis but will take estrogen only if the risk is high, bone densitometry may prove useful in establishing the risk for a particular patient. Bone densitometry is also recommended for patients with bone abnormalities. Often, such patients are treated on the basis of radiographs, which are poor estimators of bone density. Without densitometry, misclassified patients will be unnecessarily treated. Bone densitometry is also appropriate for monitoring patients on long-term glucocorticoid therapy, since chronic administration of these drugs may result in a loss of bone mass. Bone densitometry may also be important for the evaluation of primary hyperparathyroidism. Hyperparathyroidism is often asymptomatic, and is discovered only on the basis of excess calcium found in a blood test. Bone densitometry can identify patients with asymptomatic hyperparathyroidism who are, in fact, at high risk for fracture and for whom medical intervention might be most appropriate. Of course, as more experience with bone densitometry accumulates, the recommendations for its use may change. (Consumer Summary produced by Reliance Medical Information, Inc.)
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
The rate of bone growth is greatest between infancy and puberty. During this time the rate of bone growth increases seven-fold. Calcium is required for healthy bone development during childhood and adolescence. Since the body does not make calcium, the only available source is the diet. Dairy products provide a major source of dietary calcium. The body requires the most calcium during childhood and adolescence, when bone mass is increasing. This is an important period of bone development because the formation of strong bones is necessary to prevent bone fractures at a later time. The amount of calcium present in the body depends on the amount consumed from the diet, the amount that is absorbed in the intestines, and the amount that is lost from the body in urine, sweat and feces. In order to have enough calcium for normal bone growth and development, the amount of calcium absorbed from diet has to be greater than the amount of calcium lost in urine, sweat and feces, combined with the amount utilized for bone development. Previous studies have shown that the amount of calcium absorbed from the diet is similar in adolescents and adults, even though adolescents require more calcium for bone growth. Based on data showing the rates of calcium absorption and loss from the body, it has been estimated that 1,000 milligrams (mg) of calcium per day for males and 850 mg for females is not enough for optimal bone development during childhood. It is likely that children who consume even less than these amounts do not achieve optimal bone mass. (Consumer Summary produced by Reliance Medical Information, Inc.)
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
Calcium supplementation may increase bone density in prepubertal children whose dietary calcium is close to the recommended dietary allowance. Of 45 pairs of identical twins between six and 14 years old, one twin received 1,000 milligrams (mg) of calcium citrate malate per day, and the other received a placebo, an inactive substance, over a three-year period. The average daily intake of calcium was 1,612 mg for twins given a calcium supplement, and 908 mg for those given a placebo. Among 22 pairs of twins who had not reached puberty, the twin given a supplement had a significantly larger increase in bone mineral density in the lower and distal radius (lower arm) and lumbar spine, compared with the twin given a placebo. Among 23 pairs of twins who entered puberty during the study or who were post-pubertal, the twin given a supplement did not have higher bone mineral density than the twin given a placebo.
User Contributions:
Comment about this article or add new information about this topic: