Vitamin D and bone mineral density

Vitamin D status and its associations with bone mineral density, bone turnover markers, and parathyroid hormone in Chinese postmenopausal women with osteopenia and osteoporosis

Background

Vitamin D is a key factor in bone metabolism, yet vitamin D insufficiency and deficiency are prevalent among postmenopausal women, with potential repercussions on bone mineral density (BMD), bone turnover markers (BTMs), and parathyroid hormone (PTH). Nonetheless, the findings from existing studies exhibit inconsistency, and a notable gap exists in the availability of large-scale investigations.

Methods

In this real-world study, 8,532 postmenopausal women over 50 years old with a diagnosis of osteopenia (50.9%) and osteoporosis (49.1%) at the first visit were enrolled in this study. Serum 25(OH)D level, PTH, osteocalcin (OC) and Beta-CrossLaps of type 1 collagen containing cross-linked C-telopeptide (β-CTX), were measured. BMD at all sites, including the lumbar spine, femoral neck, and total hip were obtained by dual-energy X-ray absorptiometry (DXA). The associations of serum 25(OH)D level with BMDs and BTMs were investigated using spearman correlation analysis and analysis of general linear model adjusted by age and body mass index.

Results

The serum 25(OH)D level was 22.17 ± 9.75 ng/mL among all patients included in this study. For the osteopenia group, the serum 25(OH)D level was 22.40 ± 9.41 ng/mL, while for the osteoporosis group, it measured 21.93 ± 10.08 ng/mL. In the osteopenia group, the prevalence of vitamin D deficiency, insufficiency and sufficiency was 45.8, 34.6, and 19.6%, respectively, which was close to that of the osteoporosis group (47.4, 34.3, and 18.3%) (p = 0.202). Spearman correlation analysis unveiled negative associations between serum 25(OH)D concentrations and both BTMs and PTH within both the osteopenia and osteoporosis group. In the osteoporosis group, there were positive correlations between 25(OH)D levels and femoral neck BMD (r = 0.040, p = 0.010) and total hip BMD (r = 0.053, p = 0.001). Furthermore, we found that for the osteopenia group, greater vitamin D levels were associated with greater femoral neck BMD (p = 0.020) and total hip BMD (p = 0.008) and lower β-CTX (p < 0.001), OC (p < 0.001), and PTH (p < 0.001). The same trends were seen in osteoporosis patients (p < 0.05), and with greater lumbar spine BMD with higher levels of 25(OH)D (p = 0.009).

Conclusion

This study showed high prevalence of vitamin D deficiency and insufficiency in Chinese postmenopausal women with osteopenia and osteoporosis and the relationships between vitamin D and BMD, BTMs and PTH. The results contribute to a more comprehensive understanding of how vitamin D may impact bone health.

Vitamin D and Calcium in Osteoporosis, and the Role of Bone Turnover Markers: A Narrative Review of Recent Data from RCTs

Osteoporosis is a common disease, defined primarily by a low measured bone density, which is associated with an increased risk of fragility fractures. Low calcium intake and vitamin D deficiency seem to be positively correlated with the prevalence of osteoporosis. Although they are not suitable for the diagnosis of osteoporosis, the biochemical markers of bone turnover can be measured in serum and/or urine, enabling the assessment of the dynamic bone activity and the short-term effectiveness of the osteoporosis treatment. Calcium and vitamin D are essential for maintaining bone health. The aim of this narrative review is to summarize the effects of vitamin D and calcium supplementation separately and in combination, on bone density and circulating serum and blood plasma vitamin D, calcium, parathyroid hormone levels, markers of bone metabolism concentrations, and clinical outcomes, such as falls and osteoporotic fractures. We searched the PubMed online database to find clinical trials from the last five years (2016-April 2022). A total of 26 randomized clinical trials (RCTs) were included in this review. The present reviewed evidence suggests that vitamin D alone or in combination with calcium increases circulating 25(OH)D. Calcium with concomitant vitamin D supplementation, but not vitamin D alone, leads to an increase in BMD. In addition, most studies did not detect significant changes in circulating levels of plasma bone metabolism markers, nor in the incidence of falls. Instead, there was a decrease in blood serum PTH levels in the groups receiving vitamin D and/or Ca supplementation. The plasma vitamin D levels at the beginning of the intervention, and the dosing regimen followed, may play a role in the observed parameters. However, further study is needed to determine an appropriate dosing regimen for the treatment of osteoporosis and the role of bone metabolism markers.

Association of Vitamin D and Parathyroid Hormone Status With the Aging-Related Decline of Bone Microarchitecture in Older Men: The Prospective Structure of Aging Men's Bones (STRAMBO) Study

Poor vitamin D status and high parathyroid hormone (PTH) level are associated with impaired bone microarchitecture, but these data are mainly cross-sectional. We studied the association of the baseline PTH and 25-hydroxycholecalciferol (25OHD) levels with the prospectively assessed deterioration of bone microarchitecture and in estimated bone strength in older men. Distal radius and tibia bone microarchitecture was assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline, then after 4 and 8 years in 826 men aged 60-87 years. At distal radius, total bone mineral density (Tt.BMD), cortical thickness (Ct.Th^d ), cortical area (Ct.Ar), cortical BMD (Ct.BMD), and trabecular BMD (Tb.BMD) decreased, whereas trabecular area (Tb.Ar) increased more rapidly in men with 25OHD ≤20 ng/mL versus the reference group (>30 ng/mL). Men with 25OHD ≤10 ng/mL had faster decrease in reaction force and failure load than men with 25OHD >30 ng/mL. At the distal tibia, Tt.BMD, Ct.Th^d , Ct.Ar, Ct.BMD, failure load, and reaction force decreased, whereas Tb.Ar increased more rapidly in men with 25OHD between 10 and 20 ng/mL versus the reference group. The results were similar when 12 ng/mL was used as a threshold of severe vitamin D deficiency. At distal radius, men with PTH levels above the median (>44 pg/mL) had more rapid decrease in Tt.BMD, Ct.Ar, Ct.BMD, Ct.Th^d , reaction force, and failure load, and more rapid increase in Tb.Ar versus the lowest quartile (≤34 pg/mL). At the distal tibia, men in the highest PTH quartile had faster decrease in Tt.BMD, Ct.Th^d , Ct.Ar, Ct.BMD, reaction force, and failure load and faster increase in Tb.Ar versus the lowest quartile. The results were similar in men with glomerular filtration rate >60 mL/min. The results were similar in men who took no vitamin D or calcium supplements for 8 years. In summary, vitamin D deficiency and secondary hyperparathyroidism are associated with more rapid prospectively assessed cortical and trabecular bone decline in older men. © 2022 American Society for Bone and Mineral Research (ASBMR).

Associations between serum calcium, 25(OH)D level and bone mineral density in adolescents

BACKGROUNDS

It is important to improve our understanding of the roles of calcium and vitamin D in bone health for preventing osteoporosis. We aimed at exploring the associations between serum calcium, vitamin D level, and bone mineral density (BMD) in adolescents included in the National Health and Nutrition Examination Survey (NHANES) 2001-2006.

METHODS

Weighted multivariate linear regression models were used to estimate the associations of serum calcium, 25(OH)D level with total BMD. Smooth curve fitting was used to explore the potential non-linear relationship.

RESULTS

A total of 5990 individuals aged between 12 and 19 years were included in this study. The fully-adjusted model showed serum calcium positively correlated with total BMD. However, an inverted U-shaped relationship was found when we performed the smooth curve fitting method, and the inflection point was calculated at 9.6 mg/dL using the two-piecewise linear regression model. In contrast, there was a positive correlation between serum 25(OH)D and total BMD after adjusting for potential confounders.

CONCLUSIONS

The present study revealed a positive correlation between serum 25(OH)D level and total BMD, and an inverted U-shaped relationship between serum calcium and total BMD.

The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials

BACKGROUND

Previous studies did not draw a consistent conclusion about the effects of vitamin K combined with vitamin D on human skeletal quality.

METHOD AND FINDINGS

A comprehensive search on Web of Science, PubMed, Embase and the Cochrane Library (from 1950 to February 2020) and bibliographies of relevant articles was undertaken, with the meta-analysis of eight randomized controlled trials (RCTs) including a total of 971 subjects. Vitamin K combined with vitamin D significantly increased the total bone mineral density (BMD): the pooled effect size was 0.316 [95% CI (confidence interval), 0.031 to 0.601]. A significant decrease in undercarboxylated osteocalcin (-0.945, -1.113 to -0.778) can be observed with the combination of vitamin K and D. Simultaneously, subgroup analysis showed that K2 or vitamin K (not specified) supplement was less than 500 μg d-1, which when combined with vitamin D can significantly increase the total BMD compared with the control group fed a normal diet or the group with no treatment (0.479, 0.101 to 0.858 and 0.570, 0.196 to 0.945).

CONCLUSIONS

The combination of vitamin K and D can significantly increase the total BMD and significantly decrease undercarboxylated osteocalcin, and a more favorable effect is expected when vitamin K2 is used.

Effects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The aim of the present study was to explore whether combined calcium and vitamin D supplementation is beneficial for osteoporosis in postmenopausal women.

METHODS

We searched the PubMed, Cochrane library, Web of science and Embase databases and reference lists of eligible articles up to Feb, 2020. Randomized controlled trials (RCTs) evaluating the effect of combined calcium and vitamin D on osteoporosis in postmenopausal women were included in the present study.

RESULTS

Combined calcium and vitamin D significantly increased total bone mineral density (BMD) (standard mean differences (SMD) = 0.537; 95% confidence interval (CI): 0.227 to 0.847), lumbar spine BMD (SMD = 0.233; 95% CI: 0.073 to 0.392; P < 0.001), arms BMD (SMD = 0.464; 95% CI: 0.186 to 0.741) and femoral neck BMD (SMD = 0.187; 95% CI: 0.010 to 0.364). It also significantly reduced the incidence of hip fracture (RR = 0.864; 95% CI: 0.763 to 0.979). Subgroup analysis showed that combined calcium and vitamin D significantly increased femoral neck BMD only when the dose of the vitamin D intake was no more than 400 IU d^-1 (SMD = 0.335; 95% CI: 0.113 to 0.558), but not for a dose more than 400 IU d^-1 (SMD = -0.098; 95% CI: -0.109 to 0.305), and calcium had no effect on the femoral neck BMD. Subgroup analysis also showed only dairy products fortified with calcium and vitamin D had a significant influence on total BMD (SMD = 0.784; 95% CI: 0.322 to 1.247) and lumbar spine BMD (SMD = 0.320; 95% CI: 0.146 to 0.494), but not for combined calcium and vitamin D supplement.

CONCLUSION

Dairy products fortified with calcium and vitamin D have a favorable effect on bone mineral density. Combined calcium and vitamin D supplementation could prevent osteoporosis hip fracture in postmenopausal women.

Effects of PTH and PTH Hypersecretion on Bone: a Clinical Perspective

PURPOSE OF REVIEW

Hyperparathyroidism may be due to an autonomous hypersecretion of parathyroid hormone (PTH) or occurs in response to a number of physiological stimuli. A number of recent findings have provided new insights into the importance of the calcium-parathyroid-vitamin D axis to bone in normal physiology and pathological conditions.

RECENT FINDINGS

PTH is known to affect bone microarchitecture with different effects on cortical and trabecular bone compartments. In trabecular bone, PTH may exert anabolic effects, whereas PTH promotes bone resorption in cortical bone. Vertebral fractures are prevalent in primary hyperparathyroidism (PHPT), and patients seem to fracture at higher values of bone mineral density (BMD) than patients with osteoporosis. This may be explained by changes in bone microarchitecture, which cannot be detected by measuring BMD. Even in mild PHPT, bone seems to benefit from parathyroidectomy. In secondary hyperparathyroidism, bone seems much more susceptible to fracture with insufficient levels of vitamin D compared with a replete vitamin status. If elevated PTH levels cannot be explained by conditions known to cause secondary hyperparathyroidism, the condition is termed normocalcemic PHPT, which also has been associated with an increased risk of fractures. Hyperparathyroidism is harmful to bone, which is why it is of importance to normalize PTH levels either by parathyroidectomy in PHPT or by counteracting conditions known to increase PTH in secondary hyperparathyroidism.

Associations between serum calcium, 25(OH)D level and bone mineral density in older adults

Background

Calcium and vitamin D play important roles in bone health as essential nutrients. We explored whether serum calcium, 25(OH)D were associated with bone mineral density (BMD) in older adults.

Methods

This cross-sectional study was conducted on a sample of 4595 participants (2281 men and 2314 women) aged ≥ 50 years (from 50 to 85 years, 60.1 ± 8.7 years for men and 62.0 ± 9.7 years for women) from the National Health and Nutrition Examination Survey (NHANES) 2001–2006. The independent variables were serum calcium and 25(OH)D. The dependent variable was lumbar BMD. The other variables were considered potential effect modifiers. We performed weighted multivariate linear regression models and smooth curve fittings to evaluate the associations between them. Subgroup analyses were also performed.

Results

We observed a negative association between serum calcium and lumbar BMD in the fully adjusted model. In the subgroup analyses, this association was no longer significant among males and other race/ethnicity. On the other hand, there was a positive association between serum 25(OH)D and lumbar BMD in the fully adjusted model. In the subgroup analyses, this association did not differ in different age groups, between men and women. However, the association between serum 25(OH)D and lumbar BMD followed a U-shaped curve in Mexican Americans.

Conclusions

This cross-sectional study indicated that serum calcium negatively correlated with lumbar BMD, and serum 25(OH)D positively correlated with lumbar BMD in older adults. However, the association between serum calcium and lumbar BMD in males followed a U-shaped curve.

Biomarkers of Osteoporosis: An Update

Background:

Osteoporosis, characterized by compromised bone quality and strength is associated with bone fragility and fracture risk. Biomarkers are crucial for the diagnosis or prognosis of a disease as well as elucidating the mechanism of drug action and improve decision making.

Objective:

An exhaustive description of traditional markers including bone mineral density, vitamin D, alkaline phosphatase, along with potential markers such as microarchitectural determination, trabecular bone score, osteocalcin, etc. is provided in the current piece of work. This review provides insight into novel pathways such as the Wnt signaling pathway, neuro-osseous control, adipogenic hormonal imbalance, gut-bone axis, genetic markers and the role of inflammation that has been recently implicated in osteoporosis.

Methods:

We extensively reviewed articles from the following databases: PubMed, Medline and Science direct. The primary search was conducted using a combination of the following keywords: osteoporosis, bone, biomarkers, bone turnover markers, diagnosis, density, architecture, genetics, inflammation.

Conclusion:

Early diagnosis and intervention delay the development of disease and improve treatment outcome. Therefore, probing for novel biomarkers that are able to recognize people at high risk for developing osteoporosis is an effective way to improve the quality of life of patients and to understand the pathomechanism of the disease in a better way.

Vitamin D and the Athlete: Current Perspectives and New Challenges

The last decade has seen a dramatic increase in general interest in and research into vitamin D, with many athletes now taking vitamin D supplements as part of their everyday dietary regimen. The most recognized role of vitamin D is its regulation of calcium homeostasis; there is a strong relationship between vitamin D and bone health in non-athletic individuals. In contrast, data have consistently failed to demonstrate any relationship between serum 25[OH]D and bone health, which may in part be due to the osteogenic stimulus of exercise. Vitamin D may interact with extra-skeletal tissues such as muscle and the immune system to modulate recovery from damaging exercise and infection risk. Given that many athletes now engage in supplementation, often consuming extreme doses of vitamin D, it is important to assess whether excessive vitamin D can be detrimental to health. It has been argued that toxic effects only occur when serum 25[OH]D concentrations are greater than 180 nmol·l^-1, but data from our laboratory have suggested high-dose supplementation could be problematic. Finally, there is a paradoxical relationship between serum 25[OH]D concentration, ethnicity, and markers of bone health: Black athletes often present with low serum 25[OH]D without physiological consequences. One explanation for this could be genetic differences in vitamin D binding protein due to ethnicity, resulting in greater concentrations of bioavailable (or free) vitamin D in some ethnic groups. In the absence of any pathology, screening may be unnecessary and could result in incorrect supplementation. Data must now be re-examined, taking into consideration bioavailable or "free" vitamin D in ethnically diverse groups to enable new thresholds and target concentrations to be established; perhaps, for now, it is time to "set vitamin D free".

Women have enhanced bone loss associated with phosphaturia and CD4+ cell restoration during initial antiretroviral therapy

OBJECTIVE

We compared bone mineral density (BMD) changes and their correlates, between men and women participating in two randomized trials of initial [antiretroviral therapy (ART)] regimens, with or without tenofovir disoproxil fumarate (TDF).

METHODS

Covariates in linear regression models of 48-week hip and spine %BMD changes, by dual energy X-ray absorptiometry, included baseline and 48-week changes in plasma viral load, CD4 cells, plasma C-terminal telopeptide, procollagen 1 N-terminal propeptide and glomerular filtration rates, and the 48-week area under the curve of fractional excretion of phosphate.

RESULTS

Despite overall hip and spine BMD declines of 2.8 and 2.9%, respectively, plasma viral load suppression to less than 50 vs. at least 50 copies/ml was associated 1.0% (P = 0.02) and 0.8% (P = 0.01) less BMD decline. Women had lower baseline spine (P = 0.04; n = 59 women, 418 men) and hip BMD (P = 0.01) in adjusted models, with 1.7% more hip decline on ART than men (P = 0.001). Serum phosphate was positively associated with baseline spine BMD in women (P = 0.03) but not men, and area under the curve of fractional excretion of phosphate was negatively associated with spine BMD changes, particularly in women randomized to TDF regimens (P = 0.03 and 0.054 for interactions by sex, and randomization to TDF vs. non-TDF regimens, respectively; n = 44 women, 326 men). Women also had 0.6% (P = 0.004) more hip BMD decline than men associated with each 100 CD4 cells/μl increase on ART (P = 0.02; n = 49 women, 379 men).

CONCLUSION

Women randomized to TDF-containing ART had accentuated spine loss associated with phosphaturia, and accentuated hip loss associated with CD4 restoration, regardless of TDF exposure. Viral load suppression reduced bone loss.

Vitamin D status and parathyroid hormone levels in relation to bone mineral density in apparently healthy Syrian adults

Vitamin D deficiency was highly prevalent in this study. More than half of the participants with vitamin D level less than 5 ng/mL had secondary hyperparathyroidism, which implicated a major bone health concern. After adjustment for potential predictors, parathyroid hormone (PTH) explained about 3 % of the variance in total hip bone mineral density (BMD).

PURPOSE

Bone mineral density (BMD) is known to be influenced by serum 25-hydroxyvitamin D (25OHD) and intact parathyroid hormone (PTH) levels. The relationship between 25OHD and PTH with BMD has not been well documented in Syrian adults. We aimed to determine how differences in serum 25OHD and PTH levels impacted hip and lumbar spine BMD among apparently healthy Syrian adults.

METHODS

25OHD and PTH were measured in 156 participants aged 18-53 years from Damascus and its surroundings. Lumbar spine and hip BMD measurements were measured by dual-energy X-ray absorptiometry using Hologic Discovery Wi densitometer. Multivariate regression models were used to investigate the relationships between 25OHD, PTH, and BMD.

RESULTS

All participants, except one male, had 25OHD <30 ng/mL (<75 nmol/L), and 89.1 % of them had 25OHD levels less than 20 ng/mL (50 nmol/L). Secondary hyperparathyroidism was significantly more prevalent in the lowest 25OHD quartile compared to that in the highest quartile (59 vs. 10.3 %, p < 0.0001). Mean bone mineral density at all sites in our participants was lower when compared to that of their Caucasian counterparts in Europe and North America. No significant correlation was found between 25OHD and BMD either at hip or at lumbar spine. In the multivariate analyses, after adjustment for potential predictors, PTH explained about 3 % of the variation in total hip BMD.

CONCLUSIONS

Low BMD was relatively frequent at all measured sites. PTH, but not 25OHD, was a predictor for total hip BMD in a young population.

Low vitamin D, and bone mineral density with depressive symptoms burden in menopausal and postmenopausal women

BACKGROUND

The reported association between vitamin D level and loss of Bone mineral densitometry measurements (BMD) has been controversial.

OBJECTIVE

The objectıve of the current study was to determine whether low vitamin D level and BMD are associated with depresive symptoms as burden in Arab women during the menopausal and postmenopausal period.

DESIGN AND SETTING

A cross-sectional descriptive study design was used at the Primary Health Care (PHC) Centers in Qatar.

SUBJECTS

A multi-stage sampling design was used and a representative sample of 1436 women aged 45-65 years were included during July 2012 and November 2013 and 1106 women agreed to participate (77.2%) and responded to the study.

MATERIALS AND METHODS

BMD (g/m(2)) was assessed at the BMD unit using a Lunar Prodigy DXA system (Lunar Corp., Madison, WI). The antero-posterior lumbar spine (L2-L4) and the mean of the proximal right and left femur were be measured by two technician and then reviewed by one radiologist. Data on body mass index (BMI), clinical biochemistry variables including serum 25-hydroxyvitamin D were collected. The Beck Depression Inventory (BDI) was administered for depression purposes.

RESULTS

Of the 1436 women living in urban and rural areas, 1106 women agreed to participate (77.0%) and responded to the study. The mean age and standard deviation of the subjects was 53.8 ± 3.2. The median age of natural menopausal in the present study was 49 years (mean and standard deviation 49.5 ± 3.1 and postmenopausal was 58.1 ± 3.3). There were statistically significant differences between menopausal stages with regards to ethnicity, education level, systolic and dialostic blood pressure, parity, sheesha smoking and depressive symptoms. Overall 30.4% of women were affected with osteopenia/osteoporosis in premenopausal and postmenopausal (24.4% vs 35.7%; P = 0.0442). Osteopenia in premenopausal and postmenopausal (18.7% vs 29.3%; P = 0.030) and Osteoporosis (9.9% vs 15.9%; P = 0.049) were significantly higher in post-menopausal women than in premenopausal women (P = 0.046). Similarly, vitamin D deficiency was more prevalent among postmenopausal women than menopausal women. Overall, only 15.1% of women had optimum vitamin D level and 15.5% had severe, 33.2% had moderate vitamin D insufficiency and 36.3% had mild vitamin D insufficiency in menopausal and post menopausal women (P = 0.021). The study revealed that vitamin D level, hemoglobin level, serum iron fasting plasma glucose, calcium, triglycerides, high density lipid (HDL) cholesterol, low density lipid (LDL) Cholesterol, alkaline phosphate and magnesium were considerably lower in postmenopausal compared to menopausal women (P < 0.001).

CONCLUSION

The current study revealed that there was a strong association between vitamin D level and BMD in Arab women during the menopausal and post-menopausal period.

Vitamin D, carotid intima-media thickness and bone structure in patients with type 2 diabetes

Despite aggressive treatment of cardiovascular disease (CVD) risk factors individuals with type 2 diabetes (T2D) still have increased risk of cardiovascular morbidity and mortality. The primary aim of this study was to examine the cross-sectional association between total (25-hydroxy vitamin D (25(OH)D)) and risk of CVD in patients with T2D. Secondary objective was to examine the association between 25(OH)D and bone health. A Danish cohort of patients with T2D participating in a randomised clinical trial were analysed. In total 415 patients (68% men, age 60±9 years (mean±s.d.), duration of diabetes 12±6 years), including 294 patients (71%) treated with insulin. Carotid intima-media thickness (IMT) and arterial stiffness (carotid artery distensibility coefficient (DC) and Young's elastic modulus (YEM)) were measured by ultrasound scan as indicators of CVD. Bone health was assessed by bone mineral density and trabecular bone score measured by dual energy X-ray absorptiometry. In this cohort, 214 patients (52%) were vitamin D deficient (25(OH)D <50 nmol/l). Carotid IMT was 0.793±0.137 mm, DC was 0.0030±0.001 mmHg, YEM was 2354±1038 mmHg and 13 (3%) of the patients were diagnosed with osteoporosis. A 25(OH)D level was not associated with carotid IMT or arterial stiffness (P>0.3) or bone health (P>0.6) after adjustment for CVD risk factors. In conclusion, 25(OH)D status was not associated with carotid IMT, arterial stiffness or bone health in this cohort of patients with T2D. To explore these associations and the association with other biomarkers further, multicentre studies with large numbers of patients are required.

Poor vitamin D status is prospectively associated with greater muscle mass loss in middle-aged and elderly Chinese individuals

BACKGROUND

Poor vitamin D status can increase age-related muscle mass loss. However, existing prospective evidence is limited and controversial.

OBJECTIVE

This study aimed to investigate the association of plasma 25-hydroxyvitamin D [25(OH)D] with muscle mass loss in middle-aged and elderly Chinese individuals over 6 years.

DESIGN

We conducted a prospective cohort study.

PARTICIPANTS/SETTING

This community-based study included 568 men and women aged 50 to 70 years at baseline.

MAIN OUTCOMES MEASURES

Baseline plasma concentrations of 25(OH)D and biomarkers of liver and kidney functions and inflammation were measured. Body composition was assessed at baseline and 6-year follow-up by dual-energy x-ray absorptiometry. Appendicular skeletal muscle mass (ASMM) and trunk lean mass were calculated and total body lean mass was defined as an overall measure of total nonfat and nonbone tissues.

STATISTICAL ANALYSES PERFORMED

Descriptive statistics and multiple linear regression were applied.

RESULTS

The 6-year loss of ASMM was 1.14 kg (5.3%) in men and 0.47 kg (3.1%) in women (all P values <0.001). Compared with the highest 25(OH)D tertile, participants in the lowest tertile had significantly more absolute loss of ASMM (-1.21 vs -1.00 kg; P for trend=0.024) after multivariate adjustments for conventional confounders, as well as protein intake. The association persisted after additional adjustment of bone mineral density and inflammatory markers (P for trend=0.017). No significant associations were detected between 25(OH)D and absolute loss of trunk lean mass or total body lean mass.

CONCLUSIONS

Lower 25(OH)D concentrations were prospectively associated with greater ASMM loss in middle-aged and elderly Chinese individuals independent of bone mineral density, inflammation, diet, and other risk factors.

Vitamin D status and its relationship with body composition, bone mineral density and fracture risk in urban central south Chinese postmenopausal women

AIMS

This study was designed to assess vitamin D (25(OH)D) status and its relationship with bone mineral density (BMD) and fracture risk, which was determined using the FRAX algorithm, among postmenopausal central south Chinese women, and to identify the risk factors for vitamin D deficiency and osteoporosis.

METHODS

This cross-sectional study involved 578 healthy postmenopausal central south Chinese women. Fat mass and BMD at lumbar spine (L1-L4), femur neck and total hip were measured with dual X-ray absorptiometry. Serum levels of 25(OH)D, parathyroid hormone and creatinine were measured. The 10-year probabilities of hip and major osteoporotic fracture were calculated by the FRAX model.

RESULTS

Approximately 72.1% women were vitamin D deficient (25(OH)D <50 nmol/l). Serum 25(OH)D levels did not correlate with body mass index (BMI), fat mass and weight. They positively correlated with all BMDs (p < 0.05) and negatively correlated with both 10-year fracture probabilities (p < 0.05). BMI ≤19 and age ≥65 years were risk factors for osteoporosis at all sites.

CONCLUSIONS

Vitamin D deficiency was prevalent among postmenopausal central south Chinese women. Serum 25(OH)D levels were correlated with all BMDs and negatively correlated with both 10-year fracture probabilities.

Serum 25-OH Vitamin D in relation to Bone Mineral Density and Bone Turnover

It is unclear which vitamin D status is optimal for bone health. In this study, we aimed to assess cutoffs of 25-hydroxyvitamin D (25OHD) derived by the literature (20, 25, or 30 ng/mL) in relation to bone turnover and bone mineral density (BMD). Serum 25OHD, PTH, osteocalcin, bone alkaline phosphatase, and C-telopeptide were measured in 274 consecutive postmenopausal women. BMD of the lumbar spine (L1-L4) and of femoral neck were also evaluated. 50 patients had normal BMD, while 124 had osteopenia and 100 had osteoporosis. 37.6%, 56.2%, and 70.8% subjects had serum 25OHD lower than 20, 25, or 30 ng/mL, respectively. No differences in bone turnover markers were found when comparing patients with low 25OHD defined according to the different cutoffs. However, a cutoff of 25 ng/mL appeared to differentiate better than a cutoff of 30 ng/mL in those subjects with reduced femoral neck BMD. The PTH plateau occurred at 25OHD levels of 26-30 ng/mL. In conclusion, vitamin D deficiency is common in Sicilian postmenopausal women and it may be associated with low BMD and increased bone turnover markers. Further studies are needed to better define the right cutoff for normal vitamin D levels in postmenopausal women.

Hormonal relationships to bone mass in elderly Spanish men as influenced by dietary calcium and vitamin D

We aim to evaluate whether calcium and vitamin D intake is associated with 25-hydroxyvitamin D (25-OH-Vitamin D₃) and parathyroid hormone (PTH) serum concentrations or is associated with either the phalangeal dual energy X-ray absorptiometry (pDXA) or the quantitative bone ultrasound (QUS) in independent elderly men. Serum PTH and 25-OH-Vitamin D₃ were measured in 195 healthy elderly men (mean age: 73.31 ± 5.10 year). Food intake was quantified using a dietetic scale. Participants with 25-OH-Vitamin D₃ levels ≥ 30 ng/mL (75 nmol/L) and a calcium intake of 800–1200 mg/day exhibited the lowest PTH levels (41.49 ± 16.72 ng/mL). The highest PTH levels (75.60 ± 14.16 ng/mL) were observed in the <30 ng/mL group 25-OH-Vitamin D₃ with a calcium intake >1200 mg/day. No significant differences in the serum PTH levels based on the serum 25-OH-Vitamin D3 levels were observed among participants with a calcium intake of 800–1200 mg/day. Serum PTH was inversely correlated with serum 25-OH-Vitamin D₃ in the entire patient sample (r = −0.288, p = 0.019). No differences in any of the three densitometry techniques were observed between any of the age groups in the 800–1200 mg/day and >1200 mg/day calcium intake groups. PTH levels correlate negatively with serum 25-OH-Vitamin D₃ levels, and neither calcium nor vitamin D intake exert a strong influence on either of the two parameters.

PTH level but not 25 (OH) vitamin D level predicts bone loss rates in the elderly

We assessed the impact of calciotropic hormones on bone loss in 195 elderly subjects. After a median follow up of 4 years, parathyroid hormone (PTH) correlated negatively with changes in bone mineral density (BMD) at all skeletal sites. After adjustment for potential predictors of bone loss in the elderly, PTH level alone explained 3% of the variance in BMD changes at the hip.

INTRODUCTION

This study assessed the impact of calciotropic hormones on bone loss rates in an elderly population-based cohort of 195 ambulatory men and women, aged 65-85 years and followed up for a median of 4 years.

METHODS

Calcium intake, serum calcium, and phosphorus were assessed at baseline. Serum creatinine was measured at follow up visit. The 25 (OH) vitamin D [25-OHD] and PTH were measured at baseline and at follow up. Bone mass at the lumbar spine, hip, forearm and total body, as well as body composition was measured at baseline and at follow up by dual energy X-ray absorptiometry.

RESULTS

Mean 25-OHD level was 14.7 ± 6.4 ng/ml and mean PTH level was 47.9 ± 30.4 pg/ml. Age correlated negatively with percent changes in BMD at all skeletal sites (p < 0.05). Changes in body mass index (BMI) and in body composition correlated positively with BMD changes at all sites, except at the forearm. There was no correlation between 25-OHD and changes in BMD except at the trochanter (r = 0.19, p < 0.008). Conversely, PTH negatively correlated with changes in BMD at all skeletal sites (r = -0.14 to -0.27, p < 0.05). This correlation persisted after adjustment for age, changes in BMI, changes in fat mass and lean mass, serum creatinine, calcium intake, and 25-OHD levels. PTH level alone explained 3% of the variance in BMD changes at all hip subregions.

CONCLUSIONS

Serum PTH, but not 25-OHD, predicted bone loss rates in the elderly. Thus, it is important to normalize PTH level when correcting hypovitaminosis D in the elderly.

Hypovitaminosis D in developing countries-prevalence, risk factors and outcomes

Hypovitaminosis D is a prevalent disorder in developing countries. Clinical manifestations of hypovitaminosis D include musculoskeletal disorders, such as nonspecific muscle pain, poor muscle strength and low BMD, as well as nonmusculoskeletal disorders, such as an increased risk of respiratory infections, diabetes mellitus and possibly cardiovascular diseases. In developing countries, the prevalence of hypovitaminosis D varies widely by and within regions; prevalence ranges between 30-90%, according to the cut-off value used within specific regions, and is independent of latitude. A high prevalence of the disorder exists in China and Mongolia, especially in children, of whom up to 50% are reported to have serum 25-hydroxyvitamin D levels <12.5 nmol/l. Despite ample sunshine throughout the year, one-third to one-half of individuals living in Sub-Saharan Africa and the Middle East have serum 25-hydroxyvitamin D levels <25 nmol/l, according to studies published in the past decade. Hypovitaminosis D is also prevalent in children and the elderly living in Latin America. Risk factors for hypovitaminosis D in developing countries are similar to those reported in Western countries and include extremes of age, female sex, winter season, dark skin pigmentation, malnutrition, lack of sun exposure, a covered clothing style and obesity. Clinical trials to assess the effect of vitamin D supplementation on classical and nonclassical clinical outcomes in developing countries are needed.

Polymorphism in vitamin D receptor is associated with bone mineral density in patients with adolescent idiopathic scoliosis

Low bone mass and osteopenia have been reported in the axial and peripheral skeleton of adolescent idiopathic scoliosis (AIS) patients. Furthermore, several recent studies have shown that gene polymorphisms are related to osteoporosis. However, no study has yet linked polymorphisms in the vitamin D receptor (VDR) gene and bone mass in AIS. Accordingly, the authors examined the association between bone mass and VDR gene polymorphisms in 198 girls diagnosed with AIS. The VDR BsmI (rs1544410), FokI (rs2228670) and Cdx2 (rs11568820) polymorphisms and bone mineral density at the lumbar spine (LSBMD) and femoral neck (FNBMD) were analyzed and compared to their levels in healthy controls. Mean LSBMD and FNBMD in AIS patients were lower than in age- and sex-matched healthy controls (P = 0.0022 and P = 0.0013, respectively). A comparison of genotype frequencies in AIS patients and controls revealed a significant difference for the BsmI polymorphism only (P = 0.0054). Furthermore, a significant association was found between the VDR BsmI polymorphism and LSBMD. In particular, LSBMD in AIS patients with the AA genotype was found to be significantly lower than in patients with the GA (P < 0.05) or GG (P < 0.01) genotypes. However, no significant association was found between LSBMD or FNBMD and the VDR FokI or Cdx2 polymorphisms. These results suggest that the VDR BsmI polymorphism is associated with LSBMD in girls with AIS.

Serum 25(OH)D3 vitamin status of elderly Finnish women is suboptimal even after summer sunshine but is not associated with bone density or turnover

OBJECTIVE

Concentrations of 50 and 75 nmol/l are proposed as serum 25-hydroxyvitamin D (25(OH)D) target for older people from the view of bone health. We evaluated vitamin D status of elderly Finnish women in light of these definitions, its relationship to bone mineral density (BMD) and turnover, and improvement by summer sunshine.

DESIGN

Population-based study.

METHODS

A total of 1604 ambulatory women aged 62-79 years were studied; 66% used vitamin D supplements. Serum 25(OH)D(3) was measured with HPLC before and after summer, and heel BMD in spring. In subgroups, serum parathyroid hormone (PTH) and type I procollagen aminoterminal propeptide (PINP) were analyzed.

RESULTS

In spring, 60.3% of the women had 25(OH)D(3) <or=50 nmol/l, and the target of 75 nmol/l was reached by 9.1%. For supplement users, the respective numbers were 52.1 and 11.9%. Serum 25(OH)D(3) did not determine BMD or bone turnover measured by serum PINP. Summer sunshine increased serum 25(OH)D(3) by 17.4% (P<0.0001), but in autumn 84% of the subjects remained under the target of 75 nmol/l. In supplement users, PTH remained stable but decreased in others during summer (P=0.025).

CONCLUSIONS

Vitamin D status of elderly Finnish women is suboptimal if 25(OH)D(3) levels of 50 or 75 nmol/l are used as a threshold. It is moderately increased by supplement intake and summer sunshine. However, 25(OH)D(3) concentrations did not influence bone density in terms of serum PINP and bone turnover rate.

Vitamin D receptor gene polymorphisms modulate the skeletal response to vitamin D supplementation in healthy girls

OBJECTIVES

Vitamin D receptor (VDR) gene plays an important role in bone mass regulation. We have previously shown a beneficial effect of vitamin D supplementation on bone mass in girls. This study investigated whether the musculo-skeletal response to Vitamin D was modulated by polymorphisms in VDR gene.

DESIGN

Randomized placebo-controlled trial.

METHODS

179 girls (10-17 years), were randomly assigned to placebo or Vitamin D3 for one year. VDR genotypes were determined in 167 girls using BsmI, TaqI and ApaI restriction enzymes. Bone mass at the spine, hip, forearm and total body, and lean mass were measured by DXA at baseline and at one year.

RESULTS

After one year, VDR gene polymorphisms using Bsm1 and TaqI restriction enzymes were associated with percent changes in bone area, BMC and BMD at multiple skeletal sites in the Vitamin D3 group but not in the placebo group. The least increments were observed in the BB and tt genotypes. No similar effect was observed with ApaI enzyme. This relationship between VDR genotypes and changes in BMD and BMC remained significant after adjustment for puberty, changes in lean mass, height and bone area.

CONCLUSION

VDR gene polymorphisms influence the skeletal response to vitamin D supplementation in healthy adolescent girls.

25-hydroxy vitamin D levels in healthy premenopausal women: association with bone turnover markers and bone mineral density

BACKGROUND

Vitamin D deficiency is very common in elderly people while there are very few reports on its incidence, determinants and metabolic consequences in young subjects.

RESULTS

In 608 young healthy premenopausal women participating in the BONTURNO study, levels of 25-hydroxyvitamin D [25(OH)D] below 20 ng/ml were found in almost a third of the women. Its levels were inversely (P<0.001) related with age and body mass index (BMI kg/m(2)) and directly with sunlight exposure during the summer time, and latitude: i.e. the higher the latitude over Italy, the higher the 25(OH)D level. In women on contraceptive pill the mean 25(OH)D level was significantly increased even when the data were adjusted for age, BMI and sun exposure. 25(OH)D levels, adjusted for age and BMI, were significantly and positively related with serum C-telopeptide of type 1 collagen, serum phosphate and spine bone mineral density (BMD) and negatively with serum PTH, serum magnesium, serum bone alkaline phosphatase (bone AP).

CONCLUSION

Vitamin D deficiency is rather common in young otherwise healthy Italian women and particularly among those living in the Southern part of the country. The most close determinants of vitamin D deficiency were BMI and sunlight exposure. Vitamin D insufficiency is associated with low spine BMD and increased bone AP even in young individuals.

Vitamin D status and common risk factors for bone fragility as determinants of quantitative ultrasound variables in a nationally representative population sample

Calcaneal quantitative ultrasound (QUS) can predict bone strength and fracture risk. Bone fragility has no single cause but results from a complex interplay of several etiologic or contributing factors. Vitamin D is essential for bone health even though it is still unclear how much of this vitamin is required to maintain bone strength and prevent fractures. Measurements of serum 25-hydroxyvitamin D [S-25(OH)D] have indicated a high prevalence of inadequate vitamin D status in a number of studies mostly based on selected study populations. The objective of this study was to examine the associations between S-25(OH)D, common risk factors for bone fragility, and QUS variables in a large unselected population sample. The study population consisted of 2736 men and 3299 women from a nationally representative population sample, aged 30 years or over. Information on lifestyle was elicited by means of interviews and questionnaires. Body fat mass was estimated using an impedance-meter. S-25(OH)D was measured by radioimmunoassay. Calcaneal QUS was performed on the Hologic Sahara apparatus recording broadband ultrasound attenuation (BUA) and speed of sound (SOS). The potential determinants of BUA and SOS were analysed using separate multiple linear regression models for men and women. S-25(OH)D proved to be an independent determinant of BUA (P<0.0001 for men, P<0.001 for women) and SOS (P<0.0001 for men, P<0.05 for women). BUA was also independently associated with age, height, weight, alcohol consumption, and postmenopausal status in women, and with weight, alcohol consumption, smoking and physical activity in men. All of the above variables, except for weight in women, were also found to be independent determinants of SOS in both men and women. A reverse association was found between S-25(OH)D and adiposity in spite of higher intakes of vitamin D in those with higher fat mass. In this unselected sample of men and women, vitamin D status, several lifestyle factors and physical characteristics proved to be significant determinants of BUA and SOS. Inadequate vitamin D status was common, and measures ensuring adequate intakes of vitamin D in the population thus deserve continued attention. Obesity should be taken into account in future assessments of vitamin D status in Finland as in other countries.

Lower calcaneal bone mineral density and broadband ultrasonic attenuation, but not speed of sound, in South Asian than white European women

BACKGROUND

Quantitative ultrasound (QUS) measures of bone predict fracture risk in older white women. South Asian women have low bone mineral density (BMD), perhaps related to smaller body size or vitamin D insufficiency, but it is unknown whether this is accompanied by lower QUS.

AIM

The study compared QUS, BMD and vitamin D status between South Asian and white European women.

SUBJECTS AND METHODS

Participants were 47 postmenopausal women (23 white European, 24 South Asian) aged 55-65 years. BMD was measured at the calcaneus and radius by dual X-ray absorptiometry. The QUS measurements were broadband ultrasound attenuation (BUA) at the calcaneus and speed of sound (SOS) at the calcaneus, radius and tibia. Serum 25-hydroxy vitamin D was determined in late summer.

RESULTS

South Asian women had significantly lower serum 25-hydroxyvitamin D than white Europeans (13.0 +/- 5.1 versus 30.3 +/- 7.1 ng mL(-1); p < 0.001). Calcaneal BMD and BUA were 14% and 10% lower (p = 0.016 and 0.045), respectively, in South Asian women. Radial BMD, and SOS at all sites, did not differ significantly between groups.

CONCLUSION

In this study, postmenopausal South Asian women living in the UK had a high prevalence of vitamin D insufficiency and lower calcaneal BMD than white European women, consistent with previous findings. Differences were detected in calcaneal BUA but not SOS. Further research is needed to evaluate fracture risk and its detection in South Asian women.

Vitamin D metabolites and skeletal consequences in primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism (PHPT) is associated with reduced bone mineral density (BMD) mainly at sites rich in cortical bone. However, successful parathyroidectomy causes an increase in BMD especially at sites rich in trabecular bone. Plasma 25-hydroxyvitamin D (25OHD) levels are typically reduced and plasma 1,25-dihydroxyvitamin D [1,25(OH)(2)D] slightly increased in PHPT. These variations in vitamin D metabolites may influence variations in BMD and fracture risk.

AIM

To investigate relations between preoperative vitamin D metabolites and skeletal consequences in patients with untreated PHPT and to appraise the influence of preoperative vitamin D metabolites on postoperative changes in BMD. Design Cross-sectional and cohort study.

MATERIALS

Two hundred and forty-six consecutive Caucasian PHPT patients aged 19-91 years. (median 63, 87% females).

RESULTS

BMD was reduced at the femoral neck (P < 0.001) and forearm (P < 0.001), but normal at the lumbar spine (P = 0.11). Levels of biochemical bone markers were associated with high plasma PTH, high plasma 1,25(OH)(2)D and low plasma levels of 25OHD. Moreover, low plasma 25OHD was associated with low levels of BMD at the femoral neck (r(p) = 0.23), the forearm (r(p) = 0.19) and the whole body (r(p) = 0.30), whereas plasma 1,25(OH)(2)D was inversely associated with BMD at all regional sites and the whole body. Plasma PTH only showed an inverse association with BMD at the forearm (r(p) = -0.21). No association was observed between biochemical variables and prevalent spinal fractures, all peripheral fractures or osteoporotic peripheral fractures. The annual increase in spinal BMD after surgery was positively associated with preoperative plasma PTH (r(p) = 0.40), whereas the annual increase in whole body BMD was inversely associated with plasma 25OHD (r(p) = -0.32). No change in BMD at the femoral neck and forearm was observed 1 year after surgery.

CONCLUSION

Low vitamin D status and high plasma 1,25(OH)(2)D are associated with increased bone turnover and decreased BMD in patients with PHPT.

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 and rehabilitation: improving functional outcomes

Vitamin D inadequacy is pandemic among rehabilitation patients in both inpatient and outpatient settings. Male and female patients of all ages and ethnic backgrounds are affected. Vitamin D deficiency causes osteopenia, precipitates and exacerbates osteoporosis, causes the painful bone disease osteomalacia, and worsens proximal muscle strength and postural sway. Vitamin D inadequacy can be prevented by sensible sun exposure and adequate dietary intake with supplementation. Vitamin D status is determined by measurement of serum 25-hydroxyvitamin D. The recommended healthful serum level is between 30 and 60 ng/mL. 25-Hydroxyvitamin D levels of >30 ng/mL are sufficient to suppress parathyroid hormone production and to maximize the efficiency of dietary calcium absorption from the small intestine. This can be accomplished by ingesting 1000 IU of vitamin D(3) per day, or by taking 50,000 IU of vitamin D(2) every 2 weeks. Vitamin D toxicity is observed when 25-hydroxyvitamin D levels exceed 150 ng/mL. Identification and treatment of vitamin D deficiency reduces the risk of vertebral and nonvertebral fractures by improving bone health and musculoskeletal function. Vitamin D deficiency and osteomalacia should be considered in the differential diagnosis of patients with musculoskeletal pain, fibromyalgia, chronic fatigue syndrome, or myositis. There is a need for better education of health professionals and the general public regarding the optimization of vitamin D status in the care of rehabilitation patients.

Hypovitaminosis D osteopathy: is it mediated through PTH, lean mass, or is it a direct effect?

Hypovitaminosis D is increasing worldwide and is associated with low bone mass. The effects of hypovitaminosis D on bone might be direct or mediated through decreased muscle mass and function and/or secondary hyperparathyroidism. This study systematically investigated the relative contribution of lean mass, PTH, and the direct effect of vitamin D as predictors of vitamin D mediated osteopathy in elderly individuals. 460 ambulatory subjects aged 65-85 years had their bone mass and lean body mass measured by a dual-energy X-ray absorptiometry. Serum calcium, phosphorus and alkaline phosphatase, intact parathyroid hormone (PTH) and 25-hydroxyvitamin D (25 OHD) were also measured. Serum 25 OHD correlated with lean body mass in men, r = 0.24, P = 0.002, but not in women; and with bone mass at all skeletal sites in men, r = 0.20-0.30, P < 0.02. Correlations were also noted at all skeletal sites in women except for the spine, r = 0.13-0.18, P < 0.04. In both genders, BMD at sites enriched in cortical bone was 0.4-0.7 SD lower in the group with the lowest vitamin D tertile than that in the group in the highest tertile. After controlling for PTH, the magnitude of the correlations between BMD and 25 OHD remained significant in both genders. After controlling for lean body mass, the magnitude of these correlations did not change in women and decreased but remained significant in men. After adjustment for age and height, both lean body mass and PTH had significant independent contributions to BMD variance at all skeletal sites. After adjustment for age, height, lean mass, and PTH, 25 OHD did not have any significant residual contribution to BMD variance except at the trochanter in men. This study demonstrates that vitamin D osteopathy in the elderly is in large part mediated through lean mass in men and through PTH levels in both genders, with a greater contribution of PTH in women than in men. There was little demonstrable independent relation between serum 25 OHD and bone mass.

Vitamin D, parathyroid hormone levels and bone mineral density in community-dwelling older women: the Rancho Bernardo Study

Vitamin D (25(OH)D) increases the efficiency of intestinal calcium absorption. Low levels of serum calcium stimulate the secretion of parathyroid hormone (PTH), which maintains serum calcium levels at the expense of increased bone turnover, bone loss and increased risk of fractures. We studied the association between 25(OH)D and PTH levels, and their associations with bone mineral density (BMD), bone loss, and prevalence of hip fractures in 615 community-dwelling postmenopausal aged 50-97 years. Mean level of 25(OH)D and PTH were 102.0 nmol/l+/-35.0 nmol/l and 49.4 ng/l+/-23.2 nmol/l, respectively; 49% of women were current hormone therapy users. The overall prevalence of vitamin D insufficiency (25(OH)D<50 nmol/l) was 2%, and prevalence of high PTH levels (>65 ng/l) was 17.4%. In multiple linear regression analyses hip BMD was negatively and independently associated with PTH levels (p=0.04), and positively and independently associated with 25(OH)D levels (p=0.03). There were only 23 women (3.7%) who experienced a hip fracture. In age-adjusted analyses there were no significant differences of 25(OH)D and PTH levels by hip fracture status. Across the entire range of values, the overall correlation between 25(OH)D and PTH was moderate (r=-0.20). However, after the threshold vitamin D level of 120 nmol/l, all PTH values were below 65 ng/l. Further studies are necessary to identify the optimal vitamin D levels necessary to prevent secondary hyperparathyroidism.

The relationship of vitamin D status to bone mineral density in an Italian population of postmenopausal women

Several authors have found a relationship between vitamin D status and bone mineral density (BMD). To our knowledge, no previous studies on this topic have been carried out on the Italian postmenopausal population. We studied this relationship retrospectively in 156 Italian postmenopausal women. We also investigated the relationship between parathyroid hormone (PTH) and BMD. Measurements of BMD were taken at the lumbar spine and upper femur by dual X-ray absorptiometry. Serum 25(OH)D (calcidiol), 1,25(OH)2D (calcitriol), PTH, calcium, phosphorus, creatinine, osteocalcin and urinary calcium and phosphorus were measured according to the current laboratory methods of analysis. We found a positive statistically significant correlation between BMD, both at the spine and hip, and 25(OH)D, and a negative statistically significant correlation between BMD and PTH. No statistically significant correlation was found between BMD and 1,25(OH)2D. Crude logistic regression showed age, 25(OH)D and PTH were significant predictors of low BMD, while 1,25(OH)2D was not. Backward logistic regression showed 25(OH)D was the best predictive model for spine osteoporosis together with age, and on its own it was the best predictive model for femoral neck osteoporosis.

Correlation of quantitative ultrasound parameters of the calcaneus with bone density of the spine and hip in women with prevalent hypovitaminosis D

Quantitative ultrasound (QUS) of the calcaneus correlates modestly with axial dual-energy X-ray absorptiometry (DXA). Because bone mineral density (BMD) might be influenced by vitamin D status, we assessed the correlation between both techniques in 56 Arabian women, a population with high prevalence of hypovitaminosis D. The speed of sound (SOS), broadband ultrasound attenuation (BUA), and estimated BMD of the right calcaneus were determined by QUS. Spine and right hip BMD were measured by DXA scan. The serum 25-hydroxyvitamin D (25OHD) level was measured by radioimmunoassay. The correlations of QUS parameters (estimated calcaneal BMD, BUA, and SOS) with spine and hip BMD were modest (r = 0.50, r = 0.53, r = 0.41 for the spine and r = 0.54, r = 0.56, and r = 0.46 for the hip, respectively; p < 0.01 for all comparisons), but stronger in postmenopausal women. All postmenopausal women with low estimated calcaneal BMD (T-score pound -1) had a T-score pound -1 by DXA of the spine or hip. Of the 21 premenopausal women with spine or hip T-score pound -1 who had 25OHD measurements, 20 (95.2%) had levels below 50 nmol/L and 12 (57%) had levels below 30 nmol/L. The subgroup with 25OHD < 30 nmol/L had significantly lower spine (p < 0.01) and hip BMD (p < 0.05) than the subgroup with 25OHD >/= 30 nmol/L. QUS parameters were not significantly different between the two subgroups. The QUS and DXA correlated modestly well in women with prevalent hypovitaminosis D. QUS could be used in postmenopausal women with hypovitaminosis D to identify those at risk for osteoporotic fracture.

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.

Comparative study of bone mineral density, calcium, and vitamin D status in the Gujarati and white populations of Leicester

OBJECTIVES

To evaluate differences in bone mineral density (BMD), calcium, and vitamin D status between the Gujarati (South Asian) and white populations resident in Leicester and to determine whether this was linked to lifestyle factors.

DESIGN

An observational cross sectional study of randomly selected Gujarati and white volunteers aged from 20-40 years.

SETTING

City of Leicester.

PARTICIPANTS

Subjects were randomly selected by age (20-40 years) and ethnicity. A total of 262 individuals volunteered to participate, of which 201 (51 white females, 71 Gujarati females, 37 white males, 42 Gujarati males) were eligible for the study.

MAIN OUTCOME MEASURES

Results of questionnaire, BMD at the hip and lumbar spine, and measurement of serum calcium, albumin, alkaline phosphatase, and 25-hydroxyvitamin D.

RESULTS

Male and female white subjects were significantly taller and heavier than their Gujarati counterparts. There was a statistically significant difference in BMD both at the spine (p<0.001) and hip (p<0.001) between the white and Gujarati females with the Gujaratis having a lower BMD. There was a trend for Gujarati males to have a lower BMD at the hip and spine than their white counterparts but these figures did not reach statistical significance. The intensity of cigarette smoking and the amount of alcohol consumption were both higher in the white male and female subjects. Sunlight exposure (>4 hours per day) was significantly higher in white subjects compared with Gujaratis. There were no significant differences in the mean level of serum calcium or alkaline phosphatase between the Gujaratis and whites. A significantly higher proportion (p<0.001) of the Gujarati men and women had a vitamin D level that was not measurable (that is, below the lower limit of the laboratory range of normal). Of those who had a measurable level (that is, in the normal range) mean levels of vitamin D were lower (p<0.05) in the Gujarati men and women.

CONCLUSION

The present study is the first of its kind to note a low BMD in Gujarati subjects of South Asian origin compared with their white counterparts, living in Leicester. This study also confirms the presence of low serum vitamin D levels in Gujaratis. There is a need for more research in South Asians with regard to the collection of normal BMD values. This could provide a more meaningful reference range for identifying South Asians at risk of osteoporotic fractures and may have public health implications of relevance to this ethnic group.

Assessment of vitamin D and calcium status in healthy adult Austrians

BACKGROUND

Because there is reason to assume that also in Austria calcium and vitamin D malnutrition is wide-spread, we initiated a comprehensive study on calcium and vitamin D status in relation to bone health in a large group of the normal adult population.

SUBJECTS AND METHODS

We assessed dietary calcium and vitamin D intake, serum concentrations of Ca2+, phosphate, alkaline phosphatase, 25(OH)D, 1,25(OH)2D, parathyroid hormone (PTH), follicle-stimulating hormone (FSH), sex hormones and bone mineral density (BMD) by double-energy X-ray absorptiometry at five different skeletal sites in 648 females and 400 males (age 21-76 years).

RESULTS

Mean daily intake of vitamin D (101 IU, range 0.2-320) and calcium (569 mg, range 40-2170) was significantly less than the respective recommended dietary allowances. Two hundred and seventy-one (26%) individuals had hypovitaminosis D with serum 25(OH)D < 12 ng mL(-1), while serum Ca2+ was less than normal in 82 (7.8%) subjects. Multiple regression analysis revealed significant correlations between mean calcium intake and BMD in the femoral region in the men (r = 0.13, P < 0.05) though not in the women. No consistent data could be obtained for associations between BMD and vitamin D status, except for 25(OH)D and BMD at the spine in the men (r = 0.10, P < 0.05). 25(OH)D correlated negatively (P < 0.05) with age in the women (r = -0.11) and with PTH in the women (r = -0.11) and men (r = -0.16). Inversely, a significant (P < 0.001) age-related increase in PTH was observed in both sexes (men, r = 0.19; women, r = 0.14).

CONCLUSIONS

Prevalence of hypovitaminosis D in adult Austrians is an imminent risk for development of secondary hyperparathyroidism with advancing age, and requires timely correction of nutritional deficits.

Vitamin D status in children, adolescents, and young adults with Crohn disease

BACKGROUND

Crohn disease (CD) and vitamin D deficiency are associated with decreased bone mineralization.

OBJECTIVE

We examined the prevalence of and risk factors for hypovitaminosis D in children, adolescents, and young adults with CD.

DESIGN

Growth, clinical characteristics, vitamin D intake ( micro g/d), and bone mineral density (g/cm(2)) were measured in a cross-sectional study of 112 subjects (44 females) who had CD and were 5-22 y of age. Hypovitaminosis D was defined as a serum concentration of 25-hydroxyvitamin D [25(OH)D] < 38 nmol/L.

RESULTS

The mean (+/- SD) serum concentration of 25(OH)D was 59.7 +/- 26.9 nmol/L, and 16% (95% CI: 9.3%, 23%) of the subjects had hypovitaminosis D. Hypovitaminosis D was most prevalent during the winter (31%; P = 0.02), among the African Americans (56%; P = 0.01), in the subjects with CD confined to the upper gastrointestinal tract (44%; P = 0.05), and in the subjects with a greater lifetime exposure to glucocorticoid therapy (23.7 +/- 13.5 compared with 17.5 +/- 12.2 mg/d; P = 0.05). There was no association between hypovitaminosis D and either bone mineral density (P = 0.10) or average dietary intake of vitamin D (4.6 +/- 3.6 micro g/d; P = 0.87).

CONCLUSIONS

In this sample of pediatric patients with CD, hypovitaminosis D was common and was associated with the winter season, African American ethnicity, CD confined to the upper gastrointestinal tract, and magnitude of lifetime exposure to glucocorticoid therapy. The occurrence of these factors should prompt assessment of 25(OH)D status and clinical care optimized by supplementing subjects who have low serum concentrations. The physiologic relevance of ethnicity on 25(OH)D status in children with CD remains to be determined.

Vitamin D depletion following burn injury in children: a possible factor in post-burn osteopenia

BACKGROUND

Children burned > 40% total body surface area (TBSA) have chronically low bone mineral density (BMD) and increased risk for fractures and adult-onset osteoporosis. Because they are advised to avoid sunlight to prevent burn scar hyperpigmentation, we hypothesized that they develop vitamin D depletion, which could contribute to post-burn osteopenia.

METHODS

We studied 24 children, ages 5-20 years, burned > or = 40% TBSA 7.1 +/- 3.8 (SD) years, range 1.9-13.3 years, previously (n = 12) and 2.0 +/- 0.2, range 1.4-2.1 years, previously (n = 12), of which half received recombinant human growth hormone during the first post-burn year. We measured lumbar spine BMD, serum 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), intact PTH (iPTH), and osteocalcin.

RESULTS

Serum 25(OH)D was low in 10/11 patients and 1,25(OH)2D was low in 5/11 at 7 years post-burn. Serum 25(OH)D was low in 10/12, while 1,25(OH)2D was low in 0/12 at 2 years; osteocalcin was low in 9/12 in the 7-year group; iPTH levels were in the lowest quartile in 5/12 patients at 7 years and 10/12 patients at 2 years. Serum 25(OH)D levels correlated with BMD z-scores, r = 0.53, p < 0.05, and inversely with iPTH levels, r = -0.66, p < 0.05, in the 7-year group.

CONCLUSION

Burned children have low circulating levels of 25(OH)D which correlated with BMD z-scores, suggesting that post-burn vitamin D depletion may play a role in the chronically low bone density observed in these children.

Low serum concentrations of 25-hydroxyvitamin D in young adult Japanese women: a cross sectional study

OBJECTIVES

The vitamin D nutrition status of young adult women is unclear, but a recent preliminary report suggested that they may have vitamin D insufficiency. This study assessed the serum concentrations of 25-hydroxyvitamin D (25[OH]D), an index of vitamin D nutrition status, in young adult Japanese women in comparison with those in older women and investigated whether serum 25(OH)D concentrations are associated with other calcium-related hormones and bone mass.

METHODS

A cross sectional study of 77 healthy women, age 19 to 66 y, working in nursing homes in Japan was conducted in the winter of 1999 and 2000. The investigation included blood tests, forearm bone mass measurements, and a lifestyle questionnaire.

RESULTS

The mean serum 25(OH)D concentration in women younger than 30 y was 34.0 nmol/L (standard deviation [SD] = 11.0) and significantly lower than that in women 30 y and older (50.0 nmol/L, SD = 14.4). The proportion of subjects younger than 30 y who had serum 25(OH)D concentrations less than 30 nmol/L was 42.1% and was significantly higher (P < 0.001) than the proportion of those 30 y and older (10.3%). There was a weak but significant linear association between serum 25(OH)D concentrations and forearm bone mineral content (R(2) = 0.114, P = 0.0052) but not between serum 25(OH)D concentrations and bone mineral density. The association held after adjusting for body weight (R(2) = 0.139, P = 0.0111). Serum intact parathyroid hormone concentrations were within the normal range and not associated with serum 25(OH)D concentrations.

CONCLUSIONS

Serum 25(OH)D concentrations in young adult Japanese women (<30 y old) are lower than those of older adult women (30 to 66 y), and lower serum 25(OH)D concentrations are likely associated with lower forearm bone mineral content.

Vitamin D status and bone mineral density of veiled and unveiled Turkish women

The aim of the study is to compare vitamin D status and bone mineral density (BMD) in veiled and unveiled healthy Turkish women of reproductive age. Thirty young to middle-aged volunteer veiled women and 30 age-matched control subjects with western clothing habits were enrolled in the study. The two groups had similar dietary habits, body mass index (BMI) distribution, and gestational history. Physical and laboratory examinations were performed to rule out any disease that could affect bone metabolism. Serum 25-hydroxyvitamin D (25-OHD) levels were measured, and BMD of the spine and hip were investigated by dual energy x-ray absorptiometry (DEXA). The mean age of dressing the veil was 15.7 +/- 6.13 years, and 66.7% of the veiled women claimed that they were not ever exposed to direct sunlight, as they were leading an indoor life. Compared with the control group, veiled women were less educated and physically less active (p < 0.001 and p < 0.05, respectively). 25-OHD levels were positively correlated with exposure to sunlight and negatively correlated with the duration of being veiled. None of the veiled women had vitamin D insufficiency, but their mean 25-OHD concentration (33.1 +/- 16 ng/ml) was significantly lower than that of controls (53.9 +/- 27.3 ng/ml) (p < or = 0.001), and serum alkaline phosphatase (ALP) levels were higher (p < 0.01). Differences in the absolute BMD values at the spine and hip were not statistically significant, but the mean Z value at the lumbar spine was significantly lower in the veiled subjects (p < 0.05). Veiled women have low 25-OHD status, and vitamin D supplementation should strictly be advised to these women for the prevention of osteomalacia and osteoporosis.

Vitamin D deficiency and secondary hyperparathyroidism in the elderly: consequences for bone loss and fractures and therapeutic implications

Vitamin D deficiency is common in the elderly, especially in the housebound and in geriatric patients. The establishment of strict diagnostic criteria is hampered by differences in assay methods for 25-hydroxyvitamin D. The synthesis of vitamin D3 in the skin under influence of UV light decreases with aging due to insufficient sunlight exposure, and a decreased functional capacity of the skin. The diet contains a minor part of the vitamin D requirement. Vitamin D deficiency in the elderly is less common in the United States than elsewhere due to the fortification of milk and use of supplements. Deficiency in vitamin D causes secondary hyperparathyroidism, high bone turnover, bone loss, mineralization defects, and hip and other fractures. Less certain consequences include myopathy and falls. A diet low in calcium may cause an increased turnover of vitamin D metabolites and thereby aggravate vitamin D deficiency. Prevention is feasible by UV light exposure, food fortification, and supplements. Vitamin D3 supplementation causes a decrease of the serum PTH concentration, a decrease of bone turnover, and an increase of bone mineral density. Vitamin D3 and calcium may decrease the incidence of hip and other peripheral fractures in nursing home residents. Vitamin D3 is recommended in housebound elderly, and it may be cost-effective in hip fracture prevention in selected risk groups.

Hypovitaminosis D in a sunny country: relation to lifestyle and bone markers

Hypovitaminosis D is associated with poor dietary intake and inadequate sunshine exposure. It is common worldwide, particularly in European elderly people. Information about vitamin D status in young adult populations from the Middle East is scarce. Furthermore, the relationship between hypovitaminosis D and some lifestyle factors such as style of clothing and dwelling location is not well defined. We assessed vitamin D intake and measured serum calcium, phosphorus, albumin, alkaline phosphatase, 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), osteocalcin, and urinary-free deoxypyridinoline (DPD) in 316 Lebanese volunteers (99 men and 217 women) aged 30-50 years; 156 were recruited from rural areas and 160 from urban areas. Fifty-one women from each area were veiled. The average daily vitamin D intake was 100.3 +/- 67.9 IU and was found to be higher in men compared with women, in urban subjects compared with rural ones and in nonveiled women compared with veiled ones. The mean level of 25(OH)D was 9.71 +/- 7.07 ng/ml. Hypovitaminosis D [25(OH)D < 12 ng/ml] affected 72.8% of our population. It was more common in women than in men (83.9% vs. 48.5%). Severe hypovitaminosis D [25(OH)D < 5 ng/ml] was observed in 30.7% of our subjects and was more prevalent in women (41.5%), particularly in the veiled ones (61.8%). 25(OH)D levels were the lowest in veiled women, and in women living in rural areas. Rural men had the highest 25(OH)D levels despite their very low vitamin D intake. In a multivariate model, inadequate vitamin D intake, urban dwelling, veil wearing, and high parity in women were independent predictors of hypovitaminosis D. 25(OH)D was related inversely to PTH and free DPD whereas osteocalcin achieved only a weak positive correlation with 25(OH)D. In the absence of information regarding time spent outdoors, our results show that hypovitaminosis D is common among young Lebanese people and is related mostly to low vitamin D intake. This should emphasize the need for more vitamin D in our population.