Reduced calcitonin reserve in young hypogonadic osteoporotic men

Osteoporosis, schizophrenia and antipsychotics: the need for a comprehensive multifactorial evaluation

Osteoporosis is recognised as a major public health issue leading to bone fractures, pain and disability. Awareness of an elevated risk of osteoporosis in individuals with schizophrenia is increasing. An accelerated decrease in bone mineral density (BMD) in patients with schizophrenia may be disease related or drug induced. A drug-induced decrease in BMD has been attributed mostly to hyperprolactinaemia and its consequences. However, as demonstrated in this review, decreased BMD and osteoporosis are multifactorial processes, and abnormal bone structure and functions are not limited to BMD. Multiple dynamic processes may lead to impairment of bone homeostasis and eventually to bone abnormalities. Many of these processes may be abnormal in treated as well as untreated patients with schizophrenia. Despite many publications, the epidemiology of abnormal bone structure, mineralisation and dynamics in patients with schizophrenia is still not fully determined. Comprehensive studies of bone dynamics in individuals with first-episode schizophrenia, as well as in patients treated with various current medications, are needed in order to characterise the problem(s) and then to develop relevant treatment and prevention strategies.

Therapeutic role of androgens in the treatment of osteoporosis in men

There has been much recent interest in the relationship between androgens and bone mineralization in men. Increases in serum androgens during puberty allow for skeletal maturation and the attainment of peak bone mass, and the persistence of normal testosterone secretion during adulthood is important for the maintenance of bone density. Testosterone deficiency is associated with heightened bone turnover and is a major risk factor for osteoporosis in men. The administration of testosterone to androgen-deficient men leads to an increase in bone mass, particularly in the trabecular bone compartment, and a reduction in levels of surrogate markers of bone turnover, suggesting that androgens have a dampening effect on bone remodelling. In addition, the administration of androgens to eugonadal men with idiopathic osteoporosis, with resulting supraphysiological testosterone concentrations, may lead to increases in bone mineral density. The risk of osteopenia due to androgen deficiency and the benefits of testosterone substitution therapy or supraphysiological administration on bone will be reviewed.

Decreased bone mineral density in medicated psychiatric patients

Osteoporosis is a common problem in postmenopausal women. It has been linked to estrogen deficiency, other neuroendocrine processes such as hypercortisolemia and male hypogonadism, nutritional deficiencies, and other mechanisms. Some of these changes have been also reported in male and female patients with mental disorders, especially those receiving psychotropic medications. Therefore, bone mineral density was measured by dual-photon absorptiometry in the lumbar spine and in the femoral neck of 33 female and 35 male consenting psychiatric inpatients admitted consecutively. Patients were diagnosed as having major depressive disorder (N = 21), schizophrenia (N = 33), schizoaffective disorder (N = 7), mania (N = 2), and adjustment disorder (N = 5). Plasma levels of prolactin, estrogen, cortisol, and testosterone were also measured in a subgroup of these patients. It is reported that female patients, but especially male patients, had a highly significant decrease in bone mineral density when compared with age- and sex-matched normal data. It is suggested that psychiatric patients treated with antidepressants or neuroleptics might have decreased bone mineral density than is normal for their age and sex, and may be at an increased risk for fractures. These results may be related to low levels of gonadal hormones, especially in male subjects. Data should be confirmed with a larger number of patients with and without medications to distinguish between diagnosis-related and treatment-related effects.

Androgens and bone

Androgen receptors are present at low densities in osteoblasts. Androgens are also metabolized in bone. (Non)aromatizable androgens probably induce proliferation of osteoblasts and differentiation. A direct effect of androgens on osteoclasts has not been demonstrated. Androgens may however inhibit bone resorption indirectly, by an inhibition of the recruitment of osteoclast precursors from bone marrow, by decreased secretion of interleukin-6 and/or prostaglandin E2, and/or by an increased sensitivity of marrow cells or osteoblasts for bone resorption stimulating factors such as PTH. The recent demonstration of androgen receptors in bone marrow stromal and osteoclast-like cells opens new perspectives in this respect. During puberty, androgens stimulate bone growth both directly and indirectly. Observations in androgen-resistant animals clearly demonstrated that the sexual dimorphism of bone depends on the presence of a functional androgen receptor. Optimal peak bone mass seems related to an appropriately timed androgen secretion. In adults, androgens are also involved in maintenance of the male skeleton. Androgen replacement may prevent further bone loss in hypogonadal men, however, it seems difficult to fully correct bone mass in these men.

Aetiologies of male osteoporosis: identification procedures

Secondary causes and risk factors assume far greater importance in male osteoporosis than in female osteoporosis. The principal problem in dealing with male osteoporosis, above all in young men, is the difficulty to find a curable aetiology. Six groups of aetiologies can be drawn up: toxic causes or causes due to a change in the general state of health, drug-induced causes, renal causes, hormonal causes, exceptional causes and lastly the idiopathic form. The minimum number of investigations necessary so as to be quite sure not to overlook these various aetiologies is proposed.

Physiological and pharmacological regulation of biological calcification

Biological calcification is a highly regulated process which occurs in diverse species of microorganisms, plants, and animals. Calcification provides tissues with structural rigidity to function in support and protection, supplies the organism with a reservoir for physiologically important ions, and also serves in a variety of specialized functions. In the vertebrate skeleton, hydroxyapatite crystals are laid down on a backbone of type I collagen, with the process being controlled by a wide range of noncollagenous proteins present in the local surroundings. In bone, cells of the osteoblast lineage are responsible for the synthesis of the bone matrix and many of these regulatory proteins. Osteoclasts, on the other hand, are continually resorbing bone to both produce changes in bone shape and maintain skeletal integrity, and to establish the ionic environment needed by the organism. The proliferation, differentiation, and activity of these cells is regulated by a number of growth factors and hormones. While much has already been discovered over the past few years about the involvement of various regulators in the process of mineralization, the identification and functional characterization of these factors remains an area of intense investigation. As with any complex, biological system that is in a finely tuned equilibrium under normal conditions, problems can occur. An imbalance in the processes of formation and resorption can lead to calcification disorders, and the resultant diseases of the skeletal system have a major impact on human health. A number of pharmacological agents have been, and are being, investigated for their therapeutic potential to correct these defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Male hypogonadism presenting as back pain secondary to osteoporosis

A vertebral fracture occurred in a 51-year-old man with previously undiagnosed osteoporosis. The underlying cause of the osteoporosis was primary hypogonadism. Back pain was the presenting symptom in this case of primary hypogonadism.

Absorption of intranasal salmon calcitonin in normal subjects and hypogonadic men

The absorption kinetics of intranasal salmon calcitonin were assessed in 4 normal subjects and 9 patients with Klinefelter's syndrome. After administration, absorption occurred within 5 minutes. There was a highly significant correlation between the amount administered and the amount absorbed (r = -0.83, P less than 0.0005).