Risk factors for spinal osteoporosis in men

Osteoporosis: pathophysiology and non-pharmacological management

Osteoporosis is the disease of progressive bone loss that is most often associated with ageing and the post-menopausal state in women. All people, men and women, lose bone mass with advancing age, but in some the loss is so great that the skeleton is unable to maintain optimal structural integrity and the result is susceptibility to fractures, particularly of the hip and spine. The condition is increasing dramatically in prevalence as the numbers of elderly in the population increase. In this chapter, the epidemiology, clinical features and current modes of non-pharmacological management of osteoporosis are reviewed, with discussion of the potential of nutraceuticals and functional foods to influence the course of the disease.

Randomized placebo-controlled trial of testosterone replacement in men with mild Leydig cell insufficiency following cytotoxic chemotherapy

OBJECTIVE

Testosterone deficiency is associated with significant morbidity, and androgen replacement in overt hypogonadism is clearly beneficial. However, there are few data concerning the response to therapy in young men with mild testosterone deficiency.

DESIGN AND PATIENTS

We have identified a cohort of 35 men, mean age 40.9 years, with mild Leydig cell dysfunction, defined by a raised LH level (LH >or= 8 IU/l) and a testosterone level in the lower half of the normal range or frankly subnormal (testosterone < 20 nmol/l), following treatment with cytotoxic chemotherapy for malignancy. Patients were assigned randomly to 12 months treatment with transdermal testosterone (n = 16) (Andropatch 2.5 mg patches, 1-2 patches per day) or placebo patches (n = 19) in a single blinded manner.

MEASUREMENTS

Measurements of bone mineral density (BMD) and body composition were performed at baseline, 6 months and 12 months using single and dual energy X-ray absorptiometry (SXA, DXA). In addition, spinal BMD was assessed at baseline and 12 months by quantitative CT (QCT). Subjects were reviewed at 3-monthly intervals; at each visit blood was taken for measurement of testosterone, SHBG, LH, FSH, oestradiol, lipids and IGF-1 and patients completed three questionnaires which assessed energy levels, mood and sexual function.

RESULTS

Total testosterone and calculated free testosterone increased significantly in the testosterone-treated group compared with the placebo-treated group (13.3 nmol/l and 342.9 pmol/l at baseline compared with 17.3 nmol/l and 454.8 pmol/l during the study period in the testosterone-treated group; P = 0.05 and P = 0.02, respectively). LH was suppressed into the normal range in 15 of the 16 testosterone-treated men and mean LH significantly reduced from 11.1 IU/l at baseline to 6.8 IU/l during the study. There was no significant change in BMD at the hip, spine or forearm and no change in fat or lean body mass. There was a significant reduction in physical fatigue in the testosterone-treated group compared with the placebo-treated group (P = 0.008) and a borderline improvement in activity score (P = 0.05). There were no significant effects of treatment on mood or sexual function. Neither oestradiol nor IGF-1 levels differed between the two groups during the study. There was no significant change in mean total cholesterol, HDL cholesterol or triglyceride levels, but there was a small, but significant reduction in LDL cholesterol levels in the testosterone-treated group compared with the placebo group (P = 0.02).

CONCLUSIONS

These results suggest that testosterone therapy in young men with raised LH levels and low/normal testosterone levels does not result in significant changes in BMD, body composition, lipids or quality of life, apart from a reduction in physical fatigue and a small reduction in LDL cholesterol. This implies that mild hypogonadism defined on this basis is not of clinical importance in the majority of men, and that androgen replacement cannot be recommended for routine use in these patients.

Normal bone density in male pseudohermaphroditism due to 5alpha- reductase 2 deficiency

Bone is an androgen-dependent tissue, but it is not clear whether the androgen action in bone depends on testosterone or on dihydrotestosterone. Patients with 5alpha-reductase 2 deficiency present normal levels of testosterone and low levels of dihydrotestosterone, providing an in vivo human model for the analysis of the effect of testosterone on bone.

OBJECTIVE

To analyze bone mineral density in 4 adult patients with male pseudohermaphroditism due to 5alpha-reductase 2 deficiency.

RESULTS

Three patients presented normal bone mineral density of the lumbar column (L1-L4) and femur neck, and the other patient presented a slight osteopenia in the lumbar column.

CONCLUSION

Patients with dihydrotestosterone deficiency present normal bone mineral density, suggesting that dihydrotestosterone is not the main androgen acting in bone.

Osteoporosis due to androgen deprivation therapy in men with prostate cancer

OBJECTIVES

The frequency of osteoporotic fractures is greatly increased in men receiving androgen deprivation therapy (ADT), but whether the risk of osteoporosis differs between different types of ADT or between continuous and intermittent therapy has not been determined. Techniques for modifying ADT-associated bone loss have not been clearly identified.

METHODS

Risk factors for the development of osteoporosis in men receiving ADT will be reviewed. Relations between bone mineral density (BMD) values and the development of osteoporotic fractures, along with methods for preventing both BMD loss and osteoporotic fractures, will be discussed.

RESULTS

ADT rapidly accelerates bone loss among men with prostate cancer and multiplies the risk of osteoporotic fractures among them. Factors other than ADT-associated bone loss contributing to this fracture risk include both decreased BMD before ADT and an increased tendency to fall associated with muscle weakness, impaired balance, and postural hypotension. Each of these factors may be associated with poor nutrition, advancing malignant disease, hypogonadism of non-ADT origin, advanced age, and the use of narcotic, antihypertensive, or sedative medications. Although the success of therapy designed to improve BMD values and lower the fracture rate in these patients has not been explored, regular exercise, smoking abstinence, adequate calcium, protein, and vitamin D intake, maintenance of weight, and the use of bisphosphonates or calcitonin may each have a useful therapeutic role. Theoretical considerations suggest that intermittent ADT may decrease the frequency of ADT-associated osteoporosis.

CONCLUSIONS

An urgent need exists for the definition of techniques useful in preventing osteoporotic fractures in men receiving ADT for prostate cancer.

Role of serum leptin, insulin, and estrogen levels as potential mediators of the relationship between fat mass and bone mineral density in men versus women

Although fat mass is related to bone mineral density (BMD), the potential mechanism(s) of this effect remain to be defined. Thus, we assessed the role of the candidate hormones, leptin, insulin, and estrogen in mediating fat mass effects on the skeleton. Specifically, we related these hormones and fat mass to BMD at the total hip, mid-lateral spine, and mid-distal radius in a sample of 137 premenopausal women (age range 21-54 years), 165 postmenopausal women (34-93 years), and 343 men (23-90 years) recruited from the general population. Fat mass and BMD were significantly related in pre- and postmenopausal women at multiple sites, whereas this relationship was only weakly present in men at the total hip. Serum leptin levels were also significantly related to BMD in the women, but not in the men. Insulin was associated with hip BMD in the women, and bioavailable estradiol (E2) was correlated with BMD at all sites in men and in postmenopausal women. In the women, adjusting for leptin reduced the strength of the association between fat mass and BMD, with further adjustments for insulin or bioavailable E2 having no additional effects. Adjusting for leptin in the men had no consistent effect on the relationship between fat mass and BMD. Collectively, these data suggest that there is a sexual dimorphism in the relationship of fat mass and leptin to BMD, with both being positively associated with BMD in women but not in men. In women, leptin may also mediate at least part of the protective effect of fat mass on the skeleton.

Osteoporosis in men

Osteoporosis is characterized by a reduction in bone density, associated with skeletal fragility and an increased risk of fracture after minimal trauma. Although osteoporosis is generally considered to be a condition affecting post-menopausal women, it is now clear that substantial bone loss occurs with advancing age in men, such that up to 20% of symptomatic vertebral fractures and 30% of hip fractures occur in men. This chapter highlights the incidence and prevalence of osteoporotic fractures in men and reviews the associated morbidity, excess mortality and health and social service expenditure. The determinants of peak bone mass and bone loss in men are discussed, as is the pathogenesis of osteoporosis and vertebral and hip fractures. The criteria for the diagnosis of osteoporosis in men are reviewed, together with the most appropriate investigations for secondary osteoporosis. The management of osteoporosis in men is also discussed, highlighting the most appropriate treatment options.

Androgens: biphasic dose responses

Testosterone was reported to affect a variety of reproductive endpoints. More notable were the effects of dihydrotestosterone on cell proliferation in the prostate cancer cell model LNCaP and Sertoli cell function. Testosterone production was also biphasically affected by prolactin that was administered to adult testicular cells in vitro.

Bone turnover markers and sex hormones in men with idiopathic osteoporosis

BACKGROUND

In contrast to osteoporosis in postmenopausal women, osteoporosis in men has received much less attention.

PATIENTS AND METHODS

We determined various biochemical parameters of bone metabolism and sex hormones in 31 men with idiopathic osteoporosis and 35 age matched control subjects.

RESULTS

In the men with osteoporosis, a significantly increased urinary excretion of deoxypyridinoline (5.3 +/- 0.2 vs. 4.6 +/- 0.2 nmol mmol-1 creatinine; P = 0.033) in addition to increased serum levels of the c-terminal telopeptide of type I collagen (2677 +/- 230 vs. 2058 +/- 153 pmol; P = 0.037) were found. While parameters of bone formation were not significantly different in the patients and controls, serum bone sialoprotein levels were significantly decreased in the patients (3.7 +/- 0.8 vs. 12.4 +/- 4.0 ng mL-1; P = 0.021). Moreover, in men with idiopathic osteoporosis, lower levels of estradiol (91.3 +/- 5.8 vs. 114.6 +/- 7.8 pmol L-1; P = 0.044), higher levels of sex hormone binding globulin (31.5 +/- 3.1 vs. 24.2 +/- 1.4 nmol L-1; P = 0.034) and a decreased free androgen index (42.6 +/- 5.2 vs. 56.4 +/- 5.9; P = 0.016) were seen. Serum estradiol levels correlated negatively with several parameters of bone resorption.

CONCLUSIONS

In men with idiopathic osteoporosis, bone resorption is increased and exceeds bone formation. The excessive bone resorption seen in idiopathic male osteoporosis may be due to decreased estradiol levels and low levels of bioavailable testosterone.

Age-related changes in bone density among healthy Greek males

Osteoporosis in men is increasingly recognized as a problem in clinical medicine, but it has received much less attention than its counterpart in women. It is termed idiopathic if no known cause of bone disease can be identified clinically or in the laboratory. The true incidence of idiopathic osteoporosis (IO) in males is difficult to estimate because population characteristics and referral patterns differ so widely. The aim of this study was to investigate the incidence of IO in healthy Greek male volunteers by measuring bone mineral density (BMD) at four skeletal sites and examining the relations among age, BMI, and bone status. This type of information has not yet been published. We considered osteoporosis to be present when the BMD was less than or equal to -2.5 SD from the average value for healthy young men. Three hundred and sixty-three normal male volunteers were investigated. The mean age was 51.3+/-8.7 yr, and BMI was 27.5+/-3.7 kg/m2. In all subjects BMD at four skeletal sites - lumbar spine (LS), femoral neck (FN), Ward's triangle (WT), and finally trochanter (T) - was measured using dual-energy X-ray absorptiometry (DEXA). T-score, Z-score and g/cm2 values were estimated. Forty-four subjects (11%) had BMD< or =-2.5 SD (T-score). The mean age and BMI for the men with decreased BMD was 54.8+/-6.4 yr and 26.3+/-3.3 kg/m2, whereas mean age and BMI for those with normal BMD was 51.0+/-8.9 yr and 27.6+/-3.6 kg/m2, respectively. These differences were statistically significant (p<0.001 and p<0.05, respectively). A positive correlation was found between BMI and bone density (g/cm2) at three skeletal sites: LS (r=0.235, p<0.001), WT (r=0.126, p<0.001) and FN (r=0.260, p<0.001). A positive correlation was also found between BMI and T-score at all skeletal sites studied: LS (r=0.276, p<0.001), WT (r=0.133, p<0.05), FN (r=0.233, p<0.001), and T (r=0.305, p<0.001). Finally, a positive correlation was also found between BMI and Z-score: LS (r=0.256, p<0.001), WT (r=0.117, p<0.005), FN (r=0.240, p<0.001), and T (r=0.187, p<0.001). A negative correlation was found between age and bone density (g/cm2) at FN (r=-0.157, p<0.01) and WT (r=-0.183, p<0.001). The same was true between age and T-score at FN only (r=0.137, p<0.05). Furthermore, a similar correlation was found between age and Z-score at LS (r=0.174, p<0.001). When ANOVA one-way analysis was used, a significant difference was found between the different age groups and BMD (g/cm2) at FN, T, and WT (p<0.001 for all sites). For T-score, a significant difference between age groups was found only at FN (p<0.005). Finally, a significant difference in Z-score was found at FN (p<0.001) and LS (p<0.005). When multiple regression analysis was applied, it was found that BMD (g/cm2) at two sites, FN and WT, independently correlated with age and BMI (FN: p<0.001 for both, WT: p<0.01 and p<0.05, respectively). Finally, we found an accelerated trend toward decreased BMD (g/cm2), when the odds ratio was applied. In conclusion, this study demonstrated that 11% of otherwise healthy Greek men had BMD less than or equal to -2.5 SD. A strong association was found between BMD (g/cm2) and age at three skeletal sites when ANOVA one-way analysis was applied. Moreover, BMD was positively correlated with BMI and negatively correlated with age. Currently available data are sparse and much more research is needed to increase our understanding concerning the etiology of this condition as well as illuminating the relationship between bone density and fracture.

A meta-analysis of the effects of cigarette smoking on bone mineral density

To determine the magnitude and mediators of the association between cigarette smoking and bone mass in the epidemiologic literature we reviewed articles, published abstracts, and conference proceedings, identified through MEDLINE, psychological abstracts, conference proceedings, and article bibliographies. We studied cross-sectional and prospective human studies that provided a quantitative measure of bone mass (X-ray, absorptiometry, or computed tomography) as a function of cigarette smoking exposure. Effects were expressed as pooled standardized mean differences for categorical comparisons (e.g., bone mass in current versus nonsmokers), and as pooled correlation coefficients for continuous comparisons (e.g., correlation of bone mass and pack-years of smoking). Effects were derived for combined bone sites (all bone sites pooled within each study) and four specific sites (hip, lumbar spine, forearm, and os calcis), and were examined overall and as a function of subject and methodologic characteristics (gender, age, body weight, menopausal status, health status). Data were pooled across 86 studies, enrolling 40,753 subjects. Smokers had significantly reduced bone mass compared with nonsmokers (never and former smokers) at all bone sites, averaging a one-tenth standard deviation (SD) deficit for combined sites. Deficits were especially pronounced at the hip, where the bone mass of current smokers was one-third of a SD less than that of never smokers. Overall, effects were greatest in men and in the elderly, and were dose-dependent. In prospective studies, smokers had greater rates of bone loss over time compared with nonsmokers. Bone mass differences remained significant after controlling for age and body weight differences between the two groups. Absolute effect sizes at most bone sites were greatest for current smokers compared with never smokers, intermediate for current smokers compared with former smokers, and lowest for former smokers compared with never smokers, suggesting that smoking cessation may have a positive influence on bone mass. Based on these data, it is estimated that smoking increases the lifetime risk of developing a vertebral fracture by 13% in women and 32% in men. At the hip, smoking is estimated to increase lifetime fracture risk by 31% in women and 40% in men. It appears that smoking has an independent, dose-dependent effect on bone loss, which increases fracture risk, and may be partially reversed by smoking cessation. Given the public health implications of smoking on bone health, it is important that this information be incorporated into smoking prevention and cessation efforts.

Evaluating and managing osteoporosis in men

Osteoporosis affects approximately 10 million Americans; of these, 2 million are men. An estimated 3.5 million additional men are at risk of developing the disease. Individuals with osteoporosis commonly incur fractures of the spine, hip, and forearm. The clinical spectrum of osteoporosis is similar in men and women; however, differences exist in skeletal development, age-related bone loss, modifiable and nonmodifiable risk factors, and secondary causes. Prevention and early detection is achieved through identification of risk factors and secondary causes. Treatment options include risk factor reduction, correction of underlying disease, and use of pharmacologic and nonpharmacologic therapies.

Turkish women's knowledge of osteoporosis

BACKGROUND

Preventive measures including patient education can reduce hip fractures related to osteoporosis. Sometimes osteoporosis can be diagnosed with fractures or with a serious health problem, and most women are probably unaware of the risk factors which can be changed by prevention. The first step in preventing osteoporosis in women should be to make them aware of the risk factors.

OBJECTIVES

Our aim was to determine Turkish women's knowledge about and attitudes to osteoporosis and its prevention.

METHODS

A total of 311 women who applied to the Family Medicine department of the Middle East Technical University Medical Center were asked to fill in a questionnaire about osteoporosis. Only 270 of the 311 women who completed the entire questionnaire were included in the study.

RESULTS

Nearly 90% of the women surveyed thought they were somewhat familiar with osteoporosis. However, >65% were unaware that the disease is directly responsible for disabling hip fractures, and >40% were unable to identify significant risk factors. Only 36% of the respondents could correctly identify the calcium-rich foods among the choices.

CONCLUSION

According to our survey, a considerable number of the Turkish women in our settlement are unaware of the risk factors and the consequences of osteoporosis. Therefore, the women have inadequate knowledge of osteoporosis. There should be information resources easily accessible for the patients. The most important organizational incentives for providing patient information are further health promotion by the health authorities and the support of family physicians and the primary health care team.

Bone mineral density and bone markers in hypogonadotropic and hypergonadotropic hypogonadal men after prolonged testosterone treatment

After prolonged treatment (76.4+/-10 and 70.1+/-12.3 months, respectively) (mean+/-SE) with testosterone enanthate (250 mg i.m. every 3 weeks), bone mineral density (BMD) and bone metabolism were evaluated in 12 patients (aged 29.3+/-1.4 yr) affected by idiopathic hypogonadotropic hypogonadism (IHH), in 8 patients (29.6+/-2.6 yr) affected by Klinefelter's syndrome (KS), and in 10 healthy men (30.6+/-1.7 yr) matched according to age and BMI. Spinal BMD in IHH was significantly lower than in controls (0.804+/-0.04 vs 1.080+/-0.01 g/cm2; p<0.001), while there was no difference in neck BMD (0.850+/-0.01 vs 0.948+/-0.02 g/cm2). Neither spinal (0.978+/-0.05 g/cm2) nor neck (0.892+/-0.03 g/cm2) BMD in KS were significantly different from controls. Six IHH and one KS subjects were osteoporotic, while 6 IHH and 2 KS subjects were osteopenic. A significant inverse correlation was found between spinal BMD and age at the treatment onset in IHH (r=-0.726, p=0.007). In IHH there were significant increases in bone formation (alkaline phosphatase=318.3+/-33.9 vs 205.4+/-20.0 IU/l; osteocalcin=13.44+/-1.44 vs 8.57+/-0.94 ng/ml; p<0.05) and in bone resorption (urinary cross-linked N-telopeptides of type I collagen=149.1+/-32.3 vs 47.07+/-8.4 nmol bone collagen equivalents/mmol creatinine; p<0.05) compared to controls, while such differences were not present in KS. Our results outline the importance of BMD evaluation in all hypogonadal males. Nevertheless, bone loss is a minor characteristic of KS, while it is a distinctive feature of IHH. Therefore, early diagnosis and age-related replacement therapy coupled with a specific treatment for osteoporosis could be useful in preventing future severe bone loss and associated skeletal morbidity.

Cigarette smoke inhibits osteogenic differentiation and proliferation of human osteoprogenitor cells in monolayer and three-dimensional collagen gel culture

Cigarette smoke is a risk factor not only for emphysema but also for other disorders characterized by deficient tissue repair, including osteoporosis. We hypothesized, therefore, that smoke might directly impair bone cell repair processes. To evaluate this, bone marrow osteoprogenitor cells were isolated from normal subjects and cultured in monolayer and in three-dimensional type I collagen gel culture. Human osteoprogenitor cells could be induced to differentiate toward osteoblast-like cells in both culture conditions by osteogenic supplements. Under both culture conditions, cigarette smoke extract (CSE) inhibited the proliferation of osteoprogenitor cells in a concentration-dependent manner. CSE also inhibited differentiation of osteoprogenitor cells toward osteoblast-like cells as assayed by alkaline phosphatase activity and calcium incorporation into cell layer. Cells in monolayer culture were more sensitive to the effect of smoke than cells in three-dimensional gel culture. Similar results were obtained with osteoblast-like cells derived from osteosarcomas. This study, therefore, demonstrates that cigarette smoke may affect bone progenitor cells directly and in this manner may contribute to the development of osteoporosis.

Extrapulmonary effects of chronic obstructive pulmonary disease

Although airflow obstruction is the most obvious and most studied manifestation of chronic obstructive pulmonary disease (COPD), it should not be overlooked that COPD, particularly in its later stages, is associated with many extrapulmonary features that contribute to the morbidity, reduced quality of life, and, possibly, mortality of this disease. We review here the literature on skeletal muscle dysfunction, osteoporosis, and weight loss in COPD, with particular attention to possible approaches to their management. Patients with COPD may also have other extrapulmonary effects such as hormonal abnormalities that could probably be corrected, but less is known about them. COPD, therefore, should be regarded as a systemic disorder. Its systemic manifestations should not be overlooked in the overall care of the patient, because there are important ways in which they can be addressed.

Potential side-effects of endocrine treatment of long duration in prostate cancer

Endocrine treatment of prostate cancer has been established for more than 5 decades. Focusing on immediate or short-term side effects, bilateral orchidectomy may cause psychological trauma, treatment with oral estrogens is combined with a high risk of severe cardiovascular complications, and the use of LH-RH agonists and antiandrogens as monotherapies or in combination may result in tumor flare, hot flashes, and gynecomastia. In recent years an increasing number of reports on anemia and/or osteoporosis related to endocrine treatment have been published. These side effects are regular and persistent after orchidectomy, or during treatment with LH-RH agonists, and are most often expressed with maximum androgen blockade. In contrast, anemia and/or osteoporosis are not reported with estrogen treatment or the use of nonsteroidal antiandrogens as a monotherapy regimen. Since many prostate cancer patients are treated hormonally for many years, control of Hb levels and bone mineral density before and after initiation of treatment at regular intervals is highly recommended as a standard of care.

Testosterone inhibits osteoclast formation stimulated by parathyroid hormone through androgen receptor

Androgens play an important role in the regulation of bone metabolism in animals and humans. The present study was performed to investigate whether androgens would affect osteoclast formation stimulated by parathyroid hormone (PTH) in mouse bone cell cultures and its mechanism. Testosterone as well as alpha-dihydrotestosterone (DHT) concentration-dependently inhibited osteoclast formation induced by PTH-(1-34). 10(-8) M ICI 182780, an estrogen receptor inhibitor, did not affect PTH-induced osteoclast formation antagonized by 10(-8) M testosterone, although it completely antagonized the effects of 10(-8) M 17beta-estradiol. Moreover, 3 microM 4-androsten-4-ol-3,17-dione, an aromatase inhibitor, did not affect PTH-induced osteoclast formation antagonized by testosterone. Hydroxyflutamide, an androgen receptor antagonist, concentration-dependently antagonized the inhibitory effects of testosterone as well as DHT on PTH-stimulated osteoclast formation. In conclusion, the present study first demonstrated that testosterone inhibited osteoclast formation stimulated by PTH through the androgen receptor, but not through the production of intrinsic estrogen in mouse bone cell cultures.

Osteoporosis in men

Although less common than in women, osteoporosis in men is a prevalent worldwide problem with important socioeconomic implications. Our understanding of this condition in men is growing, but there remains a great deal more to be determined. Definitions for osteoporosis in men are needed. Cost-effective guidelines on who should be investigated and treated, and how, are clearly necessary. The role of bone mineral densitometry in diagnosis and treatment decisions needs to be clarified. The efficacy of drug therapies for osteoporosis in men requires greater attention. Currently, a large multicenter study is underway in the United States and should provide much needed insight into the epidemiology of osteoporosis in men.

Hormone replacement therapy and fractures in older adults

Estrogen deficiency in women is associated with accelerated bone loss, and estrogen replacement therapy has been proven to be effective in preventing osteoporosis and fractures in postmenopausal women. The introduction of selective estrogen receptor modulators that have an estrogen-like effect on the skeleton but have a different pattern of effects on other tissues may have an important role in the management of osteoporosis in women in the near future. In men, androgen deficiency has been shown to be associated with osteoporosis. Although androgen replacement in hypogonadal men may decrease bone resorption and increase bone mass, long-term placebo-controlled trials are needed to better define the benefits and risks of such therapy before it can be recommended. Sex hormone deficiency is linked to the development of osteoporosis in both women and men. In women, hormonal replacement by estrogen or the newly developed selective estrogen receptor modulators may prevent the development of osteoporosis and its related fractures. In men, there is early evidence that testosterone replacement therapy may enhance bone mass in hypogonadal men.

Ethanol activates NFkappaB DNA binding and p56lck protein tyrosine kinase in human osteoblast-like cells

Alcoholics frequently suffer from moderate to severe bone loss that results in bone fractures. Both decreased bone production and increased bone resorption have been postulated to contribute to ethanol (ETOH)-mediated bone loss. Bone resorption is induced by several proinflammatory cytokines such as interleukin-1 and -6. The expression of these cytokines is induced by the transcription factor NFkappaB, which, in turn, is activated by several kinases. It follows that protein kinase and NFkappaB activation may contribute to ETOH-induced bone loss. Accordingly, we sought to determine if ETOH activates protein tyrosine kinases (PTK) and NFkappaB DNA binding in a human osteoblast-like cell line (HOBIT). Ethanol at 50 and 100 mmol/L (reflective of blood ethanol levels reached in chronic alcoholics) for 24 h did not alter HOBIT cell viability. In contrast, 200 mmol/L ethanol decreased cell viability by 40%. Treatment of HOBIT cells with 100 mmol/L ETOH induced nuclear NFkappaB:DNA complex formation and NFkappaB activity. Incubation of HOBIT cells with ETOH at 50 and 100 mmol/L for 30 min induced a 2.5- and 4.2-fold increase in PTK activity, respectively. Preincubation of HOBIT cells with damnacanthal (DAM), which inhibits p56lck, blocked ETOH-mediated PTK activity; whereas, preincubation with herbimycin A, which inhibits pp60src, did not. DAM inhibited both ethanol-induced NFkappaB activation in HOBIT cells and interleukin-6 expression in primary human osteoblasts. Finally, preincubation with the protein kinase C inhibitor, bisindolylmaleimide I HCl (BIS), diminished ETOH-mediated PTK activity; whereas, preincubation with the protein kinase A inhibitor, H89, did not. These data demonstrate that ETOH induces NFkappaB nuclear translocation through p56lck in HOBIT cells. BIS' inhibition of PTK activation suggests that ETOH activates PTK through a protein kinase C-dependent pathway. These data suggest that ETOH may contribute to bone loss through activation of signal transduction that results in production of an osteoclastogenic cytokine (i.e., interleukin-6) in osteoblasts.

Cigarette smoking and open tibial fractures

Complication rates were compared in 140 smoking and 133 non-smoking patients with open tibial fractures. Both the groups were evenly matched demographically and in terms of primary fracture treatment. Flap failure complicated 7 (20%) patients in the smoking group and 4 (14%) in the non-smoking group. The mean time to union was 32 weeks for smokers and 28 weeks for non-smokers (P<0.05). Bone grafting to stimulate union was required in 36 (26%) smoking patients compared with 24 (18%) non-smoking patients. In patients treated by intramedullary nailing exchange, nailing to achieve union was carried out in 24 (38%) smoking cases compared with 13 (26%) of non-smoking cases. Smoking is associated with an increased risk of complications in patients with open tibial fractures. There is an increased rate of flap failure, delayed union and non-union. We recommend patients with open tibial fractures should be advised to stop smoking to minimise these complications.

Unresolved issues in osteoporosis in men

Fragility fractures in men are a public health problem. The increasing longevity in men is likely to increase the public health burden of fractures in men. This problem remains unrecognized by doctors, the public and governments. About one third of all hip fractures occur in men but the incidence and gender ratio varies from country to country for reasons that are not understood. The prevalence of spine fractures is about half that of women in most studies, but similar to that of women in several other studies. The incidence of spine fractures is uncertain but is likely to be about half that of women except in 80+ year olds, when it appears to be similar. The causes of the higher mortality in men than in women following hip or spine fracture are not well defined. Areal bone mineral density (aBMD) predicts fracture risk in men; the relative risk for spine and hip fracture conferred by a 1 SD lower aBMD, or by a prevalent fracture, is similar in men and women. The age-specific absolute risk (number of cases per 1,000 per year) conferred by a given hip aBMD is similar in men and women. The age-specific absolute risk conferred by aBMD at the calcaneus or radius for spine fracture is similar for men and women. If the absolute and relative risks are similar then the lower incidence of fractures in men than women may reflect the lower proportion of the male population distribution below a given structural determinant of bone fragility. That is, at any age, there may be fewer men than women with smaller bones, lower volumetric bone mineral density (vBMD), thinner trabeculae or cortices, architectural disruption, or higher remodeling rates. Higher mortality and fewer falls may also contribute to the lower incidence of fractures in men. This tail end of the male population distribution (for traits like bone size, vBMD, architecture, and remodeling rates) is the likely source of fracture cases in males. Hypogonadism is a risk factor for osteoporosis. However, the definition, prevalence, causes and structural consequence of hypogonadism are inadequately defined. At what level of testosterone is bone balance negative? What structural determinants of axial and appendicular strength are regulated by testosterone, estrogen, growth hormone (GH), insulin like growth factor 1 (IGF-1) (or their interactions)? Is reduced bone size in men with spine or hip fractures due to failed growth-related or age-related periosteal expansion? If reduced vBMD is due to reduced accrual, is this due to reduced cortical thickness? What factors regulate and coregulate the periosteal and endocortical modeling and remodeling? Are reduced trabecular numbers due to failed formation at the growth plate, excess resorption of primary trabeculae or reduced formation of secondary trabeculae? Is reduced trabecular thickness due to failed prepubertal or pubertal bone formation? Is reduced cortical and trabecular thickness during aging due to excessive endosteal resorption or reduced bone formation? If the former, is this due to increased remodeling sites or increased resorption depth? Most evidence favors reduced bone formation as the cause of bone loss with trabecular bone loss occurring by reduced formation and thinning more than by increased resorption and loss of connectivity. Cortical bone loss is less than in women because endocortical resorption is less and periosteal apposition is greater. If the reduced bone formation is most important, is this due to reduced osteoprogenitors, reduced osteoblast matrix synthesis or early osteoblast apoptosis? Anti-spine-fracture efficacy has been demonstrated in only one randomized heated with alendronate drug in men. The gaps in our knowledge remain large.

Corticosteroids in chronic obstructive pulmonary disease. Clinical benefits and risks

The use of systemic and inhaled corticosteroids for COPD has increased appreciably over the past 20 years. Clearer indications for corticosteroid therapy in COPD are beginning to emerge as the results from large clinical trials become available. Systemic corticosteroids are only modestly effective for acute COPD exacerbations, increase the risk for hyperglycemia, and should be given for no more than 2 weeks. The efficacy of long-term systemic corticosteroid therapy has not been adequately evaluated in this patient population. If longer term use of systemic steroids in COPD should be found to be useful, this conclusion would have to be weighed against the risk for serious adverse effects. High doses of inhaled corticosteroids cause a small sustained increase of the FEV1 in patients with mild and moderately severe COPD, but they do not slow the rate of FEV1 decline. Based on analyses of secondary outcome, inhaled corticosteroids may improve the respiratory symptoms and decrease the number and severity of COPD exacerbations in patients with more advanced disease. Low doses of inhaled corticosteroids appear to be safe, but there is growing awareness that higher doses may not be so benign.

Fractures following thyroidectomy in women: a population-based cohort study

Hip fracture risk has been associated with hyperthyroidism and thyroidectomy in men and with hyperthyroidism in women, but the influence of thyroidectomy on fracture risk in women has not been adequately addressed. The 630 Rochester, MN women who underwent thyroidectomy in 1950-1974 were followed subsequently for 12,804 person-years (retrospective cohort study) during which 601 fractures were observed. Relative to incidence rates in the community, there was no increase in overall fracture risk (standardized incidence ratio [SIR] 0.9; 95% confidence interval [CI] 0.8-1.00). No increase was seen in limb fractures generally or in distal forearm fractures specifically (SIR 1.1, 95% CI 0.8-1.4). There was a modest but statistically significant increase in the risk of hip fractures following thyroidectomy (SIR 1.3, 95% CI 1.01-1.8), but much greater increases were apparent in the risk of subsequent fractures of the ribs, spine, and pelvis. There was almost a threefold increase in vertebral fractures (SIR 2.8, 95% CI 2.3-3.3), but the excess was mostly observed long after the original operation and may be attributable to ascertainment bias. Fracture risk was associated with advancing age and with the presence of one or more of the diseases that have been associated with secondary osteoporosis but not with a history of hyperthyroidism, extent of thyroid surgery, or subsequent use of thyroid replacement therapy. Thus, with the exception of some fractures of the axial skeleton, which might have been more completely diagnosed among affected women, there was no increase in fracture risk among women following thyroidectomy performed mainly for adenoma or goiter.

Correlates of osteoporosis in chronic obstructive pulmonary disease

The aim of this study was to analyse the correlates of reduced bone mineral density in patients with chronic obstructive pulmonary disease (COPD), with special regard to a possible protective role of hypercapnia. One hundred and four consecutive COPD inpatients in stabilized respiratory conditions underwent a comprehensive assessment of their health status. Bone mineral density was measured by X-ray absorptiometry at the lumbar site and at the femoral neck site. Differences in health-related variables between patients with (group O, n=62) and without (group N, n=42) lumbar and/or femoral neck osteoporosis were assessed first by univariate analysis and then by logistic regression analysis aimed to identify independent correlates of osteoporosis. Group O was characterized by worse nutritional status, as reflected by indices exploring either lean or fat mass, and by a trend towards lower forced expiratory volume in 1 sec/forced vital capacity ratio. Arterial tension of carbon dioxide lacked any correlation with bone mineral density. According to the logistic regression analysis, body mass index < or = 22 kg m(-2) qualified as the only and positive independent correlate of osteoporosis (odds ratio=4.18; 95% confidence intervals=1.19-14.71). In conclusion, malnutrition characterizes COPD patients with osteoporosis, while mild to moderate hypercapnia lacks either a positive or negative effect on bone mineral density. Longitudinal studies are needed to identify predictors rather than correlates of bone mineral density.

Chronic alcohol ingestion induces osteoclastogenesis and bone loss through IL-6 in mice

To investigate the role of IL-6 in alcohol-mediated osteoporosis, we measured a variety of bone remodeling parameters in wild-type (il6(+/+)) or IL-6 gene knockout (il6(-/-)) mice that were fed either control or ethanol liquid diets for 4 months. In the il6(+/+) mice, ethanol ingestion decreased bone mineral density, as determined by dual-energy densitometry; decreased cancellous bone volume and trabecular width and increased trabecular spacing and osteoclast surface, as determined by histomorphometry of the femur; increased urinary deoxypyridinolines, as determined by ELISA; and increased CFU-GM formation and osteoclastogenesis as determined ex vivo in bone marrow cell cultures. In contrast, ethanol ingestion did not alter any of these parameters in the il6(-/-) mice. Ethanol increased receptor activator of NF-kappaB ligand (RANKL) mRNA expression in the bone marrow of il6(+/+) but not il6(-/-) mice. Additionally, ethanol decreased several osteoblastic parameters including osteoblast perimeter and osteoblast culture calcium retention in both il6(+/+) and il6(-/-) mice. These findings demonstrate that ethanol induces bone loss through IL-6. Furthermore, they suggest that IL-6 achieves this effect by inducing RANKL and promoting CFU-GM formation and osteoclastogenesis.

Determinants of bone density in healthy older men with low testosterone levels

BACKGROUND

Osteoporosis is a significant problem in older men, 30% of all hip fractures occur in men and the mortality rate following hip fracture exceeds that of women. Testosterone is thought to be important in the development of peak bone mass hut its role in age-related bone loss is not established. The purpose of this study was to define the predictors of bone mass ill healthy older men with low testosterone levels but without symptomatic osteoporosis.

METHODS

Eighty-three community-dwelling white men, aged more than 65 years old, selected for low bioavailable testosterone levels (< or = 4.44 nmol/l) participated in a cross-sectional study located at a university general clinical research center. Sex hormone concentrations and markers of bone turnover were assayed in serum and urine. Risk factors for osteoporosis and physical activity were ascertained by physical examination and questionnaire, including the Physical Activity Scale in the Elderly (PASE) questionnaire. Bone mineral densities of the femoral neck (FN BMD), spine, and whole body were measured by dual x-ray absorptiometry. Lower extremity muscle strength (1 repetition maximum) was measured using a leg press machine.

RESULTS

Mean bone mineral density values were 0.93 +/- 0.14 g/cm2 for femoral neck, 1.31 +/- 0.23 g/cm2 for spine, and 1.22 +/- 0.12 g/cm2 for whole body. Thirty-one of the 82 subjects (37%) had t scores < -1 and 12 of 82 subjects (15%) had t scores < -2.5 at the femoral neck. Multiple linear regression analysis demonstrated that bioavailable testosterone, body mass index (BMI), and PASE scores were positively correlated with, and significant predictors of, femoral neck BMD, accounting for 34.4% of the variance in FN BMD (F = 10.10, p = .001). Examining each variable independently, bioavailable testosterone accounted for 20.7%, physical activity score for 9.0%, and BMI for 6.5% of FN BMD. Using analysis of variance, mean values for FN BMD were significantly different between men grouped by tertile of bioavailable testosterone (F = 6.192, p = .003). FN BMD mean values were 0.86 +/- 0.14 g/cm2 for the lowest tertile, 0.94 +/- 0.16 for the middle tertile, and 0.99 +/- 0.14 for the highest tertile. Markers of bone turnover were inversely correlated, and strength directly correlated with BMD, but did not contribute to the multiple regression model.

CONCLUSIONS

Fifty-two percent of older men with low bioavailable testosterone levels had BMD levels below the young adult normal range and are likely at an increased risk of fracture. Bioavailable testosterone, BMI, and physical activity scores were significant determinants of FN BMD in these men. These variables are potentially modifiable and, therefore, amenable to intervention. Hence, our results suggest the need for testosterone replacement and physical activity intervention trials in men at risk for osteoporotic fractures.

Osteoporosis. Pathogenesis, diagnosis, and treatment in older adults

Osteoporosis is a major cause of disability and excess mortality in older men and women. Hip fracture incidence accelerates approximately 10 years after menopause in women and after age 70 in men. Approximately 1 million Americans suffer fragility fractures each year at a cost of over 14 billion dollars. The disability, mortality, and cost of hip and vertebral fractures are substantial in the rapidly growing, aging population so that prevention of osteoporosis is a major public health concern. BMD is used to make the diagnosis of osteoporosis before incident fracture and predict fracture risk. Recommendations for treatment and prevention of osteoporosis based on BMD score have been published by the World Health Organization and the National Osteoporosis Foundation. In a process that continues throughout life, bone repairs itself by the coupled action of bone resorption followed by bone formation, sometimes referred to as bone turnover. Osteoblasts and osteoclasts are the primary cells involved in bone formation and resorption, respectively. The process of bone turnover is regulated by hormones, such as PIH and local factors such as IL-1 and prostaglandins. Following attainment of peak bone mass at age 25, bone loss begins, accelerates in women at menopause and slows again but continues into advanced years at a rate of 1% to 2% per year, similar to premenopausal bone loss rate. The leading theories of the mechanism of bone loss in older individuals is calcium deficiency leading to secondary hyperparathyroidism and sex hormone deficiency. Risk factors such as age, gender, ethnic background, smoking, exercise, and nutrition, and medical conditions associated with osteoporosis should be evaluated and modified when possible to prevent further bone loss. Osteoporosis treatment and prevention include weight-bearing exercise, calcium and vitamin D supplementation, estrogen replacement, bisphosphonates, selective estrogen receptor antagonists, and calcitonin. Although there is no currently approved treatment for osteoporosis in men, many of the treatments approved for osteoporosis in women hold promise to be beneficial in men.

Osteoporosis and osteoporotic fractures in men: a clinical perspective

The lifetime risk of any fracture of the hip, spine or distal forearm in men aged 50 years has been estimated to be 13%, compared with 40% in women. Although the overall incidence of osteoporosis is less in men than in women, the disease still represents an important public health problem. In particular, hip fractures are associated with substantial mortality and morbidity, even more so than in women. In male patients presenting with osteoporotic fractures, major causes of skeletal fragility, such as hypogonadism, glucocorticoid excess, primary hyperparathyroidism and alcohol abuse, can often be identified. In as many as 50% of osteoporotic men, however, no aetiology can be found: these men suffer from a syndrome commonly referred to as idiopathic osteoporosis, which is presumably related to some type of osteoblast dysfunction. Recent evidence indicates that the loss of skeletal integrity in ageing men may be partially related to endocrine deficiencies, including vitamin D, androgen and/or oestrogen deficiency. While the consequences of vitamin D or oestrogen deficiency in women have been well established, the skeletal impact of these (partial) age-related deficiencies in men remains to be clarified. Osteoporosis in elderly men is a multifactorial disease, as it is in women. The prevention of osteoporosis should therefore focus not only on increasing the bone strength, but also on decreasing the risk of falls. However, the prevention and therapy of osteoporotic disorders in men are virtually unexplored. To date, the use of specific osteoporotic drugs in osteoporotic men is still based on reasonable but untested assumptions.

Estrogen receptor specificity in the regulation of skeletal growth and maturation in male mice

Androgens may regulate the male skeleton directly through a stimulation of androgen receptors or indirectly through aromatization of androgens into estrogen and, thereafter, through stimulation of estrogen receptors (ERs). The relative importance of ER subtypes in the regulation of the male skeleton was studied in ERalpha-knockout (ERKO), ERbeta-knockout (BERKO), and double ERalpha/beta-knockout (DERKO) mice. ERKO and DERKO, but not BERKO, demonstrated decreased longitudinal as well as radial skeletal growth associated with decreased serum levels of insulin-like growth factor I. Therefore, ERalpha, but not ERbeta, mediates important effects of estrogen in the skeleton of male mice during growth and maturation.

Androgens and osteoporosis

Androgen receptors are present in relevant numbers in osteoblasts. Stimulation of androgen receptors in osteoblastic bone marrow stromal cells inhibits the differentiation of osteoclasts in the bone marrow cavity. Androgens not only inhibit osteoclastogenesis but also increase cortical bone formation mainly by stimulating periosteal bone formation. Clinically, androgen action is crucial for the gain of bone mass during puberty and the maintenance of bone mass after puberty. Therefore, androgen replacement is necessary in hypogonadal men. However, the role of androgen replacement in partial androgen deficiency still remains unclear. Thus far, only testosterone has established its role in androgen replacement. However, further clinical and basic research should better define the selective role of androgen versus oestrogen receptor stimulation in male skeletal homeostasis.

The impact of mild Leydig cell dysfunction following cytotoxic chemotherapy on bone mineral density (BMD) and body composition

BACKGROUND

Overt testosterone deficiency is associated with a reduction in BMD and alteration in body composition. However, there are few data concerning the impact of mild hypogonadism on these parameters.

PATIENTS AND METHOD

We have identified a cohort of 36 men aged < 55 years with mild Leydig cell impairment, defined by a raised LH level (LH >/= 8 IU/l) in the presence of a testosterone level in the lower half of the normal range or frankly subnormal (< 20 nmol/l), following treatment with procarbazine-containing chemotherapy regimens or high-dose chemotherapy for haematological malignancy. These men underwent measurements of BMD (measured by dual-energy X-ray absorptiometry (DXA), single energy X-ray absorptiometry (SXA) and quantitative CT (QCT)), body composition (DXA), markers of bone turnover, serum lipids and serum IGF-1. To allow for changes that may be directly attributable to the underlying disease or its treatment, results were compared with those obtained in 14 men who had received the same chemotherapy for the same diseases but had normal LH and testosterone levels (controls).

RESULTS

When data from all 50 men were considered together there were significant reductions in BMD of the lumbar spine both by DXA (Z = - 0.34, P = 0.01) and QCT (Z = - 1.5, P < 0. 0001), at the femoral neck (Z = - 0.52, P < 0.0001) and distal forearm (Z = - 0.21, P = 0.05). Mean femoral neck BMD was significantly lower in patients compared with controls (Z = - 0.68 vs. Z = - 0.11, P = 0.05) and there was a nonsignificant trend towards lower lumbar spine BMD measured by QCT (Z = - 1.64 vs. Z = - 1.10; P = 0.09). In addition, serum testosterone level and testosterone:LH ratio significantly correlated with femoral neck BMD (r = 0.28, P = 0.05 and r = 0.37, P = 0.008, respectively). There were no significant differences in lean body mass, fat mass and percentage fat between the patients and controls. There was, however, a difference in the distribution of body fat with a propensity for the patients to accrue truncal fat, and the serum testosterone level significantly inversely correlated with percentage of truncal fat (r = - 0.29, P = 0.04). There were no significant differences in lipid levels, IGF-1 levels or markers of bone turnover between the patients and controls.

CONCLUSIONS

These data suggest that mild Leydig cell impairment may have significant effects on bone mineral density and may result in subtle body composition changes, although in men who have received cytotoxic chemotherapy, other factors also contribute to the observed osteopenia. Testosterone replacement may be beneficial in some of these men and this requires further evaluation.

Biochemical markers and bone mineral density in patients with hip fractures in men

The purpose of this study was to determine whether males with hip fractures have associated decreased gonadal function. Second void urine and serum samples were obtained from 25 male hip fracture patients (mean age+/-SD, 78.5+/-5.9 years) and 19 age- and gender-matched controls (77.6+/-6.2 years). Serum levels of luteinizing hormone (LH), total testosterone (Te), total estradiol (E2), dehydroepiandrosterone sulfate (DHEAS), 1,25(OH)2D3, N-mid osteocalcin (OC(N-mid)), type I collagen degradation products (S-CTx) and urinary levels of pyridinoline (Pyr), deoxypyridinoline (Dpyr) and type I collagen degradation products (U-CTx) were measured. Bone mineral density (BMD) of the L2-4 spine, femoral neck, trochanter, Ward's triangle, distal one third portion of the radius and ultradistal radius were also measured in the fracture group. Serum levels of LH, E2, Te, DHEAS, 1,25(OH)2D3 and OCN-mid in the fracture group were not statistically different from those in the control group. Levels of urinary Pyr, CTx and S-CTx in the fracture group increased significantly compared with those in the control group. In the fracture group, serum levels of Te correlated positively with distal one third portion of the radius BMD and ultradistal radius BMD. U-CTx and S-CTx correlated negatively with all the BMD measurement sites in the hip region and with the radius BMD. An imbalance between bone resorption and bone formation was evident in male hip fracture patients. However, male patients with hip fractures did not show associated decreased gonadal function in this study.

Effects of hormonal replacement treatment on bone mineral density and metabolism in hypogonadal patients

We investigated 22 male patients affected by prepubertal hypogonadism with a mean age of 34.3+/-5.2. A significant reduction of bone mineral density (BMD) at both the lumbar spine (L2-L4, -14%, 1.039+/-0.11 vs. 1.217+/-0.16 g/cm(2), P=0.005) and femoral neck (-11%; 0.927+/-0.09 vs. 1.034+/-0.16 g/cm(2), P=0.01) was found in patients compared to age-matched controls. The mean Z score was -1. 55 for vertebrae and -1.33 for femur. Eleven and nine patients, respectively, had a lumbar and femoral BMD at least 1 S.D. below the normal mean; 8 and 4, respectively, 2 S.D. below. There was a strong positive correlation between BMD and duration of hormone replacement treatment (HRT) for both sites: respectively, r=0.71, P<0.005 for the vertebrae, and r=0.60, P<0.01 for the femur. A weak correlation was also present between onset of HRT and BMD: r=0.6, P<0.01 at the lumbar level, and r=0.47, P<0.05 at the femoral neck.

Prolactinomas in adolescents: persistent bone loss after 2 years of prolactin normalization

OBJECTIVE

To evaluate the effect of hyperprolactinaemia and its treatment with dopamine-agonists on bone mass and turnover in adolescent patients compared to adults.

PATIENTS

Forty patients with hyperprolactinaemia (20 with disease onset during adolescence and 20 during adulthood) and 40 healthy control subjects.

DESIGN

Open transverse (in patients and controls) and open longitudinal (in the patients).

MEASUREMENTS

Bone mineral density (BMD) at lumbar spine and femoral neck, serum osteocalcin (OC) and urinary cross-linked N-telopeptides of type-1 collagen (Ntx) levels were evaluated in patients and controls. In the 40 patients, bone mass and turnover were re-evaluated after 12 and 24 months of treatment with bromocriptine (BRC, dose 2.5-10 mg daily), quinagolide (CV, dose 0.075-0.3 mg daily) or cabergoline (CAB, dose 0.5-1.5 mg weekly).

RESULTS

Transverse study: BMD values were significantly lower in hyperprolactinaemic patients than in controls, both at lumbar spine (0.81 +/- 0.01 vs. 1.010 +/- 0.01 g/cm2; P < 0.001) and femoral neck (0.71 +/- 0.01 vs. 0.873 +/- 0.03 g/cm2; P < 0.001). Thirty-two patients (80%) had osteoporosis and/or osteopenia at one or both skeletal sites. A significant inverse correlation was found between T score values measured at lumbar spine and femoral neck and the estimated disease duration. BMD was significantly lower in young than adult patients both at lumbar spine (T score, -2.4 +/- 0.1 vs. -1.4 +/- 0.3, P < 0.01) and at femoral neck (T score, -2.1 +/- 0.05 vs. -1.5 +/- 0.2, P < 0.05). Similarly, serum OC levels were significantly lower (2.0 +/- 0.11 vs. 9.1 +/- 2.4 micrograms/l, P < 0. 01) while Ntx levels were significantly higher in patients than in controls (129.2 +/- 1.7 vs. 80.7 +/- 2.9 nmol Bone collagen equivalent (BCE)/mmol creatinine; P < 0.001). A significant inverse correlation was found between prolactin (PRL) levels and OC levels, lumbar and femoral T score values, as well as between disease duration and OC levels, lumbar and femoral T score values. A significant direct correlation was also found between Ntx levels and PRL levels and disease duration. Longitudinal study: Normalization of serum PRL levels was obtained in all patients after 6-12 months of treatment. A significant increase of serum OC levels together with a significant decrease of Ntx levels was observed after 12 and 24 months of treatment (P < 0.01). Urinary and serum calcium, phosphorus, creatinine, and serum alkaline phosphatase and parathyroid hormone levels did not change during the study period in all patients. After 12 months of therapy OC and Ntx concentrations were restored to normal. A slight but not significant increase of BMD values was recorded after 12 and 24 months of treatment. After 12 months of treatment the percent increment of BMD values in the whole group of patients was 1.13 +/- 0.6% at lumbar spine and 1.2 +/- 0.4% at femoral neck level, whereas after 24 months, it was 2.8 +/- 0.7% at lumbar spine and 3.5 +/- 0.7% at femoral neck level. After 12 months of treatment, the percent increment of BMD values was 0.7 +/- 0.2% and 1.6 +/- 1.1% at lumbar spine and 0.9 +/- 0.5% and 1.6 +/- 0.5% at femoral neck level in the young and adult patients, respectively, whereas after 24 months, it was 2.1 +/- 0.8% and 3.4 +/- 1.3% at lumbar spine and 2.6 +/- 0.8% and 4.4 +/- 1.0% at femoral neck level in the young and adult patients, respectively.

CONCLUSIONS

Adolescents with prolactinoma have osteopenia or osteoporosis, a finding that strengthens the need for a prompt diagnosis. Since normalization of PRL concentrations by dopamine agonist therapy is unable to restore the bone mass, other therapeutic approaches should be considered in order to prevent further long-term problems.

Risk factors for vertebral deformities in men: relationship to number of vertebral deformities. European Vertebral Osteoporosis Study Group

Recent epidemiological studies suggest a similar overall prevalence of vertebral deformity in men to that in women, though the influence of increasing age on the prevalence of vertebral deformity is less marked in men. However, most affected men have only a single or two vertebral deformities, which may be unrelated to osteoporosis. The aim of this study was to examine the role of risk factors, previously demonstrated to be associated with vertebral osteoporosis in females, in men with single/dual deformities compared to those with multiple deformities. Age stratified random samples of men aged 50 years and over were recruited from population registers in 30 European centers as part of the European Vertebral Osteoporosis Study (EVOS). Subjects had a lateral spinal radiograph and the presence of vertebral deformity was determined using the McCloskey algorithm. Lifestyle and other risk factor data were obtained from an interviewer-administered questionnaire. In all 6937 men with a mean age of 64.4 (SD = 8.5) years were studied of whom 738 (10.6%) subjects had one or two deformities, and 109 (1.6%) subjects had three or more deformities. There was a marked increase in the prevalence of multiple vertebral deformities with increasing age, but only a modest effect of age on the prevalence of single deformities. Associations between various risk factors for osteoporosis and vertebral deformity were analyzed separately in men with single/dual vertebral deformity from those with three or more deformities using logistic regression. After adjustment for age, there were statistically significant associations between the following risk factors and multiple deformities: previous hip fracture (odds ratio [OR] 10.5), lack of regular physical activity (OR 2.9), low body mass (OR 2.5), and previous steroid use (OR 2.3). By contrast, there were only weak associations with these same variables in males with single/dual deformities and, apart from poor self-reported general health, all of the 95% confidence intervals spanned unity. There was no difference in the reporting of very heavy levels of physical activity under the age of 50 years between men with single/dual deformities and those with multiple deformities. In conclusion, men with multiple deformities showed a similar pattern of risk factor association to those seen in women with vertebral deformity, in contrast to men with single/dual deformities.

Relative and combined effects of ethanol and protein deficiency on bone histology and mineral metabolism

This study was performed to analyze the relative and combined effects of ethanol and protein deficiency on bone histology and mineral metabolism in 4 groups of 7 animals each which were pair-fed during 8 weeks with 1) a nutritionally adequate diet; 2) a 36% (as energy) ethanol containing isocaloric diet; 3) a 2% protein, isocaloric diet; and 4) a 36% ethanol 2% protein isocaloric diet, respectively, following the Lieber-DeCarli model. Another group of five rats were fed ad libitum the control diet. The first and second lumbar vertebrae were removed after sacrifice, and processed for histomorphometrical analysis of undecalcified bone samples. Blood and 24-h urine were also collected. Protein malnutrition, but not ethanol, leads to osteoporosis and reduced osteoid synthesis, whereas ethanol and protein malnutrition both lead to impaired bone mineral apposition and increased urinary hydroxyproline excretion. These changes are accompanied by an increase in serum parathormone and serum 1,25 dihydroxy vitamin D3, a slight hypomagnesemia, hypercalciuria and hyperphosphaturia; protein deficiency plays an independent role in these alterations, whereas both ethanol and protein deficiency exert independent effects on decreasing serum testosterone levels; this last alteration may contribute to the bone changes mentioned before.

Effects of nicotine on cultured cells suggest that it can influence the formation and resorption of bone

The acute effects of nicotine [1-methyl-2-(3-pyridyl)pyrrolidine] on the formation and resorption of bone were examined in cultures of clonal rat calvarial osteogenic cells (ROB-C26) and clonal mouse calvarial preosteoblastic cells (MC3T3-E1), as well as in osteoclast-like cells formed during coculture of mouse bone marrow cells and clonal stromal cells from mouse bone marrow, ST2 cells, at concentrations that occur in the saliva of smokeless tobacco users. Nicotine stimulated the rate of deposition of Ca(2+) by ROB-C26 cells, as well as the alkaline phosphatase activity of these cells, in a dose-dependent manner. However, both activities decreased in MC3T3-E1 cells that had been exposed to nicotine. These results indicate that nicotine affected osteoblastic differentiation in osteoblast-like cells. By contrast, nicotine reduced, in a dose-dependent manner, the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs) and the formation of pits on slices of dentine, both of which are typical characteristics of osteoclasts. Our results suggest that nicotine might have critical effects on bone metabolism.

Effect of smoking on tibial shaft fracture healing

Of 146 consecutive closed and Grade I open tibia shaft fractures treated with cast immobilization, external fixation, or intramedullary rod fixation during a 4-year period, 44 of 76 (58%) tibias of patients who smoked and 59 of 70 (84%) tibias of patients who did not smoke had followup to union or followup beyond 1 year. The demographics, fracture patterns, and treatments of the two groups were similar. Two of the 44 patients who smoked had nonunions at the 1-year followup, whereas none of the patients who did not smoke had nonunions. Of the 103 tibias with complete followup to union, the median time to clinical healing for patients who smoked (269 days) was significantly greater than that of patients who did not smoke (136 days). Likewise, there was a 69% delay in radiographic union in the group that smoked as interpreted by a radiologist blinded to the two groups. Statistical differences in clinical and radiographic healing rates between those who smoked and those who did not smoke were observed for patients receiving intramedullary fixation or external fixation. Statistical differences were not seen in the clinical and radiographic healing of tibias treated with cast immobilization, although tibias of patients who smoked took 62% longer to heal. The current data suggest that tibias of patients who smoke who require treatment with intramedullary nailing or external fixation require more time to heal than do those of patients who do not smoke.

Thinness and weight loss: beneficial or detrimental to longevity?

This review examined the hypotheses that 1) low body mass index (BMI) is optimal for longevity and 2) weight loss reduces mortality rates. The preponderance of epidemiological evidence fails to support either of these hypotheses. Indeed, a number of studies show that thinness and weight loss (regardless of initial BMI) are associated with increased mortality rates. These findings cannot be attributed to smoking status or to weight loss resulting from subclinical disease. The effect of intentional weight loss on mortality rates depends upon health status. For overweight individuals in good health, there is no compelling evidence to show that mortality rates are reduced with weight loss. Even among overweight persons with one or more obesity-related health conditions, specific weight loss recommendations may be unnecessary: 1) the reduction in mortality rate associated with intentional weight loss is independent of the amount of weight loss, 2) the reductions in all-cause mortality rate associated with increased physical activity and fitness (23-44%), independent of changes in body weight, are greater than that reported for intentional weight loss (approximately 20%), and 3) many obesity-related health conditions (e.g., hypertension, dyslipidemias, insulin resistance, glucose intolerance) can be ameliorated independently of weight loss. In view of the potential risks associated with weight loss and weight cycling, it is suggested that public health may be better served by placing greater emphasis on lifestyle changes and less attention to weight loss per se.

Fracture risk after surgery for peptic ulcer disease: a population-based cohort study

In the 30-year period from 1956 to 1985, 471 Rochester, MN residents had an initial operation for peptic ulcer disease, 438 of whom were followed for at least 30 days (median 14.8 years per subject). In this population-based cohort, risk was elevated for all of the fracture sites traditionally associated with osteoporosis, including the proximal femur (standardized incidence ratio [SIR] 2.5, 95% CI 1.9-3.3), vertebra (SIR 4.7, 95% CI 3.8-5.7), and distal forearm (SIR 2.2, 95% CI 1.5-3.1). Fracture risk rose with age and was greater among women than men, but there was no influence on overall fracture risk of ulcer type or nature of the operation. In multivariate analyses, the independent predictors of vertebral fractures were age (hazard ratio [HR] per 10-year increase 1.8, 95% CI 1.6-2.0), use of corticosteroids (HR 2.3, 95% CI 1.01-5.2), thyroid replacement (HR 2.5, 95% CI 1.4-4.6), chronic anticoagulation (HR 2.3, 95% CI 1.1-4.6), and the presence of one or more conditions associated with secondary osteoporosis (HR 1.6, 95% CI 1.2-2.1). Gastrectomy with Billroth II reconstruction appeared to be relatively protective (HR 0.5, 95% CI 0.3-0.9), but such patients still had an increased risk of vertebral fractures compared with community residents generally (SIR 3.6, 95% CI 2.4-5.4). The independent predictors of hip fracture risk in this cohort were age (HR 2.7, 95% CI 2.1-3.5) and use of corticosteroids (HR 5.8, 95% CI 2.2-15.3) or anticonvulsants (HR 4.6, 95% CI 1.8-12.0), while higher body mass index was protective (HR 0.9, 95% CI 0.8-0.96). The independent predictors of distal forearm fractures were female gender (HR 4.7, 95% CI 2.2-10.1) and chronic anticoagulant use (HR 2.8, 95% CI 1.1-7.3). Thus, while the risk of osteoporotic fractures was significantly increased among patients operated for peptic ulcers, this appeared to be due more to specific characteristics of the cohort than to adverse effects of particular surgical procedures.

The effects of testosterone on osteoporosis in men

Although the pathogenesis of osteoporosis in men is multi-factorial, testosterone is known to play an important role in the maintenance of the male skeleton. This role, however, appears complicated as it may be mediated in part by aromatization to oestradiol. Testosterone replacement therapy improves bone density in men with hypogonadal osteoporosis, particularly if the epiphyses are still open. There is no well-established treatment for idiopathic osteoporosis in men, but testosterone supplementation may prove to be useful. Further studies are required to confirm the safety and efficacy of this treatment in eugonadal men with osteoporosis.

Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women

BACKGROUND

Osteoporosis and related fractures will be growing public health problems as the population ages. It is therefore of great importance to identify modifiable risk factors.

OBJECTIVE

We investigated associations between dietary components contributing to an alkaline environment (dietary potassium, magnesium, and fruit and vegetables) and bone mineral density (BMD) in elderly subjects.

DESIGN

Dietary intake measures were associated with both cross-sectional (baseline) and 4-y longitudinal change in BMD among surviving members of the original cohort of the Framingham Heart Study. Dietary and supplement intakes were assessed by food-frequency questionnaire, and BMD was measured at 3 hip sites and 1 forearm site.

RESULTS

Greater potassium intake was significantly associated with greater BMD at all 4 sites for men and at 3 sites for women (P < 0.05). Magnesium intake was associated with greater BMD at one hip site for both men and women and in the forearm for men. Fruit and vegetable intake was associated with BMD at 3 sites for men and 2 for women. Greater intakes of potassium and magnesium were also each associated with less decline in BMD at 2 hip sites, and greater fruit and vegetable intake was associated with less decline at 1 hip site, in men. There were no significant associations between baseline diet and subsequent bone loss in women.

CONCLUSION

These results support the hypothesis that alkaline-producing dietary components, specifically, potassium, magnesium, and fruit and vegetables, contribute to maintenance of BMD.

Smoking, smoking cessation, and risk of hip fracture in women

PURPOSE

To examine the effects of cigarette smoking and smoking cessation on the risk of hip fracture in women.

PATIENTS AND METHODS

We studied 116,229 female nurses, 34 to 59 years of age at baseline in 1980, who were followed for up to 12 years. Smoking habits and the occurrence of incident hip fractures (n = 377) due to low or moderate trauma were self-reported on biennial mailed questionnaires.

RESULTS

Compared with women who had never smoked, the age-adjusted relative risk (RR) of hip fracture among current smokers was 1.3 (95% confidence interval [CI] 1.0 to 1.7). The risk of hip fracture increased linearly (P = 0.09) with greater cigarette consumption (RR = 1.6, 95% CI 1.1 to 2.3 for 25 or more cigarettes per day). These associations were somewhat reduced by adjusting for other risk factors for osteoporosis (menopausal status, use of postmenopausal estrogen, physical activity, and intakes of calcium, alcohol, and caffeine): RR = 1.2, 95% CI 0.8 to 1.3 for all current smokers; RR = 1.4, 95% CI 0.9 to 2.1 for 25 or more cigarettes per day. Relative risks were further reduced when body mass index was added to the model. There was no apparent benefit from quitting smoking until 10 years after cessation. After 10 years, former smokers had a reduced risk of hip fracture (adjusted RR = 0.7, 95% CI 0.5 to 0.9) compared with current smokers.

CONCLUSION

Smokers are at increased risk of hip fracture and their risk rises with greater cigarette consumption. Risk declines among former smokers, but the benefit is not observed until 10 years after cessation. Both the increased risk among current smokers and the decline in risk after smoking cessation are in part accounted for by differences in body weight.