Vitamin D stores of urban women in Taipei: effect on bone density and bone turnover, and seasonal variation

Relation between Biochemical Parameters and Bone Density in Postmenopausal Women with Osteoporosis

Background

Osteoporosis is the most prevalent metabolic bone disease in postmenopausal women associated with reduced bone mass and increased bone fracture. Measuring bone density in the lumbar spine and hip is a reliable measure of bone mass and can therefore specify the risk of fracture. Dual-energy X-ray absorptiometry (DXA) is an accurate non-invasive system measuring bone density, with a low margin of error and no complications. The present study aimed to investigate the relationship between biochemical parameters with bone density in postmenopausal women.

Materials and Methods

This cross-sectional study was conducted on 87 postmenopausal women referred to osteoporosis centers in Isfahan. Bone density was measured in the spine and hip area using the DXA system. Serum levels of calcium, phosphorus, alkaline phosphatase, and magnesium were measured by an autoanalyzer, and serum levels of vitamin D were measured by high-performance liquid chromatography (HPLC).

Results

The mean parameters of calcium, phosphorus, alkaline phosphatase, vitamin D, and magnesium did not show a significant difference between the two groups (P-value > 0.05). In the control group, the relationship between alkaline phosphatase and bone mineral content (BMC) and bony area (BA) in the spine was significant with a correlation coefficient of - 0.402 and 0.258, respectively (P-value < 0.05) and BMD and T-score in the femoral neck area showed a direct and significant relationship with phosphorus (correlation = 0.368; P value = 0.038). There was a significant relationship between the Z-score with calcium (correlation = 0.358; P value = 0.044).

Conclusion

There was no significant relationship between the values of calcium, phosphorus, alkaline phosphatase, vitamin D, and magnesium parameters and bone density (spine and hip) in postmenopausal women with osteopenia or osteoporosis.

Vegetarian diet in dialysis patients: A significant gap between actual intake and current nutritional recommendations

Nutritional status is a predictor of mortality and morbidity in dialysis patients. This study aimed to assess dietary behaviors in dialysis patients compared to the recommendations of the Kidney Disease Outcomes Quality Initiative.Ninety five dialysis patients recruited from a hospital completed a 24-hour dietary recall questionnaire. Body weight, energy requirements, protein requirements, albumin, normalized protein catabolic rate, and 25(OH) vitamin D levels were measured.Of the 95 patients, 11 (11.6%) were below the desirable body mass index range, 59 (62.1%) were within the desired range, and 25 (26.3%) were above the desired range. However, only 32.7% of patients met the target energy intake, 29.5% reached the protein intake target, and 20.0% had adequate vitamin D concentrations. Vegetarian patients had lower energy, protein, fat, vitamin D intake, lower body mass index, serum blood urea nitrogen, creatinine, phosphate, normalized protein catabolic rate, and vitamin D status than the omnivorous patients (P < .05). After adjusting for age, sex, and body weight, vegetarianism was an independent risk factor for severe vitamin D deficiency (<10 ng/ml, P < .01).Most dialysis patients do not meet their dietary recommendations or goals. The risk of a vegetarian diet may outweigh the benefits in dialysis patients. Careful consideration of dietary behaviors is required for dialysis patients to prevent malnutrition, more so in vegetarians.

Vitamin D, Calcium, Parathyroid Hormone, and Sex Steroids in Bone Health and Effects of Aging

Bone health of the elderly is a major global health concern, since about 1 in 3 women and 1 in 5 men suffer from bone loss and fractures, often called osteoporosis, in old age. Bone health is a complex issue affected by multiple hormones and minerals. Among all the hormones involved in bone health, calcitriol (also vitamin D), parathyroid, and sex hormones (especially estrogen) have been discussed in this review paper. We have discussed the metabolism of these hormones and their effects on bone health. Vitamin D can be obtained from diet or formed from 7-dehydrocholesterol found under the skin in the presence of sunlight. The active form, calcitriol, causes dimerization of vitamin D receptor and acts on the bones, intestine, and kidney to regulate the level of calcium in blood. Similarly, parathyroid hormone is secreted when the serum level of calcium is low. It helps regulate the level of blood calcium through calcitriol. Sex hormones regulate bone modeling at an early age and remodeling later in life. Loss of ovarian function and a decrement in the level of production of estrogen are marked by bone loss in elderly women. In the elderly, various changes in the calcium and vitamin D metabolism, such as decrease in the production of vitamin D, decrease in dietary vitamin D, decreased renal production, increased production of excretory products, decrease in the level of VDR, and decreased calcium absorption by the intestines, can lead to bone loss. When the elderly are diagnosed with osteoporosis, medications that directly target bone such as bisphosphonates, RANK ligand inhibitors, estrogen and estrogen analogues, estrogen receptor modulators, and parathyroid hormone receptor agonists are used. Additionally, calcium and vitamin D supplements are prescribed.

Circulating Serum Amyloid A, hs-CRP and Vitamin D Levels in Postmenopausal Osteoporosis

Background:

Both vitamin D and inflammation were investigated as important players in the pathogenesis of postmenopausal osteoporosis. This study compared vitamin D, inflammatory the biomarkers serum levels and their association with bone mineral density (BMD) in case and control groups to evaluate the possible immune-regulatory effect of vitamin D in this population.

Materials and Methods:

Participants in post-menopausal age, were categorized to 44 osteoporotic vs. 44 healthy aged-matched women according to WHO criteria. Total BMD, T- scores, Z-scores as well as fracture risk were measured in both groups, using Hologic system Dual-energy X-ray absorptiometry (DEXA). Serum 25-OH vitamin D, high sensitive CRP (hs-CRP) and serum amyloid A (SAA) were compared between groups. The association between serum biomarkers level and BMD were also investigated. The same evaluations were performed for vitamin D deficient (<20 ng/mL) and non-deficient (≥20 ng/mL) subgroups.

Results:

Vitamin D deficiency was higher in the osteoporotic group (32.6%) in comparison with the control group (25.6%), but the differences were not significant (P=0.47). There were no significant differences in serum levels of hs-CRP and SAA (P=0.83 and P=0.39) as well. No significant association between serum inflammatory biomarkers, vitamin D, and BMD were detected (P≥0.05). The results were the same for vitamin D deficient and non-deficient subgroups (P≥0.05).

Conclusion:

In the current study, the beneficial effects of vitamin D as a result of its immune-regulatory mechanisms was not reached. Larger scale studies might pave the way to define vitamin D benefits in postmenopausal osteoporosis.

Calciotropic Hormones and the Prevalence of Vertebral Fractures in Chinese Postmenopausal Women with Vitamin D Insufficiency: Peking Vertebral Fracture Study

This case-control study aimed to examine the effect of high serum parathyroid hormone (PTH) level, especially the effect of secondary hyperparathyroidism (SHPT) related to hypovitaminosis D, on bone metabolism and bone phenotypes. We included a total of 830 Chinese postmenopausal women aged ≥ 50 years with serum 25-hydroxyvitamin D (25(OH)D) level < 30 ng/ml, among whom 415 women had prevalent vertebral fractures (VFs) and others were age-matched controls. We measured serum levels of 25(OH)D, PTH and bone turnover markers (BTMs), which included C-terminal telopeptide of type I collagen (β-CTX), N-aminoterminal prepeptide of type I procollagen (P1NP) and osteocalcin (OC). Bone mineral densities (BMDs) at lumbar spine and femoral neck were quantified by dual-energy X-ray absorptiometry. Morphometric VFs were validated by lateral radiograph of thoracolumbar spine. Compared to fracture-free controls, women with VFs exhibited a higher serum level of PTH and a higher percentage of SHPT (both p < 0.05), but had a similar serum level of 25(OH)D (p = 0.166). Positive correlations were depicted between PTH and BTMs (all p < 0.01), and between 25(OH)D and bone formation markers (p = 0.013 for OC, p = 0.068 for P1NP), whereas no significant correlation was identified between both calciotropic hormones and BMDs or between 25(OH)D and β-CTX (all p > 0.05). Increasing PTH was associated with an increased risk of VFs independent of 25(OH)D and BMD [odds ratio (OR) per SD increase in PTH 1.016, 95% confidence interval (95% CI) 1.006-1.027]. Moreover, women with SHPT (i.e., > 68 pg/ml) had about three times odds for VF compared to women with normal PTH levels (OR 3.270, 95% CI 1.581-6.760). These data suggest that evaluated serum PTH level might promote the bone remodeling and then lead to increased risks of VFs among Chinese postmenopausal women with vitamin D insufficiency.

Prevalence of Vitamin D Inadequacy Among Chinese Postmenopausal Women: A Nationwide, Multicenter, Cross-Sectional Study

Purpose: We aimed to investigate the status of serum 25-hydroxyvitamin D [25(OH)D] among Chinese postmenopausal women in a multicenter cross-sectional study. Methods: Non-institutionalized postmenopausal women aged ≥55 years were recruited from urban and rural areas in 7 geographically different regions in China. Subject enrollment was executed during the summer and the winter. Vitamin D insufficiency and deficiency were defined as 25(OH)D < 30 and< 20 ng/ml, and was measured by liquid chromatography-tandem mass spectrometry. Women were referred to a dual-energy x-ray absorptiometry (DXA) if they had a medium-to-high fracture risk suggested by Osteoporosis Self-Assessment Tool for Asians (OSTA). Results: Among all subjects, 91.2% (1,535/1,684, 95%CI: 89.7, 92.5) had vitamin D insufficiency and 61.3% had vitamin D deficiency (1,033/1,684, 95%CI: 59.0, 63.7). The prevalence of vitamin D deficiency was significantly higher in urban dwellers (64.9 vs. 57.7% in rural, P = 0.002) and in winter-enrolled subjects (84.7 vs. 41.3% in summer, P < 0.0001). The prevalence of vitamin D inadequacy did not increase in trend by latitude and was numerically lower in women who had high fracture risk and osteoporosis. A non-curvilinear change of intact parathyroid hormone (iPTH) levels was observed at 25(OH)D >16.78 ng/mL. Conclusions: The prevalence of vitamin D inadequacy was remarkable among Chinese postmenopausal women and independent of fracture risk assessed by OSTA or osteoporosis suggested by DXA. Winter season, urban residence, however not latitude, were significantly associated with a higher likelihood of vitamin D deficiency. Optimal vitamin D status for iPTH and bone-related outcomes merits further investigation in this population.

Circulating 25-hydroxyvitamin D and physical performance in older adults: a nationwide study in Taiwan

BACKGROUND

A previous study indicated that 31% of the elderly in Taiwan have a vitamin D deficiency. Vitamin D adequacy has been associated with physical performance in the elderly.

OBJECTIVES

The first aim of the current study was to identify the determinants for vitamin D deficiency. The second aim was to evaluate the association between vitamin D status and physical performance.

DESIGN

A total of 5664 community-dwelling participants aged ≥55 y were recruited since 2008. Plasma total 25-hydroxyvitamin D concentrations were originally determined by ELISA and calibrated to a chemiluminescence measurement. Physical performance was assessed by handgrip strength, the Short Physical Performance Battery, timed up and go, a 6-min walk test, and single-leg stands. Multiple linear regression and logistic regression were used to estimate the cross-sectional associations.

RESULTS

Vitamin D inadequacy (<50 nmol/L) was related to higher education (P-trend < 0.01), body mass index [(BMI; in kg/m²) ORs (95% CIs) for ≥30 compared with 18.5 to <25 were 1.78 (1.14, 2.78) for men and 1.53 (1.11, 2.11) for women], and vegetable intake [fourth compared with first quartile, 1.58 (1.15, 2.18) for men and 2.38 (1.82, 3.12) for women]. Higher intakes of fish [fourth compared with first quartile, 0.44 (0.33, 0.59) for men and 0.27 (0.21, 0.36) for women] and milk [fourth compared with first quartile, 0.46 (0.31, 0.69) for men and 0.69 (0.49, 0.95) for women] were associated with lower risk of vitamin D inadequacy. Few subjects had 25-hydroxyvitamin D concentrations <30 nmol/L. Above that concentration, there was no dose-effect relation with physical performance except for single-leg stands.

CONCLUSIONS

The factors associated with vitamin D inadequacy in Taiwan were higher education, higher BMI, and lower fish and milk intakes. No dose-effect relation existed between vitamin D concentration and physical performance except for single-leg stands. This study was registered at www.clinicaltrials.gov as NCT02677831.

Vitamin D status and its relationship with bone mineral density in a healthy Iranian population

Objectives

Considering the controversial results regarding the relationship between vitamin D levels and bone mineral density in different populations, the present study was designed to evaluate this correlation in a healthy Iranian population.

Methods

Using a random cluster sample of apparently healthy men and women, this multicenter cross-sectional study was carried out among 4450 individuals living in urban areas of five major cities in Iran. Bone mineral density (BMD) values at different sites were analyzed along with the serum levels of 25(OH)D and PTH. Analysis of variance (ANOVA) was used to estimate the main effects, through comparing the mean values of these markers based on the bone mineral density status of the study group in each sex.

Results

25(OH)D levels were inversely correlated with BMD values at total hip (r = −0.062 in men and r = −0.057 in women) and spine (r = −0.076 in men and r = −0.107 in women). After adjusting the data for age, the inverse correlation was no longer statistically significant.

Conclusion

Serum 25(OH)D levels are inversely correlated with bone mass values in both sexes.

Vitamin D status and bone mineral density in the Chinese population: a review

Low vitamin D status is associated with low bone mass which, in turn, is an important predictor of fracture. However, data on this relationship in non-Caucasian populations are scarce. This review shows such an association in the Chinese population in five of the 11 included studies.

INTRODUCTION

In the elderly population, the serum 25-hydroxyvitamin D [25(OH)D] concentration is often inadequate. This may cause a lower bone mineral density (BMD), which is an important predictor of fracture. It is estimated that by 2050 more than half of all hip fractures worldwide will occur in Asia. However, data on the relationship between vitamin D status and BMD in a non-Caucasian population are scarce. Therefore, this study reviews the literature on the relationship between serum 25(OH)D and BMD in the Chinese population.

METHODS

A search was made in PubMed, EMBASE, Web of Science and Cochrane Library (up to December 2014) to identify relevant studies using the terms vitamin D status, bone mineral density, and Chinese.

RESULTS

Of the 293 studies identified, 11 fulfilled the inclusion and exclusion criteria and were analyzed. Mean serum 25(OH)D concentrations ranged from 29-82 nmol/L. In 5 of the 11 studies, an association was found between vitamin D status and BMD in the Chinese population.

CONCLUSION

The evidence for a relationship between the serum 25(OH)D concentration and BMD in the middle-aged and elderly Chinese population living in Asia appears to be limited and inconsistent.

Determinants of serum 25-hydroxyvitamin D in Hong Kong

Vitamin D plays an important role in skeletal health throughout life. Some studies have hypothesised that vitamin D may reduce the risk of other diseases. Our study aimed to estimate age-specific and sex-specific serum 25-hydroxyvitamin D (25(OH)D) status and to identify the determinants of serum 25(OH)D status in Hong Kong, a subtropical city in southern China. In 2009–2010, households in Hong Kong were followed up to identify acute respiratory illnesses, and sera from 2694 subjects were collected in three to four different study phases to permit measurement of 25(OH)D levels at different times of the year. A questionnaire survey on diet and lifestyle was conducted among children, with simultaneous serum collection in April and May 2010. The mean of serum 25(OH)D levels in age groups ranged from 39 to 63 nmol/l throughout the year with the mean values in all age groups in spring below 50 nmol/l. Children aged 6–17 years, and girls and women had significantly lower serum 25(OH)D levels than adults, and boys and men, respectively (allP< 0·001). We estimated that serum 25(OH)D levels in Hong Kong followed a lagged pattern relative to climatic season by 5 weeks with lowest observed levels in early spring (March). For children aged 6–17 years, reporting a suntan, having at least 1 servings of fish/week and having at least 1 serving of eggs/week were independently associated with higher serum 25(OH)D levels. Adequate sunlight exposure and increased intake of dietary vitamin D could improve vitamin D status, especially for children and females in the winter and spring.

Total 25-hydroxyvitamin D concentration as a predictor for all-cause death and cardiovascular event risk among ethnic Chinese adults: a cohort study in a Taiwan community

BACKGROUND

Evidence of an inverse association between serum 25-hydoroxyvitamin D [25(OH)D] and the risk of all-cause death and cardiovascular disease from prospective studies is inconsistent. We tested the relationship between 25(OH)D and the risk among adult ethnic Chinese in Taiwan.

METHODS

We conducted a community-based cohort study of 1816 participants (age 60.2±10.2 yrs, 45.0% women) in the Chin-Shan Community Cardiovascular Cohort Study who were free of cardiovascular diseases at baseline and provided 25(OH)D measurements.

RESULTS

During a median 9.6 (interquartile range, 8.8- 10.5) years' follow-up period, totally 263 cases developed cardiovascular death events and 559 participants were documented to death from any cause. As 25(OH)D concentration increased, the incidence rates of cardiovascular events and all-cause death decreased progressively. 25(OH)D was inversely associated with all-cause death: the adjusted hazard ratio was 0.49 (95% confidence interval [CI], 0.25-0.97) for the third quartile and a significant J-shape relationship was found. The performance measures by integrated discriminative improvement showed significant improvement after adding 25(OH)D information (0.14%, 95% CI, 0.03-0.31, P=0.050, for all-cause death and 0.32%, 95% CI, 0.02-0.62, P=0.018 for cardiovascular events).

CONCLUSION

These findings suggested a modest inverse association between 25(OH)D and the risk of all-cause death among diabetic participants and a good predictive factor in the community. Further studies to investigate the mechanism of vitamin D role on health effect are warranted.

Vitamin D and calcium abnormalities in the HIV-infected population

The prevalence of vitamin D deficiency among HIV-infected persons is substantial and comparable to the general population. The factors associated with vitamin D deficiency are similar for both populations but additional factors (ie, use of certain antiretroviral agents) also contribute to vitamin D deficiency among HIV-infected persons. The adverse outcomes associated with vitamin D deficiency considerably overlap with non-AIDS defining illnesses (NADIs) that are increasingly becoming widespread in the aging HIV-infected population. However, there is scant evidence to support any causal inference. Further studies are warranted as efforts to identify and address modifiable risk factors contributing to NADIs continue.

Vitamin D status in non-supplemented postmenopausal Taiwanese women with osteoporosis and fragility fracture

BACKGROUND

Vitamin D is essential for calcium metabolism, Vitamin D deficiency can precipitate osteoporosis, cause muscle weakness and increase the risk of fracture. The aim of this study was to assess the prevalence of vitamin D inadequacy among non-supplemented postmenopausal women with osteoporosis and fragility fractures of the hip or vertebrae in Taiwan.

METHODS

This multi-center, cross-sectional, observational study analyzed the vitamin D inadequacy [defined as 25(OH) D level less than 30 ng/mL] in Taiwanese postmenopausal osteoporotic patients who suffered from a low trauma, non-pathological fragility hip or vertebral fracture that received post-fracture medical care when admitted to hospital or at an outpatient clinic.

RESULTS

A total of 199 patients were enrolled at 8 medical centers in Taiwan; 194 patients met the study criteria with 113 (58.2%) and 81 (41.8%) patients diagnosed with hip and vertebral fracture, respectively. The mean serum 25(OH) D level was 21.1 ± 9.3 ng/mL, resulting in a prevalence of vitamin D inadequacy of 86.6% of the patients.

CONCLUSIONS

High prevalence of vitamin D inadequacy across all age groups was found among non-supplemented women with osteoporosis and fragility hip or vertebral fracture in Taiwan.

A systematic review of vitamin D status in populations worldwide

Vitamin D deficiency is associated with osteoporosis and is thought to increase the risk of cancer and CVD. Despite these numerous potential health effects, data on vitamin D status at the population level and within key subgroups are limited. The aims of the present study were to examine patterns of 25-hydroxyvitamin D (25(OH)D) levels worldwide and to assess differences by age, sex and region. In a systematic literature review using the Medline and EMBASE databases, we identified 195 studies conducted in forty-four countries involving more than 168 000 participants. Mean population-level 25(OH)D values varied considerably across the studies (range 4·9-136·2 nmol/l), with 37·3 % of the studies reporting mean values below 50 nmol/l. The highest 25(OH)D values were observed in North America. Although age-related differences were observed in the Asia/Pacific and Middle East/Africa regions, they were not observed elsewhere and sex-related differences were not observed in any region. Substantial heterogeneity between the studies precluded drawing conclusions on overall vitamin D status at the population level. Exploratory analyses, however, suggested that newborns and institutionalised elderly from several regions worldwide appeared to be at a generally higher risk of exhibiting lower 25(OH)D values. Substantial details on worldwide patterns of vitamin D status at the population level and within key subgroups are needed to inform public health policy development to reduce risk for potential health consequences of an inadequate vitamin D status.

Vitamin D and bone disease

Vitamin D is important for normal development and maintenance of the skeleton. Hypovitaminosis D adversely affects calcium metabolism, osteoblastic activity, matrix ossification, bone remodeling and bone density. It is well known that Vit. D deficiency in the developing skeleton is related to rickets, while in adults is related to osteomalacia. The causes of rickets include conditions that lead to hypocalcemia and/or hypophosphatemia, either isolated or secondary to vitamin D deficiency. In osteomalacia, Vit. D deficiency leads to impairment of the mineralisation phase of bone remodeling and thus an increasing amount of the skeleton being replaced by unmineralized osteoid. The relationship between Vit. D and bone mineral density and osteoporosis are still controversial while new evidence suggests that Vit. D may play a role in other bone conditions such as osteoarthritis and stress fractures. In order to maintain a “good bone health” guidelines concerning the recommended dietary intakes should be followed and screening for Vit. D deficiency in individuals at risk for deficiency is required, followed by the appropriate action.

Prevalence of vitamin D insufficiency and low bone mineral density in elderly Thai nursing home residents

Background

Numerous emerging data from research on osteoporosis among Asians found differences from Caucasians. Therefore, the aim of this study was to determine the prevalence of vitamin D insufficiency and osteoporosis in elderly participants from two nursing homes in Thailand, a country located near the equator.

Methods

The subjects of this cross-sectional study comprised 93 elderly Thai women who were living in institutional long-term nursing homes for the aged. Demographic data, daily food and calcium intake, physical activity, and sunlight exposure were measured. Lumbar spine and femoral neck bone mineral density (BMD) and biochemical levels including serum 25 hydroxyvitamin D [25(OH)D] and bone turnover markers were assessed. Vitamin D insufficiency was defined as 25(OH)D level < 70 nmol/l.

Results

The mean age of subjects was 75.2 ± 6.0 (SD) years. Dietary calcium intake was low (322 ± 158 mg/day) The mean 25(OH)D level was 64.3 ± 14.9 nmol/L and the prevalence of vitamin D insufficiency was 38.7% (95% CI: 28.8%, 49.4%). There was no correlation between serum 25(OH)D concentrations and age (r = −.11, p = 0.3). The mean BMD of lumbar spine and femoral neck were 0.92 ± 0.19 and 0.65 ± 0.10 g/cm², respectively. Nearly a half of the subjects had osteopenia (44.1%, 95% CI: 33.8%, 54.8%) and osteoporosis (47.3%, 95% CI: 36.9%, 57.9%). Circulating C-terminal telopeptide of type I collagen (CTx) level correlated significantly with both lumbar spine (r = −0.26, p = 0.01) and femoral neck BMD (r = −0.25, p = 0.02).

Conclusions

More than one-third of Thai elderly women residing in nursing homes had vitamin D insufficiency. Almost all nursing home residents had osteoporosis and/or osteopenia.

A global representation of vitamin D status in healthy populations

PURPOSE

This paper visualizes the available data on vitamin D status on a global map, examines the existing heterogeneities in vitamin D status and identifies research gaps.

METHODS

A graphical illustration of global vitamin D status was developed based on a systematic review of the worldwide literature published between 1990 and 2011. Studies were eligible if they included samples of randomly selected males and females from the general population and assessed circulating 25-hydroxyvitamin D [25(OH)D] levels. Two different age categories were selected: children and adolescents (1-18 years) and adults (>18 years). Studies were chosen to represent a country based on a hierarchical set of criteria.

RESULTS

In total, 200 studies from 46 countries met the inclusion criteria, most coming from Europe. Forty-two of these studies (21 %) were classified as representative. In children, gaps in data were identified in large parts of Africa, Central and South America, Europe, and most of the Asia/Pacific region. In adults, there was lack of information in Central America, much of South America and Africa. Large regions were identified for which the mean 25(OH)D levels were below 50 nmol/L.

CONCLUSIONS

This study provides an overview of 25(OH)D levels around the globe. It reveals large gaps in information in children and adolescents and smaller but important gaps in adults. In view of the importance of vitamin D to musculoskeletal growth, development, and preservation, and of its potential importance in other tissues, we strongly encourage new research to clearly define 25(OH)D status around the world.

The levels of bone turnover markers in Chinese postmenopausal women: Peking Vertebral Fracture study

OBJECTIVE

The aim of this study was to evaluate serum N-aminoterminal propeptide of type I collagen (P1NP), C-terminal telopeptide of type I collagen (β-CTX), and vitamin D status in healthy Chinese postmenopausal women. The study was also designed to investigate their possible relationships with osteoporosis phenotypes.

METHODS

A community-based population of 1,724 postmenopausal women in Beijing was randomly selected. Serum bone turnover markers and 25-hydroxyvitamin D [25(OH)D] were tested by an automated Roche electrochemiluminescence system. Dual-energy x-ray absorptiometry was used to measure bone mineral density (BMD).

RESULTS

The mean (SD) values of serum β-CTX and P1NP were 0.439 (0.210) and 56.7 (27.9) ng/mL, respectively. The 25(OH)D level of postmenopausal women in Beijing was remarkably low (13.2 ± 5.4 ng/mL). Serum β-CTX and P1NP levels were negatively correlated with BMDs of lumbar spine, femoral neck, and total hip (all P < 0.01). The cubic regression model better fitted the relationships of BMD and bone turnover markers. Serum β-CTX levels were significantly higher in women with sustained osteoporotic fracture or vertebral fracture (P = 0.006 and 0.012, respectively). No association between P1NP and fracture or vertebral fracture was detected. The same situation applied to 25(OH)D. 25(OH)D was negatively correlated with β-CTX and P1NP (r = -0.073 and -0.088, P = 0.002 and <0.001, respectively).

CONCLUSIONS

Serum β-CTX and P1NP levels were negatively correlated with BMD. β-CTX was significantly higher in postmenopausal women with sustained fracture or vertebral fracture. Vitamin D deficiency was highly prevalent in postmenopausal women in Beijing.

The effect of soy isoflavone on bone mineral density in postmenopausal Taiwanese women with bone loss: a 2-year randomized double-blind placebo-controlled study

The treatment of 300-mg/day isoflavones (aglycone equivalents) (172.5 mg genistein + 127.5 mg daidzein) for 2 years failed to prevent lumbar spine and total proximal femur bone mineral density (BMD) from declining as compared with the placebo group in a randomized, double-blind, two-arm designed study enrolling 431 postmenopausal women 45-65 years old.

INTRODUCTION

This study evaluated the effects of soy isoflavones on bone metabolism in postmenopausal women.

METHODS

Four hundred and thirty-one women, aged 45-65 years, orally consumed 300-mg/day isoflavones (aglycone equivalents) or a placebo for 2 years in a parallel group, randomized, double-blind, two-arm study. Each participant also ingested 600 mg of calcium and 125 IU of vitamin D(3) per day. The BMD of the lumbar spine and total proximal femur were measured using dual-energy X-ray absorptiometry at baseline and every half-year thereafter. Serum bone-specific alkaline phosphatase, urinary N-telopeptide of type 1 collagen/creatinine, and other safety assessments were examined regularly.

RESULTS

Two hundred out of 217 subjects in the isoflavone group and 199 out of 214 cases in placebo group completed the treatment. Serum concentrations of isoflavone metabolites, genistein and daidzein, of the intervention group were remarkably elevated following intake of isoflavones (p < 0.001). However, differences in the mean percentage changes of BMD throughout the treatment period were not statistically significant (lumbar spine, p = 0.42; total femur, p = 0.39) between the isoflavone and placebo groups, according to the generalized estimating equation (GEE) method. A significant time trend of bone loss was observed at both sites as assessed by the GEE method following repeated measurement of BMD (p < 0.001). Differences in bone marker levels were not significant between the two treatment groups.

CONCLUSION

Treatment with 300-mg/day isoflavones (aglycone equivalents) failed to prevent a decline in BMD in the lumbar spine or total femur compared with the placebo group.

Vitamin D status in relation to obesity, bone mineral density, bone turnover markers and vitamin D receptor genotypes in healthy Saudi pre- and postmenopausal women

The various factors that may contribute to vitamin D deficiency or insufficiency were examined among healthy Saudi pre- and postmenopausal women. Vitamin D deficiency was highly prevalent among studied Saudi women with obesity, poor sunlight exposure, poor dietary vitamin D supplementation and age as the main risk factors.

INTRODUCTION

The various factors that may contribute to vitamin D deficiency or insufficiency in relation to bone health among Saudi women are not known. The main objectives of the present study were to determine the factors influencing vitamin D status in relation to serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone (PTH), bone turnover markers (BTMs), bone mineral density (BMD), and vitamin D receptor genotype (VDR) in healthy Saudi pre- and postmenopausal women.

METHODS

A total number of 1,172 healthy Saudi women living in the Jeddah area were randomly selected and studied. Anthropometric parameters, socioeconomic status, sun exposure index together with serum levels of 25(OH)D, calcitriol, intact PTH, Ca, PO4, Mg, creatinine, albumin, and biochemical BTMs were measured. BMD was measured by a dual energy X-ray absorptiometry and VDR genotypes were also determined.

RESULTS

About 80.0% of Saudi women studied exhibited vitamin D deficiency (serum 25(OH)D<50.0 nmol/L) with only 11.8% of all women were considered with adequate vitamin D status (serum 25(OH)D>75 nmol/L). Secondary hyperparathyroidism was evident in 18.5% and 24.6% in pre- and postmenopausal women with 25(OH)D<50 nmol/L. Serum 25(OH)D was lower (P<0.001) and intact PTH higher (P<0.001) in the upper quintiles of body mass index (BMI) and waist-to-hip ratio (WHR). Multiple linear regression analysis showed that BMI, sun exposure index, poor dietary vitamin D supplementation, WHR, and age were independent positive predictors of serum 25(OH)D values.

CONCLUSIONS

Vitamin D deficiency is highly prevalent among healthy Saudi pre-and postmenopausal women and largely attributed to obesity, poor exposure to sunlight, poor dietary vitamin D supplementation, and age.

The association between vitamin D status and circulating adiponectin independent of adiposity in subjects with abnormal glucose tolerance

Vitamin D status assessed by serum 25-hydroxyvitamin D levels (25(OH)D) has been shown to be inversely associated with insulin resistance. The underlying basis for such association is less clear. In the present study, we assessed the prevalence of inadequate vitamin D levels and its relationship to glucose tolerance status and circulating adiponectin in healthy Thai population. The cohort of 246 subjects was classified into two groups according to 75 g oral glucose tolerance test (OGTT) results. There were 86 subjects and 160 subjects in normal glucose tolerance group (NGT) and abnormal glucose tolerance group (AGT), respectively. Anthropometric variables were recorded for each individual. Fasting blood samples were assayed for 25(OH)D, adiponectin, glucose, and insulin levels. Insulin resistance (HOMA-IR) and insulin secretion index (HOMA-B) were calculated by the homeostasis model assessment. Pearson and partial correlation analyses were performed. There were 35 males and 211 females with a mean age of 62.4 +/- 7.2 years in this study. The mean levels of 25(OH)D were 21.4 +/- 6.6 ng/ml. The prevalence of vitamin D deficiency defined by 25(OH)D levels less than 20 ng/ml and vitamin D inadequacy defined by 25(OH)D levels less than 30 ng/ml were 44.3 and 91.9%, respectively. The mean levels of 25(OH)D obtained from samples collected in the rainy season (19.4 +/- 4.6 ng/ml) were significantly lower than those collected in the winter (22.6 +/- 8.3 ng/ml) and summer period (23.1 +/- 4.6 ng/ml). AGT subjects had slightly lower average 25(OH)D levels than the NGT group (21.0 +/- 6.8 vs. 22.1 +/- 6.2 ng/ml, P = 0.09). 25(OH)D levels were positively associated with adiponectin levels (r = 0.20, P < 0.05) and negatively associated with HOMA-IR and BMI (r = -0.22, P < 0.01 and r = -0.22, P < 0.01, respectively) only in AGT subjects. An independent association between 25(OH)D and adiponectin levels was demonstrated after controlling for BMI (r = 0.17, P < 0.05). High prevalence of vitamin D inadequacy and seasonal variation of vitamin D status are found in Thai population. We demonstrated an association between insufficient vitamin D status and lower circulating adiponectin in subjects with abnormal glucose tolerance independently of adiposity which may indicate the role of adiponectin as a link between vitamin D status and insulin resistance.

Association between vitamin D and bone mineral density in Iranian postmenopausal women

The role of vitamin-D in determining bone mineral density (BMD), especially in less severe vitamin D deficiency, is still unclear. To investigate the possible association between 25-hydroxyvitamin D [25(OH)D] and BMD, 245 healthy free-living postmenopausal women, aged between 40 and 80, were randomly selected from participants of a population-based study. BMD was measured at the lumbar spine and hip by dual X-ray absorptiometry (Lunar DPXMD 7164). Serum 25(OH)D, parathyroid hormone (PTH), calcium, phosphorus, total and bone alkaline phosphatases, and urine deoxypyridinoline were measured. PTH was logarithmically transformed (LnPTH). Linear regression models were developed to determine the association between serum 25(OH)D and BMD at different sites. Means of age and duration of menopause were 57.7 +/- 7 and 9.4 +/- 6.8 years, respectively. Mean 25(OH)D was 73.0 +/- 62.3 nmol/l; 5.3% (n = 13) had 25(OH)D < 25 nmol/l and 37.6% (n = 92) had 25(OH)D between 25 and 50 nmol/l. Eleven percent of the women (n = 27) were osteoporotic in femoral neck and 25.3% of them (n = 62) were osteoporotic in lumbar spine sites. 25(OH)D correlated inversely with LnPTH (r = -0.25, P < 0.01). In the multivariate analyses, no association was found between 25(OH)D and BMD at any of the skeletal sites after adjusting for age, duration of menopause, body mass index, calcium, and LnPTH. However, BMD was associated inversely with LnPTH only in femoral neck but not in the other sites. This study did not show any association between 25(OH)D and BMD in free-living Iranian postmenopausal women.

Vitamin D inadequacy in postmenopausal women in Eastern Asia

OBJECTIVE

To review data on the prevalence of vitamin D inadequacy and its causes in postmenopausal women in Eastern Asia.

RESEARCH DESIGN AND METHOD

Data were obtained from the published biomedical literature as well as abstracts and posters presented at scientific meetings. Using MEDLINE, EMBASE and BIOSIS databases (to July 2007), epidemiological studies were identified using the search terms: 'human', 'vitamin D', 'vitamin D deficiency', 'vitamin D inadequacy', 'vitamin D insufficiency' and 'hypovitaminosis D', 'osteomalacia' and 'osteoporosis'. Additional references were also identified from the bibliographies of published articles.

RESULTS

The prevalence of vitamin D inadequacy in studies of postmenopausal women (ambulatory or with osteoporosis or related musculoskeletal disorders) in Eastern Asia ranged from 0 to 92%, depending on the cut-off level of serum 25-hydroxycholecalciferol [25(OH)D] that was applied (range < or =6-35 ng/mL [< or = 15-87 nmol/L]). One large international study found that 71% of postmenopausal women with osteoporosis in Eastern Asia had vitamin D inadequacy, defined as serum levels of 25(OH)D < 30 ng/mL (75 nmol/L). Prevalence rates using this cut-off level were 47% in Thailand, 49% in Malaysia, 90% in Japan and 92% in South Korea. High prevalences of vitamin D inadequacy were evident in two studies using a lower 25(OH)D level cut-off value of < 12 ng/mL (30 nmol/L) - 21% in China and 57% in South Korea. Dietary deficiency and inadequate exposure or reactivity to sunlight (due to lifestyle choices, cultural customs and/or aging) were identified as important risk factors for vitamin D inadequacy.

CONCLUSIONS

Non-uniform, epidemiological studies indicate a high prevalence of vitamin D inadequacy in postmenopausal women in Eastern Asia. Recommended remedial approaches are education campaigns and broad-based provision of vitamin D supplementation.

A seasonal variation of calcitropic hormones, bone turnover and bone mineral density in early and mid-puberty girls – a cross-sectional study

The importance of the seasonal variation of calcitropic hormones to growing skeleton has not been established. We studied whether there exists a seasonal variation in calcitropic hormones, bone mineral density (BMD) and bone remodelling markers in early puberty girls. One hundred and ninety-six girls, mean age 11.4 (sd 0.4) years, in Tanner stage 2 (early puberty) and 3 (mid-puberty) were studied during September to March. The BMD was measured from the lumbar vertebrae and the left femur by dual-energy X-ray absoptiometry. Their serum 25-hydroxyvitamin D (S-25-OHD), serum intact parathyroid hormone (S-iPTH), serum osteocalcin, urinary pyridinoline and urinary deoxypyridinoline were analysed from fasting samples. The concentration of S-25-OHD and serum osteocalcin differed among months (P < 0.01), reflecting a seasonal variation. The parathyroid hormone correlated negatively with S-25-OHD (r -0.325, P < 0.001). Moreover, the BMD in the femur (P = 0.047) and to a lesser extent in vertebrae (P = 0.057) differed between months in early puberty girls but this was not seen in mid-puberty. Seasonal variation in S-25-OHD and bone remodelling markers accompanied by negative correlation between S-25-OHD and S-iPTH was seen in this cross-sectional study of adolescent girls. In addition, the seasonal rhythm contributed 7.0-7.6 % difference in the BMD of lumbar vertebrae and left femur in early puberty girls. This variation should be avoided since it could hamper peak bone mass attainment.

Supplementation with oral vitamin D3 and calcium during winter prevents seasonal bone loss: a randomized controlled open-label prospective trial

Bone metabolism follows a seasonal pattern with high bone turnover and bone loss during the winter. In a randomized, open-label 2-year sequential follow-up study of 55 healthy adults, we found that supplementation with oral vitamin D3 and calcium during winter abolished seasonal changes in calciotropic hormones and markers of bone turnover and led to an increase in BMD. Supplementation with oral vitamin D3 and calcium during the winter months seems to counteract the effects of seasonal changes in vitamin D and thus may be beneficial as a primary prevention strategy for age-related bone loss.

INTRODUCTION

Bone metabolism follows a seasonal pattern characterized by high bone turnover and bone loss during winter. We investigated whether wintertime supplementation with oral vitamin D3 and calcium had beneficial effects on the circannual changes in bone turnover and bone mass.

MATERIALS AND METHODS

This prospective study comprised an initial observation period of 12 months ("year 1"), followed by an intervention during parts of year 2. Fifty-five healthy subjects living in southwestern Germany (latitude, 49.5 degrees N) were randomized into two groups: 30 subjects were assigned to the treatment group and received oral cholecalciferol (500 IU/day) and calcium (500 mg/day) during the winter months of year 2 (October-April), while 25 subjects assigned to the control group obtained no supplements. Primary endpoints were changes in calciotropic hormones [serum 25(OH)D, 1,25(OH)2D, and parathyroid hormone], markers of bone formation (serum bone-specific alkaline phosphatase) and of bone resorption (urinary pyridinoline and deoxypyridinoline), and changes in lumbar spine and femoral neck BMD.

RESULTS

Forty-three subjects completed the study. During year 1, calciotropic hormones, markers of bone turnover, and BMD varied by season in both groups. During the winter months of year 1, bone turnover was significantly accelerated, and lumbar spine and femoral BMD declined by 0.3-0.9%. In year 2, seasonal changes in calciotropic hormones and markers of bone turnover were either reversed or abolished in the intervention group while unchanged in the control cohort. In the subjects receiving oral vitamin D3 and calcium, lumbar and femoral BMD increased significantly (lumbar spine: +0.8%, p = 0.04 versus year 1; femoral neck: +0.1%, p = 0.05 versus year 1), whereas controls continued to lose bone (intervention group versus control group: lumbar spine, p = 0.03; femoral neck, p = 0.05).

CONCLUSIONS

Supplementation with oral vitamin D3 and calcium during winter prevents seasonal changes in bone turnover and bone loss in healthy adults. It seems conceivable that annually recurring cycles of low vitamin D and mild secondary hyperparathyroidism during the winter months contributes, at least in part and over many years, to age-related bone loss. Supplementation with low-dose oral vitamin D3 and calcium during winter may be an efficient and inexpensive strategy for the primary prevention of bone loss in northern latitudes.

Associations with Vitamin D deficiency in "at risk" Australians

In a study of 185 elderly living in assisted care and 192 frail aged living in the community in the Sydney metropolitan area, nursing home residents were found to be at a 3-fold and hostel dwellers at a 2-fold risk of Vitamin D [25(OH)D] deficiency (<25 nmol/L) compared to self care residents. Middle Eastern people were found to be at 4-fold risk and Vietnamese a 3-fold risk of deficiency compared to their Australian counterparts. In recently arrived Chinese immigrants, Vitamin D deficiency, was found in 28%, and marginal levels (<37 nmol/L) in 60%, compared to the 34 and 76% found in our nursing home population, and 25 and 57% in hostel care residents. Of the Middle Eastern elderly, 58% were deficient and 83% marginal; although only 18% of Vietnamese were deficient, 68% had marginal Vitamin D status. Other factors associated with Vitamin D deficiency were mobility and sun exposure in assisted care, and low dietary Vitamin D and calcium intake, reduced exercise levels and high % body fat levels in the immigrant groups.

Influência da sazonalidade na determinação da densidade mineral óssea

OBJETIVO: Em locais onde a exposição aos raios do sol durante o inverno é limitada, a densidade mineral óssea (DMO) pode apresentar variações sazonais, elevando-se durante o período do verão e diminuindo durante o inverno. Tem sido sugerido que esta variação pode influenciar a avaliação prospectiva de estudos de DMO. O objetivo deste estudo foi avaliar se a estação do ano está associada a variações nos valores de DMO. MÉTODOS: Estudo transversal, de base clínica, desenvolvido no estado do Rio Grande do Sul (RS). Estudos densitométricos representativos dos períodos do verão/inverno foram selecionados para análise. As densitometrias foram realizadas em aparelho Hologic 4500 através da técnica dual energy X-ray absorptiometry. RESULTADOS/CONCLUSÕES: De 853 exames densitométricos realizados durante um período de 12 meses, 201 foram realizados no verão e 321 no inverno. Os valores de DMO, corrigidos para o peso corporal, não diferiram significamente entre o grupo de indivíduos que realizou o exame no verão ou no inverno (P>0,05). Em conclusão, no RS a estação do ano não afeta os resultados da DMO e não precisa ser levada em conta quando da interpretação dos estudos densitométricos. Este achado, provavelmente, pode ser extrapolado para as demais regiões do Brasil, uma vez que o inverno nestas regiões é menos severo que no RS.

Seasonal variation in bone density in postmenopausal women

We investigated seasonal variation in bone density by cross-sectional designs in two large cohorts of women (N = 2337) in Sweden. One cohort was strictly population-based (all 75 yr old, N = 1044), and one cohort was patient-based (age > or = 55 yr, mean age 68, N = 1293). Each woman was assessed once and the inclusion was continuous throughout almost all days of the year. Bone mineral density (BMD) of the total body, hip, and lumbar spine was determined by means of dual X-ray absorptiometry (DXA). For both cohorts, the BMD was similar in those assessed during the period April-September compared to those assessed during the period October-March. On the other hand, when women who had been assessed during July-December were compared with women assessed during January-June, we found the BMD to be up to 5% lower during July-December in all skeletal regions in the population-based sample, and 4% lower at the Ward's triangle and trochanter in the patient-based sample. After correction for small differences in age and weight, women of both cohorts who had been assessed during July-December still had lower BMD at the hip compared with women assessed during January-June. In conclusion, we found no variation in bone density during the period April-September compared to the period October-March in these two cohorts of postmenopausal women. In elderly women living at a northern latitude, BMD may be a few percent lower during the period July-December compared to the period January-June.

Older people in China and the United Kingdom differ in the relationships among parathyroid hormone, vitamin D, and bone mineral status

To explore whether there are ethnic differences in relationships among parathyroid hormone (PTH), vitamin D, and bone mineral status, 352 healthy volunteers, 60-83 years old, were studied in Shenyang, Peoples' Republic of China (108 men, 110 women), and in Cambridge, UK (67 men, 67 women), in late winter. Early morning fasting blood and 2-h fasting urine were analyzed for 25-hydroxyvitamin D (25OH-D), PTH, and free deoxypyridinoline (DPD). Hip bone mineral status was measured using dual-energy X-ray absorptiometry (Lunar). There were significant differences (P < 0.001) in plasma 25OH-D and PTH concentrations between Shenyang and Cambridge [25OH-D nmol/L: Shenyang = 29.0 (SD 12.7), Cambridge = 35.7 (12.9)]; PTH ng/L: Shenyang = 34.3 (13.4), Cambridge = 25.2 (11.0)]. PTH was negatively related to 25OH-D in both populations. The relationship was exponential, best described by an inverse log-log equation with no break point (P < 0.001), indicating that the exponential curve did not tend toward a low plateau. PTH was higher for a given 25OH-D and decreased less with increasing 25OH-D in Shenyang than in Cambridge (country-ln25OH-D interaction, P = 0.0005). After adjusting for bone area, weight, height, age, and sex, hip bone mineral content (BMC) was significantly related to PTH concentration in Cambridge but not in Shenyang [femoral neck coefficient: Cambridge = -0.064 (SE 0.027), P = 0.02; Shenyang = -0.027 (0.028), P = 0.3; trochanter: Cambridge = -0.116 (0.034), P = 0.001; Shenyang = -0.019 (0.027), P = 0.5]. There was a significant country-lnPTH interaction at the trochanter (P = 0.02), but not at the femoral neck (P = 0.7). A weak positive association between BMC at the femoral neck and 25OH-D concentration was found in Cambridge [coefficient: 0.054 (0.028), P = 0.05] but not in Shenyang (coefficient: -0.013, P = 0.5; country-ln25OH-D interaction, P = 0.07). Urinary DPD concentration was also positively related to plasma PTH concentration in Cambridge subjects only [coefficient: 0.2 (0.08), P = 0.02]. These data suggest that although PTH increases when 25OH-D decreases, and Chinese people have a higher PTH for a given 25OH-D, older Chinese adults may be more resistant than Britons to the effects of PTH on bone.

Absence of marked seasonal change in bone turnover: a longitudinal and multicenter cross-sectional study

The effect of season on bone turnover is controversial. No information is available on seasonality of new serum markers of bone resorption. In this study, we have been unable to confirm findings of a marked wintertime increase in bone formation and resorption within the general population. Seasonality was assessed by cosinor analysis.

INTRODUCTION

We investigated the effect of season on seven markers of bone turnover in a longitudinal study (six men and six premenopausal women; age, 24-44 years) and a separate large population-based multicenter European study (n = 2780 women, Osteoporosis and Ultrasound Study [OPUS]).

MATERIALS AND METHODS

Measurements included serum Crosslaps, procollagen type I N-terminal propeptide (PINP), osteocalcin (OC), and the N-telopeptide fragment of type I collagen in urine (NTX). Seasonality was assessed by cosinor analysis with Hotelling's T2 test.

RESULTS

Serum 25(OH) vitamin D showed a marked seasonal rhythm. There was no significant seasonal component for any marker of bone turnover in the longitudinal analysis (cosinor analysis, p > 0.05). The percentage of within subject variance accounted for by any seasonal trend was very small for all markers (less than 2.5%). Less than 1% of the between-person variance was accounted for by seasonality in the cross-sectional analysis for all markers (n = 2780). There was a small but statistically significant summertime increase in OC and PINP in the healthy postmenopausal population after exclusions based on disease or medication use (remaining n = 1226, amplitudes 5.6% and 5.4%, respectively, p < 0.001).

CONCLUSIONS

We have been unable to confirm findings of a marked wintertime increase in bone formation and resorption within the general population. The absence of marked seasonality was irrespective of age, menopausal status, reported supplemental Vitamin D intake, age or geographical location. The small but statistically significant summertime increase in bone formation in this and other studies is unlikely to confound clinical interpretation of these measurements.

Determination of serum 25-hydroxyvitamin D(3) levels in early postmenopausal Iranian women: relationship with bone mineral density

Serum levels of 25-hydroxyvitamin D(3) (25-OHD(3)) and bone mineral density (BMD) were determined in 73 selected, early postmenopausal women referred to the Bone Densitometry Center, Loghman-Hakim Hospital, Tehran, Iran. The relationship between them was also assessed. 25-OHD(3) levels were measured using high-performance liquid chromatography. BMD was measured with dual-energy X-ray absorptiometry of the lumbar spine and proximal femur regions. 25-OHD(3) levels ranged from 3.8 to 64.0 ng/mL (mean +/- SD: 17.1 +/- 11.3). Twenty-six subjects (36%) were vitamin D-deficient (<12 ng/mL). In the lumbar spine (L2-4) BMD measurements, 28 subjects (38%) were normal (T score > -1), 26 (36%) were osteopenic (T < or = -1 to >-2.5), and 19 (26%) were osteoporotic (T < -2.5). In the hip (total) BMD measurements, 41 subjects (56.1%) were normal, 31 (42.5%) were osteopenic, and 1 (1.4%) was osteoporotic. There was a significant correlation between spine BMD (Z score) and 25-OHD(3) (r = 0.23, p < 0.05), but the correlation was not significant for hip BMD. It was concluded that vitamin D deficiency was evident in early postmenopausal Iranian women, and serum 25-OHD(3) was weakly correlated with spine BMD, which may have physiological significance.

Relationships between bone mineral density, serum vitamin D metabolites and calcium:phosphorus intake in healthy perimenopausal women

OBJECTIVES

To determine the relationships between serum vitamin D metabolites, bone mass, and dietary calcium and phosphorus in a cohort of 510 healthy Danish perimenopausal women.

DESIGN

A population-based cross-sectional study.

SUBJECTS

A total of 510 healthy women aged 45-58 years, with amenorrhoea for 3-24 months. None of the women was using hormone replacement therapy.

MEASUREMENTS

Measurements of total bone mineral content and regional bone mineral density were performed by dual-energy X-ray absorptiometry. Analyses of serum levels of 25-OHD and 1,25-(OH)2D, intact PTH, ionized calcium and phosphate, as well as biochemical markers of bone turnover in blood and urine. Assessment of calcium and phosphorus intake using dietary records.

RESULTS

A consistent inverse relationship between serum 1,25-(OH)2D and bone mineral content/ density was found in whole-body mineral content (P = 0.001), spine (P = 0.005) and femoral neck (P<0.05). There was a positive relationship between levels of 1,25-(OH)2D and biochemical bone markers, indicating that high levels of 1,25-(OH)2D are accompanied by increased bone turnover. The dietary calcium:phosphorus ratio was inversely related to serum 1,25-(OH)2D (P = 0.04) and positively related to bone mineral density (P<0.0005). No relationships could be detected between levels of PTH, serum ionized calcium and phosphate, and serum vitamin D metabolites.

CONCLUSION

Within normal physiological range, elevated levels of 1,25-(OH)2D were associated with decreased bone mineral density and content, reduced calcium:phosphorus ratio in the diet and increased bone turnover.