Postmenopausal osteoporosis is more related to hormonal aberrations than to lifestyle factors

Retrospective study: risk assessment model for osteoporosis-a detailed exploration involving 4,552 Shanghai dwellers

Background

Osteoporosis, a prevalent orthopedic issue, significantly influences patients' quality of life and results in considerable financial burden. The objective of this study was to develop and validate a clinical prediction model for osteoporosis risk, utilizing computer algorithms and demographic data.

Method

In this research, a total of 4,552 residents from Shanghai were retrospectively included. LASSO regression analysis was executed on the sample's basic characteristics, and logistic regression was employed for analyzing clinical characteristics and building a predictive model. The model's diagnostic capacity for predicting osteoporosis risk was assessed using R software and computer algorithms.

Results

The predictive nomogram model for bone loss risk, derived from the LASSO analysis, comprised factors including BMI, TC, TG, HDL, Gender, Age, Education, Income, Sleep, Alcohol Consumption, and Diabetes. The nomogram prediction model demonstrated impressive discriminative capability, with a C-index of 0.908 (training set), 0.908 (validation set), and 0.910 (entire cohort). The area under the ROC curve (AUC) of the model was 0.909 (training set), 0.903 (validation set), and applicable to the entire cohort. The decision curve analysis further corroborated that the model could efficiently predict the risk of bone loss in patients.

Conclusion

The nomogram, based on essential demographic and health factors (Body Mass Index, Total Cholesterol, Triglycerides, High-Density Lipoprotein, Gender, Age, Education, Income, Sleep, Alcohol Consumption, and Diabetes), offered accurate predictions for the risk of bone loss within the studied population.

Does Drinking Coffee and Tea Affect Bone Metabolism in Patients with Inflammatory Bowel Diseases?

Patients suffering from Crohn’s disease and ulcerative colitis are at higher risk of osteoporosis due to lower bone mineral density. Risk factors of osteoporosis are divided into unmodifiable, namely, age, gender, genetic factors, as well as modifiable, including diet, level of physical activity, and the use of stimulants. Coffee and tea contain numerous compounds affecting bone metabolism. Certain substances such as antioxidants may protect bones; other substances may increase bone resorption. Nevertheless, the influence of coffee and tea on the development and course of inflammatory bowel diseases is contradictory.

Hearing loss but not bone-regulating hormones predicts fractures in older women-a 17-year follow-up of the Gothenburg BEDA study

High-frequency hearing loss and S-Ca, but not hormones related to bone structure and strength, or lifestyle factors, predicted incident fractures during 17 years of follow-up in women up to 97 years of age.

INTRODUCTION

The fracture risk increases and inner ear function deteriorates with increasing age. The aim of this study was to investigate whether hearing loss was of greater importance than bone-regulating hormones for the risk of fracture in elderly women.

METHODS

In 1997, a random population sample of 63-82-year-old women, n = 552, underwent a physical examination, audiometry and blood sampling for analyses of serum albumin-adjusted calcium (S-Ca), parathyroid hormone (PTH), 25(OH) vitamin D and insulin-like growth factor-1 (IGF-1). Data on medication, lifestyle, previous fractures, hearing, vision and dizziness were obtained using questionnaires. Data on subsequent fractures were retrieved, and censored at death, through December 2013.

RESULTS

In 1997, 228 women (41%) reported a previous fracture, most commonly of the wrist (18%). During the following 17 years, 323 fractures occurred in 207 women (38%). Hip fractures were the most frequent, in 96 women (17%). In a Cox regression analysis adjusted for age and previous fractures, hearing loss, reflected by a high pure tone average ≥ 59 dB, almost doubled the risk of a subsequent fracture (hazard ratio (HR) 1.81, 95% CI 1.25; 2.61, p = 0.002). S-Ca (HR 1.21 (1.02; 1.44) p = 0.028) also predicted future fractures, whereas PTH, IGF-1, 25(OH) vitamin D, hormone replacement therapy, smoking, degree of physical activity, impaired vision and dizziness did not.

CONCLUSION

Hearing loss and higher S-Ca, but not bone-regulating hormones, medication or lifestyle factors predicted incident fractures, mainly caused by falling, during 17 years of follow-up in women up to 97 years of age.

Effect of Growth Hormone Treatment on Fractures and Quality of Life in Postmenopausal Osteoporosis: A 10-Year Follow-Up Study

CONTEXT

Growth hormone (GH) treatment increases bone mineral density (BMD) in women with postmenopausal osteoporosis.

OBJECTIVE

The objective was to report bone data, fractures, and quality of life (QoL) in a 10-year follow-up of women who had received GH for 3 years and compared with controls followed in parallel.

DESIGN AND SETTING

A follow-up of a double-blind, placebo-controlled study conducted at Sahlgrenska University Hospital was performed.

PATIENTS

Eighty women aged between 50 and 70 years with osteoporosis and estrogen hormone replacement were studied and compared with an age-matched random population sample of women (n = 120) from the World Health Organization Monitoring of Trends and Determinants in Cardiovascular Disease project (Gothenburg, Sweden).

INTERVENTIONS

Patients were randomized to GH 1.0 U or GH 2.5 U recombinant human GH or placebo sc daily during 3 years. All received calcium 750 mg and vitamin D 400 U and were followed up during 10 years.

MAIN OUTCOME MEASURES

BMD and bone mineral content were measured with dual-energy X-ray absorptiometry. QoL was estimated with the 36-item Short Form.

RESULTS

GH increased BMD and bone mineral content dose dependently in all regions (P = .01, GH 1.0 U, and P = .0006, GH 2.5 U vs placebo). After 10 years the number of fractures decreased from 56% to 28% (P = .0003) in patients evenly distributed between groups. In controls, fractures increased from 8% to 32% (P = .0008). QoL did not change during GH treatment or during the 10-year follow-up and did not differ compared with controls.

CONCLUSION

GH treatment was beneficial for bone and fracture outcome after 10 years but did not affect the QoL of the women with postmenopausal osteoporosis.

Interrelationship among muscle, fat, and bone: connecting the dots on cellular, hormonal, and whole body levels

While sarcopenia and sarcopenic obesity have been recognized in the last decade, a combined concept to include decreased muscle mass and strength, as well as decreased bone mass with coexistence of adiposity is discussed here. We introduce a new term, osteopenic obesity, and operationalize its meaning within the context of osteopenia and obesity. Next, we consolidate osteopenic obesity with the already existing and more familiar term, sarcopenic obesity, and delineate the resulting combined condition assigning it the term osteosarcopenic obesity. Identification and possible diagnosis of each condition are discussed, as well as the interactions of muscle, fat and bone tissues on cellular level, considering their endocrine features. Special emphasis is placed on the mesenchymal stem cell commitment into osteoblastogenic, adipogenic and myogenic lineages and causes of its deregulation. Based on the presented evidence and as expounded within the text, it is reasonable to say that under certain conditions, osteoporosis and sarcopenia could be the obesity of bone and muscle, respectively, with the term osteosarcopenic obesity as an encompassment for all.

Long-chain polyunsaturated fatty acids may mutually benefit both obesity and osteoporosis

The overconsumption of n-6 polyunsaturated fatty acids (PUFA), resulting in a high ratio of n-6 to n-3 PUFA, may contribute to the increased pathogenesis of obesity and osteoporosis by promoting low-grade chronic inflammation (LGCI). As evidence suggests, both obesity and osteoporosis are linked on a cellular and systemic basis. This review will analyze if a relationship exists between LGCI, fat, bone, and n-3 PUFA. During the life cycle, inflammation increases, fat mass accumulates, and bone mass declines, thus suggesting that a connection exists. This review will begin by examining how the current American diet and dietary guidelines may fall short of providing an anti-inflammatory dose of the n-3 PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). It will then define LGCI and outline the evidence for a relationship between fat and bone. Inflammation as it pertains to obesity and osteoporosis and how EPA and DHA can alleviate the associated inflammation will be discussed, followed by some preliminary evidence to show how mesenchymal stem cell (MSC) lineage commitment may be altered by inflammation to favor adipogenesis. Our hypothesis is that n-3 PUFA positively influence obesity and osteoporosis by reducing LGCI, ultimately leading to a beneficial shift in MSC lineage commitment. This hypothesis essentially relates the need for more focused research in several areas such as determining age and lifestyle factors that promote the shift in MSC commitment and if current intakes of EPA and DHA are optimal for fat and bone.

A study of bone mineral density and prevalence of osteoporosis in Chinese people of Han nationality from Changchun

We investigated bone mineral density (BMD) and analyzed the changes in peak bone mass and BMD in Chinese Han population. The main results are as follows: (1) The peak BMD in males (0.625 ± 0.109) and females (0.506 ± 0.058) was observed at the age of 30-34 years; (2) osteoporosis prevalence was 7.7% vs. 6.97% in males and females aged 50-59 years; 18.13% vs. 35.97% in males and females aged 60-69 years; 36.41% vs. 59.55% in males and females aged 70-79 years; and 57.53% vs. 75.56% in males and females aged >80 years; (3) BMD differed significantly between genders, and among age groups studied; and (4) peak BMD of Han Chinese was greater than that of Japanese and Danish, as well as ethnicities in China.

PURPOSE

The reference data on BMD and osteoporosis among Chinese people are lacking. We, therefore, investigated the BMD and analyzed the changes in peak bone mass and BMD in Han population.

METHODS

BMD at the one third of distal radius and ulna of non-dominant forearm was measured by DTX-200 BMD detector in 16,019 Han individuals in Changchun divided into different groups based on age and gender. The mean BMD, T-score, and bone loss rate were analyzed using SPSS 13.0 statistical software.

RESULTS

The peak BMD in males and females was 0.625 ± 0.109 and 0.506 ± 0.058, respectively, which was observed in the age group of 30-34 years. BMD decreased gradually after 40 years. The prevalence of osteoporosis was as follows: 7.7% in males and 6.97% in females in the age group of 50-59 years; 18.13% in males and 35.97% in females aged 60-69 years; 36.41% in males and 59.55% in females aged 70-79 years; and 57.53% in males and 75.56% in females aged over 80 years.

CONCLUSIONS

There was a significant difference (P < 0.01) in BMD in different age groups and between genders within the same age group. In different age groups, the prevalence of osteoporosis was significantly higher in females than in males (P < 0.01). The peak BMD in this region was higher than that reported in Japan and Denmark, and was comparable to that in Beijing. Furthermore, differences were significant (P < 0.01) as Han population of Changchun was compared with Dai population of Xishuangbanna, Tibet, and Dongxiang population of Gansu province.

Serum 25-hydroxyvitamin D levels and rate of hip bone loss in older men

CONTEXT

Vitamin D deficiency is common among older adults, but the association between 25-hydroxyvitamin D [25(OH)D] levels and rates of bone loss is uncertain.

OBJECTIVE

Our aim was to test the hypothesis that lower 25(OH)D levels are associated with higher rates of hip bone loss in older men.

DESIGN AND SETTING

We conducted a prospective cohort study in six U.S. centers.

PARTICIPANTS

A total of 1279 community-dwelling men aged 65 yr or older with 25(OH)D levels (liquid chromatography-tandem mass spectroscopy) and hip bone mineral density (BMD) (dual-energy x-ray absorptiometry) at baseline and repeat hip BMD an average of 4.4 yr later participated in the study.

MAIN OUTCOME MEASURE(S)

We measured the annualized percentage rate of change in hip BMD.

RESULTS

After adjustment for multiple potential confounders, the average rate of decline in total hip BMD was -0.59%/yr among men with 25(OH)D levels below 15.0 ng/ml, -0.54%/yr among men with 25(OH)D levels 15.0-19.9 ng/ml, -0.35%/yr among men with 25(OH)D levels 20.0-29.9 ng/ml, and -0.37%/yr among men with 25(OH)D levels of at least 30 ng/ml (P trend = 0.008 for multivariable model). Evidence was strong to support an association among men aged 75 yr and older (P trend <0.001), but not among younger men (P trend = 0.55). Findings were similar when 25(OH)D level was expressed in quintiles and when BMD at hip subregions was substituted for total hip BMD.

CONCLUSIONS

In this cohort of community-dwelling older men, men with 25(OH)D levels below 20 ng/ml had greater subsequent rates of hip bone loss, but rates of loss were similar among men with higher levels. These results lend support to the view that low 25(OH)D levels are detrimental to BMD in older men.

Impaired body balance, fine motor function and hearing in women with Turner syndrome

OBJECTIVE

Fractures are related to falling. Turner syndrome (TS) is associated with hypogonadism, osteoporosis and fractures and has been considered as a syndrome of early ageing. The aim was to study whether fine motor function (FM) and body balance (BB) were impaired and related to genotype, fractures, metabolic variables and hearing.

DESIGN

Cross-sectional study.

PATIENTS

TS women, n = 75, mean age 30 years (range 16-59) and treated with oestrogen hormone replacement therapy (HRT) at the out-patient clinic, Sahlgrenska University Hospital, Göteborg, Sweden, and 31 healthy controls, mean age 37 years (range 24-63).

MEASUREMENTS

Six FM and eight BB tests with open and closed eyes, respectively, were done. Bone mineral density was estimated with Dual energy X-ray Absorptiometry. Presence/absence of fractures was noted, blood samples were taken and audiometry was done in the TS women.

RESULTS

TS women had poorer FM (27.4 +/- 6.0 vs. 32.8 +/- 2.2; P < 0.0001) and BB (28.0 +/- 8.1 vs. 34.7 +/- 2.4; P < 0.0001) than controls. FM was poorer in TS women with hearing aids compared to those without (P < 0.05). FM and BB were negatively correlated with age, waist : hip ratio and positively correlated with hearing, and bone mineral density, and BB was negatively correlated with physical activity in TS women. BB correlated negatively with age in controls. FM, BB and hearing function were poorer in 45,X, nonmosaics, than in 45,X/46,XX, mosaics.

CONCLUSIONS

FM and BB were poorer in adult TS women on HRT than in controls. Higher age, hearing impairment, osteoporosis, abdominal obesity, a sedentary lifestyle and the TS per se were strong determinants, and mosaicism mitigated both fine motor function and BB in TS.

Relationship among insulinlike growth factor I concentrations, bone mineral density, and biochemical markers of bone turnover in postmenopausal women: a population-based study

OBJECTIVE

: To assess the association among serum insulinlike growth factor I (IGF-I) concentrations, bone mineral density (BMD), and biochemical markers of bone turnover in a large group of postmenopausal women from the general population.

DESIGN

: As an extension of a larger epidemiological study, the Iranian Multicentral Osteoporosis Study, a total of 406 healthy postmenopausal women (age, 59.0 +/- 7.6 years) were randomly selected from 13 clusters in Bushehr Port. IGF-I, serum CrossLaps, degradation products of C-terminal telopeptides of type I collagen, and osteocalcin were measured by highly specific enzyme-linked immunosorbent assay. BMD was determined for the lumbar spine (L2-4) and proximal femur using dual-energy x-ray absorptiometry.

RESULTS

: The mean (+/- SD) serum IGF-I concentration for all postmenopausal women was 183.35 +/- 65.60 ng/mL. In age-adjusted analyses, there was no correlation between IGF-I and BMD at the lumbar spine and femoral neck. Compared with women in the lowest quartile of IGF-I, women in the highest quartile had a significantly greater means of osteocalcin (P = 0.04) and alkaline phosphatase (P = 0.01). Analysis by quartiles of IGF-I did not reveal an association with serum CrossLaps.

CONCLUSIONS

: Circulating IGF-I is associated with biochemical markers of bone formation, but there is no relationship among IGF-I, degradation products of C-terminal telopeptides of type I collagen, and BMD in postmenopausal women. Clearly more work will be needed before serum IGF-I can be used in clinical practice as a risk predictor for postmenopause-associated loss of bone mass.

Menopause, the metabolic syndrome, and mind-body therapies

Cardiovascular disease risk rises sharply with menopause, likely due to the coincident increase in insulin resistance and related atherogenic changes that together comprise the metabolic or insulin resistance syndrome, a cluster of metabolic and hemodynamic abnormalities strongly implicated in the pathogenesis and progression of cardiovascular disease. A growing body of research suggests that traditional mind-body practices such as yoga, tai chi, and qigong may offer safe and cost-effective strategies for reducing insulin resistance syndrome-related risk factors for cardiovascular disease in older populations, including postmenopausal women. Current evidence suggests that these practices may reduce insulin resistance and related physiological risk factors for cardiovascular disease; improve mood, well-being, and sleep; decrease sympathetic activation; and enhance cardiovagal function. However, additional rigorous studies are needed to confirm existing findings and to examine long-term effects on cardiovascular health.

Effects of growth hormone administration on bone mineral metabolism, PTH sensitivity and PTH secretory rhythm in postmenopausal women with established osteoporosis

INTRODUCTION

Growth hormone (GH) replacement improves target organ sensitivity to PTH, PTH circadian rhythm, calcium and phosphate metabolism, bone turnover, and BMD in adult GH-deficient (AGHD) patients. In postmenopausal women with established osteoporosis, GH and insulin like growth factor-1 (IGF-1) concentrations are low, and administration of GH has been shown to increase bone turnover and BMD, but the mechanisms remain unclear. We studied the effects of GH administration on PTH sensitivity, PTH circadian rhythm, and bone mineral metabolism in postmenopausal women with established osteoporosis.

MATERIALS AND METHODS

Fourteen postmenopausal women with osteoporosis were compared with 14 healthy premenopausal controls at baseline that then received GH for a period of 12 mo. Patients were hospitalized for 24 h before and 1, 3, 6, and 12 mo after GH administration and half-hourly blood and 3-h urine samples were collected. PTH, calcium (Ca), phosphate (PO(4)), nephrogenous cyclic AMP (NcAMP), beta C-telopeptide of type 1 collagen (betaCTX), procollagen type I amino-terminal propeptide (PINP), and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] were measured. Circadian rhythm analysis was performed using Chronolab 3.0 and Student's t-test and general linear model ANOVAs for repeated measures were used where appropriate.

RESULTS

IGF-1 concentration was significantly lower in the women with established osteoporosis compared with controls (101.5 +/- 8.9 versus 140.9 +/- 10.8 mug/liter; p < 0.05) and increased significantly after 1, 3, 6, and 12 mo of GH administration (p < 0.001). Twenty-four-hour mean PTH concentration was higher in the osteoporotic women (5.4 +/- 0.1 pM) than in healthy controls (4.4 +/- 0.1 pM, p < 0.001) and decreased after 1 (5.2 +/- 0.1 pM, p < 0.001), 3 (5.0 +/- 0.1 pM, p < 0.001), 6 (4.7 +/- 0.1 pM, p < 0.001), and 12 mo (4.9 +/- 0.1 pM, p < 0.05) of GH administration compared with baseline. NcAMP was significantly lower in osteoporotic women (17.2 +/- 1.2 nM glomerular filtration rate [GFR]) compared with controls (21.4 +/- 1.4 nM GFR, p < 0.05) and increased after 1 (24.2 +/- 2.5 nM GFR, p < 0.05), 3 (27.3 +/- 1.5 nM GFR, p < 0.001), and 6 mo (32.4 +/- 2.5 nM GFR, p < 0.001) compared with baseline. PTH secretion was characterized by two peaks in premenopausal women and was altered in postmenopausal women with a sustained increase in PTH concentration. GH administration also restored a normal PTH secretory pattern in the osteoporotic women. The 24-h mean adjusted serum calcium (ACa) concentration increased at 1 and 3 mo (p < 0.001) and PO(4) at 1, 3, 6, and 12 mo (p < 0.001). 1,25(OH)(2)D concentration increased after 3, 6, and 12 mo of GH (p < 0.05). An increase in urine Ca excretion was observed at 3 and 6 mo (p < 0.05), and the renal threshold for maximum tubular phosphate reabsorption rate (TmPO4/GFR) increased after 1, 3, 6, and 12 mo (p < 0.05). betaCTX concentration increased progressively from 0.74 +/- 0.07 mug/liter at baseline to 0.83 +/- 0.07 mug/liter (p < 0.05) at 1 mo and 1.07 +/- 0.09 mug/liter (p < 0.01) at 3 mo, with no further increase at 6 or 12 mo. PINP concentration increased progressively from baseline (60 +/- 5 mug/liter) to 6 mo (126 +/- 11 mug/liter, p < 0.001), with no further increase at 12 mo. The percentage increase in PINP concentration was significantly higher than betaCTX (p < 0.05).

CONCLUSIONS

Our study shows that GH has a regulatory role in bone mineral metabolism. GH administration to postmenopausal osteoporotic women improves target organ sensitivity to PTH and bone mineral metabolism and alters PTH secretory pattern with greater increases in bone formation than resorption. These changes, resulting in a net positive bone balance, may partly explain the mechanism causing the increase in BMD after long-term administration of GH in postmenopausal women with osteoporosis shown in previous studies and proposes a further component in the development of age-related postmenopausal osteoporosis.

UVB therapy increases 25(OH) vitamin D syntheses in postmenopausal women with psoriasis

BACKGROUND

Vitamin D3 is produced in the epidermis by ultraviolet (UV) radiation (290-315 nm) of 7-dehydrocholesterol. A similar range of 290-320 nm (broadband UVB) has been successfully used for years to treat psoriasis. The aim of this study was to investigate whether UVB therapy was able to influence vitamin D synthesis in psoriasis patients.

METHODS

Twenty-four postmenopausal, white Caucasian women, aged 69 +/- 5.9 (mean +/- SD), with active plaque psoriasis, were treated with broadband UVB two to three times per week for 8-12 weeks. The serum concentrations of calcidiol (25(OH)D3), calcitriol (1,25(OH)2D3), intact parathyroid hormone (PTH), thyroid hormones, osteocalcin, calcium and creatinine were measured before the first and after the last dose of radiation. Bone density was measured using Dual-Energy X-ray Absorptiometry (Hologic Delphi A) at the hip and lumbar spine.

RESULTS

Serum levels of 25(OH)D3 increased from 36.8 +/- 17 ng/ml (mean +/- SD) to 59.6 +/- 18.7 ng/ml (P<0.001) after the UVB treatment period. Serum PTH decreased from 62.8 +/- 25.7 ng/l to 48.2 +/- 17.4 ng/l (P<0.001). Secondary hyperparathyroidism (PTH>65 ng/l) was revealed in seven patients (29%) in whom PTH values were suppressed by the UVB therapy. The serum levels of calcitriol, calcium, osteocalcin, thyroid hormones and creatinine were unaltered.

CONCLUSION

UVB therapy in elderly psoriatic women improved psoriasis, increased serum 25(OH)D3 synthesis and reduced serum PTH concentrations.

The study of bone mineral density and bone turnover markers in postmenopausal women with active rheumatoid arthritis

The aim of this study was to investigate determinants of reduced bone mineral density (BMD) in postmenopausal women with active rheumatoid arthritis (RA) and to evaluate whether there are common markers of bone loss. We evaluated BMD of the femoral neck using dual-energy X-ray absorptiometry, and the measured biochemical markers included serum bone-specific alkaline phosphatase (BALP), serum osteocalcin (OC), and serum cross-linked N-telopeptidases of type I collagen (NTx). Serum BALP and NTx concentrations were measured by enzyme-linked immunsorbent assay, and OC was measured using an immunoradiometric assay. One hundred and forty postmenopausal Japanese women who had not received treatment with bisphosphonates or hormone replacement therapy were entered into the study. Thirty-four patients (41.0%) had femoral osteopenia (T score -1 to -2.5) and 23 patients (27.7%) had osteoporosis (T < -2.5). The body mass index of patients with normal BMD (T score >or= -1.0) was significantly higher (P < 0.01) than in patients with osteoporosis at the femoral neck. The T score exhibited a significant negative correlation with age and the duration of RA disease. Serum BALP and serum OC, markers of osteoblast function, were negatively related to erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and matrix metalloproteinase-3 (MMP-3). However, serum NTx, a marker of resorptive function, exhibited a positive correlation with ESR, CRP, and MMP-3. From these results, this study suggests that generalized bone loss occurs in active RA and is characterized by evidence of bone resorption that is correlated with the high levels of inflammation. Body mass index, disease duration, and high serum NTx level were common risk factors in osteoporosis of postmenopausal women with RA.

Insulin-Like Growth Factor I Levels in Healthy Adults

Insulin-like growth factor I (IGF-I) levels mainly reflect secretion of growth hormone (GH) in the body. The aims of this study were to compare different IGF-I assay methods in healthy individuals, test the reliability of the methods and discuss the utility of IGF-I measurement in adults. The Nichols Institute Diagnostics radioimmunoassay was used to evaluate IGF-I in two random population samples of men and women (aged 25-64 years, n = 392) taken 10 years apart, in 1985 and 1995. This method for IGF-I testing was also compared with an immunoradiometric assay (IRMA) method in 387 men and women participating in the World Health Organization MONICA (MONItoring of trends and determinants for CArdiovascular diseases) Project, Goteborg, Sweden, in 1995. Serum IGF-I decreased with increasing age in both men and women. IGF-I was higher in young women compared with young men in both cohorts, while the opposite was found in the highest age group. Age-adjusted significant correlations were found between IGF-I and smoking, fibrinogen, coffee consumption, lipoprotein (a), osteocalcin and IGF-binding protein 3. The two cohorts showed similar mean IGF-I concentrations irrespective of method. The correlation between the Nichols and the IRMA methods was high: r = 0.93 (p < 0.0001). Based on this and previous studies, population-based IGF-I measurements are robust irrespective of which commercially available method of assay is used. IGF-I levels can be used in diagnosing acromegaly as well as providing target values. IGF-I assay can be used as a complement to stimulation testing in the diagnosis of GH deficiency, and as a tool for GH dose titration.

Bone metabolism in relation to alterations in systemic growth hormone

Growth hormone (GH) has a major role in the maintenance of bone mass in adults by regulating bone remodeling through a complex interaction of circulating GH, insulin-like growth factors (IGFs), IGF binding protein (IGFBPs), and locally produced IGFs and IGFBPs, acting in an autocrine and paracrine way. In vitro data has greatly increased our understanding of GH and IGFs effects and regulation in bone cells under controlled conditions, and especially the molecular pathways involved. However, the GH-and type I IGF-receptor are present in many tissues and various systemic factors may potentially regulate local expression of IGFs and IGFBPs in the intact organism. The use of genetically altered mice has changed this and had a major impact on defining the role of IGFs in skeletal homeostasis, and especially the role of systemic IGF-I in the development and maintenance of the adult skeleton. The focus of this review is to describe recent work on the effect of GH/IGF on remodeling in the adult skeleton emphasizing on data obtained in patient populations (i.e. acromegaly, GH deficiency, postmenopausal osteoporosis) and experimental models (i.e. animals with genetically altered expression of different GH and IGF family members) characterized by different systemic levels of these proteins. The role of IGF-I as a coupling agent between resorption and bone formation through effects on osteoprotegerin (OPG) and receptor activator of NFkappaB ligand (RANKL) are also discussed.

Radiographic joint destruction in postmenopausal rheumatoid arthritis is strongly associated with generalised osteoporosis

OBJECTIVES

To investigate determinants of joint destruction and reduced bone mineral density (BMD) in postmenopausal women with active rheumatoid arthritis (RA) not treated with bisphosphonates or hormone replacement therapy and to evaluate if there are common markers of erosive disease and bone loss.

METHODS

BMD was measured using dual x ray absorptiometry and joint damage was examined by x ray examination according to the Larsen method in 88 patients with RA. Associations between BMD and Larsen score, and between demographic and disease related variables, including proinflammatory cytokines, HLA-DR4 epitopes, and markers of bone and cartilage turnover, were examined bivariately by simple and multiple linear regression analyses.

RESULTS

49/88 (56%) patients had osteoporosis in at least one site. Reduced BMD and increased joint destruction were associated with: at the forearm and femoral neck, high Larsen score, low weight, and old age (R(2)=0.381, p<0.001; R(2)=0.372, p<0.001, respectively); at the total hip, low weight, high Larsen score, and dose of injected glucocorticosteroids (R(2)=0.435, p<0.001); at the lumbar spine, low weight, reduced cartilage oligomeric matrix protein, and increased carboxyterminal propeptide of type I procollagen (R(2)=0.248, p<0.001). Larsen score was associated with long disease duration and increased C reactive protein (CRP) (R(2)=0.545, p<0.001).

CONCLUSIONS

Osteoporosis is common in postmenopausal patients with RA. Low weight and high Larsen score were strongly associated with BMD reduction. Increased CRP and long disease duration were determinants of erosive disease in postmenopausal women with RA. These findings indicate common mechanisms of local and generalised bone loss in RA.

Hormonal regulation of the human sterol 27-hydroxylase gene CYP27A1

The nucleotide sequence data reported in this paper will appear in EMBL Nucleotide Sequence Database under the accession number AJ 544720. The mitochondrial sterol 27-hydroxylase (CYP27A1) is a multifunctional cytochrome P450 enzyme that catalyses important hydroxylations in the biosynthesis of bile acids and bioactivation of vitamin D(3). Previous results [Babiker, Andersson, Lund, Xiu, Deeb, Reshef, Leitersdorf, Diczfalusy and Bj örkhem (1997) J. Biol. Chem. 272, 26253-26261] suggest that CYP27A1 plays an important role in cholesterol homoeostasis and affects atherogenesis. In the present study, the regulation of the human CYP27A1 gene by growth hormone (GH), insulin-like growth factor-1 (IGF-1), dexamethasone, thyroid hormones and PMA was studied. HepG2 cells were transfected transiently with luciferase reporter gene constructs containing DNA fragments flanking the 5'-region of the human CYP27A1 gene. GH, IGF-1 and dexamethasone increased the promoter activity by 2-3-fold, whereas thyroxine (T(4)) and PMA repressed the activity significantly when measured with luciferase activity expressed in the cells. The endogenous CYP27A1 enzyme activity in the cells was stimulated by GH, IGF-1 and dexamethasone, whereas T(4) and PMA inhibited the activity. Experiments with progressive deletion/luciferase reporter gene constructs indicated that the response elements for GH may be localized in a region upstream to position -1094 bp. The putative response elements for dexamethasone were mapped to positions between -792 and -1095 bp. The -451 bp fragment of the human CYP27A1 gene was found to confer the activation by IGF-1, and the inhibition by T(4) and PMA. Results of the present study suggest that CYP27A1 is regulated in human cells by hormones and signal-transduction pathways.

Growth hormone increases bone mineral content in postmenopausal osteoporosis: a randomized placebo-controlled trial

Eighty osteoporotic, postmenopausal women, 50-70 years of age, with ongoing estrogen therapy (HRT), were randomized to recombinant human growth hormone (GH), 1.0 U or 2.5 U/day, subcutaneous, versus placebo. This study was double-blinded and lasted for 18 months. The placebo group then stopped the injections, but both GH groups continued for a total of 3 years with GH and followed for 5 years. Calcium (750 mg) and vitamin D (400 U) were given to all patients. Bone mineral density and bone mineral content were measured with DXA. At 18 months, when the double-blind phase was terminated, total body bone mineral content was highest in the GH 2.5 U group (p = 0.04 vs. placebo). At 3 years, when GH was discontinued, total body and femoral neck bone mineral content had increased in both GH-treated groups (NS between groups). At 4-year follow-up, total body and lumbar spine bone mineral content increased 5% and 14%, respectively, for GH 2.5 U (p = 0.01 and p = 0.0006 vs. placebo). Femoral neck bone mineral density increased 5% and bone mineral content 13% for GH 2.5 U (p = 0.01 vs. GH 1.0 U). At 5-year follow-up, no differences in bone mineral density or bone mineral content were seen between groups. Bone markers showed increased turnover. Three fractures occurred in the GH 1.0 U group. No subjects dropped out. Side effects were rare. In conclusion, bone mineral content increased to 14% with GH treatment on top of HRT and calcium/vitamin D in postmenopausal women with osteoporosis. There seems to be a delayed, extended, and dose-dependent effect of GH on bone. Thus, GH could be used as an anabolic agent in osteoporosis.

Beneficial effects of hormonal replacement therapy on chromium status and glucose and lipid metabolism in postmenopausal women

OBJECTIVES

Postmenopausal women exhibit an increased incidence of cardiovascular diseases, and type 2 diabetes mellitus compared with younger women. However, women receiving hormonal replacement therapy (HRT) seem to be protected. Since chromium (Cr) functions in glucose, lipid and corticosteroid metabolism and these variables, as well as Cr status, decline with age, Cr status may be a contributing factor in the effects of hormone replacement therapy. Therefore, the objective of this study was to determine the effects of hormonal replacement therapy (HRT) on serum and urinary Cr, plasma lipids, glucose, fructosamine and the related hormonal variables, estradiol, insulin, leptin, cortisol, and DHEA-sulfate.

METHODS

Forty-four healthy postmenopausal women 50-60 years old participated in the study. Eighteen were treated by combined oral hormonal replacement therapy (estradiol 2 mg per day during days 1-25 and 10 mg of dydrogesterone on days 10-25) for at least 2 years, and 26 were untreated.

RESULTS

Serum Cr concentrations were significantly lower in untreated postmenopausal women than in women receiving HRT (0.070+/-0.008 vs. 0.100+/-0.008 ng/ml) whereas urinary Cr excretion was increased (0.14+/-0.02 vs. 0.07+/-0.01 ng of Cr/mg creatinine). The urinary losses of Cr were inversely correlated with plasma estradiol. Median value of urinary Cr was higher in postmenopausal women exhibiting endogenous estradiol levels below 250 pmol/l, whereas women with estradiol levels >250 pmol/l, exhibited lower Cr values. Plasma fructosamine, total and LDL cholesterol and TC/HDL ratio, which are all decreased by improved Cr nutrition, were also improved in the women receiving HRT. There were also nonsignificant decreasing trends in DHEA-sulfate (P<0.06) and cortisol (0.07).

CONCLUSIONS

Chromium status, based upon blood and urinary analyses, and glucose, insulin and lipid variables were improved in postmenopausal women receiving HRT. Additional studies are needed to determine if improved Cr status due to supplemental Cr can elicit effects consistent with those of hormone replacement therapy.

The contribution of IGF-I to skeletal integrity in postmenopausal women

OBJECTIVES

The pathogenic role of the decline in serum concentrations of IGF-I in postmenopausal osteoporosis is not fully elucidated. We investigated the associations among IGF-I, bone mineral density (BMD), ultrasound parameters and prevalence of vertebral fractures in postmenopausal women.

DESIGN

A cross-sectional study.

PATIENTS

One hundred and fifty-four ambulatory postmenopausal women (61 +/- 7 years) referred for osteoporosis screening.

MEASUREMENTS

IGF-I was measured by radioimmunoassay and BMD using dual-energy X-ray absorptiometry. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) at calcaneus were measured by a quantitative ultrasound system.

RESULTS

IGF-I was significantly lower in osteoporotic subjects and correlated positively with BMD, BUA and SOS. After adjusting for age, years since menopause and body mass index, IGF-I accounted for 8.5% of the variance at lumbar spine BMD, 4.6% at femoral neck and 7.1% at calcaneal BUA. BUA was associated with IGF-I independently of BMD. IGF-I was lower in women with vertebral fractures (91 +/- 39 microg/l vs. 114 +/- 44 microg/l; P = 0.003). The osteoporosis densitometric criteria (t-score < or = -2.5 SD) was the most strongly independent associated variable with prevalent vertebral fractures [odds ratio (OR): 3.3 (1.4-7.6)], followed by IGF-I levels below 75th percentile [OR: 3 (1-8.8)].

CONCLUSIONS

Our study shows that IGF-I is strongly associated with bone mineral density and reflects aspects of bone quality. The contribution of IGF-I to skeletal integrity in postmenopausal women is clinically relevant.