Optimal serum concentration of 25-hydroxyvitamin D for bone health in older Korean adults

Optimal Serum 25(OH)D Levels and Vitamin D Intake in Korean Postmenopausal Women

Vitamin D plays a crucial role in regulating the growth and maintenance of the musculoskeletal system. Postmenopausal women are vulnerable to bone fractures because of the decrease in bone mineral density (BMD). Therefore, this study aimed to identify the determinants that influence BMD and the 25(OH)D levels in Korean postmenopausal women. This study collected general and dietary intake information, measured biochemical indices, and conducted BMD tests in 96 postmenopausal women residing in a metropolitan area in Korea. This study analyzed factors that influenced serum 25-hydroxyvitamin D (25(OH)D) and BMD, as well as the correlation between the intact parathyroid hormone (iPTH) and serum 25(OH)D levels. The serum 25(OH)D levels increased by 0.226 ng/mL in the summertime, 0.314 ng/mL in the wintertime, and 0.370 ng/mL on annual average when vitamin D intake rose by 1 µg/1000 kcal. When the serum 25(OH)D levels were ≥18.9 ng/mL, the iPTH levels did not rapidly increase. To maintain the serum 25(OH)D levels at ≥18.9 ng/mL, a daily vitamin D intake of ≥13.21 µg was required. Consequently, consuming vitamin D-fortified foods or vitamin D supplements is necessary to improve both bone health and vitamin D nutritional status.

Vitamin D intake and bone mineral density in Korean adults: analysis of the 2009-2011 Korea National Health and Nutrition Examination Survey

BACKGROUND/OBJECTIVES

The prevalence of vitamin D deficiency in Koreans is quite high; however, until recently, Korean National Health and Nutrition Survey (KNHANES) had not analyzed the vitamin D intake among Koreans. Additionally, the Korean Dietary Reference Intake for vitamin D was established based on insufficient evidence. Therefore, we investigated vitamin D intake and its relationship with bone mineral density (BMD) in Korean adults using the combined data from the 2009-2011 KNHANES.

MATERIALS AND METHODS

This study was conducted in 11,949 healthy adults. Vitamin D intake was assessed using a 24-h recall method, and the BMD was measured using dual-energy X-ray absorptiometry.

RESULTS

The prevalence of vitamin D deficiency (< 20 ng/mL) was 64% in men and 77% in women. In women aged ≥ 50 yrs and men aged < 50 yrs, there was a significant positive correlation between vitamin D intake and serum 25-hydroxyvitamin D level after sun exposure adjustment. The BMD of postmenopausal women aged ≥ 50 yrs with a vitamin D intake of 5 µg/day or more was significantly higher than that of women with intake less than 5 µg/day. After adjusting for age, energy, and calcium intake, the vitamin D intake of the osteoporotic group was significantly lower than that of the osteopenia group in women.

CONCLUSIONS

Since the relationship between vitamin D intake and BMD was observed in women aged ≥ 50 yrs, further research is needed to clarify these findings using cohort or randomized controlled trials.

Reconsidering vitamin D optimal values based on parathyroid hormone levels in a North Algerian cohort: stratification by gender and season

"Health-based threshold value" is used to define the optimal cutoff of vitamin D. This approach is based on the hypothesis of a secondary hyperparathyroidism associated with hypovitaminosis D. We define the optimal values in a North Algerian population. The optimal value is 25.0 ng/ml in men and 30.0 ng/ml in women.

PURPOSE/INTRODUCTION

There is no consensus defining the vitamin D optimal values. The aim of this study is to establish vitamin D optimal values in the Northern Algerian population, based on its skeletal effects as represented by the inverse relationship between 25-hydroxy vitamin D (25(OH) D) and parathyroid hormone (PTH).

METHODS

451 healthy volunteers of both genders, aged 19 to 79 years, were enrolled in a cross-sectional study conducted at the medical analysis laboratory of the University Hospital of Blida, Algeria. 25(OH) D was assessed by a sequential competitive immuno-fluoroassay technique. Determination of vitamin D optimal values was performed based on the kinetic relationship between 25(OH) D and PTH, as explored by inverse nonlinear regression on a spline plots curve. The optimal value represents the 25(OH) D level at which PTH ceases to increase and reaches a virtual plateau.

RESULTS

In men and women, respectively, the 25 (OH) D thresholds are estimated at 25.0 ng/ml and 30 ng/ml, above this value, PTH stabilizes in a virtual plateau, estimated at 22.3 pg/ml and 26.8 pg/ml. In warm and cold seasons, respectively, the 25 (OH) D cut-offs are estimated at 30.0 ng/ml and 25.0 ng/ml, from these values, the PTH stabilizes in a virtual plateau, estimated at 21.5 pg/ml and 27.7 pg/ml.

CONCLUSION

In this study, the optimal values of 25(OH) D were defined for the first time in a North Algerian adult population. The optimal value is 25.0 ng/ml in men and 30.0 ng/ml in women.

Vitamin D Deficiency and Sarcopenia in Hip Fracture Patients

Background

Vitamin D plays a critical role in the proliferation and differentiation of skeletal muscle and bone metabolism. We compared the prevalence of vitamin D deficiency in elderly patients undergoing hip fracture surgery (HFS) with those undergoing elective primary total hip arthroplasty (THA). We also evaluated the association between vitamin D deficiency and sarcopenia.

Methods

This prospective study included 70 patients in the HFS group, and 100 patients in the elective THA group. The HFS group included 42 women, while the elective THA group included 74 women. The mean age in the HFS and elective THA groups was 79.8 and 75.4 years, respectively, and the mean preoperative Koval score was 2.1 and 2.3, respectively. Serum 25-hydroxy-vitamin D3 levels were measured by I125 radioimmunoassay. Bone mineral density and appendicular skeletal muscle mass (ASM) were measured using dual X-ray absorptiometry. Sarcopenia index was calculated by dividing ASM (kg) by the body mass index (kg/m²). Sarcopenia was diagnosed when the sarcopenia index was <0.789 in men and <0.512 in women.

Results

Serum vitamin D levels were lower, and the percentages of patients with vitamin D insufficiency and deficiency were higher in the HFS group than in the elective THA group. In the HFS group, the prevalence of sarcopenia was higher in men (57%, 16/28) than in women (29%, 12/42; P=0.025).

Conclusions

Vitamin D deficiency was more prevalent in patients undergoing HFS than in patients undergoing elective THA. Among patients undergoing HFS, vitamin D deficiency was more prevalent in sarcopenic than in non-sarcopenic patients.

Low serum 25-hydroxyvitamin D levels, tooth loss, and the prevalence of severe periodontitis in Koreans aged 50 years and older

PURPOSE

Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss.

METHODS

Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008-2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions. Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed.

RESULTS

Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis.

CONCLUSIONS

This population-based cross-sectional study indicates that low serum 25(OH)D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

Is There a Role for Vitamin D in Amyotrophic Lateral Sclerosis? A Systematic Review and Meta-Analysis

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative condition characterized by the progressive loss of motor neurons. Patients usually die 3–5 years after diagnosis from respiratory failure. Several studies investigated the role of vitamin D as a biomarker or a therapeutic option for ALS patients. To clarify the scientific evidence, we performed a systematic review and different meta-analyses regarding the potential role of vitamin D in ALS.

Methods: We performed a systematic review of clinical trials, cohorts, and case–control studies retrieved from PubMed, EMBASE, and Cochrane databases reporting vitamin D levels as a putative biomarker for ALS diagnosis or prognosis or the effect of vitamin D supplementation in ALS patients. Whenever possible, data were pooled using a random-effects model, with an assessment of heterogeneity.

Results: Out of 2,996 articles retrieved, we finally included 13 research articles, 12 observational studies (50% prospective), and 1 clinical trial. We found that ALS patients had slightly lower levels of vitamin D than controls (mean difference −6 ng/ml, 95% CI [−10.8; −1.3]), but important confounding factors were not considered in the studies analyzed. We found no relationship between vitamin D levels and ALS functional rate score—revised (ALSFRS-R), with highly heterogeneous results. Discordant results were reported in three studies regarding survival. Finally, five studies reported the effects of vitamin D supplementation with discordant results. Two of them showed a small improvement, whereas two others showed a deleterious effect on ALSFRS-R. One very small clinical trial with important methodological limitations showed some improvement in ALSFRS-R with high doses of vitamin D compared with normal doses.

Conclusions: Our review did not find evidence to support the role of vitamin D on ALS diagnosis, prognosis, or treatment. Most studies had important limitations, mostly regarding the risk of bias for not considering confounding factors. Vitamin D supplementation should be offered to ALS patients to avoid other health issues related to vitamin D deficiency, but there is not enough evidence to support the use of vitamin D as a therapy for ALS.

Preoperative vitamin D level does not affect the short-term functional outcome after total knee arthroplasty in elderly women

Background

We aimed to evaluate the effect of vitamin D levels on the functional outcome of elderly women who underwent total knee arthroplasty (TKA).

Methods

Seven hundred and four patients (1013 knees) who underwent primary TKA were included in our retrospective study. Preoperative vitamin D levels were measured and the relationship analyzed between these and age, weight, height, body mass index, and bone mineral density. Two hundred and twenty patients (220 knees) who received unilateral TKA and were followed up for more than 1 year after operation were divided into two groups: Group 1, serum 25-hydroxyvitamin D3 (25(OH)D3) level < 20 ng/ml; and Group 2, 25(OH)D3 level ≥ 20 ng/ml. Both groups were evaluated for the relationship between vitamin D levels and postoperative Visual Analogue Scale (VAS) score, Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) score.

Results

The number of vitamin D-deficient patients (< 20 ng/ml of serum 25(OH)D3 level) was 556 (79.0%). In the correlation analysis, the vitamin D level was negatively correlated with weight only (p = 0.033). No significant differences were observed between the groups in terms of postoperative VAS score, KSKS, KSFS, and WOMAC score.

Conclusions

Vitamin D deficiency was highly prevalent in patients who underwent TKA. Vitamin D levels negatively correlated with weight. Low vitamin D level was not a risk factor for unsatisfactory TKA outcome in elderly women.

Vitamin D Status and Related Factors among Korean Stroke Survivors: A Nationwide Population-Based Study

The aim of this study was to investigate the vitamin D status and related factors in community-dwelling Korean stroke survivors. Data of 23,872 individuals ≥20 y who participated in the Korea National Health and Nutrition Examination Surveys (KNHANES) were analyzed. Participants who had ever been diagnosed with stroke by a doctor were defined as stroke survivors (n=431). The serum 25-hydroxyvitamin D (25(OH)D) level was measured by radioimmunoassay, and vitamin D deficiency was defined as 25(OH)D<20 ng/mL. The association between vitamin D and stroke status was analyzed using multivariable general linear models and logistic regression models adjusted for sociodemographic and clinical covariates. The adjusted mean 25(OH)D level of stroke survivors was significantly lower than that of nonstroke controls; however, after adjustment for systolic blood pressure level and use of antihypertensive medication, the difference was no longer statistically significant. The burden of 25(OH)D deficiency was not higher in stroke survivors than in nonstroke controls (adjusted OR=1.14; 95% CI, 0.81-1.62). Current smoking was independently associated with 25(OH)D deficiency among stroke survivors (adjusted OR=3.17; 95% CI, 1.33-7.55). These findings indicated that treatment of high blood pressure and smoking cessation may be important measures to control vitamin D levels in stroke survivors.

Association between vitamin D intake and bone mineral density in Koreans aged ≥ 50 years: analysis of the 2009 Korea National Health and Nutrition Examination Survey using a newly established vitamin D database

BACKGROUND/OBJECTIVES

Vitamin D plays an important role in skeletal growth and maintenance and in the prevention of various diseases. We investigated the relationship between vitamin D intake and bone mineral density (BMD) in Korean adults aged ≥ 50 years using the 2009 Korea National Health and Nutrition Examination Survey data.

SUBJECTS/METHODS

This study was conducted in 1,808 subjects aged ≥ 50 years with BMD data in Korea. Dietary vitamin D levels were assessed by the 24-hour recall method. BMD was measured using dual-energy X-ray absorptiometry. We investigated general characteristics and the association between these characteristics, vitamin D status, and BMD.

RESULTS

Vitamin D intake was significantly lower in the osteoporosis group among women (P < 0.05). Among all subjects, the higher the serum 25(OH)D concentration, the higher the whole-body total BMD (WBT-BMD), femoral total hip BMD, and femoral neck BMD (P < 0.01). In the serum vitamin D-deficient group of both the total population and women, serum 25(OH)D concentration was associated with WBT-BMD (P < 0.05). Among women with a calcium intake < 537.74 mg/day, BMD of those with a vitamin D intake > 2.51 µg/day (average intake of women) was higher than that of women with a vitamin D intake ≤ 2.51 µg/day (P < 0.001).

CONCLUSIONS

Korean adults should increase their BMD by increasing serum 25(OH)D concentration. Furthermore, increasing vitamin D intake could improve BMD, especially in Korean women who consume less calcium than the estimated average requirement.

The Association between 10-Year Atherosclerotic Cardiovascular Diseases Risk Score Calculated Using 2013 American College of Cardiology/American Heart Association Guidelines and Serum 25-Hydroxyvitamin D Level among Aged 40-79 Years in Korea: The Sixth Korea National Health and Nutrition Examination Surveys

BACKGROUND

We examined the relationship between 10-year predicted atherosclerosis cardiovascular disease (ASCVD) risk score and 25-hydroxyvitamin D in Koreans aged 40-79 years.

METHODS

A population-based, cross-sectional design was used from data based on the Korea National Health and Nutrition Examination Survey 2014.

RESULTS

A total of 1,134 healthy Koreans aged 40-79 years were included. A positive relationship between serum 25-hydroxyvitamin D level and ASCVD score was shown in women (β=0.015) after adjusting for central obesity, physical activity, and supplement intake. The chances of being in the moderate to high risk (risk group, ASCVD score ≥5%) with vitamin D sufficiency (serum 25-hydroxyvitamin D ≥20 ng/mL) was 1.267-fold (95% confidence interval, 1.039-1.595) greater than the chance of being included in the group with vitamin D deficiency (serum 25-hydroxyvitamin D <20 ng/mL) after adjustments in women.

CONCLUSION

Our research indicated a significantly positive association between 25-hydroxyvitamin D and ASCVD score. Further detailed studies to evaluate this correlation are needed.

Relationship between vitamin D levels and intravenous immunoglobulin resistance in Kawasaki disease

Purpose

Vitamin D is associated with various pathological conditions such as cardiovascular diseases and cancer. We investigated the relationship between vitamin D and Kawasaki disease (KD).

Methods

We performed a retrospective review of the medical records of patients with KD between February 2013 and March 2016 in Daegu Fatima Hospital. Study participants were grouped according to vitamin D serum concentration. Group 1 included patients with 25(OH)-vitamin D ≥20 ng/mL. Group 2 included patients with 25(OH)-vitamin D <20 ng/mL. We analyzed the clinical characteristics and laboratory data of the 2 groups.

Results

Of the 91 patients, 52 were included in group 1, and 39 in group 2. Group 1 patients had significantly higher levels of calcium, phosphate, albumin and sodium than group 2 patients did. There were no differences in clinical characteristics, but the proportion of patients with polymorphic rash was significantly higher in group 2. Resistance to intravenous immunoglobulin was more frequent in group 2 (P=0.023). No significant difference in the incidence of coronary artery complications was observed.

Conclusion

Low vitamin D levels are associated with resistance to intravenous immunoglobulin therapy in KD. Vitamin D deficiency might be a risk factor for immunoglobulin resistance in KD.

Survey on the levels of 25-hydroxy vitamin D and bone metabolic markers and evaluation of their correlations with osteoporosis in perimenopausal woman in Xi'an region

It has been accepted that vitamin D (VD) plays an important role in bone metabolism. However, the levels of VD in people of different regions are quite different and there is still no final conclusion on the significant correlation between VD and osteoporosis. 245 cases of peri-menopausal women were collected to study the relationship between VD and osteoporosis in western China. The mean value of 25-hydroxyvitamin D for the participants was 14.39 ng/mL. The average values of parathyroid hormone (PTH), calcium (Ca) and phosphorus (P) were 47.62 pg/mL, 2.26 mmol/L and 1.18 mmol/L, respectively. The average value of bone mineral density (BMD) in lumbar vertebrae was -1.20 SD and that in femoral neck was -0.04 SD. Compared with normal group, PTH of VD deficiency group was significantly increased (P < 0.05), Ca was remarkably decreased (P < 0.01) while the BMD between these two groups showed no significant difference (P > 0.05). VD was in positive correlation with the age (P < 0.01) and Ca (< 0.01) of the participants, negative correlation with PTH (P < 0.01) while no significant correlation with the BMD of lumbar vertebrae and femoral neck (P > 0.05). The risk factors resulting in the occurrence of osteoporosis in the lumbar vertebrae of the participants covered Ca increase (OR = 66.247, P<0.05), age growth (OR = 1.194, P<0.01) and menopause (OR = 2.285, P<0.05). This study has found that the status of VD deficiency showed no significant correlation with the level of BMD, which hinted that independent measurement of the bone metabolic markers, including Ca, P, VD and PTH, was difficult to accurately reflect the status of BMD in peri-menopausal women of this region. It's necessary to combine multi-site bone scanning to diagnose the patients' status of osteoporosis so as to provide reasonable guidance for early clinical prevention and treatment.

The association between serum 25-hydroxyvitamin D level and recurrent falls in the elderly population: a cohort study

Introduction

Serum vitamin D concentration is a major contributing factor for increasing the risk of fall and fall-related injuries in older adults. However, when prescribed and supplemented for these populations, the outcomes are controversial, and in several cases no improvement has been reported in reducing the risk of recurrent falls. This study aimed to examine the association between serum vitamin D concentration and recurrent falls in Iranian older adults.

Methods

This cohort study was conducted in the emergency departments of two university hospitals. A cohort of 82 elderly participants aged over 60 and suffered from an unintentional episode of falling was evaluated six months after their first ED visit. A structured, self-administered checklist was developed to obtain the participants’ demographic and clinical information. Participants also were asked about any recurrent fall experience during follow-up.

Results

The mean (SD) age of the study population was 75 (8). Over half of the participants were male (57.3%). The mean (median) serum 25-hydroxyvitamin D (25 (OH)D) concentration was 38 (34) ng/ml. Mean serum 25(OH)D levels varied slightly between gender groups (p=0.450). An inverse but insignificant association was found between the age of participants and their serum 25(OH)D levels (r=−0.03, p=0.7). A small but insignificant association also was found between the mean serum 25(OH)D level and the number of recurrent falls in elderly patients irrespective of their age, gender, or physical activity groups (OR=1.008, p=0.992).

Conclusion

In contrast to previous studies, no significant association of serum 25(OH)D concentration was found with recurrent falls in Iranian older adults.

Vitamin D levels are not predictors of survival in a clinic population of patients with ALS

OBJECTIVE

This study aimed to measure serum 25-hydroxyvitamin D [25(OH)D] concentrations, bone mineral density (BMD), and the parameters of bone metabolism in amyotrophic lateral sclerosis (ALS) patients, and their correlation with survival.

METHODS

We retrospectively analysed data of 100 ALS patients who consecutively visited a single referral ALS clinic between January and December 2011. Sex; age and site of symptom onset; and death were recorded. Serum 25(OH)D concentration was dichotomized as <10ng/ml and ≥10ng/ml.

RESULTS

There was absent relationship between serum 25(OH)D and concentration of bone turnover parameters or between 25(OH)D and BMD. According to the results of the Kaplan-Meier analysis with log-rank test, the survival rates of patients without (≥10ng/ml) and of those with severe vitamin D deficiency (< 10ng/ml) were not significantly different. Cox regression analysis showed that a poor prognosis was most correlated with older age at onset and bulbar onset after adjustment for all the clinical factors.

CONCLUSIONS

In conclusion, vitamin D levels were not correlated to other bone markers and survival in a clinic population of ALS patients.

Thresholds for Serum 25(OH)D Concentrations With Respect to Different Outcomes

CONTEXT

Vitamin D is essential for bone health. In addition, vitamin D has recently been proposed to play a role in the pathophysiology of many chronic diseases. Despite the large number of studies published on vitamin D, the threshold for a sufficient serum 25-hydroxyvitamin D [25(OH)D] concentration is still debated and may differ according to outcomes and subgroups.

OBJECTIVE

The objective of the study was to estimate the thresholds for serum 25(OH)D concentration with respect to the different outcomes and for different subgroups.

DESIGN, SETTING, AND PARTICIPANTS

Observational data from the Longitudinal Aging Study Amsterdam, an ongoing population-based Dutch cohort study [n = 1164, mean (SD) age 75.2 (6.5) y], were used.

MAIN OUTCOME MEASURES

Falling, fractures, hypertension, cardiovascular disease, blood pressure, PTH, grip strength, physical performance, functional limitations, body mass index (BMI), and mortality were measured. To determine thresholds, spline curves were used. Visual inspection and the statistical best fit of the spline regression models were used together to estimate the best estimate of the thresholds.

RESULTS

Thresholds for serum 25(OH)D concentrations in the whole sample ranged from 46 nmol/L (PTH) to 68 nmol/L (hypertension). On average, women, the oldest old (≥ 75 y), and individuals with a high BMI (>25 kg/m(2)) had lower thresholds compared with men, the youngest old (65-75 y), and individuals with a low to normal BMI (<25 kg/m(2)).

CONCLUSION

The results indicate that thresholds for serum 25(OH)D may vary according to different outcomes and subgroups. This study does not support the high thresholds (>75 nmol/L) as advised by some experts, and the higher requirements in women, older persons, and those with high BMI.

Vitamin D status is associated with bone mineral density and bone mineral content in preschool-aged children

This study examined the associations between vitamin D status, bone mineral content (BMC), areal bone mineral density (aBMD), and markers of calcium homeostasis in preschool-aged children. Children (n=488; age range: 1.8-6.0 y) were randomly recruited from Montreal. The distal forearm was scanned using a peripheral dual-energy X-ray absorptiometry scanner (Lunar PIXI; GE Healthcare, Fairfield, CT). A subset (n=81) had clinical dual-energy X-ray absorptiometry (cDXA) scans (Hologic 4500A Discovery Series) of lumbar spine (LS) 1-4, whole body, and ultradistal forearm. All were assessed for plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone concentrations (Liaison; Diasorin), ionized calcium (ABL80 FLEX; Radiometer Medical A/S), and dietary vitamin D and calcium intakes by survey. Age (p<0.001) and weight-for-age Z-score (p<0.001) were positively associated with BMC and aBMD in all regression models, whereas male sex contributed positively to forearm BMC and aBMD. Having a 25(OH)D concentration of >75 nmol/L positively associated with forearm and whole body BMC and aBMD (p<0.036). Sun index related to (p<0.029) cDXA forearm and LS 1-4 BMC and whole-body aBMD. Nutrient intakes did not relate to BMC or aBMD. In conclusion, higher vitamin D status is linked to higher BMC and aBMD of forearm and whole body in preschool-aged children.

Interactions between dietary calcium intake and bone mineral density or bone geometry in a low calcium intake population (KNHANES IV 2008-2010)

CONTEXT

Little is known about the interactions between dietary calcium intake and bone strength parameters in populations or areas with low calcium intake.

OBJECTIVE

The objective of the study was to investigate the relationship between dietary calcium intake and bone mineral density (BMD) or bone geometry in an Asian population with low calcium intake.

DESIGN AND SETTING

This was a cross-sectional study of data from the Korea National Health and Nutrition Examination Survey, 2008-2010.

PARTICIPANTS

A total of 3448 men and 3812 women older than 50 years were stratified by daily dietary calcium intake: less than 400 mg/d, 400-799 mg/d, 800-1199 mg/d, and 1200 mg/d or greater.

MAIN OUTCOME MEASURES

BMD was measured by dual-energy X-ray absorptiometry and the geometric index was calculated.

RESULTS

Mean daily calcium intake was 470 mg/d in this population. BMD in the lumbar spine (both sexes) and femoral neck (women) was significantly lower only when calcium intake was less than 400 mg/d. In men, femoral neck and total hip BMD was positively related to calcium intake up to 1200 mg/d. Calcium intake less than 400 mg/d was negatively related to femoral cortical thickness and buckling ratio. These interactions disappeared when the 25-hydroxyvitamin D level was 30 ng/mL or greater in men and 20 ng/mL or greater in women.

CONCLUSIONS

Low calcium intake was significantly related with low BMD and increased risk of osteoporosis. However, the association between calcium and BMD was not consistently linear, and a sufficient vitamin D level appears to compensate for the negative influences of low calcium intake on bone.

Physicians' attitudes to contemporary issues on osteoporosis management in Korea

Background

In management of osteoporosis, several concerns here have been raised. The current issue included the utilization of dual energy X-ray absorptiometry (DXA) and fracture-risk assessment (FRAX), screening of vitamin D deficiency and secondary osteoporosis, and long-term use of bisphosphonate and calcium supplements. There was no study on physicians' attitude on these current issues in Korea. Therefore, we investigated the physicians' attitude on these issues by survey.

Methods

We administered a 30-item questionnaire to all members of Korean Society for Bone and Mineral Research by email survey form. One hundred participants answered the questionnaire. The questionnaire included the questions about the physicians' attitude to current issues and the barriers to osteoporosis treatment in Korea.

Results

Most physicians used bone densitometry devices (99%) and, central DXA was the most accessible device (95%). Eighty-eight percent were aware of FRAX®, but among them, only 19.3% used it. The main reason for not using FRAX® was the lack of time in their proactive (76%). Screening for vitamin D status and secondary osteoporosis was performed by 59% and 52% of the respondents, respectively. The lack of awareness among patients and high costs of medication were perceived as the most important barriers to osteoporosis management in Korea.

Conclusions

This study provides physicians' perspective to the current issue for diagnostic and treatment of osteoporosis in Korea. To further improve osteoporosis management, educational programs for patients and doctors, and the improvement of reimbursement system should be considered in Korea.

High prevalence of vitamin D deficiency in adults aged 50 years and older in Gwangju, Korea: the Dong-gu Study

Vitamin D plays an important role in bone metabolism and maintaining bone health. Recently, new evidence has revealed that vitamin D affects chronic diseases such as autoimmune diseases, cardiovascular diseases and certain cancers. The aim of this study was to evaluate the vitamin D status and the prevalence of vitamin D deficiency in an urban Korean population. This study included 8,976 participants (3,587 men and 5,389 women) aged 50 yr and older. Serum 25(OH)D level was measured by chemiluminescent microparticle immunoassay. The prevalence of vitamin D deficiency [25(OH)D < 20 ng/mL] was 59.7% and 86.5% in men and women, respectively. The prevalence of vitamin D deficiency increased significantly with age in men, but not in women and it decreased from April to July, more prominently in men than in women. These results suggest that sun exposure, intake of vitamin D supplement, and regular physical activities is recommended in an urban Koreans, especially in women.

Additive association of vitamin D insufficiency and sarcopenia with low femoral bone mineral density in noninstitutionalized elderly population: the Korea National Health and Nutrition Examination Surveys 2009-2010

Vitamin D insufficiency and sarcopenia are crucial risk factors for osteoporosis. In a study of noninstitutionalized elderly subjects, we investigated the simultaneous effect of vitamin D and sarcopenia on bone mineral density (BMD) and found that sarcopenia was associated with low BMD in the femur, especially in those with suboptimal vitamin D levels.

INTRODUCTION

Although vitamin D insufficiency and sarcopenia are prevalent in the elderly population worldwide, their possible influence on BMD has not been determined. We aimed to investigate the different effect of vitamin D insufficiency and sarcopenia on BMD in the elderly Korean population.

METHODS

Individuals aged 60 or older were selected from those who participated in the Fourth and Fifth Korea National Health and Nutrition Examination Surveys conducted in 2009 and 2010; 1,596 males and 1,886 females were analyzed. Appendicular skeletal muscle mass (ASM) and BMD were assessed by dual-energy X-ray absorptiometry; serum 25-hydroxyvitamin D [25(OH)D] and a panel of clinical and laboratory parameters were also measured.

RESULTS

The study population was divided into four groups according to their vitamin D and sarcopenic status. BMD in total femur and in the femoral neck but not the lumbar spine was markedly decreased in sarcopenic subjects with vitamin D insufficiency [25(OH)D < 20 ng/ml] comparing to other groups, regardless of gender. Multivariable linear regression models showed that BMD was significantly associated with ASM and high daily calcium intake as well as conventional risk factors such as age, body mass index (BMI), and history of fracture. Independent predictors for low femur BMD included sarcopenia, low daily calcium intake, low 25(OH)D levels, age, and BMI.

CONCLUSIONS

These data showed that an association between vitamin D insufficiency and low BMD was more prominent in elderly subjects with sarcopenia.