Regional bone mineral density interrelationships in normal and osteoporotic postmenopausal women

We describe a prospective study in which bone mineral density (BMD) was measured in total body and regions, proximal femur, lumbar spine, and forearm in 84 apparently normal postmenopausal women with normal spinal radiographs and in 47 women with 1-10 wedged or compressed vertebrae. There was a history of peripheral fracture in 35 of the 84 controls and 30 of the 47 osteoporotics (p < 0.02) but there was no association between vertebral fracture and wrist fracture. At all sites and regions, the differences in BMD between the "normal"and "osteoporotic" women was highly significant and all but "ribs" and "arms" remained significant after correction for menopausal age. In the whole set, and in both subgroups, the coefficients of correlation between sites and regions were all highly significant (p < 0.001). Nonetheless, some sites discriminated better between the two groups than others. Standardized odds ratios (OR) for vertebral fracture versus no-fracture were calculated by logistic regression and expressed as the rise in OR for each standard deviation (SD) fall in bone density. This ratio was greatest (3.4) in "pelvis" and weakest (1.7) in "ribs" but all were statistically significant. Geometric mean regression equations were calculated for all the 78 possible pairs of sites and regions in the 84 normal subjects and the deviations of the osteoporotic women from these normal slopes calculated. In most pairs of sites and regions, the vertebral fracture cases were scattered around the normal group's slope but fell lower down on both axes. The bone deficits in the osteoporotics compared with young normal women ranged from -14% in "head" to -40% in Ward's triangle and the T-scores ranged from -1.9 in "ribs" to -3.9 in the forearm. Sensitivity ranged from 17% in "ribs" to 36.2% in Ward's triangle. Specificity varied between 88 and 94% and the percent correctly classified ranged from 62.6% in "ribs" to 72.5% in Ward's triangle. We conclude that primary postmenopausal osteoporosis affects the entire skeleton but that some sites discriminate better between vertebral fracture and nonfracture cases regardless of whether they represent cortical or trabecular bone.     

The effect of long-term thyroxine on bone mineral density and serum cholesterol

The effect of thyrotrophin suppression on bone mineral density (BMD) and serum cholesterol concentration was assessed in 31 treated hypothyroid women. Measurements of the BMD of the lumbar spine and femoral neck were repeated in seven of those with the lowest value after an average period of 22.7 months. Final cholesterol concentrations were compared with values before thyroxine was started. The dose of thyroxine was based on clinical assessment, serum triiodothyronine concentrations kept within the normal range, and thyrotrophin values within the normal range or suppressed. The patients had taken thyroxine replacement for a mean of 12.7 years. Two-thirds (21 subjects) had suppressed thyrotrophin concentrations, and it was normal in one-third (10). Fifteen subjects had a past history of thyrotoxicosis. BMD and cholesterol concentrations were compared between those with suppressed and normal thyrotrophin concentrations and between those with and without a past history of thyrotoxicosis. No patient had a pathological fracture. One had a Z value for the femoral neck of -1.6, denoting early but definite osteoporosis, and five had borderline osteoporosis with Z values for one or other site between -1.1 and -1.5. None of the seven with the lowest BMDs had any significant change when measurements were repeated. The difference in Z values between subjects with suppressed and normal thyrotrophin concentrations was not significant for either the lumbar spine (p = 0.68) or the femoral neck (p = 0.28). A past history of thyrotoxicosis had a greater effect on BMD for both sites than thyrotrophin suppression, but again the difference between those with and without a past history of thyrotoxicosis was significant neither for the lumbar spine (p = 0.18) nor for the femoral neck (p = 0.34). The combination of thyrotrophin suppression and a past history of thyrotoxicosis also failed significantly to reduce the BMD of the lumbar spine (p = 0.38) or femoral neck (p = 0.30) in comparison with those who had neither thyrotrophin suppression nor a past history of thyrotoxicosis. The mean fall in serum cholesterol concentration was 2.1 mmol/l (SD 1.78) (p = 0.001) in those with a suppressed thyrotrophin concentration taking a mean daily dose of thyroxine of 171 micrograms (SD: 34.7), compared with a fall of 0.89 mmol/l (SD: 1.04) (p = 0.065) in those whose thyrotrophin concentration was not suppressed on a mean daily thyroxine dose of 140 micrograms (SD: 50). No patient had atrial fibrillation or cardiographic evidence of coronary artery disease (CAD). The serum cholesterol concentration should play at least as important a part in influencing the dose of thyroxine as a fear of osteoporosis. Fractures are not a feature in the natural history of treated hypothyroidism, whereas CAD is a common cause of death in these patients.     

Body weight and bone mineral density in postmenopausal women with primary hyperparathyroidism

OBJECTIVE: To assess bone mineral density and body composition in postmenopausal women with primary hyperparathyroidism. DESIGN: Cross-sectional study with an age-matched control group. SETTING: University teaching hospital. PATIENTS: 41 postmenopausal women with mild primary hyperparathyroidism and 43 eucalcemic, age-matched controls. MEASUREMENTS: Total body, lumbar spine, and proximal femoral (femoral neck, Ward's triangle, and trochanter) bone mineral density; body composition; and fat distribution were measured using dual-energy x-ray absorptiometry. RESULTS: Women with primary hyperparathyroidism were heavier (75.5 kg compared with 66.3 kg; difference, 9.2 kg [95% CI, 3.7 to 14.7 kg]; P = 0.002), had a higher fat mass (33.3 kg compared with 26.1 kg; difference, 7.2 kg [CI, 3.0 to 11.4 kg]; P = 0.001), and had a more android pattern of fat distribution (android-to-gynoid fat ratio, 1.05 compared with 0.84; difference, 0.21 [CI, 0.1 to 0.32]; P = 0.0004) than the controls. Unadjusted bone mineral density was similar in patients and controls at all sites: total body, 0.990 compared with 1.023 g/cm2 (difference, 0.033; CI, -0.004 to 0.070); posteroanterior lumbar spine, 1.032 compared with 1.018 g/cm2 (difference, 0.014; CI, -0.031 to 0.059); lateral lumbar spine, 0.569 compared with 0.528 g/cm2 (difference, 0.041; CI, -0.022 to 0.104); femoral neck, 0.799 compared with 0.825 g/cm2 (difference, 0.026; CI, -0.072 to 0.124); Ward's triangle, 0.653 compared with 0.677 g/cm2 (difference, 0.024; CI, -0.035 to 0.089); trochanter, 0.734 compared with 0.733 g/cm2 (difference, 0.001; CI, -0.024 to 0.026); and arms, 0.720 compared with 0.739 g/cm2 (difference, 0.019; CI, -0.015 to 0.053). After adjustment for body weight, bone mineral density in women with primary hyperparathyroidism was lower than that in controls for total body (P = 0.0004), femoral neck (P = 0.001), Ward's triangle (P = 0.01), trochanter (P = 0.02), and arms (P = 0.0006). Spinal bone mineral density did not differ between groups. CONCLUSIONS: Body weight, total body fat mass, and proportion of android fat are increased in postmenopausal women with primary hyperparathyroidism; these unexplained factors may be relevant to the increased incidence of cardiovascular disease in this condition. Unadjusted bone mineral density values are similar in patients with primary hyperparathyroidism and in controls, suggesting that this condition is not associated with an increased risk for fracture.     

Bone mineral density in periodontally healthy and edentulous postmenopausal women

(Osteoporosis is the most common metabolic disease among postmenopausal women. Reduced masticatory function caused by tooth loss may be a contributing risk factor of osteoporosis. The present study examined the effect of dentate state on skeletal bone mineral density (BMD) in postmenopausal women. Fourteen periodontally healthy dentate subjects (group H; mean age: 64.0 + 5.5 years) and 12 edentulous subjects (group E; mean age: 67.1 + 2.9 years) were randomly selected from the clinics of the departments of Periodontology and Gerodontology, respectively. Informed consent was obtained from all participants. BMD of the lumbar spine (L2-L4) was measured by dual energy x-ray absorptiometry. In addition, occlusal force was measured in 11 group H subjects and 8 group E subjects by using an occlusal diagnostic system. Risk factors associated with osteoporosis including age, calcium intake, physical activity, and cigarette smoking and causes of tooth loss were assessed by interview and questionnaire sent to all participants. The BMD of group H was 1.07 t 0.21 g/cm2 and that of group E was 0.89 + 0.17 g/cm2, which was significantly different(P< 0.05). The occlusal force of group H and E patients was 312.4 + 148 Nand 56.3 + 36 N, respectively, which was significantly different (P< 0.05). Risk factors such as calcium intake, physical activity, and smoking did not differ significantly between the 2 groups. Thus, the periodontally healthy dentate women, who showed about 6 times higher occlusal force than edentulous women, maintained significantly higher BMD of the lumbar spine than edentulous women. Our results suggest that sufficient masticatory function with periodontally healthy dentition may inhibit or delay the progress of osteoporotic change in skeletal bone or that edentulous women may be more susceptible to osteoporosis.     

Nutrition and bone mineral density in premenopausal women

Environmental factors have an important role in osteoporosis. Diet and, in particular, nutrients like calcium, vitamin D or phosphorus were extensively studied as determinants of bone mineral density, but the results remain conflicting and there is no clear evidence for an independent effect of such factors in the bone density of premenopausal women. We studied 66 healthy premenopausal women (20-40 years-old) aiming to relate bone mineral density, as measured in three different sites (distal forearm, lumbar spine and femoral neck) using single X ray and dual energy X-ray absorptiometry, with nutritional intake as estimated by a semi-quantitative food frequency questionnaire. Demographic, anthropometric and other life style variables were also assessed. There was a significant correlation between distal forearm and femoral neck (r = 0.57) or lumbar spine (r = 0.45) bone mineral density. No significant effect of age was observed for distal forearm bone mineral density in these women. In a stepwise multiple linear regression model, evaluating the contribution of all the variables studied, only body mass index (p=0.038) and vitamin A ingestion (p = 0.020) had an independent contribution for the variation in distal forearm bone mineral density. Mean bone mineral density, assessed in the femoral neck (p = 0.003) or the lumbar spine (p = 0.056) was different across tertiles of alcohol ingestion, being higher in non-drinkers. However, among regular drinkers there was a significant positive correlation between alcohol ingestion and femoral neck bone mineral density (Spearman's r = 0.53, p = 0.015). This study shows that the effect of nutrition seems dependent on the anatomical site assessed and that there is a weak correlation between nutritional intake and the actual bone mineral density.     

Polymorphisms of the calcitonin receptor gene are associated with bone mineral density in postmenopausal Italian women

Recognition of a major genetic component in bone mass determination represented the basis for studies aiming to the identification of underlying major and minor genes. Bone mineral density (BMD) represents the continuous trait to be quantified in order to evaluate segregation of candidate genes with risk of osteoporosis. Polymorphisms at the vitamin D receptor (VDR), estrogen receptor, (ER), collagen type I, and interleukin 6 (IL6) gene loci have been correlated to BMD. However, in a polygenic disorder, such as osteoporosis, the number of genes expected to influence BMD is very large. In the present study we examined the presence of restriction fragment length polymorphisms (RFLPs) for the calcitonin receptor (CTR) gene in postmenopausal women. We identified a polymorphic (Tt) site at the CTR gene locus using the Taq I restriction fragment enzyme. Three genotypes were observed, whose Tt was the most frequent in our population (49.7%). In addition, Ancova analysis and Tukey's test showed that women with tt genotype had significantly lower lumbar BMD in comparison with Tt genotype (Tukey's test: p = 0.005). In conclusion, evidence of RFLPs at the CTR gene locus in Caucasian postmenopausal women of Italian origin made it possible to identify the involvement of another gene, the CTR gene, in the determination of bone mass.     

Not all postmenopausal women on chronic steroid and estrogen treatment are osteoporotic: predictors of bone mineral density

Electronic mail (e-mail) offers the potential for near-instantaneous transfer of messages and files across thousands of miles. The same message can be sent simultaneously to multiple recipients and forwarded without retyping. Messages can be sent or read at any time, eliminating "telephone tag," and, because the system is paperless, lost, blurred, and incomplete, facsimile transmissions can be minimized. Additionally, e-mail is less expensive than overnight letter services or long-distance faxes. All healthcare epidemiologists should enter the information superhighway using e-mail. This article provides basic information needed to understand and begin using e-mail.     

The predictive value of biochemical markers of bone turnover for bone mineral density in early postmenopausal women treated with hormone replacement or calcium supplementation

To compare the relative sensitivity and specificity of bone turnover indexes for bone loss or gain in early postmenopausal women, we performed a multicenter trial in 236 menopausal women (mean age, 51 yr), who were randomized to hormone replacement therapy (HRT) or calcium supplementation (CS; 500 mg/day) for 1 yr. Two markers of bone formation, osteocalcin (OC) and bone alkaline phosphatase (BSAP), and two markers of bone resorption, urinary N-telopeptide (NTx) and urinary free deoxypyridinoline (fDpd), as well as spine and femoral neck bone mineral density (BMD) were measured at baseline and 3, 6, and 12 months after treatment. Women receiving HRT (n = 105) showed a significant increase in spine BMD (+2.5%; P < 0.0001) and hip BMD (+1.0%; P = 0.02) compared to women receiving CS, who showed a decline at both sites (-1.1%; P < 0.01). All four markers showed time-dependent decreases in women receiving HRT (P < 0.001) and no change in women receiving CS alone. When baseline indexes of turnover were stratified by quartile, there was a significantly greater increase in BMD among those with the highest NTx, OC, and BSAP levels compared to that in those with the lowest NTx, OC, and BSAP levels (P < 0.05). The highest quartile for percent change from baseline to 6 months in fDpd, BSAP, and NTx was also associated with the greatest change in spine BMD at 1 yr. Receiver operator characteristic curves for percent change from baseline to 6 months in an individual marker to 1 yr change in BMD during HRT revealed that the percent change in NTx provided the greatest discrimination between gain and loss of BMD. When subjects receiving HRT were compared by their positive or negative skeletal response at 1 yr and their baseline turnover marker, initial NTx values were significantly higher in those that gained bone than in those that lost bone (P = 0.0002). CS women in the highest quartile for NTx at baseline had significantly greater decreases in spine BMD than subjects with the lowest NTx values (P < 0.005), although this was not true for fDpd (P < 0.20). In conclusion, for early postmenopausal women there are differential responses of biochemical markers to HRT and CS. Baseline urinary NTx and serum OC were the most sensitive predictors of change in spine BMD after 1 yr of either HRT or CS. Similarly, the percent change in NTx and OC from baseline to 6 months best predicted bone gain or loss. We conclude that markers of bone formation and resorption can be used clinically to predict future BMD in early postmenopausal women.     

Timing of menopause, reproductive years, and bone mineral density: a cross-sectional study of postmenopausal Japanese women

Age at menopause has been found to be associated positively with bone mineral density, and age at menarche has been found to be associated negatively with bone mineral density. However, there have been few studies on the relations of timing of menopause and length of the reproductive period with bone mineral density. The purpose of this study was to examine the relations of timing of menopause and reproductive years (calculated as age at menopause minus age at menarche) with mineral density of the second metacarpal bone in postmenopausal Japanese women. The study population consisted of 1,035 naturally menopausal women aged 40-70 years who were screened in 1996-1997. Using computed x-ray densitometry, the authors measured bone mineral density by analyzing radiographic films of the right second metacarpal bone. Using the women with early menopause (age < 49 years) as the reference group and adjusting for age, subjects with late menopause were at decreased risk for low bone mineral density (odds ratio (OR) = 0.69, 95% confidence interval (CI) 0.49-0.97). After adjustment for additional covariates (grip strength, physical activity, body mass index, smoking, and calcium intake), the association was unchanged (OR = 0.70, 95% CI 0.50-0.99). Postmenopausal women with more reproductive years (> or = 40 years) were at decreased risk for low bone mineral density compared with those with fewer reproductive years, after adjustment for age (OR = 0.73, 95% CI 0.40-1.30) and potentially confounding factors (OR = 0.76, 95% CI 0.41-1.37); the p-value for trend was not statistically significant. In multiple linear regression analysis, early menopause and fewer reproductive years were independent predictors of low bone mineral density. In this study, postmenopausal Japanese women who had a late menopause and more reproductive years were at decreased risk for low bone mineral density, and may therefore be less prone to osteoporosis.     

Associations between body morphology and bone mineral density in premenopausal women

To investigate whether body morphology, obesity and its long time evolution were associated with lumbar and femoral bone mineral density (BMD) in premenopausal women of the same age. DESIGN: Cross-sectional study. SUBJECTS: 72 healthy premenopausal women born in 1950 (42 years) with a regular physical activity. MEASUREMENTS: BMD measured by dual-X-ray absorptiometry (DEXA) at lumbar spine and proximal femur; body weight, body mass index (BMI), BMI at 20 years (BMI-20), increase in BMI since age of 20 (BMI->20), body circumferences (breast, waist, hip) and their ratios (WHR, BHR, WBR), smoking and alcohol intake. RESULTS: Lumbar spine BMD did not correlate with any anthropometric measurement. Femoral BMDs correlated positively with weight, BMI, BMI-20, breast, waist, WHR and BHR. The BMI-20 explained the 5% and the current BMI the 13% of variance of total femur BMD. After adjustment for weight or BMI, breast circumference and BHR remained significantly correlated with all femoral BMDs sites except neck. Weight was the best predictor for neck BMD (R2 = 0.08; p < 0.02), and BHR for Ward's triangle (R2 = 0.12; p < 0.01) and trochanter (R2 = 0.10; p < 0.001). Alcohol intake, cigarette smoking, and age of menarche were not related to BMDs. CONCLUSION: In premenopausal women of the same age, lumbar spine BMD was not associated with any anthropometric measurement. Greater BHR and its long time of evolution may be determinants of greater femoral BMD (trabecular), whereas body weight may be determinant of femoral neck BMD (cortical). Further studies are needed to determine whether large breast to hip ratio may be considered as a protective factor for femoral osteoporosis.     

Comparison of effects of tamoxifen and toremifene on bone biochemistry and bone mineral density in postmenopausal breast cancer patients

Congenital or infantile fibrosarcoma is a rare soft-tissue neoplasm that should be considered in the differential diagnosis of a large extremity mass presenting at birth. These tumors are notoriously misdiagnosed at birth as either hemangiomas or lymphatic malformations. Definitive diagnosis is made by physical examination, special radiologic studies, and biopsy. Although histologically similar to fibrosarcomas occurring in adults, the congenital lesions differ in their clinical behavior; metastases are rare, local recurrence is common, and the prognosis is good with wide local excision combined with chemotherapy. Amputation should be reserved for chemoresistant patients in whom the involvement of neurovascular structures by the tumor make a limb-sparing aggressive excision impossible.     

Prediction of low bone mineral density in postmenopausal women by artificial neural network model compared to logistic regression model

Measuring bone mineral density (BMD) is currently the best modality to diagnose osteoporosis and predict future fractures. The use of risk factors to predict BMD and fracture risk has been considered to be inadequate for precise diagnostic purpose, but it may be helpful as a screening tool to determine who actually needs BMD assessment. Recently, artificial neural network (ANN), a nonlinear computational model, has been used in clinical diagnosis and classification. In the present study, we evaluated the risk factors associated with low BMD in Thai postmenopausal women and assessed the prediction of low BMD using an ANN model compared to a logistic regression model. The subjects consisted of 129 Thai postmenopausal women divided into 2 groups, 100 subjects in the training set and the remaining 29 subjects in the validation set. The subjects were classified as having either low BMD or normal BMD by using BMD value 1 SD lower than the mean value of young adults as the cutoff point. Decreased body weight, decreased hip circumference and increased years since menopause were found to be associated with low BMD at the lumbar spine by logistic regression. For the femoral neck, increased age and decreased urinary calcium were associated with low BMD. The models had a sensitivity of 85.0 per cent, a specificity of 11.1 per cent and an accuracy of 62.0 per cent for the diagnosis of low BMD at the lumbar spine when tested in the validation group. For the femoral neck, the sensitivity, specificity and accuracy were 90.5 per cent, 12.5 per cent, and 69.0 per cent, respectively. Models based on ANN correctly classified 65.5 per cent of the subjects in the validation group according to BMD at the lumbar spine with a sensitivity of 80.0 per cent and a specificity of 33.3 per cent while it correctly classified 58.6 per cent of the subjects at the femoral neck with a sensitivity of 76.2 per cent and a specificity of 12.5 per cent. There was no significant difference in terms of accuracy, sensitivity and specificity in the prediction of low BMD at the lumbar spine or the femoral neck between ANN model and logistic regression model. We concluded that ANN does not perform better than convention statistical methods in the prediction of low BMD. The less than perfect performance of the prediction rules used in the prediction of low BMD may be due to the lack of adequate association between the commonly used risk factors and BMD rather than the nature of the computational models.     

Calcium supplements increase bone mineral density in women with low serum calcium levels during long-term estrogen therapy

In order to clarify whether the long-term effect of estrogen on bone mineral density (BMD) is reinforced by low dose calcium supplements, 600-800 mg of calcium lactate was administered to postmenopausal or oophorectomized women who had been undergoing unopposed estrogen therapy for at least 2 years and whose serum calcium level was suppressed to below the normal range. To patients whose serum calcium levels had been within the normal range, the same dose of estrogen alone was continued. Changes in lumbar spine BMD before and after calcium supplementation was measured by dual-energy X-ray absorptiometry. Lumbar spine BMD decreased by -0.37% for 2 years in women treated with estrogen alone, while that of women treated with estrogen and calcium increased by 2.78% (P = 0.003). These results indicate that low dose calcium supplements potentiate the effect of estrogen in women with decreased serum calcium during long-term hormone replacement therapy.     

Association of bone mineral density with vitamin D receptor gene polymorphism--changes in radial bone mineral density with long-term follow-up: longitudinal study

Recent studies have shown that genetic effects on bone mineral density (BMD) and bone turnover are related to vitamin D receptor (VDR) gene polymorphism. However, discordant studies have been published and it is still not clear whether VDR genotypes influence bone mass accretion and/or postmenopausal bone loss. To assess allelic influence of the VDR gene on BMD, we determined changes in 1/6-radial-BMD by several repeat measurements in the same subjects for about ten years and analyzed VDR polymorphism of BsmI restriction enzyme in 53 normal healthy Japanese women (age: 50.3 +/- 4.7 years, mean +/- SD). Twenty-seven (age: 53.2 +/- 4.7 years) of the subjects were post-menopausal (POST group). Among these 53 subjects, the distribution of bb, Bb and BB genotypes was 64.2%, 34% and 1.9%, respectively. The genotype frequencies in this study were very similar to those in previous reports concerning other Japanese women. There was no difference between the b group (women with bb genotype) and B group (women with BB or Bb genotype) in age, body weight, height, body mass index (BMI), years since menopause, serum osteocalcin and serum alkaline phosphatase values. In the POST group, BMD of the B group at menopause was lower than that of the b group (p < 0.05). About ten years after menopause, BMD did not differ significantly between these groups because the decrease in BMD in the b group was larger than that in the B group. Regarding changes in BMD in the POST group for four years after menopause, BMD of the b group was significantly decreased compared with the B group (p < 0.01). Our findings suggest that the differences in BMD by VDR genotype were larger among pre- and pri-menopausal women and seemed to decrease with years after menopause. It is suggested that there are other factors influencing BMD and postmenopausal bone loss in elderly women.     

Vitamin D and estrogen receptor allelic variants in Italian postmenopausal women: evidence of multiple gene contribution to bone mineral density

Bone mass and bone turnover are under genetic control. Restriction fragment length polymorphisms (RFLPs) at the vitamin D receptor (VDR) gene locus have been recently correlated to bone mineral density (BMD) and rate of bone loss. However, agreement on this relationship is not universal. The existence of ethnical and environmental differences between populations, a health-based selection bias in several previous studies, and the involvement of other genes could explain these discordant findings. In this study, we examined the relationship of VDR and estrogen receptor (ER) gene RFLPs with lumbar spine and upper femur BMD in 426 Italian postmenopausal women, 57.7 +/- 0.4 yr old (144 normal, 106 osteopenic, and 176 osteoporotic). VDR gene RFLPs for ApaI, Bsm I, and TaqI restriction endonucleases and ER RFLPs for PvuII and XbaI restriction endonucleases were assessed by Southern blotting analysis and were indicated, respectively, as A-a, B-b, T-t, P-p, and X-x (uppercase letters signifying the absence and lowercase letters the presence of the restriction site). After correcting for potential confounding factors (age, height, weight, age since menopause, osteophytosis, and facet joint osteoarthritis), a statistically significant VDR genotype effect on lumbar BMD (P = 0.01, analysis of covariance), but not on femoral BMD, was detected, with subjects in AABBtt genotype showing a 13% lower BMD than those with aabbTT genotype (P < 0.05, Tukey's test). Moreover, a statistically significant prevalence of AABBtt genotype in osteoporotics, and of AabbTT and aabbTT genotypes in nonosteoporotics, were detected. Conversely, there was no significant relationship of ER genotype to either lumbar or femoral BMD, even though a trend for higher BMD values in women with the ER PP genotype (with respect to those with ER pp genotype) was detected. When mean lumbar BMD was calculated for women grouped by ER and VDR genotype, we observed a significant difference between those within the 2 opposite associations AABBtt-PPXX and aabbTT-ppxx (0.71 +/- 0.05 vs. 0.97 +/- 0.03 g/cm2, P < 0.05 Tukey's test). These results are consistent with a segregation of the VDR AABBtt genotype with a higher risk of developing osteoporosis, in the Italian female population. The introduction of another variable, the ER genotype, in the analysis of VDR genetic determination of BMD, may represent a useful model in the identification of patients at risk of developing a multigenic disorder like osteoporosis.     

Nutritional influences on bone mineral density: a cross-sectional study in premenopausal women

The association between current and past dietary intake and bone mineral density (BMD) was investigated in 994 healthy premenopausal women aged 45-49 y. BMD was measured with dual-energy X-ray absorptiometry (DXA). Dietary intake was assessed with a food-frequency questionnaire (FFQ). Energy-adjusted nutrient intakes were grouped into quartiles and mean BMD at the lumbar spine (LS), femoral neck (FN), femoral trochanter (FT), and femoral Wards (FW) were calculated. With higher intakes of zinc, magnesium, potassium, and fiber, LS BMD was significantly higher (P < 0.05-0.006), and a significant difference in LS BMD was also found between the lowest and highest quartiles for these nutrients and vitamin C intake (P < 0.05-0.01). These results remained significant after adjustment for important confounding factors. LS BMD and FT BMD were lower in women reporting a low intake of milk and fruit in early adulthood than in women with a medium or high intake (P < 0.01). High, long-term intake of these nutrients may be important to bone health, possibly because of their beneficial effect on acid-base balance.     

Vitamin D receptor gene polymorphism is associated with urinary calcium excretion but not with bone mineral density in postmenopausal women

Polymorphism of vitamin D receptor (VDR) gene has been found to be associated with serum osteocalcin (OC) levels and bone mineral density (BMD) in Caucasian identical twins and unrelated postmenopausal women. Being ethnically different and living in a geographic area with adequate vitamin D status due to abundant sunshine exposure, it is unclear whether VDR gene polymorphism will affect bone mass in Thai population. In the present study, we investigated the association between VDR gene polymorphism and bone metabolism in Thai postmenopausal women. Subjects consisted of 84 postmenopausal women. Bsm I, Taq I and Apa I polymorphisms of VDR gene were determined by PCR-RFLP. B, T and A represent the absence of the corresponding restriction sites while b, t and a indicate the presence of the restriction sites. Data were expressed as mean +/- SE. Sixty-six subjects (78.6%) had bb genotype while 18 (21.4%) had Bb genotype. None of the subjects was found to have BB genotype. Taq I restriction site was in linkage disequilibrium to the Bsm I site. For Apa I polymorphism, 33 (39.3%), 42 (50.0%) and 9 (10.7%) of the subjects had aa, Aa and AA genotypes, respectively. There was no significant difference in serum intact OC levels and BMD at various skeletal sites among subjects with different genotypes. Despite the lack of difference in BMD and intact OC levels, subjects with bb genotype had higher 24-hour urinary calcium excretion than those with Bb genotype (bb, 6.1 +/- 0.3 mmol/day; Bb, 4.4 +/- 0.6 mmol/day; p < 0.05). The effect of Bsm I VDR genotype was still significant (p < 0.05) after dietary calcium intake was controlled using analysis of covariance. Despite the difference in urinary calcium levels, there was no significant difference in fractional excretion of calcium among subjects with different Bsm I-related genotypes, suggesting that the effect of the VDR gene polymorphism on urinary calcium excretion is more likely due to the effect on intestinal calcium absorption rather than renal tubular calcium reabsorption. We conclude that VDR genotype distributions in Thai postmenopausal women are different from those reported in Caucasians. VDR gene polymorphism does not appear to be associated with BMD or bone turnover in Thai postmenopausal women. However, Bsm I VDR polymorphism may have physiologic role in calcium homeostatasis by modulating intestinal calcium absorption.     

Peripheral body fat has a protective role on bone mineral density in elderly women

OBJECTIVES: To determine whether bone mineral density is lower in women living in homes for the elderly as compared to free dwelling control subjects, and to investigate factors affecting possible differences. This is the first study with this objective as the primary aim. DESIGN: Case-control study. SUBJECTS AND METHODS: Institutionalised independent elderly women (n = 22, mean age = 75.1 y+/-6.43 s.d.) randomly selected in a home for the elderly and 22 age-matched control women randomly selected from a sample representative of the independent non institutionalised local population who underwent dual energy X-ray absorptiometry (DXA) at the lumbar spine and right femoral neck; anthropometric measurements (height, weight, subscapular and triceps skinfold thickness); general questionnaire. RESULTS: Mean bone mineral density at the femoral neck was 0.618 g/cm2 (+/-0.130s.d.) in institutionalised women and 0.709 g/cm2 (+/-0.106 s.d.) in controls (P = 0.02, t-test). Controlling for confounding factors in the analysis of covariance, triceps skinfold thickness and living in a home for the elderly turned out to be significant determinants of bone mineral density. CONCLUSION: When compared to free dwelling control subjects, institutionalised women show lower bone density, that is the main risk factor for fracture. Reduced peripheral body fat was significantly associated with the low bone mineral density observed. Health programs aimed at decreasing the incidence of fractures among institutionalised subjects will also have to consider the effect of nutritional or life style factors that reduce peripheral body fat.