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Robert R Recker

Publications and source records attributed to Robert R Recker.

At least 37 records · Page 2Linked to original sources

Linkage exclusion mapping with bone size in 79 Caucasian pedigrees.

Bone size is an important risk factor of osteoporotic fractures and has strong genetic determination. However, genetic studies on bone size variation are relatively rare. In the present study, we conducted a linkage exclusion mapping for bone size variation on chromosomes 1, 4, 6, and 17 in 79 Caucasian pedigrees. For hip bone size variation, several genomic regions were excluded at effect sizes of 10% or greater, including regions of 61-77cM at 1p35-p34, 43-59cM at 4p15-p13, 1-59cM at 6p25-p21, 82-88cM at 17q23-q24, and 113-114cM at 17q25. For spine bone size, at effect sizes of 10% or greater, we excluded regions of 115-122cM at 1p31-p22, 136-141cM at 1p21, 207-260cM at 1q31-q42, 20-89cM at 4p16-q21, 11-21cM at 6p24-p23, and 1-6cM at 17p13. These results suggested that a number of candidate genes located in the excluded regions, such as the growth hormone (GH) gene, tumor necrosis factor-alpha (TNF-alpha) gene, and bone morphogenetic protein-3 (BMP3) gene, are unlikely to have a substantial effect on bone size variation in this Caucasian population.

Adult↗

Linkage and association between CA repeat polymorphism of the TNFR2 gene and obesity phenotypes in two independent Caucasian populations.

Previously, our group has reported a suggestive linkage evidence of 1p36 with body mass index (BMI) (LOD = 2.09). The tumor necrosis factor receptor 2 (TNFR2) at 1p36 is an excellent positional and functional candidate gene for obesity. In this study, we have investigated the linkage and association between the TNFR2 gene and obesity phenotypes in two large independent samples, using the quantitative transmission disequilibrium tests (QTDT). The first group was made up of 1,836 individuals from 79 multi-generation pedigrees. The second group was a randomly ascertained set of 636 individuals from 157 US Caucasian nuclear families. Obesity phenotypes tested include BMI, fat mass, and percentage fat mass (PFM). A significant result (P = 0.0056) was observed for linkage with BMI in the sample of the multigenerational pedigrees. Our data support the TNFR2 gene as a quantitative trait locus (QTL) underlying BMI variation in the Caucasian populations.

Adult↗

Polymorphisms of the vitamin D receptor gene predict the onset of surgical menopause in Caucasian females.

We tested association of four single nucleotide polymorphisms (SNPs) of the vitamin D receptor gene (VDR) with age at surgical and natural menopause in a sample of Caucasians composed of 153 women with surgical and 260 with natural menopause. A significant association was observed between age at surgical menopause and two SNPs, rs1544410 (BsmI) and rs731236 (TaqI) (p < 0.05). For rs1544410, homozygotes of the minor allele, AA, had about two-fold higher risk of surgical menopause than homozygotes of the major allele, GG (95% confidence ratio (CI) 1.09-3.82). For rs731236, the CC subjects had a greater chance of surgical menopause than the TT subjects (odds ratio = 2.01, 95% CI 1.07-3.78). Since rs1544410 and rs731236 are in strong linkage disequilibrium, the haplotypes based on these two loci were also tested. The haplotype AC was highly significantly associated with age at surgical menopause (p = 0.008). Women with this haplotype had surgical menopause on average 2.8 years earlier than non-carriers. These results reveal the potential effect of the VDR gene on ovaries and uterus, and suggest that its SNPs can be used as predictors of genetic susceptibility for early surgical menopause and respective causal health problems.

Age of Onset↗

Molecular genetic studies of gene identification for osteoporosis: a 2004 update.

This review summarizes comprehensively the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of December 2004. It is intended to constitute a sequential update of our previously published review covering the available data up to the end of 2002. Evidence from candidate gene association studies and genome-wide linkage studies in humans, as well as quantitative trait locus mapping animal models are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. An important extension of this update is incorporation of functional genomic studies (including DNA microarrays and proteomics) on osteogenesis and osteoporosis, in light of the rapid advances and the promising prospects of the field. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.

Animals↗

Genomic regions identified for BMD in a large sample including epistatic interactions and gender-specific effects.

UNLABELLED: A genome-wide linkage scan was conducted using a large white sample to identify QTLs for BMD. We found QTLs in the total sample and the gender-specific subgroups, as well as significant epistatic interactions underlying BMD variations. INTRODUCTION: Low BMD is an important risk factor for osteoporosis and under strong genetic control. MATERIALS AND METHODS: To identify quantitative trait loci (QTLs) for regulation of BMD, we performed a large-scale whole genome linkage scan (WGS) involving 4126 individuals from 451 families. In addition to the conventional linkage analyses in the total combined sample of males and females, we conducted epistatic interaction analyses and gender-specific linkage analyses. RESULTS: Significant linkage was detected on 5q23 for wrist BMD (LOD = 3.39) and 15q13 for female spine BMD (LOD = 4.49). For spine BMD, we revealed significant epistatic interactions between 3p25 and 2q32 (p = 0.0022) and between 3p25 and 11q23 (p = 0.0007). We replicated several genomic regions that showed linkage with BMD in previous studies by others and ours, such as 3p21, 1p36, and Xq27. CONCLUSIONS: This study highlights the importance of large sample size, incorporation of epistatic interaction, and consideration of gender-specific effects in identifying QTLs for BMD variation. The results of this study provide a foundation for the future fine mapping and gene identification in our population.

Bone Density↗

Robust and comprehensive analysis of 20 osteoporosis candidate genes by very high-density single-nucleotide polymorphism screen among 405 white nuclear families identified significant association and gene-gene interaction.

UNLABELLED: Many "novel" osteoporosis candidate genes have been proposed in recent years. To advance our knowledge of their roles in osteoporosis, we screened 20 such genes using a set of high-density SNPs in a large family-based study. Our efforts led to the prioritization of those osteoporosis genes and the detection of gene-gene interactions. INTRODUCTION: We performed large-scale family-based association analyses of 20 novel osteoporosis candidate genes using 277 single nucleotide polymorphisms (SNPs) for the quantitative trait BMD variation and the qualitative trait osteoporosis (OP) at three clinically important skeletal sites: spine, hip, and ultradistal radius (UD). MATERIALS AND METHODS: One thousand eight hundred seventy-three subjects from 405 white nuclear families were genotyped and analyzed with an average density of one SNP per 4 kb across the 20 genes. We conducted association analyses by SNP- and haplotype-based family-based association test (FBAT) and performed gene-gene interaction analyses using multianalytic approaches such as multifactor-dimensionality reduction (MDR) and conditional logistic regression. RESULTS AND CONCLUSIONS: We detected four genes (DBP, LRP5, CYP17, and RANK) that showed highly suggestive associations (10,000-permutation derived empirical global p < or = 0.01) with spine BMD/OP; four genes (CYP19, RANK, RANKL, and CYP17) highly suggestive for hip BMD/OP; and four genes (CYP19, BMP2, RANK, and TNFR2) highly suggestive for UD BMD/OP. The associations between BMP2 with UD BMD and those between RANK with OP at the spine, hip, and UD also met the experiment-wide stringent criterion (empirical global p < or = 0.0007). Sex-stratified analyses further showed that some of the significant associations in the total sample were driven by either male or female subjects. In addition, we identified and validated a two-locus gene-gene interaction model involving GCR and ESR2, for which prior biological evidence exists. Our results suggested the prioritization of osteoporosis candidate genes from among the many proposed in recent years and revealed the significant gene-gene interaction effects influencing osteoporosis risk.

Adult↗

Genome-wide scan identified QTLs underlying femoral neck cross-sectional geometry that are novel studied risk factors of osteoporosis.

UNLABELLED: A genome-wide screen was conducted using a large white sample to identify QTLs for FNCS geometry. We found significant linkage of FNCS parameters to 20q12 and Xq25, plus significant epistatic interactions and sex-specific QTLs influencing FNCS geometry variation. INTRODUCTION: Bone geometry, a highly heritable trait, is a critical component of bone strength that significantly determines osteoporotic fracture risk. Specifically, femoral neck cross-sectional (FNCS) geometry is significantly associated with hip fracture risk as well as genetic factors. However, genetic research in this respect is still in its infancy. MATERIALS AND METHODS: To identify the underlying genomic regions influencing FNCS variables, we performed a remarkably large-scale whole genome linkage scan involving 3998 individuals from 434 pedigrees for four FNCS geometry parameters, namely buckling ratio (BR), cross-sectional area (CSA), cortical thickness (CT), and section modulus (Z). The major statistical approach adopted is the variance component method implemented in SOLAR. RESULTS: Significant linkage evidence (threshold LOD = 3.72 after correction for tests of multiple phenotypes) was found in the regions of 20q12 and Xq25 for CT (LOD = 4.28 and 3.90, respectively). We also identified eight suggestive linkage signals (threshold LOD = 2.31 after correction for multiple tests) for the respective geometry traits. The above findings were supported by principal component linkage analysis. Of them, 20q12 was of particular interest because it was linked to multiple FNCS geometry traits and significantly interacted with five other genomic loci to influence CSA variation. The effects of 20q12 on FNCS geometry were present in both male and female subgroups. Subgroup analysis also revealed the presence of sex-specific quantitative trait loci (QTLs) for FNCS traits in the regions such as 2p14, 3q26, 7q21 and 15q21. CONCLUSIONS: Our findings laid a foundation for further replication and fine-mapping studies as well as for positional and functional candidate gene studies, aiming at eventually finding the causal genetic variants and hidden mechanisms concerning FNCS geometry variation and the associated hip fractures.

Adult↗

Predictive factors for age at menopause in Caucasian females.

OBJECTIVE: Early onset of menopause results in the premature exposure to low estrogen levels and is associated with a number of postmenopausal health problems and higher risk of mortality. The aim of this study was to determine genetic and environmental factors associated with age at natural and surgical menopause. METHODS: Multiple regression analysis using a sample of Caucasians composed of 154 females with surgical and 248 with natural menopause. RESULTS: Breastfeeding is a significant predictor of earlier natural menopause (P<0.05). Use of oral contraceptives and smoking were not significantly associated with age at menopause. Females who did not have history of pregnancies are at significantly higher risk (P<0.001) of getting early surgical menopause than those who did. We also tested the association of seven single nucleotide polymorphisms (SNPs) of the estrogen receptor alpha (ER-alpha) gene with age at menopause. No association was observed with age at menopause but the PvuII p allele was overrepresented in women with surgical menopause and associated with menopause per se (P=0.029; OR=1.8, 95% CI=1.1-3.0). CONCLUSIONS: Breastfeeding and alcohol consumption are significantly associated with earlier natural menopause. No significant effects of the ER-alpha genotypes were observed on the age of menopause. Given the important role of the ER-alpha in estrogen signaling, which directly influences the menopausal process, further studies are required to better define the relationship between this gene and age at menopause.

Age of Onset↗

Contribution of genotype and ethnicity to bone mineral density variation in Caucasians and Chinese: a test for five candidate genes for bone mass.

BACKGROUND: Ethnicity is shown to be one of important factors affecting bone mineral density (BMD). The present study was performed to compare the association of six markers for five candidate genes with BMD variation in two populations of different ethnicity, Caucasian and Chinese, and the contribution of genotype and ethnicity to this variation in the populations. METHODS: The studied restriction fragment length polymorphisms were BsaH I of the calcium-sensing receptor gene, SacI of the alpha2HS-glycoprotein (AHSG) gene, PvuII and XbaI of the oestrogen receptor alpha gene, ApaI of the vitamin D receptor (VDR) gene and BstBI of the parathyroid hormone gene. The association of these markers with BMD was analysed by one-way and two-way ANOVA with adjustment for covariates. RESULTS: Two polymorphisms, AHSG-SacI and VDR-ApaI, showed no association with BMD, while the others were associated with BMD variation at some skeletal sites in either males or females. The polymorphisms indicated clear distinctions between the associations depending on ethnicity, gender and skeletal site. Similar patterns were observed in their contribution to the total population BMD variation. Ethnicity appears to have a larger effect on the total population BMD variation in females than in males. It may account, on the average, for about 2% total population BMD variation at the spine of females and about 1% at the hip of males and females. CONCLUSION: The results of the present study suggest that significant interethnic differentiation at some loci may contribute to the significant interethnic difference in BMD. However, this contribution apparently is not large.

Adult↗

Linkage exclusion analysis of two candidate regions on chromosomes 7 and 11: leptin and UCP2/UCP3 are not QTLs for obesity in US Caucasians.

Leptin (LEP) and the uncoupling proteins 2 and 3 (UCP2/UCP3) are key molecules involved in the regulation of food intake and energy expenditure. However, their contribution to variation of obesity phenotypes in the general population remains controversial. The present study is to investigate whether chromosomal regions 7q and 11q, which contain LEP and UCP2/UCP3, respectively, can be excluded for linkage with obesity phenotypes. The obesity phenotypes include body mass index (BMI), fat mass, and percentage fat mass (PFM), with the latter two measured by dual-energy X-ray absorptiometry. We conducted exclusion linkage analyses using a variance component approach in a sample of 1816 individuals coming from 79 extended Caucasian pedigrees. In this study, we were able to exclude chromosomal region 7q containing LEP as having an effect on fat mass and PFM at effect sizes of 5% or greater, and on BMI at effect sizes of 10% or greater. We were able to exclude chromosomal region 11q containing UCP2/UCP3 as having an effect on fat mass and PFM at effect sizes of 10% or greater, and on BMI at effect sizes of 5% or greater. Our results suggest that the LEP and UCP2/UCP3 genes are unlikely to have a substantial effect on variation in obesity phenotypes in this particular US Caucasian population.

Carrier Proteins↗

A novel pathophysiological mechanism for osteoporosis suggested by an in vivo gene expression study of circulating monocytes.

Bone mineral density (BMD) is a major risk factor for osteoporosis. Circulating monocytes may serve as early progenitors of osteoclasts and produce a wide variety of factors important to bone metabolism. However, little is known about the roles of circulating monocytes in relation to the pathophysiology of osteoporosis. Using the Affymetrix HG-U133A GeneChip(R) array, we performed a comparative gene expression study of circulating monocytes in subjects with high and low BMD. We identified in total 66 differentially expressed genes including some novel as well as some already known to be relevant to bone metabolism. Three genes potentially contributing to bone metabolism, CCR3 (chemokine receptor 3), HDC (histidine decarboxylase, i.e. the histamine synthesis enzyme), and GCR (glucocorticoid receptor), were confirmed by quantitative real-time reverse transcriptase-PCR as up-regulated in subjects with lower BMD. In addition, significant negative correlation was observed between expression levels of the genes and BMD Z-scores. These three genes and/or their products mediate monocyte chemotaxis, histamine production, and/or sensitivity to glucocorticoids. Our results suggest a novel pathophysiological mechanism for osteoporosis that is characterized by increased recruitment of circulating monocyte into bone, enhanced monocyte differentiation into osteoclasts, as well as osteoclast stimulation via monocyte functional changes. This is the first in vivo microarray study of osteoporosis in humans. The results may contribute to identification of new genes and their functions for osteoporosis and suggest genetic markers to discern individuals at higher risk to osteoporosis with an aim for preventive intervention and treatment.

Aged↗

A new concept for bisphosphonate therapy: a rationale for the development of monthly oral dosing of ibandronate.

Oral daily and weekly bisphosphonates represent the current mainstay of treatment for postmenopausal osteoporosis (PMO). However, the inconvenience of frequent dosing is known to negatively affect adherence to therapy in the long term. This has prompted the development of convenient oral bisphosphonate regimens that feature simple, less frequent dosing schedules. Such regimens require high potency agents, which can be given at low effective doses and that also have good tolerability. Ibandronate is a potent, nitrogen-containing bisphosphonate with proven efficacy when given intermittently to estrogen-depleted beagle dogs, rats and cynomolgus monkeys. Clinically, a pivotal prospective study has established that oral ibandronate has significant vertebral fracture efficacy in PMO, whether given daily (2.5 mg) or intermittently (20 mg every other day for 12 doses every 3 months; extended between-dose interval>2 months). Both oral regimens were well tolerated, which is noteworthy as patients with a history of gastrointestinal (GI) disturbance were not specifically excluded. As a result of these findings, a large, multinational, randomized, double-blind study (Monthly Oral iBandronate In LadiEs: MOBILE) is currently exploring the non-inferiority of once-monthly oral ibandronate (100 or 150 mg) to the oral daily ibandronate (2.5 mg) regimen with proven anti-fracture efficacy, in terms of lumbar spine bone mineral density (BMD) change. As with the trials investigating the weekly administration of other bisphosphonates, vertebral fracture efficacy will be inferred if the study demonstrates the non-inferiority of once-monthly ibandronate to the proven oral daily regimen in terms of spinal BMD change. The availability of this once-monthly ibandronate regimen is expected to offer benefits in terms of convenience (by having to follow dosing recommendations once a month vs. once daily or weekly) and potentially tolerability (by reducing the potential for upper GI irritation that can result from frequent, repeated exposure). Greater convenience and tolerability may enhance the therapy adherence and, hence, improve long-term therapeutic outcomes in PMO.

Administration, Oral↗

Association tests of interleukin-6 (IL-6) and type II tumor necrosis factor receptor (TNFR2) genes with bone mineral density in Caucasians using a re-sampling approach.

Interleukin 6 (IL-6) and tumor necrosis factor (TNF) are important cytokines for bone turnover. In this study, a promoter C-174G single-nucleotide polymorphism (SNP) within the IL-6 gene affecting the transcription rate of IL-6 and an exon 6 T676G SNP of the TNF receptor 2 (TNFR2) gene causing an M196R amino-acid change were examined for their relationship with bone mineral density (BMD). Four hundred and five multi-offspring Caucasian families, including 389 male children and 744 female children, were used. One thousand re-samplings were conducted and in each data set, one child was randomly chosen from each family. For each data set, one-way analysis of variance (ANOVA) test was independently implemented using age, age2, sex, height and weight as covariates. There were 523, 288, 204 and 369 significant results out of 1,000-replicate re-samplings of the data of the IL-6 SNP (P<0.05) for one-third, mid-distal, ultradistal radius BMD, and the first principal component (PC1) extracted from the three radial BMDs, respectively, which means that the confidences for associations of the C-174G SNP in the IL-6 gene with one-third, mid-distal, ultradistal radius (totally called distal forearm) BMDs, and PC1, were 52.3, 28.8, 20.4 and 36.9%, respectively. For this SNP with BMD at other skeletal sites and the TNFR2 T676G SNP with BMD at any site, significant results were far less than 200 times out of 1,000 re-sampling replicates. The exceedingly consistent permutation results further improved the confidence of the associations. It may imply that the IL-6 C-174G SNP is associated with distal forearm BMD, but there is no evidence that the TNFR2 T676G SNP is related with BMD in US Caucasians. This is the first attempt to conduct association test utilizing a re-sampling approach. Our results may be more informative than other association analyses that were only based on one sampling result. The results also suggest that different samplings could produce significantly diverse results even for the same population and the results from one sampling are unlikely to be conclusive. Our results have significant implications for association studies and interpretation of non-reproducible association findings.

Body Weights and Measures↗

Linkage and association analyses of the UCP3 gene with obesity phenotypes in Caucasian families.

Uncoupling protein 3 (UCP3) uncouples ATP production from mitochondrial respiration, thereby dissipating energy as heat and affecting the efficiency of energy metabolism. Genetic variations in the UCP3 gene have been conceived to affect body weight in the general population. In this study, using the quantitative transmission disequilibrium test (QTDT), we assessed linkage and association between the UCP3 gene and obesity phenotypes in a large sample of 1,873 subjects from 405 United States Caucasian nuclear families. Obesity phenotypes tested include body mass index (BMI), fat mass, percent fat mass (PFM), and lean mass, with the latter three measured by dual-energy X-ray absorptiometry. We first selected five single nucleotide polymorphisms (SNPs) and then analyzed three highly polymorphic ones, namely, -55 C/T (promoter), Tyr99Tyr (exon 3), and Tyr210Tyr (exon 5), in the total sample. Significant linkage disequilibria (0.392 <or= D' <or= 0.940, P < 0.0001) were observed between pairs of SNPs. In single-locus analyses, we found statistically significant association (P = 0.034) and linkage (P = 0.031) between -55 C/T and BMI. This polymorphism explains 2.29% of BMI variation, and subjects carrying the T allele had an average of 3.5% lower BMI than those without it (P = 0.003). In haplotype analyses, we also observed evidence of linkage (P = 0.002) and association (P = 0.035) with BMI. In summary, our results suggest that UCP3 gene polymorphisms may contribute to BMI variation in this Caucasian population.

Alleles↗

Monthly oral ibandronate therapy in postmenopausal osteoporosis: 1-year results from the MOBILE study.

UNLABELLED: Once-monthly (50/50, 100, and 150 mg) and daily (2.5 mg; 3-year vertebral fracture risk reduction: 52%) oral ibandronate regimens were compared in 1609 women with postmenopausal osteoporosis. At least equivalent efficacy and similar safety and tolerability were shown after 1 year. INTRODUCTION: Suboptimal adherence to daily and weekly oral bisphosphonates can potentially compromise therapeutic outcomes in postmenopausal osteoporosis. Although yet to be prospectively shown in osteoporosis, evidence from randomized clinical trials in several other chronic conditions shows that reducing dosing frequency enhances therapeutic adherence. Ibandronate is a new and potent bisphosphonate with antifracture efficacy proven for daily administration and also intermittent administration with a dose-free interval of >2 months. This report presents comparative data on the efficacy and safety of monthly and daily oral ibandronate regimens. MATERIALS AND METHODS: MOBILE is a 2-year, randomized, double-blind, phase III, noninferiority trial. A total of 1609 women with postmenopausal osteoporosis were assigned to one of four oral ibandronate regimens: 2.5 mg daily, 50 mg/50 mg monthly (single doses, consecutive days), 100 mg monthly, or 150 mg monthly. RESULTS: After 1 year, lumbar spine BMD increased by 3.9%, 4.3%, 4.1%, and 4.9% in the 2.5, 50 /50, 100, and 150 mg arms, respectively. All monthly regimens were proven noninferior, and the 150 mg regimen superior, to the daily regimen. All monthly regimens produced similar hip BMD gains, which were larger than those with the daily regimen. All regimens similarly decreased serum levels of C-telopeptide, a biochemical marker of bone resorption. Compared with the daily regimen, a significantly larger proportion of women receiving the 100 and 150 mg monthly regimens achieved predefined threshold levels for percent change from baseline in lumbar spine (6%) or total hip BMD (3%). All regimens were similarly well tolerated. CONCLUSIONS: Monthly ibandronate is at least as effective and well tolerated as the currently approved daily ibandronate regimen in postmenopausal osteoporosis.

Absorptiometry, Photon↗

Ibandronate produces significant, similar antifracture efficacy in North American and European women: new clinical findings from BONE.

OBJECTIVES: BONE (oral iBandronate Osteoporosis vertebral fracture trial in North America and Europe) determined whether less frequent dosing of ibandronate (dose-free interval > 2 months) provided similar antifracture efficacy to daily dosing. As osteoporosis medications must be effective across different populations, an additional objective of BONE was to investigate and report the effect of oral ibandronate in North American and European women, as described here. PATIENTS AND METHODS: BONE was a randomized, double-blind, placebo-controlled, fractureprevention study in 2946 postmenopausal women (age 55 years-80 years; > or = 5 years since menopause) with osteoporosis (low lumbar spine bone mineral density and one to four prevalent vertebral fractures [T4-L4]). Participants received daily calcium (500 mg) and vitamin D (400 IU) plus either placebo, oral daily ibandronate (2.5 mg) or oral intermittent ibandronate (20 mg every other day for 12 doses every 3 months). The efficacy and tolerability of ibandronate were assessed independently in both North American and European populations. RESULTS: Consistent, significant efficacy was observed in the North American (new vertebral fracture risk reduction: 60% and 54% with daily and intermittent ibandronate, respectively) and European patient populations (50% and 48%, respectively). Both ibandronate regimens also significantly reduced the incidence of new, worsening, and acute clinical, vertebral fractures. Daily and intermittent ibandronate significantly increased bone density at the spine in both North American (5.4% and 4.4% vs. baseline with daily and intermittent ibandronate, respectively) and European (7.1% and 6.3% vs. baseline, respectively) populations. Significant increases were also observed for total hip bone density (2.6% and 3.7% vs. baseline for daily, and 2.5% and 3.1% for intermittent; North American and European populations, respectively). Comparable, significant decreases in biochemical markers of bone turnover (reductions in urinary excretion of C-telopeptide levels of 53.5% and 67.1% vs. baseline for daily, and 50.0% and 53.8% for intermittent; North American and European populations, respectively) were also observed in both populations (p < 0.004 for all cited measurements in each ibandronate group vs. placebo). Oral ibandronate was well tolerated in both North American and European patients, with a safety profile similar to placebo. CONCLUSIONS: Oral ibandronate, administered daily or intermittently, effectively reduced vertebral fracture risk in North American and European women with postmenopausal osteoporosis. These results demonstrate the efficacy of ibandronate administered with extended dose-free intervals, regardless of patients' geographical origin. Research investigating other less frequent ibandronate regimens, such as once-monthly oral administration, is underway.

Administration, Oral↗

The genetics of osteoporosis.

Osteoporosis is a common health problem among the elderly, especially postmenopausal women. It is characterized by fragile bones susceptible to low-trauma fractures. Osteoporosis is a complex disease determined by genetic and environmental factors, as well as the possible interactions among these factors. Twin and family studies have shown that genetic factors play an important role in osteoporosis. Numerous genetic studies have been performed to hunt for genes underlying the disease risk. In this review, we briefly summarize and discuss the current status of knowledge about osteoporosis, with special emphasis on the progress achieved recently in: 1) heritability and choice of osteoporosis study phenotypes; 2) the approaches for gene mapping and identification for osteoporosis; 3) the candidate gene association studies; 4) the linkage mapping studies for osteoporosis; 5) some potential explanations for the inconsistent results; and 6) the pharmacogenetic studies for osteoporosis.

Animals↗