PvuII Polymorphisms of the Estrogen Receptor α and Bone Mineral Density in Healthy Southern Chinese Women

The association between PvuII polymorphisms of the estrogen receptor α (ERα) gene and total as well as regional bone mineral density (BMD) in healthy Chinese women (n = 182) was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), where P indicated the absence and p the presence of PvuII restriction sites. Subjects with PP genotype had significantly higher BMD at the thoracic spine and ribs (both P < 0.05) when compared with those with Pp and pp genotypes. Although PP genotype had slightly higher BMD values at the lumbar spine L2-L4 region and hip by 8% and 7%, respectively, the results failed to reach statistical significance. After adjusting for age, height, weight, and years since menopause, PP genotype had higher BMD at the left (P < 0.02) and right (P < 0.05) rib region but not at the thoracic spine (P= 0.056). Analyzing the premenopausal subjects alone (n = 64) revealed that subjects with PP genotype had higher adjusted BMD at the right rib region (P < 0.05). When only the postmenopausal women (n = 118) were analyzed, the adjusted BMD of the PP genotype at the thoracic spine was significantly higher (P < 0.05) than the other two groups. In conclusion, estrogen receptor gene has a role in determining bone mass but the clinical impact on its own is probably small. Received: 10 September 1999 / Accepted: 11 January 2000     

Association of Estrogen Receptor α and Vitamin D Receptor Gene Polymorphisms with Bone Mineral Density in Chinese Males

Osteoporosis is a common health problem not only in females but also in males, however, studies of osteoporosis in males are relatively rare compared to those in females. This is especially true in genetics studies. We evaluated the effects of PvuII and XbaI polymorphisms in the estrogen receptor (ER-) gene and ApaI polymorphism in the vitamin D receptor (VDR) gene on BMD variation in a random sample of 352 unrelated males from 401 Chinese nuclear families. BMD was measured at the lumbar spine (L1–L4) and hip (femoral neck, trochanter, intertrochanteric region). Raw BMD values were adjusted by age, age², height, and weight as covariates. We found no significant results for the 3 individual markers on BMD variation, however, ER- haplotype analyses yielded some interesting results. Carriers of haplotype pX had a 4.98% lower BMD at the trochanter (P = 0.02) and 3.55% lower BMD at the lumbar spine (P = 0.09) than non-carriers. PX subjects had a 3.42% higher BMD at the trochanter and 3.26% higher BMD at the lumbar spine than others (P = 0.07 and P = 0.10, respectively). Such results were highly comparable with the significant or nearly significant interactions between ER-PvuII and ER-XbaI on BMD values at the trochanter (P = 0.03) and spine (P = 0.11). No significant results were observed for the interactions between ER-PvuII and VDR-ApaI, between ER-XbaI and VDR-ApaI, and between any of ER- haplotypes and VDR-ApaI locus. Our results suggest that the ER- haplotypes, not individual markers, may be associated with BMD variation at some skeletal sites in our Chinese male samples.     

Estrogen Receptor α Gene Polymorphisms and Bone Mineral Density in Healthy Children and Young Adults

The accretion of peak bone mass is largely under genetic control, and one of the potential candidate genes is the estrogen receptor (ER) gene. The association of ER gene polymorphisms with bone mineral density (BMD) was investigated in a group of 147 healthy caucasian children, adolescents, and young adults (57 boys and 90 girls) in a cross-sectional and longitudinal study. The mean age was 11.3 years (4.3–19.9 years) at baseline and 15.6 years (7.6–25.3 years) at follow-up. Lumbar spine, total body BMD, and body composition were measured by dual energy X-ray absorptiometry and expressed as age- and sex-adjusted standard deviation scores (SDS). We analyzed two restriction fragment length polymorphisms, Pvull and Xbal, and haplotypes thereof.Subjects homozygous for haplotype 1 (px) (33% of the population) had 0.4 SD (standard deviation) lower lumbar spine BMD (P = 0.02) and bone mineral apparent density (BMAD) (P = 0.04) than those heterozygous or noncarriers for haplotype 1 (px) at baseline. Analysis of the follow-up data gave similar results. The association was stronger for the prepubertal than for the postpubertal subjects. Vertebral width SDS, total body BMD SDS, height SDS, body mass index SDS, lean body mass SDS, and percentage fat SDS did not significantly differ between the haplotypes. The age of menarche was not related to any of the haplotypes in girls.The present study shows that Pvull-Xbal ER gene polymorphism is associated with BMD during childhood.     

Estrogen Receptor β Dinucleotide (CA) Repeat Polymorphism is Significantly Associated with Bone Mineral Density in Postmenopausal Women

Significant associations between the lengths of a highly polymorphic dinucleotide (CA) repeat located within the human estrogen receptor beta (ESR2) gene on chromosome 14, bone mineral density (BMD) and androgen levels have been reported previously in premenopausal women. We measured the size of this microsatellite repeat in 226 healthy women (60–98 years). After adjustment for age, body mass index, hormone replacement status, and other variables known to influence BMD, women with <25 CA repeats had significantly higher BMD measured in the total skeleton, lumbar spine, and femoral neck when compared with women having longer alleles. Women with shorter alleles also had higher circulating estrone and estradiol levels that approached statistical significance as compared with women harboring longer alleles after appropriate adjustments were performed in linear regression models. Women having both short and long CA repeats had BMD values in all regions of the skeleton that were midway between those found in women homozygous for longer or shorter repeat sizes. Because the ESR2 CA repeat size was neither associated with change in BMD nor serum levels of biochemical markers of bone turnover, it is likely that ESR2 CA repeat genotype is significantly linked to the attainment of peak bone mass in women.This work was supported by grants AG10149 and AG02049 from the National Institutes of Health.     

Prognostic Role of Estrogen Receptor α and Estrogen Receptor β in Gastric Cancer

Background  

The presence of estrogen receptor α (ERα) and estrogen receptor β (ERβ) have been reported in cell and tissue level in gastric cancer, but its impact on patients’ survival remains unclear. This study was designed to investigate the expression level of ERα and ERβ and to assess clinical significance of ERα and ERβ expression in gastric cancer.     

Does the Severity of Obesity Influence Bone Mineral Density Values in Premenopausal Women?

The aim of this study was to compare bone mineral content (BMC), bone mineral density (BMD), and geometric indices of hip bone strength among 3 groups of adult obese premenopausal women (severely obese, morbidly obese, and super morbidly obese). This study included 65 young adult premenopausal women whose body mass index (BMI) > 35 kg/m². They were divided into 3 groups using international cut-offs for BMI. Body composition and bone variables were measured by DXA. DXA measurements were completed for the whole body (WB), lumbar spine, total hip (TH), and femoral neck (FN). Geometric indices of FN strength (cross-sectional area, cross-sectional moment of inertia [CSMI], section modulus [Z], strength index [SI], and buckling ratio) were calculated by DXA. Results showed that age and height were not significantly different among the 3 groups. WB BMC values were higher in super morbidly obese women compared to severely and morbidly obese women. WB BMD, L1-L4 BMD, total hip BMD, FN BMD, cross-sectional area, CSMI, Z, and buckling ratio values were not significantly different among the 3 groups. SI values were lower in super morbidly obese compared to morbidly and severely obese women. In the whole population (n = 65), body weight, BMI, lean mass, fat mass, and trunk fat mass were positively correlated to WB BMC and negatively correlated to SI. Weight and lean mass were positively correlated to WB BMD and CSMI. Our findings suggest that the severity of obesity does not influence BMD values in premenopausal women.     

Transforming Growth Factor-β1 Gene Polymorphisms and Bone Turnover,Bone Mineral Density and Fracture Risk in Southern Chinese Women

Genetic contributions play an important role in determining bone mineral density (BMD) and bone turnover. Transforming growth factor- (TGF-) is abundant in bone and has been implicated as an important regulator of both bone formation and resorption. Several polymorphisms of the TGF-1 gene have recently been suggested to be associated with BMD and susceptibility to osteoporotic spine fractures. To determine the relationship between TGF-1 polymorphisms and BMD in southern Chinese women, three SNPs at C^–1348-T, T²⁹-C, and T^861-20-C of TGF-1 gene were analyzed in 237 postmenopausal southern Chinese women by RFLP and direct sequencing. BMD at the lumbar spine and hip region, biochemical markers of bone turnover, as well as serum levels of TGF-1 were measured. Only the T²⁹-C polymorphism of TGF-1 gene was associated with BMD and fracture risk. The prevalence of fragility fractures was significantly higher in individuals with TC genotype (P < 0.05). Serum alkaline phosphatase and osteocalcin levels as well as urinary N-telopeptide excretion were significantly higher in women with TC than with TT or CC genotypes, and the difference remained significant after adjusting for age and BMI (all P < 0.05). Women with TC genotype had lower BMD at the trochanteric (P < 0.03) and total hip region (P = 0.05). No difference was observed in the serum TGF-1 levels among the three genotypes. In conclusion, an association between T²⁹-C polymorphisms of TGF-1 gene and BMD, bone turnover as well as fragility fractures were demonstrated in postmenopausal southern Chinese women.     

The Effect of Interleukin-1α Polymorphisms on Bone Mineral Density and the Risk of Vertebral Fractures

Interleukin-1α (IL-1α) stimulates bone resorption via osteoclasts. Mononuclear cells from patients with osteoporosis show increased IL-1α production, and IL-1α mRNA is more often detected in bone biopsies from osteoporotic compared to normal postmenopausal women. Polymorphisms have been identified in the IL-1α gene; however, none of these has been examined for an effect on bone phenotypes in Caucasians. We investigated if the polymorphisms in the IL-1α gene affect the risk of osteoporotic fractures, bone mineral density (BMD), and bone turnover in 462 osteoporotic patients and 336 normal controls. Based on previous studies of polymorphisms in the gene and data from the International Hap-Map Project, four polymorphisms needed examination in order to investigate the effect of known polymorphisms in the IL-1α gene. We examined C⁻¹²⁰²-T(rs1800794), C^–889-T(rs1800587), T^{155 + 209}-C(rs2071373), C^{155 + 320}-T(rs2856838), and G³⁹⁸-T(rs 17561) by Taqman and restriction fragment-length polymorphism assays. BMD was examined by dual-energy X-ray absorptiometry. Bone turnover was evaluated by serum osteocalcin, serum carboxy-terminal propeptide of human type I procollagen, serum bone-specific alkaline phosphatase, serum carboxy-terminal telopeptide of type I collagen, and urinary hydroxyproline/creatinine. Genotype distributions were in Hardy-Weinberg equilibrium. All polymorphisms were in strong linkage disequilibrium. The C allele of the C^{155 + 320}-T polymorphism tended to be more common among patients with vertebral fractures (P = 0.06) and patients with BMD T score <–2.5 (P = 0.05). Furthermore, haplotype 1 was associated with reduced risk of having BMD T score <–2.5 (P = 0.02). None of the other polymorphisms or haplotypes was associated with fracture risk or BMD T score <–2.5. BMD and bone turnover were not associated with any of the genetic variants. In conclusion, all the polymorphisms within the IL-1α gene are in strong linkage disequilibrium and not convincingly associated with fracture risk, BMD, or bone turnover.     

Reproductive, Menstrual and Menopausal Factors: Which Are Associated with Bone Mineral Density in Early Postmenopausal Women?

The associations between a number of reproductive and menopausal factors and bone mineral density (BMD) were studied in a sample of early postmenopausal women. The study included 580 women aged 45–61 years who completed a risk factor questionnaire containing sections on obstetric and menstrual history. BMD measurements were taken at the anteroposterior (AP) spine, greater trochanter, femoral neck, total radius and whole body, along with whole body bone mineral content (BMC). In analyses adjusting for key confounders, number of pregnancies was more strongly associated with increased BMD than number of live births at all sites (p<0.05 at femoral neck and total radius), and menstrual years was more strongly associated with increased BMD than years since menopause (p<0.05 at all sites). Hysterectomized women had a significantly higher adjusted mean BMD than non-hysterectomized women at all sites (AP spine: 0.999 g/cm² vs 0.941 g/cm², p<0.001), although there were no significant differences in BMD between hysterectomized women who had a bilateral oophorectomy and those whose ovaries were preserved. Negative associations between the duration of hot flushes and BMD were statistically significant (p<0.05) at the three non-hip sites. In multiple regression analyses containing all reproductive terms, duration of hormone replacement therapy (HRT) use, menstrual years and hysterectomy status were significantly associated with BMD at all five sites, whilst oral contraceptive use before the age of 23 years was significantly associated with increased BMD at all sites except the total radius. Breastfeeding duration, the duration of oral contraceptive use and premenopausal amenorrhea were found to have no association with BMD. Results for whole body BMC were consistent with those for the five BMD sites, across all the variables considered here. These findings confirm the importance of HRT use and duration of menses as predictors of BMD, whilst the results for hysterectomy status and early oral contraceptive use require further consideration. Received: 26 July 2000 / Accepted: 5 April 2001     

Fracture Risk Prediction Using Phalangeal Bone Mineral Density or FRAX®?—A Danish Cohort Study on Men and Women

In this prospective study, we investigated the ability of Fracture Risk Assessment Tool (FRAX), phalangeal bone mineral density (BMD), and age alone to predict fractures using data from a Danish cohort study, Danish Health Examination Survey 2007–2008, including men (n = 5206) and women (n = 7552) aged 40–90 yr. Data were collected using a self-administered questionnaire and by phalangeal BMD measurement. Information on incident and prevalent fractures, rheumatoid arthritis, and secondary osteoporosis was retrieved from the Danish National Patient Registry. Survival analyses were used to examine the association between low, intermediate, and high risk by phalangeal T-score or FRAX and incident fractures, and receiver operating characteristic curves were obtained. Mean follow-up time was 4.3 yr, and a total of 395 persons (3.1%) experienced a fracture during follow-up. The highest rate of major osteoporotic fractures was observed in persons with a high combined risk (FRAX ≥20% and T-score ≤−2.5; women: 32.7 and men: 27.6 per 1000 person-yr). This group also had the highest risk of hip fractures (women: 8.1 and men: 7.2 per 1000 person-yr). FRAX and T-score in combination analyzed as continuous variables performed overall best in the prediction of major osteoporotic fractures. In predicting hip fractures, there was a tendency of T-score performing worse than the other methods.     

Association of Transforming Growth Factor-b1 (TGFb1) T29?C Gene Polymorphism with Bone Mineral Density (BMD), Changes in BMD, and Serum Concentrations of TGF-b1 in a Population-Based Sample of Postmenopausal German Women

TGF-beta1 is thought to play an important role in bone turnover. Thus, the gene encoding TGF-beta1 is a prime candidate for the genetic regulation of bone density. Recent studies have suggested that a T29 --> C polymorphism in the signal sequence region of the TGF-beta1 gene may be related to bone mineral density (BMD) and bone loss in postmenopausal Japanese women. In the present study, we examined the relationship between this polymorphism and BMD in a population-based sample of 102 estrogen-deficient postmenopausal women from the Heidelberg cohort of the European Vertebral Osteoporosis Study (EVOS). Average BMD in women with the TT genotype was approximately 10% higher at both the lumbar spine and the femoral neck compared with women with the CC genotype (spine: 980 vs. 887 mg/cm2, P = 0.05; femoral neck: 755 vs. 674 mg/cm2; P = 0.02). Women with the TT genotype also experienced less overall bone loss at the total hip, compared with women with the CC genotype. Serum levels of TGF-beta1 were higher in women with the TT genotype than in those with the CC genotype (46.5 ng/ml vs. 32.3 ng/ml, P = 0.001). These data are clearly in contrast to findings in postmenopausal Japanese women where the CC genotype was associated with higher BMD and decreased bone loss. Further studies are therefore necessary to clarify the relationship between this polymorphism and BMD.     

Urinary α and β C-Telopeptides of Collagen I: Clinical Implications in Bone Remodeling in Patients with Anorexia Nervosa

Fragments derived from degradation of type I collagen C-telopeptide (CTX) can be nonisomerized (α) or β-isomerized (β) depending on the age of bone; i.e., mainly the α form is derived from new bone and the β form from old bone. We have studied 41 female patients with anorexia nervosa (AN), aged 18.5 ± 2.2 years (range 16–24 years), and with an evolution time between 1.5 and 11 years, and 31 healthy control females (C), with a mean age of 19 ± 2.3 years (range 16–24 years). The AN patients showed a significant decrease in bone mass, with a mean Z-score of bone mineral density (BMD) of −3.2 ± 0.8 (range −0.9 to −5.4). The aim of our study was to determine the levels of urinary α- and β-CTX markers of bone resorption, the α/β ratio (α/β), and the level of bone alkaline phosphatase (bAP), a biochemical marker of bone formation, in order to relate them to the degree of osteopenia and the status of bone remodeling. Statistical analysis was by the Mann–Whitney test. The degree of osteopenia correlated with bAP levels (p= 0.0027) but not with the other parameters. Patients with AN were divided into three groups according to their levels of bAP: high (H), normal (N) or low (L). We found that BMD was significantly lower, and α- and β-CTX were significantly higher, in groups H and N than in group L. Bone AP correlated significantly with α-CTX (p= 0.0042) and α/β (0.0095) in the controls, but not with β-CTX, while in AN patients bAP correlated with β-CTX (p= 0.0000) and with α-CTX (p= 0.022) but not with the α/β ratio. The ratio CTX/bAP (resorption/formation) was similar in AN patients and controls. It is concluded that: (1) patients with AN have a high degree of osteopenia which correlated with bAP levels; (2) urinary CTX fragments found in AN patients seem to come mainly from old bone (β-CTX), while CTX found in healthy adolescent control females come from new bone (α-CTX). For this reason, α-CTX is more suitable than β-CTX for measuring bone resorption in controls and β-CTX is more suitable in patients with AN; (3) the resorption/formation ratio (CTX/bAP) was similar in AN patients and controls. From points (2) and (3) it is possible to suggest that, although bAP reflects bone formation in control females, this marker does not reflect effective bone mineralization in AN patients, a similar feature to that of patients with osteomalacia. Received: 20 January 1999 / Accepted: 28 May 1999     

Circulating Sex Steroids,Sex Hormone-Binding Globulin,and Longitudinal Changes in Forearm Bone Mineral Density in Postmenopausal Women and Men: The Tromsø Study

Bone loss during advancing age in women and men is partly the result of sex steroid deficiency. As the contribution of circulating sex steroids and sex hormone-binding globulin (SHBG) to bone loss remains uncertain, we sought to determine whether levels of sex steroids or SHBG predict change in bone mineral density (BMD) in women and men. A population-based study in the city of Tromsø of 6.5 years’ duration (range 5.4-7.4) included 927 postmenopausal women aged 37–80 years and 894 men aged 25–80 years. Total estradiol and testosterone, calculated free levels, and SHBG were measured at baseline, and BMD change at the distal forearm was determined using BMD measurements in 1994–1995 and 2001. Bone loss was detected in postmenopausal women and men. Free estradiol and SHBG predicted age-adjusted bone loss in postmenopausal women, but only free estradiol was associated after further adjustment for body mass index and smoking in mixed models (P < 0.05). After same adjustment, only SHBG persisted as a significant independent predictor of bone loss in men (P < 0.001). However, only 1% of the variance in bone loss was accounted for by these measurements. We therefore conclude that the relations between sex steroids and bone loss are weak and measurements of sex steroids are unlikely to assist in clinical decision making.     

Effects of Nicotine Administration and Nicotine Cessation on Bone Histomorphometry and Bone Biomarkers in Sprague–Dawley Male Rats

Nicotine is a major alkaloid of tobacco, which can increase free radical formation, leading to osteoporosis. The effects of nicotine administration and cessation on bone histomorphometry and biomarkers were studied in 28 Sprague–Dawley male rats. Rats aged 3 months and weighing 250–300 g were divided into four groups: control (C, normal saline for 4 months), nicotine for 2 months (N2), nicotine for 4 months (N4), and nicotine cessation (NC). The NC group was given nicotine for the first 2 months and then allowed to recover for the following 2 months without nicotine. Histomorphometric analysis was done using an image analyzer. ELISA kits were used to measure serum osteocalcin (bone formation marker) and pyridinoline (PYD, bone resorption marker) levels at month 0, month 2, and month 4. All test groups showed a significant decrease in BV/TV, Ob.S/BS, dLS/BS, MAR, BFR/BS, and osteocalcin levels and an increase in sLS/BS and PYD levels compared to group C. No significant differences were observed in all parameters measured among the test groups, except for MAR and BFR/BS. In conclusion, nicotine administration at a dose of 7 mg/kg for 2 and 4 months has detrimental effects on bone metabolism. Nicotine administration at 7 mg/kg for 2 months is sufficient to produce significant effects on bone histomorphometric parameters and biomarkers. In addition, prolonging the treatment for another 2 months did not show any significant differences. Cessation of nicotine for 2 months did not reverse the effects.     

Vertebral Bone Mineral Density, Content and Area in 8789 Normal Women Aged 33–73 Years Who Have Never Had Hormone Replacement Therapy

The vertebral bone mineral density (BMD), bone mineral content (BMC) and bone area of the lumbar spine were measured using a bone densitometer in 8789 women aged 33–73 years who had had no previous hormone replacement therapy (HRT). The overall relationship between BMD and age was analyzed on a year-by-year basis, and comprised three separate regions that could each be described by a straight line: 33–46 years (gradient = 0.00166 g cm⁻²/year), 47–63 years (gradient = 0.0121 g cm⁻²/year) and 64–73 years (gradient = 0.0045 g cm⁻²/year). Above the age of 50 years our results were higher than the BMD in most previous reports. In those 3198 women who knew the time of their last menstrual period (mean age 49.25 years, SD 4.83) bone loss was most rapid in the first 10 menopausal years. In the whole group, the relationship between BMC and age was found to be similar to that of BMD, with three distinct regions, including a rapid drop between the ages of 47 and 63 years (gradient 0.781 g/year). Bone area showed a much more gradual (though significant) decrease with age. Based on WHO definitions and using BMD as an indicator, the percentage of women with osteoporosis varied from zero in the younger age group to about 30% of women aged over 70 years; in contrast, where BMC was used, although the trend with age had a similar shape, the percentages at each year were about half those derived from the corresponding BMD values. Osteopenia derived in the same way occurred in about 50% of women over 70 years using either BMD or BMC. The results presented here provide a reliable local reference range for lumbar spine bone densitometry measurements. They also show that for this site BMD and BMC cannot be used interchangeably to define osteoporosis. Received: 13 March 1998 / Accepted: 23 September 1998     

Influence of Heredity and Environment on Bone Density in Adolescent Boys: A Parent–Offspring Study

The purpose of the present parent–offspring study was to investigate the influence of heredity and environment on bone density in young men. Another aim was to discover whether the same genetic factors influence bone mass, lean mass and muscle strength. Fifty families including a father, mother and one son were investigated. The mothers (aged 44.5 ± 4.4 years) and fathers (aged 47.1 ± 4.4 years) generally had a sedentary lifestyle with little physical activity. As a contrast, all but three of the sons (aged 17.0 ± 0.4 years) were active in ice hockey training. Bone mineral density (BMD, g/cm²) of the total body, head, lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry. Muscle strength of the hamstrings and quadriceps muscles was also measured in the boys. BMD values of different sites in the fathers, mothers and sons were adjusted for weight, height, age, and any significant influence of environment. Heritability estimates were obtained as regression coefficients with the boys’ adjusted BMD as dependent variable and the adjusted midparent bone density (father BMD + mother BMD/2) as independent variable. Accordingly, heritability explained 34–54% of the variation in the sons’ BMD. Midparent BMD of several sites also predicted the boys’ lean mass and quadriceps strength, and midparent–offspring differences in lean mass predicted midparent–offspring differences in BMD of the total body, head and spine (β= 0.30–0.51, p<0.05). The sons were found to have almost 30% higher femoral neck BMD than their fathers, and physical activity (hours/week) predicted BMD at several sites among the sons β= 0.26–0.34, p <0.05). In conclusion, heritability is a main determinant of the variance in BMD in young men. Based on the results we suggest that the same genetic factors may influence bone mass, lean mass and muscle strength by affecting body size. The present study also emphasizes the importance of physical activity for the development and maintenance of BMD in men. Received: 26 October 1998 / Accepted: 24 February 1999