Risk factors for spinal osteoporosis in men

Smoking and hip fracture; a study of 3617 cases

We analysed the characteristics and outcome for 467 hip fracture patients, who reported that they were currently smoking at the time of admission, against 3150 non-smoking hip fracture patients. Those patients who smoked were younger (72 years versus 81 years mean age), more likely to be male (35.3% versus 19.5%), more mobile and less likely to be living in institutional care (7.5% versus 25.0%). Preoperative outcomes and complication rates were similar, despite the smokers' relative youth. Mortality at 30 days was similar for the two groups (6.2% versus 7.6%), but lower for the smokers at one year (22.7% versus 27.6%). However, with adjustment for the younger age and sex of these patients, this difference in mortality was not statistically significant. These findings suggest that smoking results in hip fracture occurring at a younger age. Despite this, the outcome for smokers was similar to that for the average hip fracture patient.

Estrogen and androgen play distinct roles in bone turnover in male mice before and after reaching sexual maturity

Aromatase is the sole enzyme which converts androgen into estrogen. We have reported that aromatase-knockout (ArKO) mice showed bone loss by increased bone resorption not only in female but also in male mice, suggesting essential roles of estrogen in bone metabolism in both sexes. However, loss of testicular androgen by orchidectomy (ORX) could induce bone loss in male mice. To clarify the relationship between estrogen and androgen in bone metabolism in male mice, 7-week-old ArKO mice were orchidectomized (ORX) to induce a double deficiency of estrogen and androgen. Bone loss in ORX/ArKO mice was more severe than that in ORX/wild-type and sham/ArKO mice because of advanced bone resorption, indicating that androgen and estrogen individually regulate bone mass by suppressing bone resorption in male mice after reaching sexual maturity. Cortical bone formation was elevated in sham/ArKO mice, but ORX did not influence cortical bone formation in the adult male mice. To examine the influence of androgen deficiency in weaning stage, 3-week-old wild-type mice were orchidectomized. Four weeks after operation, periosteal bone formation in the femur was markedly reduced in ORX mice. Since cortical bone in the same age of ArKO mice was normal, testicular androgen is indispensable for cortical bone formation especially at puberty in male mice. Therefore, estrogen and androgen may play distinct roles in bone turnover of male mice before and after reaching sexual maturity.

Estrogen and testosterone use different cellular pathways to inhibit osteoclastogenesis and bone resorption

Using human peripheral blood CD14(+) osteoclast precursors, we show that testosterone directly inhibits osteoclast formation and bone resorption at physiological concentrations. Instead, estrogen has no direct effects, whereas its action seems to be mediated through osteoblasts by producing osteoprotegerin. Both estrogen and testosterone acts through their cognate receptors.

INTRODUCTION

Estrogen (E2) deficiency is associated with both the development of postmenopausal and senile form of osteoporosis in elderly women. Testosterone (Te) deficiency, on the other hand, may cause osteoporosis in men. In both sexes, osteoporosis is associated with disturbed bone turnover, including increased bone resorption caused by enhanced osteoclast formation and increased osteoclast activity. However, the mechanisms by which E2 or Te act on bone are not fully understood, and one of the central questions is whether these hormones act directly on osteoclast precursors or whether their action is mediated through osteoblastic cells.

MATERIALS AND METHODS

We cultured human peripheral blood CD14(+) osteoclast precursors in the presence of RANKL, macrophage-colony stimulating factor (M-CSF), TNF-alpha, and dexamethasone to induce them to differentiate into osteoclasts. To study the possible osteoblast-mediated effects, osteoclast precursors were also co-cultured either with human MG-63 or SaOS-2 osteoblast-derived osteosarcoma cells. These cultures were treated with 10(-8)-10(-12) M of E2 or Te for 7 days.

RESULTS

E2 did not have any direct effect on osteoclast formation, whereas testosterone inhibited osteoclast formation and bone resorption in a dose-dependent manner. In co-cultures, where MG-63 or SaOS-2 cells were present, E2 and Te inhibited osteoclast formation in a dose-dependent manner. At the same time, E2 and Te treatment in MG-63 or SaOS-2 cell-containing cultures stimulated significantly the formation of osteoprotegerin (OPG) compared with untreated cultures measured by ELISA assay from the culture medium. The effects of E2 and Te on osteoclast formation and bone resorption were completely antagonized by an E2 receptor (ER) antagonist, ICI 182,780, and an androgen receptor (AR) antagonist, flutamide, suggesting ER- and AR-mediated mechanisms, respectively, in these cultures.

CONCLUSIONS

Te is likely to have direct and indirect inhibitory effects on human osteoclast formation and bone resorption, whereas the effect of E2 on osteoclast precursors and osteoclasts seems to be mediated by osteoblastic cells. Inhibitory effect of E2 is associated with the stimulated secretion of OPG by osteoblast-derived osteosarcoma cells. Mechanism of action of E2 and Te is mediated by ER and AR, respectively.

Obesity in older adults: technical review and position statement of the American Society for Nutrition and NAASO, The Obesity Society

Obesity causes serious medical complications and impairs quality of life. Moreover, in older persons, obesity can exacerbate the age-related decline in physical function and lead to frailty. However, appropriate treatment for obesity in older persons is controversial because of the reduction in relative health risks associated with increasing body mass index and the concern that weight loss could have potential harmful effects in the older population. This joint position statement from the American Society for Nutrition and the NAASO, The Obesity Society reviews the clinical issues related to obesity in older persons and provides health professionals with appropriate weight-management guidelines for obese older patients. The current data show that weight-loss therapy improves physical function, quality of life, and the medical complications associated with obesity in older persons. Therefore, weight-loss therapy that minimizes muscle and bone losses is recommended for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss.

[Prolactinomas and bone mineral density in men]

Throughout the years evidence has been accumulated on the morbidity of hyperprolactinemia, particularly in terms of bone mineral density decrease. This complication of hyperprolactinemia affects both women and men. In this paper, we analyze aspects related to bone loss in men with hyperprolactinemia due to prolactinomas: prevalence, clinical relevance, physiopathology, diagnosis and the consequences of the treatment of hyperprolactinemia and hypogonadism on bone mineral density.

The relationship between serum resistin, leptin, adiponectin, ghrelin levels and bone mineral density in middle-aged men

OBJECTIVE

Body weight is a significant predictor of bone mass. Hormonal factors such as sex hormones, insulin, leptin and adiponectin are thought to play a role in the mechanisms controlling the association of body weight and fat mass with bone mass. However, contradictory results have been reported for the association between serum adipocytokines and bone mineral density (BMD). We therefore examined whether the serum adipocytokine and ghrelin levels, markers of fat metabolism, are associated with BMD in male adults.

PATIENTS AND MEASUREMENTS

For 80 male adults (average age 54.5 +/- 6.4 years; average body mass index (BMI) 24.4 +/- 2.5 kg/m2), the correlations between serum resistin, leptin, adiponectin and ghrelin levels with BMD were investigated.

RESULTS

Among the adipocytokines, serum resistin levels were negatively correlated with lumbar spine BMD (r = -0.237, P = 0.05). After adjustment was made for age and BMI, log-transformed serum leptin showed a significant negative correlation with lumbar spine BMD, which was not seen on bivariate analysis (r = -0.237, P = 0.039). Femoral neck BMD was marginally associated only with serum adiponectin levels (r = -0.226, P = 0.062). In multiple regression analyses, among the adipokines, only resistin was a significant determinant of lumbar spine BMD, although the variance was small (R2 = 0.256). Serum ghrelin levels were not correlated with the BMD of either body site.

CONCLUSIONS

Serum resistin level showed a significant negative correlation with lumbar spine BMD, although the variance was small. Further studies are needed to elucidate the role of adipocytokines in bone metabolism.

Osteoporosis

Bone is a complex organ which contains an organic matrix which serves as scaffolding, includes mineral as calcium distributed in a pattern providing structure and serves as an ion reservoir for the body. Throughout life it dynamically changes in response to changes in activity, body mass, and weight bearing. It is important to define patients at risk for bone loss, since accrued bone loss leading to osteoporosis in the older population of both men and women is unacceptable. There are many different therapies including biphosphonates which can decrease loss of bone and decrease fracture risk in patients who already have had sustained a fracture. Newer therapies such as parathyroid hormone may improve the fracture risk even more than biphosphonates over a shorter period of time.

Bone mineral density in patients with prostate cancer without bone metastases treated with intermittent androgen suppression

OBJECTIVES

To evaluate prospectively the effects of intermittent androgen suppression (AS) on bone mineral density (BMD) in patients with prostate cancer without bone metastases.

METHODS

A total of 19 hormone-naive patients with Stage D0 disease were treated with a luteinizing hormone-releasing hormone analog and an antiandrogen for 9 months, after which AS was discontinued. When the prostate-specific antigen level reached a predetermined threshold, AS was restarted. BMD was measured at baseline, after 9 months of AS, and at the end of the first off-treatment period or at 1 year, whichever occurred first.

RESULTS

Of the 19 patients, 17 had normal BMD at baseline; 2 patients with osteopenia at baseline were excluded from the analysis. All but 1 of the 17 patients with normal baseline BMD experienced a decline in BMD in the lumbar spine or hip, or both, during AS. After 9 months, the mean BMD in these patients had decreased by 4.5% at the lumbar spine (P = 0.0007) and by 2.5% at the hip (P = 0.00013). After a median off-treatment period of 7.9 months, the mean change in BMD of the lumbar spine and hip relative to the post-AS values was 1.5% (P = 0.06) and -0.01% (P = 0.09), respectively.

CONCLUSIONS

The observed loss of BMD during 9 months of AS is significantly greater than the expected 0.5% to 1% annual loss. Interruption of AS attenuated the rate of bone loss, although full recovery to the baseline BMD was not achieved in all patients. These data suggest that men treated with AS should undergo baseline and periodic follow-up BMD assessments, because significant bone loss can occur during the first 9 months of AS.

Alcohol intake as a risk factor for fracture

High intakes of alcohol have adverse effects on skeletal health, but evidence for the effects of moderate consumption are less secure. The aim of this study was to quantify this risk on an international basis and explore the relationship of this risk with age, sex, and bone mineral density (BMD). We studied 5,939 men and 11,032 women from three prospectively studied cohorts comprising CaMos, DOES, and the Rotterdam Study. Cohorts were followed for a total of 75,433 person-years. The effect of reported alcohol intake on the risk of any fracture, any osteoporotic fracture, and hip fracture alone was examined using a Poisson model for each sex from each cohort. Covariates examined included age and BMD. The results of the different studies were merged using weighted beta-coefficients. Alcohol intake was associated with a significant increase in osteoporotic and hip fracture risk, but the effect was nonlinear. No significant increase in risk was observed at intakes of 2 units or less daily. Above this threshold, alcohol intake was associated with an increased risk of any fracture (risk ratio [RR] = 1.23; 95% CI, 1.06-1.43), any osteoporotic fracture (RR = 1.38; 95% CI, 1.16-1.65), or hip fracture (RR = 1.68; 95% CI, 1.19-2.36). There was no significant interaction with age, BMD, or time since baseline assessment. Risk ratios were moderately but not significantly higher in men than in women, and there was no evidence for a different threshold for effect by gender. We conclude that reported intake of alcohol confers a risk of some importance beyond that explained by BMD. The validation of this risk factor on an international basis permits its use in case-finding strategies.

Adequacy of androgen replacement influences bone density response to testosterone in androgen-deficient men

OBJECTIVE

Androgen deficiency (AD) leads to bone loss and contributes to osteoporotic fractures in men. Although low bone mineral density (BMD) in AD men is improved by testosterone replacement, the responses vary between individuals but the determinants of this variability are not well defined.

DESIGN AND METHODS

Retrospective review of dual energy X-ray absorptiometry (DEXA) of the lumbar spine and proximal femur in men with established AD requiring regular androgen replacement therapy (ART). After a DEXA scan all men were treated with testosterone implants (800 mg, approximately 6 month intervals). Patients were classified as having a congenital, childhood, or post-pubertal onset, as well as according to the adequacy of treatment prior to their first DEXA scan as untreated, partially treated or well treated.

RESULTS

Men with AD requiring regular ART (n = 169, aged 46.3+/-1.1 years, range 22-84 years) underwent a DEXA scan prior to being treated with testosterone implants (800 mg, approximately 6 month intervals). In cross-sectional analysis at the time of the first DEXA scan untreated men (n = 24) had significantly reduced age-adjusted BMD at all four sites (L1-L4, femoral neck, Ward's triangle and trochanter). Well-treated men (n = 77) had significantly better age-adjusted BMD at all four sites compared with those who were partially treated (n = 66) or untreated (n = 24) with their age-adjusted BMD being normalized. In a longitudinal assessment of men (n = 60) who had two or more serial DEXA scans, at the second DEXA scan after a median of 3 years, men who were previously partially treated (n = 19) or untreated (n = 11) had proportionately greater improvements in BMD, significantly for Ward's triangle (P = 0.025) and the trochanter (P = 0.044) compared with men (n = 30) previously well treated.

CONCLUSIONS

The present study demonstrates a positive relationship between adequacy of testosterone replacement and BMD in men with overt organic AD. Additionally, the BMD of well-treated AD men approximates that of age-matched non-AD controls. The greatest BMD gains are made by those who have been either untreated or partially treated, and optimal treatment over time (median 3 years) normalizes BMD to the level expected for healthy men of the same age.

Antipsychotic-induced hyperprolactinaemia: mechanisms, clinical features and management

Hyperprolactinaemia is an important but neglected adverse effect of antipsychotic medication. It occurs frequently with conventional antipsychotics and some atypical antipsychotics (risperidone and amisulpride) but is rare with other atypical antipsychotics (aripiprazole, clozapine, olanzapine, quetiapine, ziprasidone). For this reason the terms 'prolactin-sparing' and 'prolactin-raising' are more useful than 'atypical' and 'conventional' when considering the effect of antipsychotic drugs on serum prolactin. During antipsychotic treatment prolactin levels can rise 10-fold or more above pretreatment values. In a recent study approximately 60% of women and 40% of men treated with a prolactin-raising antipsychotic had a prolactin level above the upper limit of the normal range. The distinction between asymptomatic and symptomatic hyperprolactinaemia is important but is often not made in the literature. Some symptoms of hyperprolactinaemia result from a direct effect of prolactin on target tissues but others result from hypogonadism caused by prolactin disrupting the normal functioning of the hypothalamic-pituitary-gonadal axis. Symptoms of hyperprolactinaemia include gynaecomastia, galactorrhoea, sexual dysfunction, infertility, oligomenorrhoea and amenorrhoea. These symptoms are little researched in psychiatric patients. Existing data suggest that they are common but that clinicians underestimate their prevalence. For example, well conducted studies of women treated with conventional antipsychotics have reported prevalence rates of approximately 45% for oligomenorrhoea/amenorrhoea and 19% for galactorrhoea. An illness-related under-function of the hypothalamic-pituitary-gonadal axis in female patients with schizophrenia may also contribute to menstrual irregularities. Long-term consequences of antipsychotic-related hypogonadism require further research but are likely and include premature bone loss in men and women. There are conflicting data on whether hyperprolactinaemia is associated with an increased risk of breast cancer in women. In patients prescribed antipsychotics who have biochemically confirmed hyperprolactinaemia it is important to exclude other causes of prolactin elevation, in particular tumours in the hypothalamic-pituitary area. If a patient has been amenorrhoeic for 1 year or more, investigations should include bone mineral density measurements. Management should be tailored to the individual patient. Options include reducing the dose of the antipsychotic, switching to a prolactin-sparing agent, prescribing a dopamine receptor agonist and prescribing estrogen replacement in hypoestrogenic female patients. The efficacy and risks of the last two treatment options have not been systematically examined. Antipsychotic-induced hyperprolactinaemia should become a focus of interest in the drug treatment of psychiatric patients, particularly given the recent introduction of prolactin-sparing antipsychotics. Appropriate investigations and effective management should reduce the burden of adverse effects and prevent long-term consequences.

Adipogenic effect of alcohol on human bone marrow-derived mesenchymal stem cells

BACKGROUND

In addition to a decrease in bone mass in alcoholics their osteopenic skeletons show an increase in bone marrow adiposity. Human bone marrow mesenchymal stem cells (hMSC) in vivo differentiate into several phenotypes including osteogenic and adipogenic cells, both of which remain as resident populations of bone marrow. In vitro, the lineage commitment and differentiation of hMSC toward the adipogenic pathway can be promoted by alcohol.

METHODS

Human male and female mesenchymal stem cells from joint replacement surgery were cultured. Cells were grouped as: 1) Control (no additions to the culture medium), 2) EtOH (50 mm alcohol added to the culture medium), 3) OS (osteogenic inducers added to the culture medium), and 4) OS + EtOH (osteogenic inducers and 50 mm alcohol added to the culture medium). Cultures stained with Nile Red confirmed the development of differentiated adipocytes. Population analysis was performed using fluorescence-activated cell sorting. Gene expression of early, middle, late, and terminal differentiation stage markers (PPAR)gamma2, lipoprotein lipase, adipsin, leptin, and adipocyte P2 (aP2)] was studied by Northern hybridization, and protein synthesis of aP2 was determined by Western analysis.

RESULTS

Nile red staining confirmed increased adipocyte development 10 days after the onset of treatment with 50 mm alcohol and osteogenic induction. By day 21 the number of adipocytes increased to 13.6% of the total population. Alcohol up-regulated the gene expression of PPARgamma2 whereas no up-regulation was observed for the other genes. Protein production of aP2 was significantly increased in hMSC cells by culture in the presence of alcohol.

CONCLUSIONS

The data suggest that alcohol's adipogenic effect on cultured hMSC is through up-regulation of PPARgamma2 at the point of lineage commitment as well as through enhancement of lipid transport and storage through increased aP2 synthesis. The alcohol-induced expression and synthesis changes account for the increased Nile red staining of cultured hMSC.

Epidemiology of male osteoporosis and prostate cancer

PURPOSE OF REVIEW

In this review, we will discuss the increasing importance of male osteoporosis, risk factors for the disease, its relationship to prostate cancer and androgen deprivation treatment modalities for prostate cancer, and recent trials describing therapeutic intervention.

RECENT FINDINGS

Osteoporosis has become an increasingly important problem in men's health, accounting for significant morbidity in the aging United States male population. Hypogonadism is a major risk factor. Patients treated with androgen deprivation therapy for advanced or metastatic prostate cancer are at risk for both hypogonadism and osteoporosis. These patients may suffer additional morbidity from decreased bone mineralization, such as skeletal fracture. There is a direct association with fracture and decreased quality of life and increased mortality.

SUMMARY

Male osteoporosis is an important clinical entity, particularly in aging men and in men with prostate cancer treated with androgen deprivation therapy. No screening recommendations currently exist; however, patients at risk for decreased bone mineralization should be screened and treated to prevent consequent fractures.

Prevalence of osteopenia in men with prolactinoma

The aim of this cross-sectional study was to analyze bone mineral density (BMD) and prevalence of osteopenia and osteoporosis in 30 men with prolactinoma, and compare them to 22 control subjects. BMD of lumbar spine and femur was evaluated by dual-energy X-ray absorptiometry. PRL, testosterone, estradiol, sexual hormone-binding globulin and free androgen and estrogen indexes (FAI and FEI, respectively) were measured in all the subjects. In patients with prolactinoma, mean values of PRL and testosterone were calculated for the 12-month period that preceded the study. The mean T-score of the four sites analyzed by bone densitometry was lower in men with prolactinoma than in controls (p-values: lumbar spine=0.015, femoral neck <0.0001, trochanter=0.037, total femur=0.036), and 55.6% of the former presented osteopenia or osteoporosis at one or more sites (p =0.035). The lumbar spine was the most seriously affected site, where 29.6% had osteopenia and 14.8% had osteoporosis. By the time of BMD determination, significant associations were found between BMD and PRL, testosterone, FAI, estradiol, FEI, and duration of hypogonadism. Considering the period of 12 months that preceded BMD evaluation, trochanter BMD was associated with mean PRL levels, while there was an association between lumbar spine BMD and mean testosterone levels. However, the multiple regression analysis showed that estradiol was the main determinant of BMD. In conclusion, men with prolactinoma have high prevalence of osteopenia and osteoporosis. Bone loss in such patients is associated with hyperprolactinemia and hypogonadism, and mainly influenced by estrogen.

Factors affecting bone mineral density in patients with prostate carcinoma before and after orchidectomy

BACKGROUND

Orchidectomy is an accepted form of androgen-deprivation therapy (ADT) for prostate carcinoma. Osteoporosis is common in elderly individuals and is accelerated by ADT. The authors studied changes in bone mineral density (BMD) after ADT and factors that affected those changes.

METHODS

Fifty patients with prostatic adenocarcinoma who opted to undergo orchidectomy were studied prospectively. All patients completed 6 months of follow-up, and 20 of those patients completed 12 months of follow-up. Patients' age, weight, height, body mass index (BMI), physical activity, addiction (smoking, alcohol), dietary calcium intake, and lactose tolerance status were noted. Lumbar spinal (L1-L3) trabecular BMD was measured with quantitative computed tomography (QCT) at baseline and every 6 months for 1 year and was compared with preoperative values. The effects of various patient characteristics on preoperative BMD and changes in BMD also were analyzed.

RESULTS

The mean +/- standard deviation (SD) age of the patients was 69.5 +/- 8.1 years, BMI was 23.5 +/- 3.9 kg/m2, dietary calcium intake was 1066.1 +/- 443.3 mg per day. Thirty-eight percent of patients were lactose intolerant. Sixty-two percent of patients were in the light weight-bearing activity group. The mean +/- SD preoperative BMD was 119.2 +/- 34.9 mg/cc, with T-scores of - 1.77 +/- 1.22 and Z-scores of 0.43 +/- 1.27. A decrease in BMD during the first 6 months ( approximately 13%) was statistically significant (P = 0.0001) and continued further during next 6 months (BMD loss of approximately 18% at 12 months). Patients with osteoporosis, as defined by T-scores < or = - 2.5, increased from 24% at baseline to 48% at 6 months. Nonsmokers, nonalcoholics, patients with higher physical activity, and patients with a BMI > 25 kg/m2 had statistically significant higher BMD compared with their counterparts (P < 0.05). Body weight < 60 kg and BMI < 25 kg/m2 were significant risk factors for loss of BMD (P < 0.05). Dietary calcium had a discernible but statistically insignificant effect on BMD (P = 0.16). Lactose intolerance had no significant effect on BMD or bone loss.

CONCLUSIONS

Osteoporosis was common in the population affected by prostate carcinoma. Orchidectomy led to accelerated bone loss. Periodic measurement of BMD after ADT would help in the early detection of osteoporosis. Maintenance of high BMI, weight-bearing physical activity, avoidance of alcohol and smoking, and possibly high dietary calcium intake help in maintaining bone mass.

Complications of androgen deprivation therapy for prostate cancer

PURPOSE OF REVIEW

Androgen deprivation as a form of treatment for prostate cancer has been used for decades. Within the last decade, however, there has been a significant increase in its use. Therefore, it is incumbent upon the physician to be familiar with the side effects associated with this treatment.

RECENT FINDINGS

Some of the side effects such as osteoporosis, changes in lipid profiles, and anemia may have significant morbidity associated with them, while other side effects such as impotence, decreased libido, fatigue, and hot flashes primarily affect the patient's quality of life. Prevention strategies and treatments exist for many of these side effects.

SUMMARY

This review will update physicians treating patients with androgen deprivation therapy on the side effects associated with this treatment. Once physicians are aware of the potential side effects, they can educate patients on what to expect when starting androgen deprivation therapy. More importantly, physicians can now prevent some of these complications prior to their occurrence, and when these complications occur they have knowledge of the latest treatments.

The impact of osteoporosis in men treated for prostate cancer

Prostate cancer patients are at significant risk for SREs, with up to 50% of androgen-insensitive patients experiencing an SRE at 24 months. The risk increases with the duration and type of cancer treatment. SREs decrease HRQOL, increase the cost of care, and are associated negatively with overall survival. Screening men at greatest risk (slender white men and men with hormone refractory disease or metastatic disease) with BMD measurements, and initiating empiric therapy (vitamin D3, calcium, parenteral estrogens, bisphosphates) may be warranted.

Risk factors for incident vertebral fractures in men and women: the Rotterdam Study

Low BMD and prevalent vertebral fractures are known risk factors for incident vertebral fractures. In 3001 men and women from the Rotterdam Study, prevalent nonvertebral fractures, early menopause, current smoking, and walking aid use were also strong risk factors for incident vertebral fractures.

INTRODUCTION

Thus far, age, low BMD, and prevalent vertebral fractures are the only well-known risk factors for incident vertebral fractures. Therefore, our aim was to investigate other potential risk factors for incident vertebral fractures in the elderly.

MATERIALS AND METHODS

This study was based on the Rotterdam Study, a large prospective population-based cohort study among men and women > or =55 years of age. For 3001 subjects, spinal radiographs were obtained at baseline and again approximately 6.3 years later. These follow-up radiographs were scored for vertebral fractures using the McCloskey-Kanis method. Whenever a vertebral fracture was detected, the radiograph was compared with the baseline radiograph. If this fracture was not already present at baseline, it was considered incident. At baseline, information on potential risk factors was obtained.

RESULTS

Low BMD and prevalent vertebral fractures were strong risk factors for incident vertebral fractures in both men and women (RR 2.3 [1.6-3.3] and 2.2 [0.9-5.0] for men and RR 2.1 [1.6-2.6] and 4.1 [2.5-6.7] for women, respectively). For women, age, early menopause (< or =45 years of age; RR 1.0 [1.1-3.5]), current smoking (2.1 [1.2-3.5]), and walking aid use (2.5 [1.1-5.5]) were additional independent risk factors. For men, only a history of nonvertebral fractures was a significant independent risk factor (OR 2.4 [1.2-4.8]).

CONCLUSION

Apart from low BMD and prevalent vertebral fractures, prevalent nonvertebral fractures are associated with an increased incident vertebral fracture risk in men. In women, early menopause, current smoking, and walking aid use are additional independent risk factors for incident vertebral fractures.

Androgens and bone

Loss of estrogens or androgens increases the rate of bone remodeling by removing restraining effects on osteoblastogenesis and osteoclastogenesis, and also causes a focal imbalance between resorption and formation by prolonging the lifespan of osteoclasts and shortening the lifespan of osteoblasts. Conversely, androgens, as well as estrogens, maintain cancellous bone mass and integrity, regardless of age or sex. Although androgens, via the androgen receptor (AR), and estrogens, via the estrogen receptors (ERs), can exert these effects, their relative contribution remains uncertain. Recent studies suggest that androgen action on cancellous bone depends on (local) aromatization of androgens into estrogens. However, at least in rodents, androgen action on cancellous bone can be directly mediated via AR activation, even in the absence of ERs. Androgens also increase cortical bone size via stimulation of both longitudinal and radial growth. First, androgens, like estrogens, have a biphasic effect on endochondral bone formation: at the start of puberty, sex steroids stimulate endochondral bone formation, whereas they induce epiphyseal closure at the end of puberty. Androgen action on the growth plate is, however, clearly mediated via aromatization in estrogens and interaction with ERalpha. Androgens increase radial growth, whereas estrogens decrease periosteal bone formation. This effect of androgens may be important because bone strength in males seems to be determined by relatively higher periosteal bone formation and, therefore, greater bone dimensions, relative to muscle mass at older age. Experiments in mice again suggest that both the AR and ERalpha pathways are involved in androgen action on radial bone growth. ERbeta may mediate growth-limiting effects of estrogens in the female but does not seem to be involved in the regulation of bone size in males. In conclusion, androgens may protect men against osteoporosis via maintenance of cancellous bone mass and expansion of cortical bone. Such androgen action on bone is mediated by the AR and ERalpha.

Inhibitory effect of alcohol on osteogenic differentiation in human bone marrow-derived mesenchymal stem cells

BACKGROUND

Alcohol-induced osteoporosis is characterized by a considerable suppression of osteogenesis. The objective of this investigation was to determine the effect of alcohol on gene expression, protein synthesis, and mineralization in human bone marrow-derived mesenchymal stem cells induced toward osteogenic differentiation in vitro.

METHODS

Human bone marrow-derived mesenchymal stem cells induced toward osteogenesis were cultured in the presence or absence of 50 mM alcohol. Stem cells were characterized by using SH2 antibody to the cell-surface antigen CD105/endoglin, and their proliferation in the presence of alcohol was quantified. The expression of genes for early, middle, and late markers of the osteogenic lineage was quantified by Northern analysis, and bone matrix protein synthesis was assayed. The effect of alcohol on cell-mediated matrix mineralization in terminally differentiated cultures was determined by von Kossa staining.

RESULTS

Fluorescence-activated cell sorting analysis of human mesenchymal stem cells separated with a Percoll gradient proved 99% homogeneity by using SH2 antibody to the surface antigen CD105. Dose-dependent inhibition of proliferation of these stem cells occurred at concentrations greater than 50 mM alcohol. Gene expression of osteoblast-specific factor 2/core binding factor a1 (Osf2/Cbfa1), type I collagen, alkaline phosphatase, and osteocalcin (early, middle, and late markers for osteogenesis, respectively) was analyzed with and without osteogenic induction and treatment with 50 mM alcohol. After induction, Osf2/Cbfa1 levels were unresponsive to alcohol. To determine the effect of alcohol on human mesenchymal stem cell progression along the osteogenic pathway, messenger RNA (mRNA) levels for type I collagen, alkaline phosphatase, and osteocalcin were examined after osteogenic induction. After osteogenic induction, alcohol down-regulated the gene expression of type I collagen and significantly reduced its synthesis. Alcohol did not alter mRNA expression of alkaline phosphatase, a midstage marker for osteogenesis, but significantly decreased its activity compared with osteogenic induction alone. After induction, osteocalcin remained unchanged by alcohol at both the mRNA and protein levels. Histochemistry revealed decreased alkaline phosphatase staining and fewer alkaline phosphatase-positive cells in alcohol-treated human mesenchymal stem cell cultures. von Kossa staining revealed a reduction in the number of mineralizing nodules in stem cell cultures after alcohol treatment.

CONCLUSIONS

Collectively, the data suggest that alcohol alters osteogenic differentiation in human bone marrow-derived mesenchymal stem cell cultures during lineage progression and provide further insight into alcohol-induced reduced bone formation.

Long-term fracture risk following adult-onset asthma: a population-based study

There are few data on skeletal outcomes in the growing population of patients with adult-onset asthma. We conducted a population-based retrospective (historical) cohort study among 226 residents of Rochester, Minnesota, USA, who were 35 years of age or older when first diagnosed with asthma. Fractures were ascertained by review of comprehensive community medical records, and observed fractures were compared with expected numbers based on incidence rates in the local population (standardized incidence ratios, SIR). During 4,022 person-years of follow-up, 100 patients experienced 211 fractures, for an actuarially estimated cumulative incidence of 63% after 30 years compared with 59% expected ( p=0.004). Statistically significant increases were seen for moderate trauma fractures of the vertebrae (SIR, 2.9; 95% CI, 2.1 to 3.8) and ribs (SIR, 2.0; 95% CI, 1.2 to 3.2), as well as the proximal femur (SIR, 1.8; 95% CI, 1.02 to 2.8). As assessed by proportional hazards models, the only independent predictors of any subsequent moderate trauma fracture were age (hazard ratio [HR] per 10-year increase, 1.7; 95% CI, 1.5 to 2.1) and cumulative corticosteroid dose greater than the median of 1,775 mg (HR, 1.8; 95% CI, 1.1 to 3.0). In another multivariate analysis, the predictors of a moderate trauma vertebral fracture were older age (HR, 1.6; 95% CI, 1.3 to 2.1), concomitant chronic obstructive pulmonary disease (HR, 2.4; 95% CI, 1.2 to 4.9), cigarette smoking (HR, 2.3; 95% CI, 1.2 to 4.8), and cumulative corticosteroid dose greater than the median (HR, 2.6; 95% CI, 1.4 to 5.0). Other asthma therapies did not contribute significantly to these models. Thus, a 70% increase in overall fracture risk among unselected community patients with adult onset asthma was mainly confined to the subset who also had chronic obstructive pulmonary disease and was influenced by substantial corticosteroid use.

Blood leptin and adiponectin as possible mediators of the relation between fat mass and BMD in perimenopausal women

Fat mass is a predictor of BMD; however, the mechanisms involved remain uncertain. Two adipokines, leptin and adiponectin, were examined as potential mediators of this relation in 80 perimenopausal women. Adiponectin did not exert any effect on BMD, whereas leptin exerted a negative one, with insulin acting as a confounder to this relation.

INTRODUCTION

Fat mass is an important determinant of bone density, but the mechanism involved in this relation is uncertain. Leptin and adiponectin, as circulating peptides of adipocyte origin, are potential contributors to this relation. We investigated the role of leptin and adiponectin in mediating fat mass effects on the skeleton of perimenopausal women.

MATERIALS AND METHODS

Twenty-five premenopausal and 55 postmenopausal, healthy women (42-68 years old) participated in our study. Lumbar spine BMD (BMD(L2-L4)) and total body BMC (TBBMC) were measured with DXA, leptin levels with ELISA, and adiponectin levels with radioimmunoassay (RIA). Additionally, body composition analysis was performed, as well as measurements of several hormones.

RESULTS

It was shown that serum leptin levels were negatively correlated with BMD (beta = -0.005, p = 0.027) and TBBMC (beta = -14.32, p = 0.013). The above correlation was observed only when serum insulin levels were included, as an independent variable, in the regression analysis model. Adiponectin was not significantly correlated with BMD(L2-L4) nor with TBBMC, either in the presence or absence of insulin.

CONCLUSION

Circulating adiponectin does not seem to exert any effect on bone mass. In contrast, circulating leptin showed a negative correlation with bone mass, dependent on serum insulin levels.

Bone mineral density changes in hypercalciuretic osteoporotic men treated with thiazide diuretics

A few studies suggest that thiazide diuretic agents may have modest beneficial effects on bone. Few data are available on the effects of these medications in patients with osteoporosis and hypercalciuria.

OBJECTIVE

To evaluate the effects of thiazide diuretic therapy on bone mass and urinary calcium excretion in hypercalciuretic osteoporotic male patients.

PATIENTS AND METHODS

Osteoporosis was defined as a greater than 2.5 standard deviation (S.D.) decrease in bone mineral density (BMD) at the lumbar spine or hip (T-score). We used an open-label prospective design to compare 14 patients with hypercalciuretic osteoporosis treated with a thiazide diuretic for 18 months and 13 patients with primary osteoporosis treated with calcium and vitamin D supplementation. Mean age was 53.5 +/- 9.6 years in the thiazide group and 48.7 +/- 8.4 years in the calcium-vitamin D supplementation group. The following serum parameters were assayed at baseline: 25OH-D3, 1,25OH-D3, parathyroid hormone (PTH), and bone turnover markers. Urinary calcium excretion and BMD by dual-energy X-ray absorptiometry at the spine and hip were determined at baseline and after 18 months of treatment.

RESULTS

Annual BMD increases were similar in the two groups during the 18-month treatment period: lumbar spine, 0.6 +/- 2.5% (P = 0.47) in the thiazide group and 0.004 +/- 3% (P = 0.78) in the supplementation group; femoral neck, 0.47 +/- 2.6% (P = 0.89) and 1.1 +/- 3.2% (P = 0.22); total hip, 0.65 +/- 2.5% (P = 0.37) and 0.12 +/- 2.1% (P = 0.51). Urinary calcium excretion fell by 45.9% in the thiazide group from baseline to study completion (P = 0.0015).

CONCLUSION

We found no evidence that thiazide therapy increased bone mass in patients with hypercalciuria and osteoporosis as compared to calcium-vitamin D supplementation in patients with osteoporosis but no hypercalciuria. In contrast, our results establish the efficacy of thiazide diuretics in reducing urinary calcium excretion, an effect that may decrease the risk of urinary lithiasis. Studies in larger patient cohorts treated for longer periods are needed to confirm or refute our findings.

Management of Bone Loss in Men With Prostate Cancer

PURPOSE

Bone loss is increasingly recognized as a common occurrence in men receiving androgen deprivation therapy (ADT) for prostate cancer. Skeletal metabolism and osteoporosis in men, assessment of bone mineral density (BMD), effects of ADT on BMD, management strategies and potential therapies for osteopenia or osteoporosis in men with prostate cancer are reviewed.

MATERIALS AND METHODS

Relevant literature is reviewed concerning bone loss and osteoporosis in men with and without prostate cancer, techniques of assessing BMD, data on bone loss and fracture risk and management strategies.

RESULTS

The incidence of osteoporotic fractures usually increases a decade later in men than in women. ADT causes significant loss of BMD, which may hasten the development of osteoporosis. Men who are treated with hormonal therapy for an increasing prostate specific antigen and who may live for many years should have baseline BMD assessments. Osteopenia or osteoporosis should be treated to minimize the risk of osteoporotic fracture. Treatment with zoledronic acid seems appropriate since it has been shown to increase BMD in men treated with ADT and to reduce the rate of skeletal related events in men with early hormone refractory prostate cancer with metastatic disease.

CONCLUSIONS

Monitoring BMD is warranted in men contemplating or receiving ADT but prophylactic therapy to prevent bone loss currently is not recommended. Men with evidence of significant bone loss who are receiving ADT should be treated. Zoledronic acid is a logical choice based on available data.

Fracture risk associated with smoking: a meta-analysis

OBJECTIVES

To assess fracture risk associated with smoking.

DESIGN

Systematic review.

DATA SOURCES

Cohort, case-control, and cross-sectional studies identified by searching PubMed and EMBASE, and by recursive screening of reference lists.

SUBJECTS

Fifty studies including 512 399 subjects were included.

MAIN OUTCOME MEASURE

Fracture occurrence in current, previous, and never smokers.

RESULTS

Fracture risk was significantly increased in current smokers for all fracture types combined (pooled relative risk 1.26, 95% CI 1.12-1.42) and for hip (1.39, 95% CI 1.23-1.58) and spine fractures (1.76, 95% CI 1.10-2.82), but not for wrist fractures (0.86, 95% CI 0.46-1.60). In previous smokers the estimate was significantly lower for as well all types of fractures (1.02, 95% CI 0.85-1.22, P = 0.03 compared with current smokers), as for hip fractures (1.19, 95% CI 1.06-1.34, P = 0.04). There was a trend towards higher risk estimates in previous smokers for hip fractures in case-control studies than in cohort studies. A similar difference between case-control and cohort studies was not present for current smokers. There was a geographical heterogeneity: the risk of hip fractures associated with current smoking increased with latitude, i.e. the risk was higher in Northern Europe and the USA than in Southern Europe and countries close to the equator.

CONCLUSIONS

Smoking is associated with an increased overall fracture risk, an increased risk of hip and spine but not wrist fractures. Cessation of smoking seems associated with a decrease in fracture risk. The impact of smoking varied geographically with an increase with latitude.

Prostate cancer and bone metastases: medical treatment

Prostate cancer is the most common malignancy in men in the United States. With the long natural history of the disease, management of skeletal morbidity related to advanced prostate cancer becomes a major public health issue. The standard of care in advanced prostate cancer is androgen deprivation therapy. This may accelerate the development of osteoporosis and further exacerbate the risks of having adverse skeletal-related events develop. Recently, the use of bisphosphonates in men who have not responded to androgen deprivation therapy has been shown to reduce the incidence of skeletal-related events with time. Questions remain as to whether bisphosphonates should be broadly applied to earlier stages of the disease or tailored to men at higher risk of having bone-related morbidity. Work is ongoing to improve other approaches to the medical treatment of bone metastases in patients with advanced prostate cancer including the use of radiopharmaceuticals and combined chemotherapy.

Risk factors for male osteoporosis

Hypogonadism from long-term androgen deprivation therapy (ADT), either by bilateral orchiectomy or administration of gonadotropin-releasing hormone (GnRH) agonists, causes significant and accelerated bone loss that may increase the risk of bone fractures in men with prostate cancer. Recent reports, as well as new data from our institution, have shown a high prevalence of pre-existing osteopenia and osteoporosis in men with prostate cancer before receiving ADT, and this is of great concern because of the risk of further bone loss during ADT. Data from these studies suggest the urgent need for clinical guidelines for screening, prevention, and treatment of these cases. This article reviews the prevalence and risk factors associated with osteoporosis in men and addresses risk factors in men with prostate cancer not receiving ADT. Considerations for the patient selection and timing of bone densitometry will also be discussed.

Osteoporosis in pulmonary clinic patients: does point-of-care screening predict central dual-energy X-ray absorptiometry?

STUDY OBJECTIVES

Patients in a pulmonary clinic have disorders that predispose them to osteoporosis and may use glucocorticoid therapy, which has been associated with low bone mineral density (BMD) and increased fracture risk. Ideally, all patients at risk for osteoporosis would be screened using the best test available, which is central BMD by dual-energy x-ray absorptiometry (DXA). We proposed to stratify the risk for osteoporosis by the use of a simple questionnaire and point-of-care heel ultrasound BMD measurements.

DESIGN

Cross-sectional screening study.

SETTING

Pulmonary clinic in a single Veterans Affairs Medical Center.

PATIENTS

Approximately 200 male and female patients who had not had previous BMD testing were eligible for the study, and 107 gave consent.

INTERVENTIONS

One hundred seven men (white, 71 men; black, 35 men; and Asian, 1 man) underwent heel BMD testing and filled out a questionnaire. Ninety-eight men underwent a central DXA.

RESULTS

Of 98 subjects, 24.5% had a spine, total hip, or femoral neck (FN) T-score of <or= -2.5, which is the generally accepted definition of osteoporosis diagnosed using DXA, and 44.9% had a T-score of <or= -2.0. The best-fit models for predicting FN or total hip BMD included body weight, heel BMD, corticosteroid use for >or= 7 days, and race, which accounted for 52 to 57% of the variance. When a heel ultrasound T-score of -1.0 was tested to predict a central DXA T-score of -2.0, the sensitivity was 61% and the specificity 64%. Adding the questionnaire score and body mass index (BMI) to the heel T-score improved sensitivity but not specificity. Moreover, BMI and age predicted central BMD with similar sensitivity and specificity. Importantly, of 24 patients with a central DXA T-score of <or= -2.5, only 14 were identified by a heel T-score of <or= -1.0.

CONCLUSIONS

Although the findings from a heel ultrasound plus the answers to a questionnaire were reasonably good indicators for predicting the presence of low BMD, little predictability was gained over the use of BMI and age. In a group of pulmonary clinic patients, the prevalence of osteoporosis was clinically significant, and central DXA testing was the preferable technique for identifying patients who were at risk for fracture.

Growth hormone, insulin growth factor-1, and igf binding protein-3 axis relationship with bone mineral density among healthy men

The aim of this study was to investigate serum levels of growth hormone (GH), insulin growth factor-I (IGF-I), and insulin growth factor binding protein-3 (IGFBP-3) in 363 healthy caucasian men with and without decreased bone density, who had never experienced fractures. Mean age was 51+/-8.7 years. Height and weight were measured and BMI was calculated using the formula weight (kg)/height (m(2)). Bone mineral density (BMD) was assessed: in 4 skeletal sites (lumbar spine [LS], femoral neck [FN], Ward's triangle [WT], and trochanter [T]) using dual-energy X-ray absorpsiometry (DEXA). After an overnight fasting, blood samples were taken at 8:00 a.m. Serum concentrations of GH, IGF-I, and IGFBP-3 were measured using the immunofunctional (GH) and IRMA (IGF-I and IGFBP-3) methods. The BMD at the 4 skeletal sites is expressed as mean value+/-SD in g/cm(2) and T score. Forty-four men (11%) had bone mineral density (BMD)<-2.5 SD (T score). Mean GH, IGF-I, and IGFBP-3 levels were 0.2+/-0.1, 186.1+/-177.3, and 4990+/-1460 ng/mL, respectively. There were no significant differences between men with normal BMD and men with reduced BMD concerning GH, IGF-I, and IGFBP-3 measurements. In normal men (319), mean GH, IGF-I, and IGFBP-3 levels were 0.4+/-0.1, 192+/-87, and 4960+/-1530 ng/mL, respectively. In the subgroup with reduced BMD (44), mean GH, IGF-I and IGFBP-3 levels were 0.2+/-0.1, 179+/-72 and 5230+/-1270 ng/mL, respectively. An age-dependent attenuation of GH, IGF-I, and IGFBP-3 levels was also found. No correlation was revealed between BMD and GH in the 4 skeletal sites tested. On the contrary, a positive correlation was established between BMD and IGF-I levels in 3 skeletal sites (LS, FN, T). The same was true between BMD and IGFBP-3 in 2 skeletal sites (LS, FN). In conclusion, 11% of Greek healthy males had decreased bone density. No fractures were demonstrated in any individuals. No significant differences were found between men with normal and reduced BMD, with regards to serum GH, IGF-I, and IGFBP-3, although these levels decreased with age. No correlation was found between BMD and GH levels in the 4 skeletal sites. A positive correlation was found between BMD and IGF-I levels in 3 skeletal sites and IGFBP-3 in 2 skeletal sites.

Cigarette smoke extract inhibits chemotaxis and collagen gel contraction mediated by human bone marrow osteoprogenitor cells and osteoblast-like cells

Cell migration and matrix remodeling are key events in tissue repair and restructuring. Osteoblasts are responsible for the production of new bone matrix during bone remodeling. The activity of these cells can be modulated by a number of factors. The current study evaluated the hypothesis that cigarette smoke extract can alter repair and remodeling responses of human osteoprogenitor cells and osteoblast-like cells and, therefore, could explain one mechanism by which cigarette smoking leads to osteoporosis. Human osteoprogenitor cells were isolated from normal human bone marrow and maintained in culture under either control conditions or conditions that induced differentiation into osteoblast-like cells. Both cell types migrated toward fibronectin and PDGF-BB as chemoattractants. Neither responded to TGF-beta1. The osteoprogenitor cells were more active in their chemotactic response. The chemotactic response of both cell types was inhibited by cigarette smoke extract in a concentration-dependent manner. Both cell types, when cultured in three-dimensional native collagen gels maintained in floating culture, induced contraction of their surrounding matrices. Contraction was augmented by serum, PDGF-BB, and TGF-beta1. Osteoprogenitor cells were less active in inducing contraction than were osteoblast-like cells. Contraction of both cell types was inhibited by cigarette smoke extract. Cigarette smoke extract also inhibited the production of fibronectin by both cell types maintained in three-dimensional culture. Addition of exogenous fibronectin partially restored the ability of the cells to contract three-dimensional collagen gels. The current study demonstrates that cigarette smoke can interfere with the ability of bone cells to participate in repair and remodeling events. Such an effect may be one mechanism leading to the development of osteoporosis.

Leptin: a potential mediator for protective effects of fat mass on bone tissue

Body weight is among the most powerful predictors of bone status, and adipose tissue plays a substantial role in weight-related protective effects on bone. An understanding of the mechanisms underlying the relation between adipose tissue and bone may open up new perspectives for treatment. Leptin, which is known to regulate appetite and energy expenditures, may also contribute to mediate the effects of fat mass on bone. Although reported data are somewhat conflicting, there is some evidence that leptin may decrease bone formation via a central nervous effect and may stimulate both bone formation and bone resorption via direct peripheral effects on stromal precursor cells. The net result of these central and peripheral effects may depend on serum leptin levels and blood-brain barrier permeability, of which the first increase and the second decrease as obesity develops. Further work is needed to improve our understanding of these effects.

A potential role for the mast cell in the pathogenesis of idiopathic osteoporosis in men

Osteoporosis is increasingly being recognized in men. Secondary causes are often implicated, but the mechanism of bone loss remains unclear in about a third of patients. The mast cell is a complex cell that stores a number of factors known to affect bone metabolism. Patients with systemic mastocytosis often demonstrate osteoporosis and bone marrow mast cells may be increased in osteoporotic postmenopausal women. We address the possible role of the mast cell in the pathophysiology of male osteoporosis by studying the relationship between bone marrow infiltration with mast cells and the 24 h urine excretion of N-methylhistamine, and the severity of osteoporosis in 48 consecutive men with idiopathic osteoporosis (bone mineral density Z score of <-1 and/or at least one prevalent vertebral fracture). Secondary causes for osteoporosis were excluded and none of the patients had systemic manifestations of enhanced mast cell activity. A widely variable number of morphologically normal mast cells were counted in toluidine blue-stained sections from 42 of 46 evaluable bone marrow biopsies. In 4 of the 42 biopsies (9%), clusters of abnormal mast cells were identified. These four patients were the only ones who also demonstrated increased 24 h urine excretion of N-methylhistamine. There was a significant positive relationship between mast cell number and the 24 h urine excretion of N-methylhistamine reflecting mast cell activity (p = 0.0001), and this latter measurement correlated negatively with bone mineral density (BMD) at the lumbar spine (p < 0.001). We identified clinically important bone marrow cell infiltration with pathologic mast cells in the absence of systemic manifestations of mast cell hyperactivity as an additional secondary cause for osteoporosis in some 9% of men with idiopathic osteoporosis, and found urinary excretion of N-methylhistamine to be above the upper limit of the normal laboratory reference range diagnostic for this cause of secondary osteoporosis. The more continuous spectrum in the relationship between mast cell activity and BMD supports a potential role for this cell in the pathogenesis of idiopathic male osteoporosis.

Risk factors for osteoporosis in a subgroup of elderly men in a Veterans Administration nursing home

BACKGROUND

General risk factors for osteoporosis in men include cigarette smoking, alcohol consumption, and diseases known to affect calcium or bone turnover. The aim of this study was to determine the specific incidence and major risk factors for osteoporosis in those at high risk for falling in a Veterans Administration nursing home that included a high proportion of psychiatric patients.

METHODS

We performed a cross-sectional analysis of Veterans Administration Medical Center nursing home residents with high fall risk. Thirty-nine men with a previous episode of falling or who were considered to be at high fall risk were enrolled. A review of the medical histories and pertinent hormonal and biochemical laboratory values was performed. Bone mineral density was measured by performing dual energy x-ray absorptiometry for all participants.

RESULTS

We reviewed the medical records of 39 male nursing home residents with high fall risk. The patients' mean age was 74.7 +/- 6.8 years. A significant (p = 0.00045) association was found between chronic obstructive pulmonary disease and osteoporosis independent of oral corticosteroid use. Additional risk factors found to be associated with osteoporosis included hypogonadism, lower body weight, antipsychotic medication use, and smoking.

CONCLUSION

In a Veterans Administration nursing home population at high risk for falls, including psychiatric patients, chronic obstructive pulmonary disease independent of the use of corticosteroids, lower body weight, hypogonadism, use of antipsychotic medications, and smoking was found to be associated with osteoporosis.

Relationship of serum leptin concentration with bone mineral density in the United States population

Overweight is associated with both higher bone mineral density (BMD) and higher serum leptin concentrations. In humans, little is known about the relationship of leptin concentration and bone density. We studied this relationship in a large, national population-based sample. Participants included 5815 adults in the Third U.S. National Health and Nutrition Examination Survey (NHANES III; 1988-1994) who underwent DXA of the proximal femur and measurement of fasting serum leptin. Mean +/- SE BMD (gm/cm2) of the total hip was 1.01 +/- 0.005 in men, 0.94 +/- 0.004 in premenopausal women, and 0.78 +/- 0.007 in postmenopausal women. Bone density increased with increasing leptin concentration in men (p = 0.003), premenopausal women (p < 0.001), and postmenopausal women (p < 0.001). However, after adjusting for body mass index (BMI) and other bone density-related factors, an inverse association emerged in men (p < 0.001), being most evident among men < 60 years old. There was no association of leptin and BMD in premenopausal women (p = 0.66) or postmenopausal women (p = 0.69) in multivariate analysis. Controlling for leptin had no effect on the strong positive association of BMI and BMD in either men or women. Serum leptin concentration did not appear to affect directly BMD. If present, the association appeared to be limited to younger men who are at lower risk of osteoporosis.

Season modifies the relationship between bone and blood lead levels: the Normative Aging Study

Bone serves as a repository for 75% and 90-95% of lead in children and adults, respectively. Bone lead mobilization heightens during times of increased bone turnover, such as pregnancy, lactation, hyperthyroidism, and the rapid growth of childhood. Blood lead levels show seasonal periodicity. Children demonstrate peak blood lead levels in mid-summer and a secondary peak in late winter. Pregnant women demonstrate the highest mean blood lead levels in winter (January-March) and the lowest in summer (July-September). This fluctuation in blood lead levels may be related to seasonal patterns of environmental exposures, but it may also be partially related to the increased mobilization of bone lead stores during the winter months. We performed bone lead measurements using a K-x-ray fluorescent instrument to determine micrograms of lead per gram of bone mineral (parts per million) in middle-aged and elderly men who participated in the Normative Aging Study. We obtained measurements of blood and bone lead during the high sun exposure months of May-August (summer; n = 290); the intermediate sun exposure months of March, April, September, and October (spring/fall; n = 283); and the low sun exposure months of November-February (winter; n = 191). Mean blood lead concentrations were 5.8 microg/dl, 6.1 microg/dl, and 6.6 microg/dl for the summer, spring/fall, and winter, respectively. Mean patella (trabecular bone) lead concentrations were 34.3 microg/gm, 29.7 microg/gm, and 29.0 microg/gm for the summer, spring/fall, and winter time periods, respectively. In multivariate regression models, adjusted for age, smoking, alcohol ingestion, and dietary intake of iron and vitamin C, the authors found a strong interaction between season and bone lead level--with bone lead levels exerting an almost 2-fold greater influence on blood levels during the winter months than the summer months. The authors concluded that elevated blood lead levels in winter may be related to increased mobilization of endogenous bone lead stores, potentially from decreased exposure to sunlight, lower levels of activated vitamin D, and enhanced bone resorption.

Is leptin the link between fat and bone mass?

Recently, leptin has emerged as a potential candidate responsible for protective effects of fat on bone tissue. However, it remains difficult to draw a clear picture of leptin effects on bone metabolism because published data are sometimes conflicting or apparently contradictory. Beyond differences in models or experimental procedures, it is tempting to hypothesize that leptin exerts dual effects depending on bone tissue, skeletal maturity, and/or signaling pathway. Early in life, leptin could stimulate bone growth and bone size through direct angiogenic and osteogenic effects on stromal precursor cells. Later, it may decrease bone remodeling in the mature skeleton, when trabecular bone turnover is high, by stimulating osteoprotegerin (OPG) expression. Leptin negative effects on bone formation effected through central nervous system pathway could counterbalance these peripheral and positive effects, the latter being predominant when the blood-brain barrier permeability decreases or the serum leptin level rises above a certain threshold. Thus, the sex-dependent specificity of the relationship between leptin and bone mineral density (BMD) in human studies could be, at least in part, caused by serum leptin levels that are two- to threefold higher in women than in men, independent of adiposity. Although these hypotheses remain highly speculative and require further investigations, existing studies consistently support the role of leptin as a link between fat and bone.

Non-participants differ from participants as regards risk factors for vertebral deformities: a source of misinterpretation in the European Vertebral Osteoporosis Study

Interpretation of data in epidemiological cohort studies may be confounded if differences exist between non-participants and participants. In the Malmö part of the European Vertebral Osteoporosis Study (EVOS), which was designed to evaluate the prevalence of vertebral deformity in 50-80-year-old persons, we compared 74 men and 95 women who had been invited, but declined to participate with age- and gender-matched participants as regards alcohol abuse, previous fractures and subsequent mortality, factors known to affect the prevalence of vertebral deformity. We found more men with alcohol abuse, more men with a previous fragility fracture and a tendency to more men with a previous clinical vertebral fracture among the non-participants than in the male participants. In contrast, there were fewer female non-participants than female participants with a previous clinical vertebral fracture. The mortality rate during the decade after the baseline examination was higher among both male and female non-participants. The "true" prevalence of vertebral deformity in the whole male population at risk in Malmö seems to be underestimated in the EVOS study. In women, it is more difficult to estimate the combined result of the confounding factors. Conclusions based on the EVOS participants may not be applicable to the whole population at risk.

Osteoporosis: prevention and diagnostic work-up

Prevention of osteoporosis has assumed a paramount role in the decrease of osteoporotic fractures and the associated medical costs. A thorough diagnostic work-up of the patient with osteoporosis helps the physician exclude secondary causes of bone loss and acquire useful data for staging the disease, and contributes to planning the correct therapeutic management.

Osteoporosis in men: pathophysiology, evaluation, and therapy

Osteoporosis is a serious health problem for men. An advance in our understanding of the pathophysiology and treatment of this disorder has resulted in the possibility of a gender-specific approach to screening, diagnosis, and treatment. Here we review the data on osteoporosis in men, discuss controversies regarding whom to screen, whom to treat, and how to treat. Recent treatment data as they relate to men are reviewed, and a clinical treatment algorithm is presented.

Bone density and bone-related biochemical variables in normal men: a longitudinal study

BACKGROUND

The objective of this study was to determine the pattern of forearm bone loss and its relationship to markers of bone turnover and sex steroids in normal men. This was a longitudinal study over a median interval of 41 months. The study was conducted in Adelaide, Australia. Study participants were 123 healthy male subjects, between the ages of 20 and 83 years.

METHODS

Fat-corrected forearm bone mineral content (fcBMC), markers of bone formation (alkaline phosphatase, osteocalcin, procollagen type 1 C-terminal extension peptide) and bone resorption (collagen type I cross-linked telopeptide, hydroxyproline/creatinine, pyridinoline/creatinine, and deoxypyridinoline/creatinine), calculated serum bioavailable testosterone, and serum estradiol were measured.

RESULTS

The mean time-weighted rate of change in forearm fcBMC was -0.33% +/- 0.72 (SD) per year. Bone loss commenced after 30 years of age and increased with age (p <.001), particularly after age 70 years. There was no relationship between the rate of change in fcBMC and either markers of bone turnover or serum sex steroids.

CONCLUSIONS

In normal men, bone loss increases with age; there does not appear to be any relationship between this loss and either markers of bone turnover or levels of free androgen or estrogen.

Sex hormone suppression by intrathecal opioids: a prospective study

OBJECTIVE

Sexual dysfunction and low testosterone levels have been observed previously in males with chronic noncancer pain treated with intrathecal opioids. To investigate the hypothesis that intrathecal opioids suppress the hypothalamic-pituitary-gonadal axis, a prospective nonrandomized investigation of the function of this axis was undertaken.

DESIGN

Ten males with chronic noncancer pain were evaluated for clinical and biochemical evidence of hypogonadism at baseline and during the first twelve weeks of intrathecal opioid therapy.

RESULTS

Intrathecal opioid administration resulted in a significant (p <0.0001) reduction in serum testosterone, from 7.7 +/- 1.1 (mean +/- SEM) nmol/L at baseline to 2.0 +/- 0.7, 2.8 +/- 0.5, and 4.0 +/- 0.9 nmol/L at 1, 4, and 12 weeks, respectively. This was associated with a reduction in libido and potency. Luteinizing hormone and follicle-stimulating hormone levels remained within reference ranges, indicating central rather than peripheral suppression.

CONCLUSIONS

Administration of intrathecal opioids may result in hypogonadotrophic hypogonadism. As part of the consent for therapy process, patients should be informed about this effect and its management. With long-term intrathecal opioid administration, the hypothalamic-pituitary-gonadal axis should be monitored. Where indicated, testosterone replacement should be undertaken to improve sexual function and prevent the potential metabolic effects of hypogonadism, in particular, osteoporosis.

Increase of bone alkaline phosphatase after androgen deprivation therapy in patients with prostate cancer

OBJECTIVES

To evaluate the behavior of bone alkaline phosphatase (BAP) after androgen deprivation therapy in patients with prostate cancer.

METHODS

BAP was determined in the serum of 35 patients with nonmetastatic prostate cancer before maximal androgen blockade. During 5 years of follow-up, BAP was determined annually. A subset of 36 patients who underwent radical prostatectomy as the only treatment for prostate cancer was selected as a control group.

RESULTS

The mean pretreatment BAP serum concentration was similar in both groups (10.8 and 10.4 ng/mL, P >0.05). However, after 5 years, the mean BAP serum concentration increased 64.8% in the study group (from 10.8 to 17.6 ng/mL, P < 0.001); it remained stable in the control group (from 10.4 to 10.4 ng/mL). The increase of serum BAP in patients receiving androgen deprivation was 32.4% during the first year (from 10.8 to 14.3 ng/ml), 16.7% during the second (from 14.3 to 16.1 ng/mL), 7.4% during the third (from 16.1 to 16.9 ng/mL), 5.5% during the fourth (from 16.9 to 17.3 ng/mL), and 2.8% during the fifth year (from 17.3 to 17.6 ng/mL).

CONCLUSIONS

Androgen deprivation produces an increase in the BAP serum concentration. A major increase seems to be produced during the first year of follow-up and thereafter this increase is reduced around 50% annually.

COPD and osteoporosis

Osteoporosis, with resulting fractures, is a significant problem in patients with advanced COPD. The etiology for the bone loss is diverse but includes smoking, vitamin D deficiency, low body mass index, hypogonadism, sedentary lifestyle, and use of glucocorticoids. Effective strategies to prevent bone loss and/or to treat osteoporosis include calcium and vitamin D, hormone replacement when indicated, calcitonin, and bisphosphonate administration. However, many patients remain undiagnosed until their first fracture because of the lack of recognition of the disease. With an increased awareness by pulmonologists and the increased use of preventive strategies, the impact of osteoporosis on those patients with COPD should decrease.

Selective anabolic effects of muteins of mid-region PTH fragments on skeletal tissues of prepubertal rats

We have demonstrated the net anabolic potential of a mid-region fragment of human parathyroid hormone (hPTH), and a protease resistant mutein derived from it, to stimulate growth of skeletal-derived tissues. The fragment hPTH (28-48), lacking the N-terminal amino acids necessary for stimulation of adenylate cyclase, and therefore unable to stimulate bone resorption by osteoclasts, was compared with the protease-resistant double-mutein hPTH (28-48) F34M L37T, full-length hPTH (1-84), the protease resistant form hPTH (1-84) L37T, 17beta estradiol (E(2)), and the combination of mid-region fragments of PTH and E(2). The hormones, at concentrations spanning a 100-fold range, were given by 14 injections (6/week, excluding Saturday), to 17-day-old female Wistar-derived rats. At the low concentration of 200 ng/day of PTH (1-84), or the molar equivalent of the fragment, and 50 ng E(2), all the hormones increased significantly the specific activity of creatine kinase (CK; a marker of skeletal cell proliferation) in tibial diaphysis and epiphysis, the width of the cortical bone in the humeral diaphysis, and the number of cells in the proliferating zone of the humeral epiphyseal growth plate. At a 10-fold lower concentration of both PTH and E(2), CK specific activity was synergistically stimulated in both diaphyseal bone and epiphyseal cartilage. However, PTH mid-region fragments at a dose of 1 microg/day did not increase trabecular bone volume.