Background for studies on the treatment of male osteoporosis: state of the art.

Male osteoporosis represents an important, although long underestimated, public health problem. Both in men and in women aging is accompanied by continuous bone loss and by an exponential increase in the incidence of osteoporotic fracture, with a female to male incidence ratio of about 2 to 3 to 1 in the elderly for hip and vertebral fractures. Morbidity after osteoporotic fractures appears to be more serious and mortality more common in men than in women. To date, no single treatment has been proved to be effective and safe in published prospective studies. The present report, based on a systematic search of the literature on male osteoporosis, summarises the state of the art on the clinical consequences of male osteoporosis and its risk factors, in relation to the present state of knowledge about female osteoporosis. This constitutes the background for the design of rational clinical development strategies for therapeutic interventions in male osteoporosis. From this review of the literature it is apparent that notwithstanding the existing sex differences in pathophysiology of osteoporosis and the difference in age-specific incidence of osteoporotic fractures, there are also important similarities between osteoporosis in women and men. The higher incidence of fracture in women than in men results from quantitative differences in risk factors rather than from different risk factors. Even though there are sex differences in bone geometry, incidence of fracture seems to be similar in men and women for a same absolute areal bone mineral density. However, the lack of data on the changes in fracture rates in men resulting from pharmacological intervention, leading to changes in bone mineral density or bone turnover, remains the main limitation for extrapolation of established treatment outcomes from women to men.

Vertebral morphometric X-ray absorptiometry (MXA): relationship with bone mineral density in perimenopausal women.

OBJECTIVE: To evaluate the relationship between vertebral morphometry and vertebral bone mineral density (BMD) in a population of perimenopausal women. METHOD: We studied 120 healthy women (mean age (S.D.) 53.4 (8.3) years) referred for baseline bone densitometry around the menopause. Morphometric X-ray absorptiometry (MXA) was performed using a Hologic QDR 4500 A apparatus and assessed the anterior, mid and posterior heights of the third lumbar vertebra (L3). The anterior to posterior height ratio (AH/PH index) and the mid to posterior height ratio (MH/PH index) were calculated. Simultaneously, BMD of L3 was measured as antero-posterior dual energy X-ray BMD (AP-BMD DXA) and as lateral DXA BMD (L-BMD DXA). Subsequently, BMD of L3 was measured using single energy quantitative computed tomography, with a Siemens Somatom device (BMD QCT). RESULTS: The AH/PH index ranged from 0.840 to 1.150, with a mean of 0.995, the MH/PH index 0.880-0.980, with a mean of 0.937. The AH/PH index showed significant correlation with either L-BMD DXA (r = 0.54, P < 0.001) or BMD-QCT (r = 0.50, P < 0.001) but not with AP-BMD DXA (r = 0.05). Using an AH/PH index threshold of 0.97 we categorized the subjects into 42 women (group A) with an AH/PH index < 0.97 and 78 women (group B) with an AH/PH index greater than or equal to 0.97. BMD values were found to be lower in group A than in group B. The difference was not significant with AP-BMD DXA (1011.5 (155.7)) versus 988.5 (193.5) mg/cm2, P = 0.47) but reached high significance (P < 0.0001) with L-BMD DXA (797.2 (166.8) versus 462.9 (131.1) mg/cm2) and with BMD QCT (135.5 (24.8) versus 83.6 (18.3) mg/cm3). CONCLUSIONS: These results suggest that the AH/PH index of L3, assessed using MXA, shows some degree of correlation with BMD in perimenopausal women.

Circulating immune complexes in old people and in diabetics: correlation with autoantibodies.

Circulating immune complexes (CIC) were detected by a solid-phase radioassay in 34% of fifty-three insulin-dependent diabetics (IDD) as compared to 18% of forty-five non-insulin-dependent diabetics (NIDD) and 14% of 173 control subjects. In control subjects, the prevalence of CIC increased with age and was higher in males than in females. In IDD, immune complexes were found with the highest frequency before the age of 30 and after 50. There was no significant difference between the incidence of CIC in old IDD and their age-matched controls. The same sera were also tested for the presence of the following autoantibodies; nuclear , thyroid, gastric, smooth and striated muscle; mitochondria, sub-maxillary and adrenal gland and liver-kidney microsome. Sera containing at least one antibody were found in 16.4% of controls, 55.3% of IDD and 40% of NIDD. The prevalence of autoantibodies increased with age in controls but not in IDD. Islet cell antibodies were present in 28.5% of IDD and 2.9% of control subjects; they were more frequent in young patients. CIC and autoantibodies were statistically associated both in controls and IDD; in the patients, CIC were associated not only with islet cell antibodies but also with other autoantibodies. The possible relation between autoimmunity, degenerative vascular diseases and CIC is discussed.