Higher Dietary Vitamin K Intake is Associated with Better Physical Function and Lower Long-Term Injurious Falls Risk in Community-Dwelling Older Women

BACKGROUND

In recent years, a potential beneficial role of Vitamin K in neuromuscular function has been recognised. However, the optimal dietary intake of Vitamin K to support muscle function in the context of falls prevention remains unknown.

OBJECTIVE

To examine the relationship of dietary Vitamin K1 and K2 with muscle function and long-term injurious fall-related hospitalisations in older women.

DESIGN

Cohort study.

PARTICIPANTS

1347 community-dwelling older Australian women ≥70 years.

MEASUREMENTS

A new Australian Vitamin K nutrient database, supplemented with published data, was used to calculate Vitamin K1 and K2 intake from a validated food frequency questionnaire at baseline (1998). Muscle function (grip strength and timed-up-and-go; TUG) as well plasma Vitamin D status (25OHD) were also assessed at baseline. Fall-related hospitalisations over 14.5 years were obtained from linked health records. Multivariable-adjusted logistic regression and Cox-proportional hazard models were used to analyse the data.

RESULTS

Over 14.5 years of follow-up (14,774 person-years), 535 (39.7%) women experienced a fall-related hospitalisation. Compared to women with the lowest Vitamin K1 intake (Quartile 1, median 49 µg/d), those with the highest intake (Quartile 4, median 120 µg/d) had 29% lower odds (OR 0.71 95%CI 0.52-0.97) for slow TUG performance (>10.2 s), and 26% lower relative hazards of a fall-related hospitalisation (HR 0.74 95%CI 0.59-0.93) after multivariable adjustment. These associations were non-linear and plateaued at moderate intakes of ~70-100 µg/d. There was no relation to grip strength. Vitamin K2 intakes were not associated with muscle function or falls.

CONCLUSION

A higher habitual Vitamin K1 intake was associated with better physical function and lower long-term injurious falls risk in community-dwelling older women. In the context of musculoskeletal health, Vitamin K1 found abundantly in green leafy vegetables should be promoted.

Calcaneal quantitative ultrasound is associated with all-cause and cardiovascular disease mortality independent of hip bone mineral density

Osteoporosis has been linked with increased risk of cardiovascular disease previously. However, few studies have detailed bone and vascular information. In a prospective study of older women, we demonstrated heel quantitative ultrasound measures were associated with increased cardiovascular and all-cause mortality, independent of established cardiovascular risk factors.

INTRODUCTION

Osteoporosis and low bone mineral density (BMD) have been previously linked to cardiovascular disease (CVD) and mortality. Calcaneal quantitative ultrasound (QUS) is used to evaluate bone material properties, especially in older women. However, it is uncertain whether it is related to risk of mortality. This study was aimed to investigate the association between calcaneal QUS measurements and 15-year all-cause and CVD mortality in 1404 older women (mean age 75.2 ± 2.7 years).

METHODS

One thousand four hundred four older women, participants of Calcium Intake Fracture Outcome study (CAIFOS), had calcaneal bone measured at baseline (1998) and followed for 15 years. The primary outcomes, any deaths, and deaths attributable to cardiovascular causes ascertained by using linked data were obtained from Western Australia data linkage system.

RESULTS

Over the 15 years of follow-up (17,955 person years), 584 of the women died, and 223 from CVD. For every standard deviation (SD), reduction in broadband ultrasound attenuation (BUA) in minimally and multivariable-adjusted model including cardiovascular risk factors increased relative hazards for all-cause (multivariable-adjusted HR 1.15; 95%CI: 1.06-1.26, p = 0.001) and CVD mortality (multivariable-adjusted HR 1.20; 95%CI: 1.04-1.38, p = 0.010). Such relationships also persisted when hip BMD was included in the model (all-cause mortality HR 1.19; 95%CI: 1.07-1.33, p = 0.002; CVD mortality HR 1.28; 95%CI: 1.07-1.53, p = 0.008).

CONCLUSION

BUA is associated with all-cause and CVD mortality in older women independent of BMD and established CVD risk factors. Understanding why and how these are related may provide further insights about the bone-vascular nexus as well as therapeutic targets benefiting both systems.

Effects of calcium supplementation on circulating osteocalcin and glycated haemoglobin in older women

One year of calcium supplementation in older women led to modest reductions in total osteocalcin and undercarboxylated osteocalcin (ucOC), with no changes in muscle or fat mass, or glycated haemoglobin. Future studies should explore whether treatments with more profound effects of suppressing ucOC may lead to impaired glycaemic control.

INTRODUCTION

Total osteocalcin (TOC) is a marker of bone turnover, while its undercarboxylated form has beneficial effects on glucose metabolism in mice. This post hoc analysis of a randomised double-blind, placebo-controlled trial examined whether 1 year of calcium supplementation affected circulating TOC, undercarboxylated osteocalcin (ucOC) or glycated haemoglobin (HbA1c) in 1368 older community-dwelling women (mean age 75.2 ± 2.7 years).

METHODS

Women enrolled in the Calcium Intake Fracture Outcome Study trial (1998-2003) were supplemented with 1.2 g/d of elemental calcium (in the form of calcium carbonate) or placebo. Circulating TOC, ucOC and HbA1c was measured at 1 year (1999).

RESULTS

After 1 year of calcium supplementation, TOC and ucOC levels were 17% and 22% lower compared with placebo (mean 22.7 ± 9.1 vs. 27.3 ± 10.9 μg/L and 11.1 ± 4.9 vs. 13.0 ± 5.7 μg/L, both P < 0.001). Carboxylated osteocalcin/ucOC was 6% lower after calcium supplementation (P < 0.05). Despite this, no differences in HbA1c were observed (calcium, 5.2 ± 0.6 vs. placebo, 5.3 ± 0.8%; P = 0.08). Calcium supplementation did not affect BMI, whole body lean or fat mass. In exploratory analyses, total calcium (dietary and supplemental) was inversely related to TOC and ucOC, indicating calcium intake is an important dietary determinant of osteocalcin levels.

CONCLUSION

One year of calcium supplementation in older women led to modest reductions in TOC and ucOC, with no changes in muscle or fat mass, or HbA1c. Future studies should explore whether treatments with more profound effects of suppressing ucOC may lead to impaired glycaemic control.

Dietary protein and bone health across the life-course: an updated systematic review and meta-analysis over 40 years

We undertook a systematic review and meta-analysis of published papers assessing dietary protein and bone health. We found little benefit of increasing protein intake for bone health in healthy adults but no indication of any detrimental effect, at least within the protein intakes of the populations studied. This systematic review and meta-analysis analysed the relationship between dietary protein and bone health across the life-course. The PubMed database was searched for all relevant human studies from the 1st January 1976 to 22nd January 2016, including all bone outcomes except calcium metabolism. The searches identified 127 papers for inclusion, including 74 correlational studies, 23 fracture or osteoporosis risk studies and 30 supplementation trials. Protein intake accounted for 0-4% of areal BMC and areal BMD variance in adults and 0-14% of areal BMC variance in children and adolescents. However, when confounder adjusted (5 studies) adult lumbar spine and femoral neck BMD associations were not statistically significant. There was no association between protein intake and relative risk (RR) of osteoporotic fractures for total (RR_(random) = 0.94; 0.72 to 1.23, I² = 32%), animal (RR _(random) = 0.98; 0.76 to 1.27, I² = 46%) or vegetable protein (RR _(fixed) = 0.97 (0.89 to 1.09, I² = 15%). In total protein supplementation studies, pooled effect sizes were not statistically significant for LSBMD (total n = 255, MD_(fixed) = 0.04 g/cm² (0.00 to 0.08, P = 0.07), I² = 0%) or FNBMD (total n = 435, MD_(random) = 0.01 g/cm² (-0.03 to 0.05, P = 0.59), I² = 68%). There appears to be little benefit of increasing protein intake for bone health in healthy adults but there is also clearly no indication of any detrimental effect, at least within the protein intakes of the populations studied (around 0.8-1.3 g/Kg/day). More studies are urgently required on the association between protein intake and bone health in children and adolescents.

Ageing Effects on 3-Dimensional Femoral Neck Cross-Sectional Asymmetry: Implications for Age-Related Bone Fragility in Falling

This paper explores the effects of aging on femoral neck (FN) anatomy in a study of women aged 20-90years in relation to implications for FN fracture propensity in buckling. Five hundred and four participants were scanned by Quantitative Computed Tomography and analyzed using Quantitative Computed Tomography Pro BIT (Mindways). FN cross-section was split through geometric center into superior and inferior sectors. Bone mass, structural measurements, and bone mineral density were analyzed. Buckling ratio was calculated as ratio of buckling radius to cortical thickness. Between 2nd decade and 8th decade, age-related integral bone mass reduction in superior sector was substantially larger than in inferior sector (33% compared to 21%), especially in cortical bone superiorly compared to inferiorly (53% vs 21%; p < 0.001), principally due to reduction in cortical thickness, averaged cortical thickness (56%) with little difference in density. Superior and inferior sector trabecular bone mineral density reduction was similar at 41% and 43% respectively. Differential cortical bone loss in superior sector resulted in a 59% inferior displacement (δ) of center-of-mass from geometric center. Differences in δ and averaged cortical thickness with age accounted for a 151% increase in mean superior buckling ratio from 9 to 23. Analysis confirms significant progressive age-related superior cortical bone loss as the major age effect on FN structure with relative preservation of inferior cortex probably related to maintenance of inferior sector by regular loading as a result of standing and walking. Computation of buckling ratio may allow prediction of fracture propensity in a sideways fall.

Utility of four sarcopenia criteria for the prediction of falls-related hospitalization in older Australian women

Numerous sarcopenia definitions are not associated with increased falls-related hospitalization risk over 5 years to 9.5 years in older community-dwelling Australian women. Measures of muscle strength and physical function, but not appendicular lean mass (measured by dual-energy X-ray absorptiometry) may help discriminate the risk of falls-related hospitalization.

INTRODUCTION

The aim of this prospective, population-based cohort study of 903 Caucasian-Australian women (mean age 79.9 ± 2.6 years) was to compare the clinical utility of four sarcopenia definitions for the prediction of falls-related hospitalization over 9.5 years.

METHODS

The four definitions were the United States Foundation for the National Institutes of Health (FNIH), the European Working Group on Sarcopenia in Older People (EWGSOP), and modified FNIH (AUS-POP_F) and EWGSOP (AUS-POP_E) definitions using Australian population-specific cut points (< 2 SD below the mean of young healthy Australian women). Components of sarcopenia including muscle strength, physical function, and appendicular lean mass (ALM) were quantified using hand grip strength, timed-up-and-go (TUG), and dual-energy X-ray absorptiometry (DXA), respectively. Incident 9.5-year falls-related hospitalization were captured by linked data.

RESULTS

Baseline prevalence of sarcopenia according to FNIH (9.4%), EWGSOP (24.1%), AUS-POP_F (12.0%), and AUS-POP_E (10.7%) differed substantially. Sarcopenia did not increase the relative hazard ratio (HR) for falls-related hospitalization before or after adjustment for age (aHR): FNIH aHR 1.00 95%CI (0.69-1.47), EWGSOP aHR 1.20 95%CI (0.93-1.54), AUS-POP_F aHR 0.96 95%CI (0.68-1.35), and AUS-POP_E aHR 1.33 95%CI (0.94-1.88). When examining individual components of sarcopenia, only muscle strength and physical function but not ALM (adjusted for height² or BMI) were associated with falls-related hospitalization.

CONCLUSION

Current definitions of sarcopenia were not associated with falls-related hospitalization risk in this cohort of community-dwelling older Australian women. Finally, measures of muscle strength and physical function, but not ALM (measured by DXA) may help discriminate the risk of falls-related hospitalization.

Differences in femoral neck structure between elderly Caucasian and Chinese populations: a cross-sectional study of Perth-Beijing cohorts

Structural skeletal differences of the femoral neck of older Beijing-Chinese and Perth-Caucasian women were compared; adjusting for frame size-related differences, Beijing-Chinese have lower periosteal width; however, indices of internal bone distribution suggest that Beijing-Chinese may exhibit increased resistance to fracture that may relate to the reduced hip fracture incidence.

INTRODUCTION

Ethnic differences in skeletal structure may relate to differences in hip fracture risk in Chinese and Caucasian populations. 2D mass, size, and structural biomechanics were compared in the two populations.

METHODS

Quantitative computed tomography-derived geometric variables were compared in age-matched community-derived female populations, 196 Beijing-Chinese 76.5 ± 4.8 (mean ± SD) years and 237 Perth-Caucasians 77.1 ± 5.0 years. These included scanned area (A), periosteal width (W), bone mineral content (BMC), aBMD, bone cross-sectional area (bCSA), section modulus (Z) and buckling ratio (BR). Assumption-free measures included sigma (σ), related to the distribution of bone in the scanned image previously identified as a predictor of hip fracture, and delta (δ), the center-of-mass displacement from the geometric center.

RESULTS

Compared to Beijing-Chinese, Perth-Caucasians were heavier (Beijing-Chinese 58.7 ± 11.8; Perth-Caucasians 66.1 ± 11.0 kg), taller (154.9 ± 16.7 vs 158.9 ± 6.0 cm), and had higher BMC, A, and W. After adjustment for frame size, BMC was not significantly different but W remained higher in Perth-Caucasians. Differences in variables aBMD, Z, BR, and σ favored higher resistance to failure with Beijing-Chinese before and after adjustment for frame size. δ was similar in both populations; bCSA was higher in Beijing-Chinese before adjustment for frame size but not after.

CONCLUSIONS

Bone mass differences in two populations were related to frame size differences. However, femoral neck width remained smaller in Beijing-Chinese suggesting effects of local genetic and environmental factors. In Beijing-Chinese participants compared to Perth-Caucasians, internal bone distribution suggests increased resistance to deformation if exposed to same force that may, in-part, relate to reduced incidence of hip fracture in Beijing-Chinese.

The Impact of Dietary Protein or Amino Acid Supplementation on Muscle Mass and Strength in Elderly People: Individual Participant Data and Meta-Analysis of RCT's

OBJECTIVES

Increasing protein or amino acid intake has been promoted as a promising strategy to increase muscle mass and strength in elderly people, however, long-term intervention studies show inconsistent findings. Therefore, we aim to determine the impact of protein or amino acid supplementation compared to placebo on muscle mass and strength in older adults by combining the results from published trials in a meta-analysis and pooled individual participant data analysis.

DESIGN

We searched Medline and Cochrane databases and performed a meta-analysis on eight available trials on the effect of protein or amino acid supplementation on muscle mass and strength in older adults. Furthermore, we pooled individual data of six of these randomized double-blind placebo-controlled trials. The main outcomes were change in lean body mass and change in muscle strength for both the meta-analysis and the pooled analysis.

RESULTS

The meta-analysis of eight studies (n=557) showed no significant positive effects of protein or amino acid supplementation on lean body mass (mean difference: 0.014 kg: 95% CI -0.152; 0.18), leg press strength (mean difference: 2.26 kg: 95% CI -0.56; 5.08), leg extension strength (mean difference: 0.75 kg: 95% CI: -1.96, 3.47) or handgrip strength (mean difference: -0.002 kg: 95% CI -0.182; 0.179). Likewise, the pooled analysis showed no significant difference between protein and placebo treatment on lean body mass (n=412: p=0.78), leg press strength (n=121: p=0.50), leg extension strength (n=121: p=0.16) and handgrip strength (n=318: p=0.37).

CONCLUSIONS

There is currently no evidence to suggest that protein or amino acid supplementation without concomitant nutritional or exercise interventions increases muscle mass or strength in predominantly healthy elderly people.

Reconsideration of the Effects of Age on Proximal Femur Structure: Implications for Joint Replacement and Hip Fracture

OBJECTIVES

In recent years quantitative computed tomography (QCT) has allowed precise non-invasive, three dimensional, in vivo measurement of hip structure in large numbers of individuals. The effects of ageing on proximal femur structure are reported and implications for the prevention of hip prosthesis loosening and hip fracture considered.

DESIGN, SETTING AND PARTICIPANTS

An observational cross-sectional study of proximal femur QCT in 719 unselected female European descent aged 20 to 89 years recruited from US and Australian populations.

MAIN OUTCOMES MEASURES

QCT scans were obtained using software that separates cortical and cancellous bone by a thresholding technique. Voxel based mineral volume and mass was computed for the integral (external), cancellous and cortical compartments of 1 mm wide sections through the femoral neck (FN), trochanter (TR) and intertrochanter (IT) regions.

RESULTS

Over the adult life span total integral volumes at the FN, TR and IT sites expand linearly by between 18 and 37% at the same time as bone mass decreased by 22 to 25% resulting in massive reductions in true volumetric BMD (vBMD) of 40 to 50%. Cancellous volume expansion was larger at 65 to 79% at the three sites. Between the ages of 65 and 75 the average increase in cancellous volume at the IT site was 3.74 cm3 (12.1%). Voxel determined FN cortical volume decreased linearly by 43%, as did cortical bone mass so that vBMD did not change substantially. TR and IT cortical volumes decreased 54 and 28% respectively, small reductions in TR and IT cortical vBMD also occurred.

CONCLUSIONS

Large endosteal expansion in the area in which hip replacement stem placement occurs may contribute to loosening. Regarding the propensity to hip fracture, periosteal expansion contributes to increased resistance to bending but cortical thinning contributes to loss of bone to resistance to bending forces. Understanding individual hip structure may contribute to individualisation of risk and subsequent targeting of management using pharmaceutical agents.

Evaluation of a simplified hip structure analysis method for the prediction of incident hip fracture events

Many attempts have been made to improve the predictive ability of areal bone mineral density (aBMD) which integrates bone mass and area. The addition of an extra variable derived from the hip dual-energy X-ray (DXA) image TR_σ, which describes distribution of mass within the scanned area of the trochanter, improved prediction of 15-year hip fracture probability in elderly women.

INTRODUCTION

Two-dimensional DXA imaging of the proximal femur to produce an aBMD is a clinically useful predictor of future fracture risk. Further analysis of the DXA image to produce an eight-variable hip structure analysis (Beck HSA) has been developed to improve understanding of structural factors determining hip bone strength at each of three proximal femur sites, the narrow femoral neck (NN), intertrochanter (TR) and shaft (S). Recently, data on four measurements derived from the currently used eight Beck HSA variables were used to capture population variation in bone structure at each site. These include two previously used variables, the localised aBMD and the sub-periosteal width (W) applying to 5-mm sections (at each sites), and two new variables, standard deviation of normalised mineral-mass projection profile distribution (σ), and displacement between centre-of-mineral mass and geometric centre-of-mineral mass of projection profile (δ).

METHODS

Using a cohort of 1159 women, mean baseline age 75, who sustained 139 hip fractures over 15 years, we determined whether these measures significantly improved 15-year hip fracture prediction compared to current approach utilising age and total hip aBMD. To describe the most parsimonious model for hip fracture risk prediction, the 12 base measures (4 from each site), total hip aBMD and age were evaluated in stepwise logistic regression models.

RESULTS

The final model included TR_σ, total hip aBMD and age and provided improved utility for hip fracture prediction compared to total hip aBMD and age alone (C-statistic 0.73 vs. 0.69, P = 0.009 and net reclassification improvement 0.164, P < 0.001, respectively).

CONCLUSIONS

Addition of TR_σ to total hip aBMD and age substantially improved prediction of 15-year hip fracture risk in this cohort of elderly women.

Consumption of a whey protein-enriched diet may prevent hepatic steatosis associated with weight gain in elderly women

BACKGROUND AND AIMS

Protein consumption has been associated with cardio-metabolic benefits, including weight loss and improved insulin sensitivity, and may have potential benefits for individuals with fatty liver disease (FLD). We investigated the effect of increasing dietary protein intake from whey relative to carbohydrate on hepatic steatosis.

METHODS AND RESULTS

A two-year randomized, double-blind, placebo-controlled trial of 30 g/day whey protein-supplemented beverage (protein) or an energy-matched low-protein high-carbohydrate beverage (control) for cardio-metabolic and bone health in 219 healthy elderly women, recruited from the Western Australian general population. Hepatic steatosis was quantified using computed tomographic liver-to-spleen (L/S) ratio. FLD was defined as liver-to-spleen difference <10 Hounsfield units. At baseline, FLD prevalence was 11.4%. Control and protein groups were similar in body mass index (BMI), insulin resistance, L/S ratio and FLD prevalence at baseline. At two-years, dietary protein increased by 20 g in the protein, but not the control, group. Total energy intake and physical activity remained similar between groups. At two-years, BMI and FLD prevalence increased in both groups, with no between group differences. L/S ratio increased in control, but not protein, group at two-years, with no between group differences. In a within group comparison, change in BMI correlated with changes in L/S ratio in control (r = 0.37, P = 0.0007), but not with protein group (r = 0.04, P = 0.73).

CONCLUSION

Increasing dietary protein intake from whey relative to carbohydrate does not reduce weight, hepatic steatosis or the prevalence of FLD in elderly women. However, it may prevent worsening of hepatic steatosis associated with weight gain.

CLINICAL TRIALS REGISTRATION

Australian New Zealand Clinical Trials Registry (Registration no. ACTRN012607000163404).

The effect of yoghurt and its probiotics on blood pressure and serum lipid profile; a randomised controlled trial

BACKGROUND AND AIMS

Despite strong mechanistic data, and promising results from in vitro and animal studies, the ability of probiotic bacteria to improve blood pressure and serum lipid concentrations in humans remains uncertain. The aim of this study was to determine the effect of Lactobacillus acidophilus La5 and Bifidobacterium animalis subsp lactis Bb12, provided in either yoghurt or capsule form, on home blood pressure and serum lipid profile.

METHODS AND RESULTS

Following a 3-week washout period, 156 overweight men and women over 55 y were randomized to a 6-week double-blinded, factorial, parallel study. The four intervention groups were: A) probiotic yoghurt plus probiotic capsules; B) probiotic yoghurt plus placebo capsules; C) control milk plus probiotic capsules; and D) control milk plus placebo capsules. Each probiotic test article provided a minimum L. acidophilus La5 and B. animalis subsp. lactis Bb12 dose of 3.0 × 10⁹ CFU/d. Home blood pressure monitoring, consisting of 7-day bi-daily repeat measurements, were collected at baseline and week 6. Fasting total cholesterol, low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), and serum triglyceride were performed at baseline and week 6. When compared to control milk, probiotic yoghurt did not significantly alter blood pressure, heart rate or serum lipid concentrations (P > 0.05). Similarly, when compared to placebo capsules, supplementation with probiotic capsules did not alter blood pressure or concentrations of total cholesterol LDLC, HDLC, or triglycerides (P > 0.05).

CONCLUSIONS

The probiotic strains L. acidophilus La5 and B. animalis subsp. lactis Bb12 did not improve cardiovascular risk factors.

Five-year decline in estimated glomerular filtration rate associated with a higher risk of renal disease and atherosclerotic vascular disease clinical events in elderly women

BACKGROUND

Estimated glomerular filtration rate (eGFR) has been demonstrated to predict atherosclerotic vascular disease (ASVD)-associated clinical events independent of traditional vascular risk factors. Recent studies have demonstrated that eGFR decline over time may improve prediction of ASVD-associated mortality risk in chronic kidney disease (CKD) patients.

AIM

The aim of this study is to evaluate the association between 5-year change in eGFR with renal disease and ASVD-associated clinical events.

DESIGN

Prospective observational study.

METHODS

A total of 1012 women over the age of 70 years from the Calcium Intake Fracture Outcome Study were included. Baseline characteristics including baseline and 5-year creatinine, participants' comorbidities and complete verified 10-year records for ASVD and renal disease-associated hospitalization and/or mortality were obtained using the Western Australian Data Linkage System.

RESULTS

Participants were stratified according to annual rate of eGFR change in quartiles [≤-1.2 (first quartile), >-1.2 to 0.1 (second quartile), >0.1-1.7 (third quartile) and >1.7 ml/min/1.73 m(2)/year (fourth quartile)]. In the adjusted model, compared with participants in the fourth quartile, those in the first and/or second quartiles of annual eGFR change had significantly higher risk of renal disease and/or ASVD-associated clinical events. However, the association with renal clinical events was more pparent in participants with baseline eGFR of <60 ml/min/1.73 m(2).

CONCLUSION

The results of this study suggest that the inclusion of long-term eGFR change over time might augment prognostication for renal disease and ASVD-associated clinical events in elderly women.

Under-reporting of energy intake in elderly Australian women is associated with a higher body mass index

OBJECTIVES

Identify the extent of under-reporting of energy intake and the characteristics associated with implausible intakes in elderly women.

DESIGN

Dietary intake was assessed using a 3-day weighed food record. Protein intake was validated by 24-hour urinary nitrogen. To examine under-reporting, participants were grouped according to their energy intake and compared to the Goldberg cut-off equation. Logistic regression was performed to assess the influence of body mass index (BMI) and social-demographic factors on under-reporting.

SETTING

Community dwelling elderly women from Perth, Western Australia.

PARTICIPANTS

217 elderly women aged 70-80 years.

RESULTS

Under-reporters had a higher physical activity level (p<0.001) compared with acceptable-reporters. The under-reporters also had a higher body weight (p=0.006), body mass index (BMI) (p=0.001), waist (p=0.011), hip circumference (p<0.001), whole body fat mass (p<0.001) and percentage body fat (p<0.001) than acceptable-reporters. Under-reporters had a significantly lower intakes of protein, fat, carbohydrate and alcohol (p<0.001) and fewer reported food items, compared with acceptable reporters. However, 24-hour urinary nitrogen was only marginally different between the two groups (p=0.053). Participants with a higher BMI were more likely to under-report their energy intake (BMI=25-29.9: odds ratio=2.98[95% CI=1.46-6.09]; BMI≥30: 5.84[2.41-14.14]).

CONCLUSION

Under-reporting energy intake in elderly women was associated with a higher BMI, body fat and higher self-reported physical activity levels. A higher BMI (≥25) appears to be most significant factor in determining if elderly women will underreport their food intake and may be related to body image. These results have implications for undertaking surveys of food intake in elderly women.

Differences in structural geometrical outcomes at the neck of the proximal femur using two-dimensional DXA-derived projection (APEX) and three-dimensional QCT-derived (BIT QCT) techniques

Structural geometric parameters at neck of the proximal femur were obtained using DXA-derived hip structural analysis (APEX 3) and quantitative computed tomography-derived (BIT QCT) techniques in 237 elderly females. Linear correlations for parameters ranged from 0.45 to 0.90. The average value of the subperiosteal width, as determined by the two techniques, was the same; variables dependent on mass measurements were different.

INTRODUCTION

There has been increasing interest in using bone structural geometry to assess bone fragility to complement bone mineral mass. The objective of this study is to compare structural geometrical differences between "2D" DXA-derived and "3D" QCT-derived techniques in unselected clinical cases.

METHODS

All 237 females had both DXA and QCT assessments of femoral neck structural geometry. Variables compared were areal bone mineral density, cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), section modulus (Z), averaged cortical thickness (Ct), endosteal width (ESW), subperiosteal width (W), and buckling ratio (BR).

RESULTS

Correlation of femoral neck variables ranged from 0.45 for ESW to 0.90 for CSA. APEX 3 and BIT QCT-derived femoral neck W values were numerically similar. However CSA, CSMI, Z and Ct values measured by APEX 3 were higher and ESW and BR values were lower than corresponding BIT QCT.

CONCLUSIONS

2D DXA structural analysis of neck of femur is related to but different from same parameters calculated from true 3D images obtained by CT. Femoral neck size values are similar for DXA and QCT, but structural geometrical variables dependent on mass calibration standards, location of neck ROI and mathematical derivation techniques are different.

An in vivo comparison of hip structure analysis (HSA) with measurements obtained by QCT

SUMMARY

In a population of elderly women, bone cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), section modulus (Z), femoral neck axis length (FNAL), and width measured with hip structure analysis (HSA) on dual-energy x-ray absorptiometry (DXA) images in the femoral neck and trochanteric regions are highly correlated to quantitative computed tomography (QCT) measurements.

INTRODUCTION

HSA is a method of obtaining measurements of proximal femur structure using 2D DXA technology. This study was designed to examine the correlations between HSA measurements and 3D QCT.

METHODS

Forty-one women (mean age, 82.8 ± 2.5 years) were measured using DXA and a 64-slice CT scanner (1 mm slice thickness, 0.29 mm in plane resolution). HSA parameters were calculated at the narrow neck (NN) and trochanteric (IT) regions on the DXA image. These regions were then translated to anatomically equivalent regions on the QCT dataset by co-registering the DXA image and QCT dataset using four DXA images acquired at different angles.

RESULTS

At the NN and IT regions, high linear correlations were measured between HSA and QCT for CSA r = 0.95 and 0.93, CSMI r = 0.94 and 0.93, and Z r = 0.93 and 0.89, respectively. All correlations were highly significant (p < 0.001), but there were differences in slope and offset between the two techniques, at least in part due to differences in calibration between the two techniques. FNAL and width of the bone at the NN and IT regions, physical measurements independent of the calibration, were highly correlated (r = 0.90-0.95, p < 0.001) and had slopes close to 1.0 (range, 0.978 to 1.003).

CONCLUSION

CSA, CSMI, Z, FNAL, and width measured by HSA correlate highly to high-resolution QCT.

The calcium scare--what would Austin Bradford Hill have thought?

Detailed consideration of the suggested association between calcium supplementation and heart attacks has revealed weakness in the evidence which make the hypothesis highly implausible.

INTRODUCTION

The aim of this study was to evaluate the strength of the evidence that calcium supplementation increases the risk of myocardial infarction.

METHODS

This study used critical examination of a meta-analysis of the effects of calcium supplements on heart attacks in five prospective trials on 8,016 men and women, and consideration of related publications by the same author.

RESULTS

The meta-analysis was found to be subject to several limitations including non-adherence to the clinical protocol, multiple endpoint testing and failure to correctly adjust for endpoint ascertainment. The main risk factors for myocardial infarction were not available for 65% of the participants, and none of the trials had cardiovascular disease as its primary endpoint. There were more overweight participants, more subjects on thyroxine and more men on calcium than on placebo. In particular, over 65% of all the heart attacks were self-reported. When the evidence was considered in the light of Austin Bradford Hill's six main criteria for disease causation, it was found not to be biologically plausible or strong or to reflect a dose-response relationship or to be consistent or to reflect the relationship between the trends in calcium supplementation and heart attacks in the community or to have been confirmed by experiment. The addition of a more recent trial on 1,460 women over 5 years reduced the relative risk to 1.23 (P = 0.0695).

CONCLUSION

Present evidence that calcium supplementation increases heart attacks is too weak to justify a change in prescribing habits.

Significant association between common polymorphisms in the aromatase gene CYP19A1 and bone mineral density in postmenopausal women

17β-Estradiol is important in maintaining bone structure, and regulation of its synthesis plays an important role in the development of postmenopausal osteoporosis. We and others have demonstrated associations between variation in the CYP19A1 gene (encoding aromatase) and areal bone mineral density (aBMD) phenotypes in women. In the present study 33 tag polymorphisms were genotyped across the CYP19A1 gene in a population of 1,185 Caucasian postmenopausal women to test the association between sequence variations, total DXA hip aBMD, and circulating 17β-estradiol levels. An in silico bioinformatics analysis was performed for single nucleotide polymorphisms (SNPs) associated with aBMD to identify putative functional effects, while linkage disequilibrium analysis of these SNPs was undertaken with previously published sequence variants. Five SNPs located in the central third of the gene were strongly associated with total-hip aBMD after adjustment for age (P = 0.006-0.013). A haplotype analysis of these five SNPs revealed an association between the haplotype C-G-G-G-C and increased aBMD (P = 0.008) and the haplotype A-A-A-A-A and a decreased aBMD (P = 0.021). The haplotype frequency was 9.0% for C-G-G-G-C and 15.4% for A-A-A-A-A, with the variation in mean total-hip aBMD explained by the haplotype analyses being 5% and 7%, respectively. None of these polymorphisms was significantly associated with circulating 17β-estradiol levels. In conclusion, common genetic variations within the CYP19A1 gene are significantly associated with aBMD in postmenopausal Caucasian women.

Homozygous deletion of the UGT2B17 gene is not associated with osteoporosis risk in elderly Caucasian women

Previously, homozygous deletion of the UGT2B17 gene has shown association with hip fracture. Using a high-throughput qRT-PCR assay, we genotyped UGT2B17 copy number variation (CNV) in 1,347 elderly Caucasian women and examined for effects on bone phenotypes. We found no evidence of association between UGT2B17 CNV and osteoporosis risk in this population.

INTRODUCTION

Genetic studies of osteoporosis commonly examine SNPs in candidate genes or whole genome analyses, but insertions and deletions of DNA, collectively called CNV, also comprise a large amount of the genetic variability between individuals. Previously, homozygous deletion of the UGT2B17 gene in CNV 4q13.2, which encodes an enzyme that mediates the glucuronidation of steroid hormones, has shown association with the risk of hip fracture.

METHODS

We used a quantitative real-time PCR assay for genotyping the UGT2B17 CNV in a well-characterized population study of 1,347 Caucasian women aged 75.2 ± 2.7 years (mean ± SD), to assess the effect of the CNV on bone mass density (BMD) at the total hip site and osteoporosis risk.

RESULTS

The UGT2B17 CNV distribution was consistent with the expected Hardy-Weinberg distribution and not different from frequencies previously reported in a Caucasian population. Data from ANCOVA of age- and weight-adjusted BMD for UGT2B17 CNV genotype showed no significant difference between genotype groups. Individuals with homozygous or heterozygous deletion of the UGT2B17 gene showed no increased risk of incident fragility fracture.

CONCLUSIONS

These data suggest that quantitative real-time PCR is a rapid and efficient technique for determination of candidate CNVs, including the UGT2B17 CNV; however, we found no evidence of an effect of UGT2B17 CNV on osteoporosis risk in elderly Caucasian women.

Adequacy and change in nutrient and food intakes with aging in a seven-year cohort study in elderly women

OBJECTIVE

As women age total dietary intake falls which may increase the risk of dietary deficiencies in some individuals. The aims of this study were to investigate the changes in nutrient and dietary intakes that occurred with aging in a seven-year longitudinal study of elderly Australian women and to evaluate the adequacy of their dietary intakes.

DESIGN

Longitudinal population based study on health with ageing.

PARTICIPANTS AND SETTING

911 free-living elderly women aged 70-85 years at baseline from a cohort of 1500 elderly women.

MEASUREMENTS

At baseline, 60 and 84 months, self-reported Food Frequency Questionnaires (FFQ) and demographics were collected and anthropometry measured.

RESULTS

During the 84 month subjects lost height (1.8 cm) and body weight (1.9 kg). Intakes of energy and macronutrients carbohydrate, fat and protein declined significantly over the 84 months. Mean energy derived from saturated fat was above, whereas energy derived from carbohydrate was below, recommended levels of intake at all time points. Intakes of vitamins and minerals all declined with age and subjects had suboptimal intakes of folate, vitamin E and calcium at all time points. The serve sizes for potato and meat and the consumption of milk, bread and variety of vegetables declined significantly over time reflecting changes in nutrient intake.

CONCLUSIONS

Ageing is associated with reduced food intake resulting in inadequate intakes in energy, and some nutrients. Nutrition policy for elderly women should include advice to maintain or increase intakes of carbohydrate, milk, vegetables and fruit whilst continuing to reduce fat intake.

Effects of a 1-year randomized controlled trial of resistance training on lower limb bone and muscle structure and function in older men

SUMMARY

A 1-year randomized controlled trial of resistance training compared with a control group was undertaken in 143 men aged 55-80 years. Although hip bone mineral density, lean body mass, and function increased in both groups, lean body mass and function but not bone density increased more in the resistance group.

INTRODUCTION

Previous studies have demonstrated a positive effect of resistance training on bone mineral density (BMD) in postmenopausal women, but the effect in men is unclear. The aim was to examine the effect of a 1-year resistance training program on bone and lean body mass in 143 men aged 55-80 years, randomized to either resistance training or active control.

METHODS

Resistance exercises were selected to provide loading at the hips. Measurements were taken at 0, 6, and 12 months for BMD (whole body, hip, and spine), lean body mass, strength, and functional fitness.

RESULTS

The intervention showed a significant increase in total hip BMD for both groups at 12 months (active control, 1,014-1,050 mg/cm(2); resistance, 1,045-1,054 mg/cm(2), p < 0.05) with no increased effect of resistance training compared to active control. However, compared to the active control group, the resistance group increased their lean body mass (active control, 0.1 +/- 2.1%; resistance, 1.5 +/- 2.7%, p < 0.05), fitness (active control, 4.6 +/- 11.1%; resistance, 13.0 +/- 13.4%, p < 0.05), and lower limb muscle strength (active control, 14.3 +/- 16.8%; resistance, 39.4 +/- 30.87%, p < 0.05).

CONCLUSIONS

In contrast to previous findings in older women, in older men, a resistance training program does not increase hip bone mass more than walking 30 min three times a week.

Comparison of QCT-derived and DXA-derived areal bone mineral density and T scores

Two-dimensional areal bone mineral density (aBMD) of the proximal femur measured by three-dimensional quantitative computed tomography (QCT) in 91 elderly women was compared to dual-energy X-ray absorptiometry (DXA) aBMD results measured in the same patients. The measurements were highly correlated, though QCT aBMD values were marginally lower in absolute units. Transformation of the QCT aBMD values to T score values using National Health and Nutrition Examination Survey (NHANES) DXA-derived reference data improved agreement and clinical utility.

INTRODUCTION

World Health Organization guidelines promulgate aBMD (g cm(-2)) measurement of the proximal femur for the diagnosis of bone fragility. In recent years, there has been increasing interest in QCT to facilitate understanding of three-dimensional bone structure and strength.

OBJECTIVE

To assist in comparison of QCT-derived data with DXA aBMD results, a technique for deriving aBMD from QCT measurements has been developed.

METHODS

To test the validity of the QCT method, 91 elderly females were scanned on both DXA and CT scanners. QCT-derived DXA equivalent aBMD (QCT(DXA) aBMD) was calculated using CTXA Hip software (Mindways Software Inc., Austin, TX, USA) and compared to DXA-derived aBMD results.

RESULTS

Test retest analysis indicated lower root mean square (RMS) errors for CTXA; F test between CTXA and DXA was significantly different at femoral neck (FN) and trochanter (TR) (p < 0.05). QCT underestimates DXA values by 0.02 +/- 0.05 g cm(-2) (total hip, TH), 0.01 +/- 0.04 g cm(-2) (FN), 0.03 +/- 0.07 g cm(-2) (inter-trochanter, IT), and 0.02 +/- 0.05 g cm(-2) (TR). The RMS errors (standard error of estimate) between QCT and DXA T scores for TH, FN, IT, and TR were 0.36, 0.40, 0.39, and 0.49, respectively.

CONCLUSIONS

This study shows that results from QCT aBMD appropriately adjusted can be evaluated against NHANES reference data to diagnose osteoporosis.

In vitro kinetic properties of the Thr201Met variant of human aromatase gene CYP19A1: functional responses to substrate and product inhibition and enzyme inhibitors

CONTEXT

The T(201)M variant (rs28757184) within exon 5 of the human aromatase gene CYP19A1, present in up to 20% of some populations, has been reported to reduce prostate cancer progression.

OBJECTIVE

We hypothesized that the T(201)M variant would alter the structure of the enzyme and thus would also affect function compared to wild-type human aromatase.

DESIGN

HEK293 cells were transiently transfected with CYP19A1 wild-type or T(201)M variant gene transcripts made by site-directed mutagenesis and enzyme activity measured using tritiated androstenedione as the substrate. The effects of differing concentrations of substrate and product (E1 and E2) and four aromatase inhibitors were assessed.

RESULTS

At all substrate concentrations tested, the T(201)M variant showed substantially increased activity compared to the wild-type (Vmax: variant, 738 +/- 36 pmol/h . mg; wild-type, 189 +/- 17 pmol/h . mg, P < 0.0001; Km: variant, 64.4 +/- 19.3 nm; wild-type, 46.6 +/- 9.1 nm, P = 0.04). Kinetic analysis showed evidence of substrate inhibition for the wild-type, but no product inhibition was demonstrated for either transcript. Formestane, chrysin, and letrozole had no differential inhibitory effect on the two transcripts, but aminoglutethimide inhibition was substantially reduced in the variant compared to wild-type (IC(50): wild-type, 1.3 +/- 0.2 nm; variant, 45 +/- 14.2 nm, P = 0.002; and Ki: wild-type, 0.7 +/- 0.2 nm; variant, 29.6 +/- 9.7 nm, P = 0.0001).

CONCLUSIONS

In addition to loss of function mutations previously described, a new naturally occurring relatively common alteration of enzyme structure at T(201)M increases enzyme activity and reduces the inhibitory effect of aminoglutethimide. These findings identify the T(201)M site, distant from the substrate-binding site and not previously considered to play a role in enzyme activity, as a functionally important area of the enzyme that may play a role in the propensity to disease. Common to other cytochrome P450 enzymes, wild-type aromatase demonstrates substrate but not product inhibition.

The effects of homocysteine and MTHFR genotype on hip bone loss and fracture risk in elderly women

SUMMARY

Few studies have evaluated the effects of homocysteine and methylenetetrahydrofolate reductase (MTHFR) genotype on age-related bone loss. In our 5-year cohort study with 1,213 women aged 70-85 years, high homocysteine is associated with greater hip bone loss but not fracture risk. The effect of MTHFR genotype on bone density and fracture is weak.

INTRODUCTION

Previous studies on the effects of homocysteine and MTHFR genotype on bone mineral density (BMD) and osteoporotic fracture risk have shown inconsistent results. Few studies have evaluated their effects on age-related bone loss. We evaluated the effects of homocysteine and MTHFR genotype variation on hip BMD and fracture risk over 5 years in a cohort of 1,213 community-dwelling women aged 70-85 years.

METHODS

Nutritional intake and prevalent fracture status were assessed at baseline, plasma homocysteine was measured at year 1, and hip dual-energy X-ray absorptiometry (DXA) BMD was measured at years 1 and 5. Clinical incident osteoporotic fractures confirmed by radiographic report were collected throughout the study and the MTHFR gene C677T and A1298C polymorphisms genotyped. Data were analyzed using analysis of covariance and Cox proportional hazard regression.

RESULTS

The highest tertile of homocysteine was associated with a greater hip BMD loss over 4 years (-2.8%) compared to the middle (-1.6%) and lowest tertiles (-1.2%) (P < 0.001). This effect remained after adjustment for covariates. There was no effect of homocysteine on fracture prevalence or incidence. MTHFR gene variation was only weakly related to one of the bone outcome measures.

CONCLUSION

In this study population, high homocysteine is associated with greater hip bone loss but not fracture risk.

The effects of high potassium consumption on bone mineral density in a prospective cohort study of elderly postmenopausal women

Few studies have investigated the long-term effects of potassium intake on BMD. In a cohort of 266 elderly women, we found that baseline potassium intake as reflected by 24-hour urine potassium excretion had positive association with BMD measured at 1 and/or 5 years later, suggesting a role of dietary potassium on osteoporosis prevention.

INTRODUCTION

High dietary potassium intake has been suggested to be beneficial for bone structure, but few studies have investigated the long-term effects of potassium intake on BMD in elderly women. We examined the relationship between potassium intake as reflected by 24-hour urine potassium excretion and bone density in a cohort of elderly women.

METHODS

The study subjects were 266 elderly postmenopausal women aged 70-80 years. Twenty-four-hour urinary potassium excretion was determined at baseline. At one year hip DXA BMD was measured, at 5 years hip and total body DXA BMD and distal radius and tibia pQCT vBMD were measured. The effects of potassium were evaluated by ANCOVA according to the quartile of baseline urinary potassium excretion.

RESULTS

After adjustment for confounding factors, subjects in the highest quartile of urinary potassium excretion had significantly higher total hip BMD at 1 (5%) and 5 years (6%), and significantly higher total body BMD (4%) and 4% distal tibia total (7%) and trabecular vBMD (11%) at 5 years than those in the lowest quartile.

CONCLUSIONS

Potassium intake shows positive association with bone density in elderly women, suggesting that increasing consumption of food rich in potassium may play a role in osteoporosis prevention.

Prevalence and predictors of osteopenia and osteoporosis in adults with Type 1 diabetes

AIMS

To determine the prevalence and biochemical/hormonal determinants of osteopenia and osteoporosis in adults with Type 1 diabetes.

METHODS

One hundred and two patients (52 female, 50 male) with Type 1 diabetes aged 20-71 years underwent cross-sectional assessment of biochemical/hormonal markers of bone metabolism, and bone mineral density (BMD) measurement at forearm, hip and spine using dual energy x-ray absorptiometry. BMD data were available for 102 age- and gender-matched population-based control subjects.

RESULTS

After adjusting for age and body mass index (BMI), osteopenia and osteoporosis were more common at the spine in males with Type 1 diabetes than in control subjects (P = 0.030). In Type 1 males, after adjustment for age and BMI, BMD, T- and Z-scores at the hip, femoral neck and spine were lower compared with age-matched control subjects (P < or = 0.048). Female Type 1 patients and control subjects had similar BMDs and T- and Z-scores at all sites. On multiple linear regression analysis, which adjusted for the natural logarithm of the sex hormone binding globulin concentration, smoking status and alcohol consumption, and (for women) menopausal status, each of BMI, serum ionized calcium and serum alkaline phosphatase (negatively) were independently associated with BMD at the hip and femoral neck in Type 1 diabetic subjects.

CONCLUSIONS

Adult males with Type 1 diabetes have reduced bone density at the hip, femoral neck and spine when compared with age-matched control subjects. Impaired bone formation may occur in Type 1 diabetes.

Bone structural effects of variation in the TNFRSF1B gene encoding the tumor necrosis factor receptor 2

The 1p36 region of the human genome has been identified as containing a QTL for BMD in multiple studies. We analysed the TNFRSF1B gene from this region, which encodes the TNF receptor 2, in two large population-based cohorts. Our results suggest that variation in TNFRSF1B is associated with BMD.

INTRODUCTION

The TNFRSF1B gene, encoding the TNF receptor 2, is a strong positional and functional candidate gene for impaired bone structure through the role that TNF has in bone cells. The aims of this study were to evaluate the role of variations in the TNFRSF1B gene on bone structure and osteoporotic fracture risk in postmenopausal women.

METHODS

Six SNPs in TNFRSF1B were analysed in a cohort of 1,190 postmenopausal Australian women, three of which were also genotyped in an independent cohort of 811 UK postmenopausal women. Differences in phenotypic means for genotype groups were examined using one-way ANOVA and ANCOVA.

RESULTS

Significant associations were seen for IVS1+5580A>G with BMD and QUS parameters in the Australian population (P = 0.008 - 0.034) and with hip BMD parameters in the UK population (P = 0.005 - 0.029). Significant associations were also observed between IVS1+6528G>A and hip BMD parameters in the UK cohort (P = 0.0002 - 0.003). We then combined the data from the two cohorts and observed significant associations between both IVS1+5580A>G and IVS1+6528G>A and hip BMD parameters (P = 0.002 - 0.033).

CONCLUSIONS

Genetic variation in TNFRSF1B plays a role in the determination of bone structure in Caucasian postmenopausal women, possibly through effects on osteoblast and osteoclast differentiation.

A cohort study of the effect of endogenous estrogen on spine fracture risk and bone structure in elderly women and an assessment of its diagnostic usefulness

The decline in endogenous estrogen concentration after menopause is associated with accelerated bone loss. However, effects in older women remain controversial and the usefulness of estrogen status as a predictor of spine fracture has not been assessed. Therefore, we undertook a prospective cohort study of 1350 women mean age 75 years in order to study the role of endogenous estrogen concentration on the risk of morphometric X-ray absorptiometry (MXA)-defined vertebral deformity and atraumatic clinical spine fracture and the association of endogenous estrogen with bone structure. At 5 years 70 patients (5.2%) had sustained > or = 1 incident spine fracture. The fracture group had significantly lower concentrations of baseline free estradiol index (FEI) median (IQ range) (0.38 (0.22-0.60) vs. 0.49 (0.29-0.84) pmol/nmol, p=0.009). The patients in the lowest tertile of FEI (FEI <0.35) had twice the risk of sustaining a clinical vertebral fracture compared to those subjects in the highest tertile (FEI >0.68) (HR 2.18: 95% CI 1.11-4.28). A low FEI was associated with an increased risk of a vertebral deformity over the 5-year study (OR 1.77: 95% CI 1.02-3.07) for the lowest compared to highest tertile. A low baseline FEI was associated with lower baseline QUS heel bone structure and DXA hip bone structure at 12 months and with deterioration in QUS heel bone structure 5 years later. The effect size of the FEI in predicting spine fracture was similar to the effect size for DXA BMD and heel QUS, probably because of the beneficial effect of the FEI on bone structure. The data suggest that the estrogen effect on reducing spine fracture is at least in part due to an effect on bone structure and its measurement does not significantly improve fracture prediction.

The clinical utility of measured kyphosis as a predictor of the presence of vertebral deformities

Meaured spinal kyphosis, as a predictor of prevalent and incident vertebral deformity, was examined in older women (>70 years) and found to not have sufficient sensitivity or specificity to justify its use as a predictor of present or future vertebral deformity risk.

INTRODUCTION

Kyphosis may be attributable to vertebral deformity and was investigated as a clinical tool for predicting the presence and future risk of vertebral deformity.

METHODS

Kyphosis was measured in 434 women aged 70 years or older and the kyphosis index (KI) calculated. Prevalent and incident vertebral deformities were assessed by morphometric X-ray absorptiometry (MXA). The predictive value of KI was examined.

RESULTS

Severity of kyphosis was categorised by tertile of KI; 65% of anterior thoracic deformities occurred in the 33% of subjects in the highest (most kyphotic) tertile. Using this tertile as a predictor of anterior thoracic deformity, the probability for a positive test rose from 14% for the whole population to 28% and for a negative test the probability fell to 8%. For any spinal deformity the highest tertile of KI increased the probability of a positive test from 34% to 42% and reduced the probability for a negative test to 30%. The incidence of new deformities was 6% over 4 years; a high KI tertile did not increase the probability of any vertebral deformity.

CONCLUSIONS

Severe kyphosis does not increase the probability of detection of a prevalent or incident spinal deformity sufficiently to make it a useful method of selecting patients for further evaluation of spinal deformity.

No associations between OPG gene polymorphisms or serum levels and measures of osteoporosis in elderly Australian women

Bone mass is the single most important risk factor for osteoporotic fractures in the elderly and is mainly influenced by genetic factors accounting for 40-75% of the inter-individual variation. Critical for the bone remodeling process is the balance between the newly discovered members of the tumor necrosis factor ligand and receptor superfamilies, osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand, which mediate the effects of many upstream regulators of bone metabolism. In the present study, we evaluated the impact of sequence variations in the OPG gene on bone mass, bone-related biochemistry including serum OPG and fracture frequency in elderly Australian women. A total of 1101 women were genotyped for 3 different single nucleotide polymorphisms (SNP) within the OPG gene (G1181C, T950C and A163G). The effects of these SNPs and serum OPG on calcaneal quantitative ultrasound measurements, osteodensitometry of the hip and bone-related biochemistry were examined. We found no significant relationship between sequence variations in the OPG gene or serum OPG and bone mass, bone-related biochemistry or fracture frequency. Our findings confirm some recent publications investigating the same SNPs but diverge from others, indicating that generalization of the relationships found in this type of study must be done with caution and signify the importance of determining associations between polymorphisms and osteoporosis in different ethnic groups.

Bone mineral density and its determinants in diabetes: the Fremantle Diabetes Study

AIMS/HYPOTHESIS

We assessed the effects of type 1 and type 2 diabetes on bone density and metabolism.

MATERIALS AND METHODS

We analysed bone mineral density (BMD) measured at the hip, spine and forearm using dual energy X-ray absorptiometry in 34 patients with type 1 and 194 patients with type 2 diabetes. Patients were from the community-based Fremantle Diabetes Study, and findings for them were compared with those from normal age- and sex-matched control subjects from the local community. Biochemical and hormonal markers of bone metabolism were measured in a subset of 70 patients.

RESULTS

After adjusting for age and BMI, there was a lower BMD at total hip (p<0.001) and femoral neck (p=0.012) in type 1 men vs control subjects, but type 1 women and matched controls had similar BMD at each site. There was a higher BMD at total hip (p=0.006), femoral neck (p=0.026) and forearm (p<0.001) in type 2 women vs control subjects, but diabetes status was not associated with BMD in type 2 men after adjustment for age and BMI. Serum oestradiol, BMI, C-terminal telopeptide of collagen type 1 and male sex were consistently and independently associated with BMD at forearm, hip and femoral neck and explained 61, 55 and 50% of the total variance in BMD, respectively, at these sites. Spine BMD was independently associated with BMI and ln(oestradiol).

CONCLUSIONS/INTERPRETATION

Men with type 1 diabetes may be at increased risk of osteoporosis, while type 2 women appear to be protected even after adjusting for BMI. Low serum oestradiol concentrations may predispose to diabetes-associated osteoporosis regardless of sex.

Klotho gene polymorphisms are associated with osteocalcin levels but not bone density of aged postmenopausal women

Osteoporosis is known to have a strong genetic basis. It has been proposed that polymorphisms within the KL (klotho) gene have a significant effect on aging, in particular, the osteoblast defect of aging. The association between polymorphisms within this gene and biochemical markers of bone formation and resorption, bone structure, and fracture rates was studied in 1,190 postmenopausal women with a mean age of 75 years. Genotyping of these polymorphic sites was carried out using Matrix-Assisted Laser Desorption Ionization--Time of Flight (MALDI-ToF) mass spectrometry. The G allele of SNP c.1775G>A was associated with a lower osteocalcin level than the A allele (P = 0.004) in a codominant model. SNPs C-387T and IVS1+8262c>t both showed nonsignificant associations with osteocalcin (P values of 0.063 and 0.068, respectively), but a haplotype analysis of 2 of 5 haplotypes of the three SNPs with a frequency greater than 4% revealed a significant association with osteocalcin (P = 0.036). None of the individual polymorphisms or haplotypes analyzed showed any associations with a marker of bone resorption the deoxypyridinoline creatinine ratio, bone structure, or fracture data. Therefore, the G polymorphism within the c.1775G>A SNP site and a haplotype including this are associated with a reduced osteoblast product osteocalcin. These data suggest that variation in the KL gene product affects osteoblast activity independent of osteoclast activity but that this defect does not result in an effect on bone structure in this population, perhaps because of "rescue" by other genetic or environmental factors in this population.

Association of an aromatase TTTA repeat polymorphism with circulating estrogen, bone structure, and biochemistry in older women

Osteoporosis is a disease that is strongly genetically determined. Aromatase converts androgens to estradiol in postmenopausal women, therefore polymorphisms of the gene for this enzyme may be associated with bone mass and fracture. We investigated the association of the TTTA microsatellite polymorphism in intron 4 of the aromatase (CYP19) gene with bone mineral density (BMD) and fracture in 1,257 women aged 70 yr and greater. The data obtained were stratified based on the presence or absence of a [TTTA]n of 7 (A2), determined from a preliminary analysis of hip dual-energy X-ray absorptiometry BMD, which was present in 27% of the population. The presence of an A2 allele was associated with a higher free estradiol index (0.52 +/- 0.49, P = 0.049) compared with the absence of an A2 allele (0.47 +/- 0.45); higher BMD at all sites of the hip (3.4% total hip, 2.3% femoral neck, 3.6% intertrochanter, 4.1% trochanter) and the lumbar spine (12.7%); higher values for the calcaneal quantitative ultrasound parameters broadband ultrasound (1.3%), speed of sound (0.4%), and stiffness (3.7%); and higher peripheral quantitative computed tomography measures for total (3.4%), trabecular (3.3%), and cortical BMD (3.3%) and the derived stress strain index (SSI) parameters SSI polar (6.4%) and SSI x (6.8%) values. A lower deoxypryridinoline creatinine ratio was observed in subjects with an A2 allele (30.3 +/- 10.4 vs. 27.1 +/- 9.1, P = 0.03). The A2 allele was associated with a lower prevalence of vertebral fracture in subjects who were osteoporotic (odds ratio 0.27, confidence interval 0.09-0.79). Therefore, a common polymorphism of the aromatase gene, perhaps in linkage disequilibrium with a functionally significant CYP19 polymorphism, is associated with bone structure and bone turnover, either by local effects or by effects on circulating bioactive estrogen.

LRP5 gene polymorphisms predict bone mass and incident fractures in elderly Australian women

Postmenopausal osteoporosis and bone mass are influenced by multiple factors including genetic variation. The importance of LDL receptor-related protein 5 (LRP5) for the regulation of bone mass has recently been established, where loss of function mutations is followed by severe osteoporosis and gain of function is related to increased bone mass. The aim of this study was to evaluate the role of polymorphisms in the LRP5 gene in regulating bone mass and influencing prospective fracture frequency in a well-described, large cohort of normal, ambulatory Australian women. A total of 1301 women were genotyped for seven different single nucleotide polymorphisms (SNPs) within the LRP5 gene of which five were potentially informative. The effects of these gene polymorphisms on calcaneal quantitative ultrasound measurements (QUS), osteodensitometry of the hip and bone-related biochemistry was examined. One SNP located in exon 15 was found to be associated with fracture rate and bone mineral density. Homozygosity for the less frequent allele of c.3357 A > G was associated with significant reduction in bone mass at most femoral sites. The subjects with the GG genotype, compared to the AA/AG genotypes showed a significant reduction in BUA and total hip, femoral neck and trochanter BMD (1.5% P = 0.032; 2.7% P = 0.047; 3.6% P = 0.008; 3.1% P = 0.050, respectively). In the 5-year follow-up period, 227 subjects experienced a total of 290 radiologically confirmed fractures. The incident fracture rate was significantly increased in subjects homozygous for the GG polymorphism (RR of fracture = 1.61, 95% CI [1.06-2.45], P = 0.027). After adjusting for total hip BMD, the fracture rate was still increased (RR = 1.67 [1.02-2.78], P = 0.045), indicating factors other than bone mass are of importance for bone strength. In conclusion, genetic variation in LRP5 seems to be of importance for regulation of bone mass and osteoporotic fractures.

Bone mass effects of a BMP4 gene polymorphism in postmenopausal women

The pathogenesis of osteoporosis involves both genetic and environmental factors. On the basis of linkage data suggesting gene effects on bone density at chromosome 14q and data locating the BMP4 gene to 14q, we performed a positional candidate study to examine a possible association of BMP4 gene polymorphisms, hip bone density (n = 1012) and fracture rates (n = 1232) in postmenopausal women (mean age 75). On genotype analysis of the three selected single nucleotide polymorphisms (SNP), the 6007C > T polymorphism was associated with total and intertrochanteric hip BMD and BMD was lower in the 32% of subjects homozygous for the C allele. This polymorphism codes for a nonsynonymous amino acid change with the T allele coding for valine, while the C allele codes for alanine. The difference in BMD was 3.1% (TT vs. CC) and 2.3% (CT versus CC) for the total hip (P = 0.023), and 3.7% (TT vs. CC) and 2.8% (CT versus CC) for the intertrochanter site (P = 0.012). Haplotype analysis demonstrated 6 haplotypes of frequency greater than 2%. A major haplotype defined by G-C-T alleles in SNPs -5826G > A, 3564C > T and 6007C > T respectively, showed association with high bone mass. No SNP showed association with fracture rates. We conclude that a polymorphism found in the BMP4 gene, affecting amino acid sequence, is associated with hip bone density in postmenopausal women, presumably via regulation of anabolic effects on the skeleton.

Effects of endogenous estrogen on renal calcium and phosphate handling in elderly women

High postmenopausal endogenous estrogen concentrations are an important determinant of preservation of bone mass and reduced fracture in elderly women. Calcium supplementation can also reduce bone loss in these patients, suggesting an interaction between estrogen deficiency and calcium balance. Potential mechanisms of estrogen on calcium transport include direct effects on the bone, the kidney, and the bowel. Previous studies have demonstrated effects of estrogen on renal phosphate handling. We have used a cross-sectional, population-based analysis of biochemical data obtained from ambulant elderly women to determine the association of endogenous estradiol with urine calcium and phosphorus excretion. The subjects were 293 postmenopausal women >70 yr old. Factors associated with renal calcium and phosphate excretion were measured, including the filtered calcium and phosphate load, parathyroid hormone (PTH), estradiol, and sex hormone-binding globulin (SHBG). The free estradiol concentration (FE) was calculated from a previously described formula. A high plasma estradiol concentration (r(2) = 0.023, P = 0.01) and a high FE (r(2) = 0.045, P = 0.001) were associated with reduced renal calcium excretion. The estradiol and FE effect on renal calcium excretion remained significant after adjusting for calcium filtered at the glomerulus and serum PTH. A high FE was associated with a reduced renal phosphate threshold in univariate analysis (r(2) = 0.023, P = 0.010). The effect remained significant after adjustment for serum PTH. The size of the effect of the FE was of the same order of magnitude as the effect of PTH on reducing renal calcium excretion and increasing renal phosphate excretion. These data support in vitro and animal data demonstrating an effect of estradiol on renal calcium and phosphate handling and indicate that, in elderly postmenopausal women, the effect is of a similar magnitude to the well-recognized effects of PTH on these physiologically regulated parameters.

Special report on the official positions of the International Society for Clinical Densitometry

The International Society for Clinical Densitometry (ISCD) periodically holds Position Development Conferences (PDCs) for the purpose of establishing standards and guidelines for indications, acquisition, and interpretation of bone density tests. Topics are selected for consideration by the ISCD Scientific Advisory Committee, reviewed by scientific working groups, and presented to an international panel of experts. Topic categories addressed to date include indications for bone density testing, selection of reference databases for T-scores and Z-scores, clinical applications for central and peripheral bone densitometry, serial bone density testing, instrument precision assessment, phantom scanning and calibration testing, requirements for a bone density report, nomenclature, and diagnosis of osteoporosis in postmenopausal women, premenopausal women, men, and children. Following an open session for public comment and discussion, the panel convenes for consideration of each topic and makes recommendations for positions to the ISCD Board of Directors. Recommendations that are accepted become the Official Positions of the ISCD. This Special Report summarizes the methodology of the ISCD PDCs and presents selected Official Positions of general interest.

A randomized clinical trial comparing oral alendronate and intravenous pamidronate for the treatment of Paget's disease of bone

Second and third generation bisphosphonates are the treatment of choice for Paget's disease of bone. These drugs are more effective than calcitonin and etidronate, but there have been no head to head, randomized controlled trials comparing potent bisphosphonates. We conducted a 2-year, randomized, open-label trial comparing oral alendronate and intravenous pamidronate in 72 subjects with Paget's disease. Randomization was stratified according to baseline plasma total alkaline phosphatase (ALP) and previous bisphosphonate treatment (yes or no). All previously treated patients had received pamidronate but not alendronate. Assigned treatments were pamidronate (60 mg) every 3 months as a single infusion or alendronate (40 mg) daily in 3-month blocks, continued until biochemical remission (defined as both ALP and urine deoxypyridinoline (DPD)/creatinine ratio in the reference range) or a clear plateau effect was observed. At 1 year, nonresponders to pamidronate were crossed over to alendronate treatment. At 1 year, 31/36 (86%) subjects randomized to alendronate achieved biochemical remission compared with 21/36 (56%) for pamidronate (P = 0.017). There was a significantly greater reduction in ALP (P < 0.001) and DPD/creatinine ratio (P < 0.001) for alendronate compared with pamidronate treatment. In previously untreated patients, alendronate resulted in remission in 20/22 (91%) subjects compared with 19/22 (86%) of pamidronate-treated subjects, which was not significantly different; however, alendronate resulted in a significantly greater reduction in ALP (P = 0.014) and DPD/creatinine ratio (P < 0.001). In previously treated patients, alendronate resulted in remission in 11/14 (79%) subjects compared with 2/14 (14%) for pamidronate (P < 0.001), with a significantly (P < 0.001) greater reduction in both ALP and DPD/creatinine ratio. Of subjects crossed over from pamidronate to alendronate, 10/14 (71%) achieved remission, including 9/11 (82%) previously treated patients. We conclude that, in patients with previously untreated Paget's disease of bone, alendronate and pamidronate have similar efficacy in achieving biochemical remission. In patients previously treated with pamidronate, alendronate is more effective.

Calcium-sensing receptor gene polymorphism A986S does not predict serum calcium level, bone mineral density, calcaneal ultrasound indices, or fracture rate in a large cohort of elderly women

Postmenopausal osteoporosis is a complex and heterogeneous disease influenced by multiple factors and related to peak bone mass achieved in early adult life, followed by a subsequent continuous bone loss. Genetic variance and polymorphisms have been shown to be of clinical significance for osteoporotic fragility fractures. Previous studies have related variations in the calcium sensor receptor (CASR) gene to circulating Ca levels and bone mass in young women and adolescent girls. The aim of this study was to investigate the impact of the A986S polymorphism of the CASR gene on calcium homeostasis and bone metabolism in elderly women. We studied the distribution of the A986S polymorphism in a large cohort of 1252 ambulatory Australian women in relation to biochemical markers of bone metabolism, bone mass evaluated by quantitative ultrasound measurements (QUS) and DXA of the hip, prevalent and 36-month incident fracture data. No effect of the polymorphism was found on circulating calcium level, renal Ca excretion, or biochemical markers of bone turnover. Moreover, A986S was not associated with bone mass or prevalent or incident fractures. Power calculations revealed that a difference in circulating calcium levels of 0.05 mmol/l, a difference in DXA bone density of 24 mg, and a 1.6-fold difference in fracture rate could have been detected with a power of 80%. In conclusion, in a large cohort of elderly women the A986S polymorphism of the CASR gene was not found to be significant for calcium homeostasis or bone mass. It is questioned whether the polymorphism has any clinical significance for postmenopausal osteoporosis.

The T869C TGF beta polymorphism is associated with fracture, bone mineral density, and calcaneal quantitative ultrasound in elderly women

Osteoporosis is a disease that is strongly genetically determined and polymorphisms present in a range of candidate genes may be involved. A number of previous studies have shown an association between the T869C functional polymorphism of the gene for transforming growth factor beta (TGF beta) and bone mineral density (BMD) and fracture, but these studies have been limited to relatively small studies of selected subjects. In a population-based study of 1337 white women over age 70 we examined the TGF beta T869 polymorphism in relation to BMD, calcaneal quantitative ultrasound (QUS), and prevalent and incident fracture. The TGF beta C allele was observed in 50% of the subjects and was associated with reduced hip BMD at all sites (2.8% total hip, 2.4% femoral neck, 2.6% intertrochanter, and 3.4% trochanter) compared to the TGF beta TT genotype. The TGF beta C allele was also associated with a reduction in the QUS parameters BUA, SOS, and stiffness of 0.87%, 0.26%, and 2.4%, respectively, compared to the TGF beta TT genotype. After adjustment for body mass index in an analysis of variance model, the effect of the TGF beta C allele remained significant at the total hip, the femoral neck, and the trochanter, and for the QUS SOS and stiffness parameters. The TGF beta C allele was associated with an increase in osteoporosis [T score < or =-2.5 SD; odds ratio (OR) 2.07; 95% confidence interval (CI) 1.19-3.60] and prevalent fracture (1.37; 95% CI 1.06-1.75). After adjustment for BMD and QUS stiffness, the association of the TGF beta C allele with prevalent fracture was still present (OR 1.40; 95% CI 1.04-1.89), suggesting that the effect of the C allele on fracture was independent of a reduction in BMD and QUS stiffness. Subjects with normal BMD and a TGF beta C allele had an increased risk of incident fracture over 3 years compared to subjects with normal BMD and a TGF beta TT genotype (relative risk 3.95; 95% CI 1.52-10.29). This association was not found in osteopenic or in osteoporotic subjects, indicating a BMD-TGF beta C allele interaction in relation to the association of the TGF beta C allele with fracture risk. These findings are of potential clinical usefulness, as the TGF beta T869C genotype could be used, in conjunction with other genetic and clinical information, to determine an individual's risk of osteoporosis.

A randomized trial comparing hormone replacement therapy (HRT) and HRT plus calcitriol in the treatment of postmenopausal osteoporosis with vertebral fractures: benefit of the combination on total body and hip density

We report a prospective, randomized, multicenter, open-label 2-year trial of 81 postmenopausal women aged 53-79 years with at least one minimal-trauma vertebral fracture (VF) and low (T-score below - 2) lumbar bone mineral density (BMD). Group HRT received piperazine estrone sulfate (PES) 0.625 - 1.25 mg/d +/- medroxyprogesterone acetate (MPA) 2.5 - 5 mg/d; group HRT/D received HRT plus calcitriol 0.25 microg bd. All with a baseline dietary calcium (Ca) of < 1 g/ d received Ca carbonate 0.6 g nocte. Final data were on 66 - 70 patients. On HRT/D, significant (P < 0.001) BMD increases from baseline by DXA were at total body - head, trochanter, Ward's, total hip, intertrochanter and femoral shaft (% group mean delta 4.2, 6.1, 9.3, 3.7, 3.3 and 3.3%, respectively). On HRT, at these 6 sites, significant deltaS were restricted to the trochanter and Wards. Significant advantages of HRT/D over HRT were in BMD of total body (- head), total hip and trochanter (all P = 0.01). The differences in mean delta at these sites were 1.3, 2.6 and 3.9%. At the following, both groups improved significantly -lumbar spine (AP and lateral), forearm shaft and ultradistal tibia/fibula. The weightbearing, site - specific benefits of the combination associated with significant suppression of parathyroid hormone-suggest a beneficial effect on cortical bone. Suppression of bone turnover was significantly greater on HRT/D (serum osteocalcin P = 0.024 and urinary hydroxyproline/creatinine ratio P = 0.035). There was no significant difference in the number of patients who developed fresh VFs during the trial (HRT 8/36, 22%; HRT/D 4/34, 12% - intention to treat); likewise in the number who developed incident nonvertebral fractures. This is the first study comparing the 2 treatments in a fracture population. The results indicate a significant benefit of calcitriol combined with HRT on total body BMD and on BMD at the hip, the major site of osteoporotic fracture.

Comparison of genome screens for two independent cohorts provides replication of suggestive linkage of bone mineral density to 3p21 and 1p36

Low bone mineral density (BMD) is a major risk factor for osteoporotic fracture. Studies of BMD in families and twins have shown that this trait is under strong genetic control. To identify regions of the genome that contain quantitative trait loci (QTL) for BMD, we performed independent genomewide screens, using two complementary study designs. We analyzed unselected nonidentical twin pairs (1,094 pedigrees) and highly selected, extremely discordant or concordant (EDAC) sib pairs (254 pedigrees). Nonparametric multipoint linkage (NPL) analyses were undertaken for lumbar spine and total-hip BMD in both cohorts and for whole-body BMD in the unselected twin pairs. The maximum evidence of linkage in the unselected twins (spine BMD, LOD 2.7) and the EDAC pedigrees (spine BMD, LOD 2.1) was observed at chromosome 3p21 (76 cM and 69 cM, respectively). These combined data indicate the presence, in this region, of a gene that regulates BMD. Furthermore, evidence of linkage in the twin cohort (whole-body BMD; LOD 2.4) at chromosome 1p36 (17 cM) supports previous findings of suggestive linkage to BMD in the region. Weaker evidence of linkage (LOD 1.0-2.3) in either cohort, but not both, indicates the locality of additional QTLs. These studies validate the use, in linkage analysis, of large cohorts of unselected twins phenotyped for multiple traits, and they highlight the importance of conducting genome scans in replicate populations as a prelude to positional cloning and gene discovery.

Bone density changes in Paget's disease 2 years after iv pamidronate: profound, sustained increases in pagetic bone with severity-related loss in forearm nonpagetic cortical bone

Bone mineral density (BMD) was measured at three sites (forearm, spine, and hip) using dual X-ray and single-photon absorptiometry in 68 patients with Paget's disease before and after treatment with iv pamidronate. Patients were treated according to the severity of their disease; the mild category (Group I, hydroxyproline excretion (Hyp(E)) <5.0 micromol/L GF) received 120 mg, the moderate category (Group II, Hyp(E) 5.0-9.99 micromol/GF) 180 mg, and the severe category (Group III, > or = 10.0 micromol/GF) 240 mg. Group I was followed for 1 year, and both Groups II and III for 2 years. At the lumbar spine in pagetic bone there were no differences between groups in early responses, with a profound increase 6 months after treatment 20.5 +/- 2.0% above baseline values to 1.403 +/- 0.063 g/cm(2) (mean +/- SEM)(P < 0.001). This increase in BMD was sustained to 2 years (1.355 +/- 0.078 g/cm(2), P < 0.001) and was 15.0 +/- 2.2% above baseline values. The pagetic total hip BMD increased after treatment in all groups, with a mean rise of 10.4 +/- 1.4% at 1 year to 1.505 +/- 0.083 g/cm(2) (P < 0.01). At the pagetic femoral neck the response was similar, with a peak significant rise at 1 year of 10.7 +/- 1.7% to 1.403 +/- 0.097 g/cm(2) (P < 0.01). In nonpagetic spinal bone there were no differences between the group responses, with a combined mean increase of 4.3 +/- 0.7% at 1 year to 0.999 +/- 0.027 g/cm(2) (P < 0.01). In both Groups II and III the increase in BMD was significantly higher than baseline values at 1 and 2 years (P < 0.01). In the nonpagetic total hip BMD remained unchanged over the 2-year period and likewise, there were no significant changes from baseline at the nonpagetic femoral neck site. In the nonpagetic forearm we found a significant loss in BMD at the ultradistal (mainly trabecular), midregion (80% cortical), and proximal shaft (95% cortical) sites in Group III, persisting to 2 years at the latter two sites. The increase in bone density in pagetic bone, persisting at least 2 years, provides a new modality of assessment of the response of pagetic bone to treatment and suggests a mechanism for the reduction in fracture risk in such bone after effective bisphosphonate treatment. Severity-dependent nonpagetic forearm bone loss, persisting to 2 years at cortical sites, suggests a potential drug-induced fracture risk at the forearm and possibly elsewhere in the absence of appropriate preventive cotreatment.

Apolipoprotein E4 is associated with reduced calcaneal quantitative ultrasound measurements and bone mineral density in elderly women

Some studies have reported an association between the apolipoprotein E4 (APOE4) allele and reduced bone density and increased propensity to fracture, but this remains controversial as other studies have not found an association between APOE4 and bone density or fracture. No information is available concerning the effect of the APOE4 allele on quantitative ultrasound (QUS) parameters. We therefore examined this issue in a population-based study of 1332 healthy elderly women, examining the effect of the APOE4 allele on QUS parameters at the calcaneus and comparing this to dual-energy X-ray absorptiometry (DEXA) bone mineral density (BMD) at the hip. In addition, we examined the effect of the APOE4 allele on fracture. Subjects who had at least one APOE4 allele (n = 308) had lower calcaneal QUS parameters and lower hip BMD at the total hip, trochanter, and intertrochanter, but not the femoral neck, compared to subjects without an APOE4 allele (n = 1024) after adjustment for age, body mass index (BMI), and smoking. The decrement in QUS parameters and BMD was approximately 2%. Those subjects having an APOE4 allele were also more likely to fall into a low bone density group, defined by a T score of <1 SD below the young normal range (odds ratio [OR] 1.55, 95% confidence interval [CI] 1.08-2.22). We compared both prevalent and incident nontraumatic fractures over 2 years in the APOE4-present group compared with the APOE4-absent group. There were 354 subjects who entered the study with a history of one or more prevalent fractures, and 104 subjects sustained a nontraumatic fracture during the study. These fractures were not associated with the presence of the APOE4 allele, but a 2% decrement in BMD was unlikely to be associated with a statistically observable increase in fractures in this study. The APOE4 allele was not associated with a difference in any biochemical measures of bone formation or resorption, or in estrogen concentration, nor was it associated with a difference in BMI. Therefore, we conclude that the APOE4 allele is associated with a consistent decrease in both QUS parameters at the calcaneus and BMD at the clinically important hip site, and that this is not associated with differences in biochemical measures of bone formation or resorption.

A randomized trial of sodium fluoride (60 mg) +/- estrogen in postmenopausal osteoporotic vertebral fractures: increased vertebral fractures and peripheral bone loss with sodium fluoride; concurrent estrogen prevents peripheral loss, but not vertebral fractures

Postmenopausal Caucasian women aged less than 80 years (n = 99) with one or more atraumatic vertebral fracture and no hip fractures, were treated by cyclical administration of enteric coated sodium fluoride (NaF) or no NaF for 27 months, with precautions to prevent excessive stimulation of bone turnover. In the first study 65 women, unexposed to estrogen (-E study), age 70.8 +/- 0.8 years (mean +/- SEM) were all treated with calcium (Ca) 1.0-1.2 g daily and ergocalciferol (D) 0.25 mg per 25 kg once weekly and were randomly assigned to cyclical NaF (6 months on, 3 months off, initial dose 60 mg/day; group F CaD, n = 34) or no NaF (group CaD, n = 31). In the second study 34 patients, age 65.5 +/- 1.2 years, on hormone replacement therapy (E) at baseline, had this standardized, and were all treated with Ca and D and similarly randomized (FE CaD, n = 17; E CaD, n = 17) (+E study). The patients were stratified according to E status and subsequently assigned randomly to +/- NaF. Seventy-five patients completed the trial. Both groups treated with NaF showed an increase in lumbar spinal density (by DXA) above baseline by 27 months: FE CaD + 16.2% and F CaD +9.3% (both p = 0.0001). In neither group CaD nor E CaD did lumbar spinal density increase. Peripheral bone loss occurred at most sites in the F CaD group at 27 months: tibia/fibula shaft -7.3% (p = 0.005); femoral shaft -7.1% (p = 0.004); distal forearm -4.0% (p=0.004); total hip -4.1% (p = 0.003); and femoral neck -3.5% (p = 0.006). No significant loss occurred in group FE CaD. Differences between the two NaF groups were greatest at the total hip at 27 months but were not significant [p < 0.05; in view of the multiple bone mineral density (BMD) sites, an alpha of 0.01 was employed to denote significance in BMD changes throughout this paper]. Using Cox's proportional hazards model, in the -E study there were significantly more patients with first fresh vertebral fractures in those treated with NaF than in those not so treated (RR = 24.2, p = 0.008, 95% CI 2.3-255). Patients developing first fresh fractures in the first 9 months were markedly different between groups: -23% of F CaD, 0 of CaD, 29% of FE CaD and 0 of E CaD. The incidence of incomplete (stress) fractures was similar in the two NaF-treated groups. Complete nonvertebral fractures did not occur in the two +E groups; there were no differences between groups F CaD and CaD. Baseline BMD (spine and femoral neck) was related to incident vertebral fractures in the control groups (no NaF), but not in the two NaF groups. Our results and a literature review indicate that fluoride salts, if used, should be at low dosage, with pretreatment and co-treatment with a bone resorption inhibitor.

Predictors of low bone density in young adolescent females with anorexia nervosa and other dieting disorders

OBJECTIVE

To compare the bone density of adolescent patients with anorexia nervosa with adolescent patients with other dieting disorders and to evaluate risk factors for low bone density in these patients.

METHOD

Sixty-nine consecutive female patients referred to an adolescent eating disorders clinic were studied by interview, blood sampling, body composition, and lumbar spine bone density measurement using dual energy X-ray absorptiometry.

RESULTS

Although patients with anorexia nervosa were more malnourished, their bone density was similar to other dieting patients. Patients were divided into a low and normal bone density group irrespective of psychiatric diagnosis. Patients with low bone density had dieted for longer, had lower lean body mass, more often had not achieved menarche, and had longer duration of secondary amenorrhea and lower estrogen levels.

DISCUSSION

Irrespective of clinical diagnosis, adolescents with dieting disorders have increased risk of low bone density when malnutrition commences early in puberty and is associated with reduced lean body mass and impaired ovarian function.

The effect of estrogen on renal phosphorus handling in the rat

BACKGROUND/AIMS

Phosphorus reabsorption in the kidney is regulated by parathyroid action on the sodium phosphorus cotransporter (Na-Pi cotransporter). There is some evidence that estrogen may also regulate renal phosphorus handling but it is not known if this is an effect of estrogen on filtered phosphorus load.

METHODS

This study examined the effect of estrogen on renal phosphorus handling during infusion with calcium or EDTA. Six month old Sprague Dawley rats were bilaterally oophorectomized (OOX) or underwent a sham operation under ether anaesthesia 6 weeks before undergoing infusion with calcium chloride or EDTA. A second study examined renal phosphorus handling after estrogen replacement in the OOX rat injected with 20 microg estradiol valerate, or vehicle alone, prior to calcium infusion.

RESULTS

A comparison of filtered phosphorus load with renal phosphorus excretion indicated that the estrogen replete rat had a higher renal excretion of phosphorus when infused with both calcium (p = 0.004) and EDTA (p = 0.037) at all filtered phosphorus loads. A similar analysis in calcium infused, estrogen replaced, OOX rats indicated an effect of estrogen to increase renal phosphorus excretion (p = 0.007) at all filtered phosphorus loads. OOX resulted in a mild metabolic alkalosis, an effect not reversed by estrogen administration, that was not related to renal phosphorus excretion. OOX decreased renal sodium excretion and uncoupled the relation between renal phosphorus and sodium excretion, an effect reversed by estrogen replacement.

CONCLUSION

Ovarian hormone deficiency in the rat results in a decrease in renal phosphorus excretion. This finding is comparable to effects of the menopause and hormone replacement therapy in postmenopausal women.