Vitamin D status and parathyroid hormone in a urban population in Vietnam

Serum Vitamin D Levels in Pediatric Tuberculosis Patients in a Tertiary Care Center in India: A Case-Control Study

Background Mycobacterium is certainly one individual organism contributing to the most deaths of children among the world's lower- and medium-income nations. According to earlier studies, vitamin D insufficiency is one of the risk factors. We undertook this study since very few case-control studies are present. This study aimed to evaluate the role of vitamin D in tuberculosis (TB). Methods This case-control study was carried out in a tertiary care center at Niloufer Hospital over a period of one year and five months. The sample size was 140. SPSS (Statistical Package for the Social Sciences) Version 19 (IBM Corp., Armonk, NY) was used for statistical analysis. Two-tailed p-values and odds ratios were obtained. The chi-square test was applied to differentiate between two categorical variables. For means, the Student t-test was applied. We usually take baseline investigations before starting ATT (anti-TB treatment) with the blood sample we tested for vitamin D levels. Results With p-values of 0.767 and 0.866, the age and sex distributions in the cases and controls were comparable. Rural and urban area distribution and malnutrition distribution were not similar in both groups, with a p-value of 0.001. The mean vitamin D level in cases was 10.4, while controls it was 22.8, and this difference is statistically significant (p = 0.001). Conclusion Vitamin D deficiency is more common in children with TB than in normal children. In addition, a severe form of vitamin D deficiency (less than 10 ng/mL) was higher among children with TB. Clinicians should be aware of associated malnutrition and low socioeconomic status as risk factors for severe vitamin D deficiencies among them.

Plasma parathyroid hormone response to vitamin D3 supplementation among women of reproductive age: A randomized double-blind placebo-control trial

While vitamin D inadequacy occurs worldwide, there is a lack of consensus internationally on the optimum plasma levels of 25(OH)D to maximally suppress the level of parathyroid hormone toward reducing bone loss. This study aimed to investigate the response of intact parathyroid hormone (iPTH) to vitamin D3 supplementation among Malaysian women of reproductive age in a randomised double-blind placebo-control trial [NMRR-15-479-25680]. A total of 106 women who fulfilled the study inclusion criteria were randomly assigned to receive daily one of these three supplement doses (i) 600 IU vitamin D3 + 500 mg calcium; (ii) 1200 IU vitamin D3 + 500 mg calcium; or (iii) 4000 IU vitamin D3 + 500 mg calcium. The placebo group received daily 500 mg calcium. The outcome examined was change in plasma iPTH concentration in response to daily vitamin D3 supplementation for 16 weeks. Fasting blood sample was obtained at baseline and post-supplementation. A total of 78 subjects (73.6%) completed the intervention. None of the supplementation groups brought about any detectable suppression of iPTH concentration post-supplementation. Vitamin D3 supplementation resulted in overall increase in plasma 25(OH)D levels, but only the 4000 IU/day group showed a significant dose effect post-supplementation (mean 49.7 ± 26.5 nmol/L) compared to placebo (29.3 ± 13.3 nmol/L). The lack of iPTH suppression is attributed to high prevalence of vitamin D insufficiency at baseline and the supplementation regimen was inadequate to raise the 25(OH)D level to cause PTH suppression. Inadequate calcium intake of the participants was also a likely contributing factor to the result. As prolonged vitamin D insufficiency and hypocalcaemia could lead to a compensatory rise in PTH resulting in accelerated bone loss, as well as posing increasing risks of non-skeletal morbidities, further clinical trials with an adequately powered sample size should be undertaken over an appropriate study duration to verify the results obtained in this study.

Low bone mineral density and its related factors in adults with congenital heart disease in Vietnam: A cross‐sectional study

Background and Aims

Recent studies have highlighted the increased risk of low bone mineral density (BMD) in adults with cardiovascular disease. However, little is known about BMD in adults with congenital heart disease (CHD), particularly in developing countries. We hypothesized that factors related to BMD would lead to a high prevalence of low BMD in adults with CHD. This study aimed to determine the prevalence of low BMD and its related factors in Vietnamese adults with CHD.

Methods

We conducted a cross‐sectional study of 73 adults diagnosed with CHD in Vietnam. Low BMD was classified based on their site‐specific Z‐scores and T‐scores at the posteroanterior lumbar spine and left proximal femur. Logistic regression analyses were performed to evaluate factors related to low BMD.

Results

Low BMD was confirmed in one‐third of the adults with CHD. There were trends of more bone loss in certain parts of the body than in others, with the prevalence of low BMD at the sites of the lumbar vertebrae (L1‒L4) and left proximal femur (femoral neck, trochanteric femur, and intertrochanteric area) of 43.9%, 31.8%, 28.8%, 33.3%, 8.8%, 1.5%, and 6.1%, respectively. The prevalence of low BMD in the lumbar spine was significantly higher than that in the left proximal femur (34.3% vs. 2.9%, p < 0.001). Moreover, the prevalence of low BMD was significantly higher in adults with CHD than in those without polycythemia and vitamin D deficiency (55.6% vs. 20.9%, p = 0.001 and 46.2% vs. 19.4%, p = 0.002, respectively). A stratified multivariate logistic regression analysis revealed that low BMD was associated with polycythemia (odds ratio: 4.72; 95% confidence interval: 1.64–13.58, p = 0.004).

Conclusions

Low BMD is common among adults with CHD in Vietnam and related to polycythemia.

Evaluation of the knowledge regarding vitamin D, and sunscreen use of female adolescents in Iran

BACKGROUND

Vitamin D (Vit D) deficiency/insufficiency is an important risk factor for several chronic conditions. We aimed to evaluate the knowledge and behavior of female adolescents with respect to the association between sunlight exposure, sunscreen use, and Vit D status.

METHODS

This cross-sectional survey was performed in northeastern Iran, among 940 female adolescents in January 2015. Each subject completed a questionnaire containing items about demographic characteristics, knowledge about Vit D and their use of sunscreen. Serum Vit D levels were measured using an electrochemiluminescence method and dietary intake of Vit D was assessed using a Food Frequency Questionnaire. Statistical analyses were conducted using SPSS software. A P value < 0.05 was considered statistically significant.

RESULTS

Few of the participants were aware of the biological functions of Vit D (8.8%), the causes of Vit D deficiency (16.7%), and the sources of Vit D (9.3%). Less than half of the participants used sunscreen during the day. The serum levels of Vit D in subjects who used sunscreen were significantly lower than those who did not (p = 0.004). However, there was no significant association between their knowledge about Vit D and serum Vit D, or dietary intake of Vit D.

CONCLUSION

There appears to be a lack of coherence between lifestyle, behavior and knowledge that may affect the Vit D status of adolescent girls in northeastern Iran. This information provides a basis for developing public health planning (workshops or training at the college level) for the prevention of Vit D deficiency especially in adolescent girls.

Community-based social and demographic assessment of knowledge, attitudes, practices and medical conditions related to vitamin D deficiency in Gilgit Baltistan, Pakistan

Vitamin D is an important nutrient for bone health, and vitamin D deficiency increases the risk of various diseases. Gilgit Baltistan, the northern-most area of Pakistan, has a high prevalence of vitamin D deficiency, despite many nutritional and food safety programmes. The present study aimed to find how knowledge, attitudes and practices associated with vitamin D related to the prevalence of vitamin D deficiency among people residing in different areas of Gilgit Baltistan. The cross-sectional study was descriptive and used data from a survey carried out between February 2019 and December 2020 on individuals of both sexes aged 10 years or over in Gilgit Baltistan. Of the 575 survey participants, 306 (53.2%) had experienced signs and symptoms of vitamin D deficiency, i.e. tiredness, fatigue and bone weakness. Approximately 64.8% had some general knowledge of vitamin D and its relation to health. Participants aged 19-25 years had the highest scores on knowledge of vitamin D. Only 22.7% of interviewees had ever taken any supplements and only 25.6% often exposed themselves to sunlight. Females' mean knowledge score (28.7; SD 7.02) was higher than that of males (24; SD 9.01). A lack of consistency was observed between attitude towards daylight exposure and knowledge of vitamin D. There was a large correlation between knowledge and attitude (p = 0.001), while a non-significant association was demonstrated between knowledge and practices (p = 0.1). Better knowledge, attitude and practices by people living in cities or more-developed regions indicates that education can be an effective way to provide awareness regarding micronutrient deficiencies. More emphasis is needed on enhancing knowledge, awareness and practices associated with vitamin D deficiency in rural areas of Pakistan. It is strongly recommended that an awareness campaign on micronutrients is launched in both rural and urban areas of Pakistan, concentrating on poor socioeconomic settings.

Impact of vitamin D deficiency on COVID-19

Background & aims

COVID-19 has emerged as a global pandemic affecting millions of people. Vitamin D deficiency is one of the risk factors for increased susceptibility to COVID-19. This study aimed to examine the correlation between the prevalence of vitamin D deficiency and COVID-19 infection and mortality rates among the adult population in European and Asian continents.

Methods

Prevalence of vitamin D deficiency in each country was retrieved through literature searching on PubMed® database for the last ten years. As of December, 31^st 2020, COVID-19 infections and mortalities per million population were extracted from the ‘real time’ statistics of the Worldometer website. The association between both vitamin D deficiency and COVID-19 infections and mortalities were explored.

Results

Forty seven countries were included in the analysis. The prevalence of vitamin D deficiency ranged from 6.9 to 81.8% in European countries and 2.0–87.5% in Asian countries. Significantly positive correlations were observed for both COVID-19 infection (r = 0.76; p < 0.001) and mortality rates (r = 0.75; p < 0.001) in the Asian continent. The correlation values for the infections and mortality rates in the European continent were (r = 0.37; p = 0.08) and (r = 0.43; p = 0.04) respectively. When both the continents were combined, the correlation results for both infection (r = 0.42; p = 0.003) and mortality (r = 0.35; p = 0.016) rates with vitamin D deficiency values remained significant.

Conclusion

Prevalence of vitamin D deficiency was significantly associated with the mortality rate of COVID-19 in Europe and Asia. The association between the infection rate and prevalence of vitamin D deficiency was significant for Asia only. Both the associations were significant when the two continents were combined in the analysis. Therefore we suggest that vitamin D supplementation could play a key role in the prevention and/or treatment of the COVID-19 patients.

Impact of the vitamin D deficiency on COVID-19 infection and mortality in Asian countries

BACKGROUND AND AIMS

COVID-19 is a pandemic that has affected beyond 100 million and caused nearly 3 million deaths globally. Vitamin D is a known risk factor for COVID-19. Therefore, we aimed to investigate the association of prevalence of vitamin D deficiency and mean vitamin D level with COVID-19 infection and mortality in Asia, predicting with other confounding factors such as median age, obesity, and diabetes.

METHODS

COVID-19 infections and mortalities among the Asian countries were retrieved from the Worldometer website. Information on prevalence of vitamin D deficiency and mean vitamin D values in each Asian country was retrieved through literature searching on PubMed® and Google scholar. The associations between COVID-19 infections and mortalities with prevalence of vitamin D deficiency and mean vitamin D level were explored with correlation coefficients. As a predictive analysis, multiple linear regression was carried out with all confounders.

RESULTS

Positive correlations were observed for prevalence of vitamin D deficiency with COVID-19 infections (r = 0.55; p = 0.01; R² = 0.31) and mortalities (r = 0.50; p = 0.01; R² = 0.25). Moreover, the associations for the COVID-19 infections and mortalities improved to r = 0.76 (p = 0.002; R² = 0.58) and r = 0.65 (p = 0.03; R² = 0.42), respectively, after predicting with confounding factors. Similarly, mean vitamin D level had a significant negative correlation with COVID-19 infections (r = -0.77; p = 0.04; R² = 0.59) and mortalities (r = -0.80; p = 0.03; R² = 0.63) when combining with confounders.

CONCLUSION

Prevalence of vitamin D deficiency is significantly positively associated whereas the mean vitamin D level is significantly negatively associated with both infection and mortality rate of COVID-19 among Asian countries upon predicting with all confounders.

Comparison of Vitamin D Levels, Bone Metabolic Marker Levels, and Bone Mineral Density among Patients with Thyroid Disease: A Cross-Sectional Study

Thyroid hormones have a catabolic effect on bone homeostasis. Hence, this study aimed to evaluate serum vitamin D, calcium, and phosphate and bone marker levels and bone mineral density (BMD) among patients with different thyroid diseases. This cross-sectional study included patients with underlying thyroid diseases (n = 64, hyperthyroid; n = 53 euthyroid; n = 18, hypothyroid) and healthy controls (n = 64). BMD was assessed using z-score and left hip and lumbar bone density (g/cm²). The results showed that the mean serum vitamin D Levels of all groups was low (<50 nmol/L). Thyroid patients had higher serum vitamin D levels than healthy controls. All groups had normal serum calcium and phosphate levels. The carboxy terminal collagen crosslink and procollagen type I N-terminal propeptide levels were high in hyperthyroid patients and low in hypothyroid patients. The z-score for hip and spine did not significantly differ between thyroid patients and control groups. The hip bone density was remarkably low in the hyperthyroid group. In conclusion, this study showed no correlation between serum 25(OH)D levels and thyroid diseases. The bone markers showed a difference between thyroid groups with no significant difference in BMD.

Osteoporosis in South-East Asian Countries

Osteoporosis (OP) is a condition where there is low bone density and microarchitectural deterioration which can predispose to fragility fractures. There is a wealth of literature on OP from the developed countries, but less so from Asia. This review will explore the field of OP research in South-East Asia with regard to the epidemiology, the diagnosis of OP and the role of laboratory tests in the management of OP, with emphasis on 25-dihydroxyvitamin D and bone turnover markers.

Vitamin D Status and Its Associated Risk Factors among Adults in the Southwest Region of Cameroon

Background

Vitamin D has been shown to exert its actions on the musculoskeletal, gastrointestinal, prostate, renal, endocrine, immune, and cardiovascular systems. Current reported data of hypovitaminosis D reveals a global pandemic, with an estimated one billion people worldwide presenting with hypovitaminosis D.

Objective

This study aimed at investigating the vitamin D status and its associated risk factors in Cameroonians from the South West Region.

Method

The study was a community- and hospital-based prospective longitudinal study. It was carried out during the dry and rainy seasons between the months of July and December 2015 in the South West Region of Cameroon involving 372 participants aged 35 years and above. After obtaining informed consent, a structured questionnaire was used to capture demographic data and risk factors of vitamin D deficiency. Blood samples were collected from the volunteer participants in the peak months of the rainy season and dry season, and the serum used to analyse for vitamin D by ELISA and calcium by spectrophotometry. 25(OH)D levels ≥75 nmol/L (≥30 ng/mL) were considered sufficient while levels <75 nmol/L were considered as hypovitaminosis D (insufficiency/deficiency).

Results

Hypovitaminosis D (deficiency/insufficiency) was prevalent in 25.8% (96) of the study population, with only 3.2% (12) deficiency and 22.6% (84) insufficiency. There was a significant inverse relationship (r=−0.119, p=0.02) between age and 25(OH)D levels; however, this relationship was not significant when controlled for gender, number of hours spent outdoors, and percentage of body covered. Gender, ethnic origin, percentage of body covered, time spent outdoors, and season did not influence serum vitamin D levels.

Conclusion

Results of this study suggest that the prevalence of hypovitaminosis D is relatively low in this study population and only age is a risk factor of vitamin D deficiency.

Is vitamin D deficiency a public health concern for low middle income countries? A systematic literature review

PURPOSE

Vitamin D deficiency has been receiving increasing attention as a potential public health concern in low and lower-middle income countries (LMICs), of which there are currently 83. We aimed to conduct a comprehensive systematic literature review (SLR) of available data on vitamin D status and prevalence of vitamin D deficiency in all 83 LMICs.

METHODS

We followed the general methodology for SLRs in the area of serum 25-hydroxyvitamin D. Highest priority was placed on identifying relevant population-based studies, followed by cross-sectional studies, and to a lesser extent case-control studies. We adopted the public health convention that a prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D < 25/30 nmol/L) at > 20% in the entire population and/or at-risk population subgroups (infants, children, women of child-bearing age, pregnancy) constitutes a public health issue that may warrant intervention.

RESULTS

Our SLR revealed that of the 83 LMICs, 65% (n = 54 countries) had no published studies with vitamin D data suitable for inclusion. Using data from the remaining third, a number of LMICs had evidence of excess burden of vitamin D deficiency in one or more population subgroup(s) using the above convention (Afghanistan, Pakistan, India, Tunisia and Mongolia) as well as possibly other LMICs, albeit with much more limited data. Several LMICs had no evidence of excess burden.

CONCLUSION

Vitamin D deficiency is a public health issue in some, but certainly not all, LMICs. There is a clear need for targeting public health strategies for prevention of vitamin D deficiency in those LMICs with excess burden.

Diabetes in Vietnam

BACKGROUND

The prevalence for diabetes, prediabetes, and gestational diabetes in Vietnam are low relative to other parts of the world, but they are increasing at alarming rates. These changes have occurred in the setting of economic and cultural transitions.

OBJECTIVES

The aim of this study was to provide relevant information depicting the diabetes burden in Vietnam.

METHODS

Literature was reviewed using PubMed and local Vietnamese sources, including papers published in the Vietnamese language.

FINDINGS

In 2012, the prevalence of diabetes was 5.4% and prediabetes 13.7%. In 2005, the prevalence of obesity was 1.7%. There is a dual burden of over- and undernutrition observed in Vietnam. Diabetes is associated with an increased waist-to-hip ratio despite normal body mass index. Nutritional transitions occurred with increased protein, fat, and fast foods, and with decreased fresh fruits and vegetables. Tobacco use is very high in Vietnam with 66% of adult men currently smoking. Challenges include endocrinology training, health care coverage, patient education, and lack of coordination among government and specialist agencies.

CONCLUSION

Diabetes is a growing problem in Vietnam and is associated with obesity, changes in dietary patterns, and other cultural transitions. More research is needed to better understand this health care problem and to devise targeted interventions.

Milk vitamin D in relation to the 'adequate intake' for 0-6-month-old infants: a study in lactating women with different cultural backgrounds, living at different latitudes

Breast-fed infants are susceptible to vitamin D deficiency rickets. The current vitamin D 'adequate intake' (AI) for 0-6-month-old infants is 10 µg/d, corresponding with a human milk antirachitic activity (ARA) of 513 IU/l. We were particularly interested to see whether milk ARA of mothers with lifetime abundant sunlight exposure reaches the AI. We measured milk ARA of lactating mothers with different cultural backgrounds, living at different latitudes. Mature milk was derived from 181 lactating women in the Netherlands, Curaçao, Vietnam, Malaysia and Tanzania. Milk ARA and plasma 25-hydroxyvitamin D (25(OH)D) were analysed by liquid-chromatography-MS/MS; milk fatty acids were analysed by GC-flame ionisation detector (FID). None of the mothers reached the milk vitamin D AI. Milk ARA (n; median; range) were as follows: Netherlands (n 9; 46 IU/l; 3-51), Curaçao (n 10; 31 IU/l; 5-113), Vietnam: Halong Bay (n 20; 58 IU/l; 23-110), Phu Tho (n 22; 28 IU/l; 1-62), Tien Giang (n 20; 63 IU/l; 26-247), Ho-Chi-Minh-City (n 18; 49 IU/l; 24-116), Hanoi (n 21; 37 IU/l; 11-118), Malaysia-Kuala Lumpur (n 20; 14 IU/l; 1-46) and Tanzania-Ukerewe (n 21; 77 IU/l; 12-232) and Maasai (n 20; 88 IU/l; 43-189). We collected blood samples of these lactating women in Curaçao, Vietnam and from Tanzania-Ukerewe, and found that 33·3 % had plasma 25(OH)D levels between 80 and 249·9 nmol/l, 47·3 % between 50 and 79·9 nmol/l and 19·4 % between 25 and 49·9 nmol/l. Milk ARA correlated positively with maternal plasma 25(OH)D (range 27-132 nmol/l, r 0·40) and milk EPA+DHA (0·1-3·1 g%, r 0·20), and negatively with latitude (2°S-53°N, r -0·21). Milk ARA of mothers with lifetime abundant sunlight exposure is not even close to the vitamin D AI for 0-6-month-old infants. Our data may point at the importance of adequate fetal vitamin D stores.

Vitamin D and Parathyroid Hormone Status in Female Garment Workers: A Case-Control Study in Bangladesh

Despite the abundant sunlight, vitamin D deficiency is prevalent in South Asian countries including Bangladesh. Information on vitamin D level is insufficient in adults particularly in female garment workers in Bangladesh. This study was designed to evaluate the status of vitamin D, parathormone (PTH), calcium, and alkaline phosphatase (ALP) among the female garment workers in Bangladesh. Blood samples were collected from female garment workers (n = 40, case group) and general female workers (n = 40, control group) in Dhaka. Serum vitamin D, PTH, calcium, and ALP were measured by chemiluminescence microparticle immunoassay. The mean level of vitamin D was significantly (p < 0.001) lower in case (14.2 ± 2.6 ng/mL) than in the control (22.4 ± 2.4 ng/mL) group. No significant difference was found at mean of PTH and calcium between case (33.9 ± 17.2 pg/mL; 9.1 ± 0.6 mg/dL, resp.) and control (35.9 ± 16.3 pg/mL; 9.3 ± 0.6 mg/dL, resp.) group. The mean ALP in case (117.2 ± 14.4 U/L) group was significantly (p < 0.001) higher than the control group (80.5 ± 30.6 U/L). Overall, PTH level did not show significant correlation with vitamin D. However, calcium and ALP levels showed a significant positive (p < 0.05) and negative (p < 0.001) correlation with vitamin D, respectively. This study indicates a high prevalence of vitamin D deficiency in the female garment workers in Bangladesh.

Lessons from the Bone Chapter of the Malaysian Aging Men Study

Male osteoporosis in Malaysia is a largely neglected problem. Therefore, a bone health study in men using quantitative ultrasonometry was launched as part of the Malaysian Aging Men Study in 2009–2012. This review aimed to summarize the findings of the aforementioned bone health study. The study examined the bone health of Chinese and Malaysian men aged 20 years and above living in Kuala Lumpur using a quantitative ultrasound device. Participants answered a questionnaire on their demographic details and physical activity status. Body anthropometry of the participants was measured and their blood collected for biochemical analysis. Results showed that a significant proportion of the Malaysian Chinese and Malay men had suboptimal bone health indicated by calcaneal speed of sound and vitamin D status. Age-related decline of the calcaneal speed of sound in these men was gradual and biphasic without ethnic difference. Body anthropometry such as height, weight, body mass index, and body fat percentage contributed to the variation of the calcaneal speed of sound in Malaysian men. Age-related changes in testosterone, insulin-like growth factor 1, and thyroid stimulating hormone also influenced the calcaneal speed of sound in these men. This study serves as a reminder that male osteoporosis in Malaysia should be an issue of concern. It is also a basis for a more comprehensive study on bone health in men in the future.

Vitamin D deficiency and depression among women from an urban community in a tropical country

Objective

To determine the association of vitamin D status with depression and health-related quality of life among women.

Design

This was a cross-sectional study conducted among women in Kuala Lumpur, Malaysia. Sociodemographic characteristics, physical activity status, perceived depression and health-related quality of life were assessed via a self-administered questionnaire. Fasting blood samples were taken for the analysis of 25-hydroxyvitamin D, parathyroid hormone, fasting blood glucose and full lipid profile. Complex samples multiple logistic regression analysis was performed.

Setting

Public secondary schools in Kuala Lumpur, Malaysia.

Subjects

Seven hundred and seventy female teachers were included.

Results

The mean age of participants was 41·15 (95 % CI 40·51, 41·78) years and the majority were ethnic Malays. Over 70 % of them had vitamin D deficiency (<20 ng/ml or <50 nmol/l) and two-thirds were at risk for depression. In the multivariate analysis, ethnic Malays (adjusted OR (aOR)=14·72; 95 % CI 2·12, 102·21) and Indians (aOR=14·02; 95 % CI 2·27, 86·59), those at risk for depression (aOR=1·88, 95 % CI 1·27, 2·79) and those with higher parathyroid hormone level (aOR=1·13; 95 % CI 1·01, 1·26) were associated with vitamin D deficiency, while vitamin D deficiency was negatively associated with mental health-related quality of life (Mental Component Summary) scores (aOR=0·98; 95 % CI 0·97, 0·99).

Conclusions

Vitamin D deficiency is significantly associated with depression and mental health-related quality of life among women in Kuala Lumpur, Malaysia.

Vitamin D level and its association with adiposity among multi-ethnic adults in Kuala Lumpur, Malaysia: a cross sectional study

Background

Vitamin D deficiency is highly prevalent in both temperate as well as tropical countries. Obesity is one of the factors contributing to vitamin D deficiency. As our country has a high prevalence of overweight and obesity, we aimed to study serum 25-hydroxyvitamin D (25(OH)D) level and its association with adiposity using various adiposity indicators; and to study other risk factors that affect serum 25(OH)D level among multi-ethnic adults in Kuala Lumpur, Malaysia.

Methods

This was a cross sectional study conducted with a multistage sampling. All permanent teachers working in government secondary schools in Kuala Lumpur were invited for the study. The data collection included serum 25(OH)D, Parathyroid Hormone (PTH), body fat percentage, waist circumference, body mass index (BMI) and blood pressure. Demographic characteristics, sun avoidance, sun exposure and physical activity were enquired from the participants using a self-administered questionnaire. The data was analyzed using a complex sample analysis.

Results

A total of 858 participants were recruited. Majority of them were Malays, females and had tertiary education. The overall prevalence of vitamin D deficiency (<20 ng/ml) was 67.4 %. Indian participants (80.9 %) had the highest proportion of vitamin D deficiency, followed by Malays (75.6 %), others (44.9 %) and Chinese (25.1 %). There was a significant negative association between serum 25(OH)D level with BMI (β = −0.23) and body fat percentage (β = −0.14). In the multivariate linear regression analysis, Malays, Indians and females (p < 0.001); higher BMI and larger waist circumference (p < 0.05) were significantly associated with lower serum 25(OH)D level. The full model explained 32.8 % of the variation between participants in the serum 25(OH)D level. The two most influential factors affecting serum 25(OH)D level were ethnicity and gender.

Conclusions

The prevalence of vitamin D deficiency among our participants was high. Adiposity was associated with serum 25(OH)D level. Skin pigmentation and gender based behaviours were more dominant in contributing to serum 25(OH)D level. Health education should be targeted in weight management, gender based behaviours on sun exposure, as skin pigmentation is non-modifiable.

Prevalence of Vitamin D Deficiency in Elderly Patients Admitted to an Inpatient Rehabilitation Unit in Tropical Singapore

Background. Data on hypovitaminosis D in elderly patients admitted to rehabilitation units in tropical countries are scarce. Objective. To assess the prevalence of vitamin D deficiency and its associated risk factors in elderly patients admitted to a rehabilitation unit in tropical Singapore. Methods. Prospective, cohort study of 134 subjects ≥ 65 years old admitted to a tertiary rehabilitation centre. Serum 25-hydroxyvitamin D3 (25OHD3) was measured on rehabilitation admission. Results. Mean age was 72.0 ± 5.7 years, and stroke was the commonest rehabilitation diagnosis (49.3%). Low 25OHD3 levels were present in 115 patients (85.6%) and 59 patients (44%) were deemed to be vitamin D deficient. The mean PTH level was significantly higher in patients with low 25OHD3 levels. (p = 0.002) Age, gender, vitamin D supplementation, premorbid ambulatory status, and admission/discharge Functional Independence Measure scores were not significantly associated with vitamin D deficiency. Malays/Indians (p = 0.013) and recurrent fallers (p = 0.029) were at significantly higher risk of vitamin D deficiency. Conclusions. Despite the tropical weather, vitamin D deficiency is common in elderly subjects admitted to a rehabilitation unit in Singapore. Routine assessment of vitamin D levels is recommended especially in those with a history of recurrent falls and patients of Indian/Malay ethnicity.

Determinants of serum 25-hydroxyvitamin D in Hong Kong

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

Vitamin D status in Malaysian men and its associated factors

Vitamin D insufficiency is a global health problem. The data on vitamin D status in Malaysian men is insufficient. This study aimed to investigate vitamin D status among Chinese and Malay men in Malaysia and its associating factors. A cross-sectional study was conducted on 383 men aged 20 years and above, residing in Klang Valley, Malaysia. Their age, ethnicity, body anthropometry and calcaneal speed of sound (SOS) were recorded. Their fasting blood was collected for serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid (PTH), total calcium and inorganic phosphate assays. Vitamin D deficiency was defined as a serum 25(OH)D level <30 nmol/L and insufficiency as a serum 25(OH)D level between 30 and 50 nmol/L. The overall prevalence of vitamin D deficiency was 0.5%, and insufficiency was 22.7%. Vitamin D deficiency and insufficiency were more prevalent in the Malays compared to the Chinese. Being Chinese, older in age, having lower body mass index (BMI) and a high physical activity status were associated significantly with a higher serum 25(OH)D level (p < 0.05). The serum PTH level was inversely associated with the serum 25(OH)D level (p < 0.05). As a conclusion, a significant proportion of Malaysian men have vitamin D insufficiency, although deficiency is uncommon. Steps should be taken to correct the vitamin D status of these men.

Is vitamin D deficiency a major global public health problem?

Vitamin D deficiency is a major public health problem worldwide in all age groups, even in those residing in countries with low latitude, where it was generally assumed that UV radiation was adequate enough to prevent this deficiency, and in industrialized countries, where vitamin D fortification has been implemented now for years. However, most countries are still lacking data, particularly population representative data, with very limited information in infants, children, adolescents and pregnant women. Since the number of recent publications is escalating, with a broadening of the geographic diversity, the objective of the present report was to conduct a more recent systematic review of global vitamin D status, with particular emphasis in at risk groups. A systematic review was conducted in PubMed/Medline in April-June 2013 to identify articles on vitamin D status worldwide published in the last 10 years in apparently healthy individuals. Only studies with vitamin D status prevalence were included. If available, the first source selected was population-based or representative samples studies. Clinical trials, case-control studies, case reports or series, reviews, validation studies, letters, editorials, or qualitative studies were excluded. A total of 103 articles were eligible and included in the present report. Maps were created for each age group, providing an updated overview of global vitamin D status. In areas with available data, the prevalence of low vitamin D status is a global problem in all age groups, in particular in girls and women from the Middle East. These maps also evidenced the regions with missing data for each specific population groups. There is striking lack of data in infants, children and adolescents worldwide, and in most countries of South America and Africa. In conclusion, vitamin D deficiency is a global public health problem in all age groups, particularly in those from the Middle East. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

Maternal vitamin D status and infant outcomes in rural Vietnam: a prospective cohort study

Objective

Vitamin D deficiency affects 1 billion people globally. It has an important role in bone homeostasis, brain development and modulation of the immune system and yet the impact of antenatal vitamin D deficiency on infant outcomes is poorly understood. We assessed the association of 25- hydroxyvitamin D levels (25-OHD) in late pregnancy and early infant growth and developmental outcomes in rural Vietnam.

Design and Methods

A prospective cohort study of 960 women who had previously participated in a double-blind cluster randomized controlled trial of antenatal micronutrient supplementation in rural Vietnam was undertaken. Maternal 25-OHD concentration was measured at 32 weeks gestation, and infants were followed until 6 months of age. Main outcome measures were cognitive, motor, socio-emotional and language scores using the Bayley Scales of Infant Development, 3^rd edition, and infant length-for-age z scores at 6 months of age.

Results

60% (582/960) of women had 25-OHD levels <75 nmol/L at 32 weeks gestation. Infants born to women with 25-OHD deficiency (<37.5 nmol/L) had reduced developmental language scores compared to those born to women who were vitamin D replete (≥75 nmol/L) (Mean Difference (MD) −3.48, 95% Confidence Interval (CI) −5.67 to −1.28). For every 25 nmol increase in 25-OHD concentration in late pregnancy, infant length-for-age z scores at 6 months of age decreased by 0.08 (95% CI −0.15 to −0.02).

Conclusions

Low maternal 25- hydroxyvitamin D levels during late pregnancy are of concern in rural Vietnam, and are associated with reduced language developmental outcomes at 6 months of age. Our findings strengthen the evidence for giving vitamin D supplementation during pregnancy.

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.

Vitamin D status and seasonal changes in plasma concentrations of 25-hydroxyvitamin D in office workers in Ankara, Turkey

BACKGROUND

Lack of sun exposure is one of the primary causes of epidemic vitamin D deficiency worldwide. The aim of this study was to investigate vitamin D status and seasonal changes in summer and winter in office workers.

METHODS

This study was conducted in Ankara located at 39° 52' 30" N, 32° 52' E. The study consisted of 118 premenopausal women and men aged between 21 and 52 years-old. Seasonal changes were evaluated in August and February. Fasting serum was obtained for intact parathyroid hormone (iPTH) and 25-hydroxyvitamin D (25OHD). Additional data were collected by a questionnaire that enquired about age, weight, height, wearing style, dietary calcium intake and sunlight exposure. Serum 25OHD concentration was measured using a precise HPLC assay. Low vitamin D status was defined as a 25OHD concentration less than 30 ng/mL.

RESULTS

Mean serum 25OHD concentration in summer was 28.4±10.4 ng/mL and 13.8±6.6 ng/mL in winter (p<0.001). 35.6% of the subjects were vitamin D insufficient in summer and 12.7% in winter (p<0.001) while 31.5% were vitamin D deficient in summer and 83.9% in winter (p<0.001). A significant increase in iPTH levels (33.1±15.9 pg/mL vs 49.6±24.3 pg/mL, p<0.001) was observed throughout the seasonal change. No significant association was found between 25OHD levels and iPTH, body mass index, age and sun exposure index (p>0.05 for all) in both seasons.

CONCLUSION

Vitamin D deficiency is very prevalent in office workers even in summer time and this should be accepted as a public health problem.

Vitamin D and its relationship with markers of bone metabolism in healthy Asian women

BACKGROUND

In this study, we aimed to determine the normal ranges of 25-hydroxy-vitamin D(3) (25-OHD(3)), parathyroid hormone (PTH), and the markers of bone turnover, procollagen type 1 N propeptide (P1NP) and C-terminal cross-linked telopeptide of type 1 collagen (CTX), in normal healthy women in Singapore, and to explore the relationship between vitamin D, PTH, and these markers of bone turnover in the women.

METHODS

One hundred and ninety-seven healthy women, aged 25 to 60, were selected from a hospital staff health screening program; 68% were Chinese, 18% Malay, and 14% Indian. P1NP, CTX, and 25-OHD(3) were measured using the Roche Cobas® electrochemiluminescence immunoassay. Serum PTH was measured using the Siemens ADVIA Centaur® immunoassay.

RESULTS

Sixty-five percent had 25-OHD(3) concentrations <50 nmol/l. Vitamin D insufficiency (25-OHD(3) < 50 nmol/l) was more prevalent in Malays (89%) and Indians (82%) compared to Chinese (56%). There was no correlation between vitamin D and age. PTH positively correlated with age, and Malays and Indians had higher PTH concentrations than Chinese. There was an inverse correlation between PTH and 25-OHD(3), but no threshold of 25-OHD(3) concentrations at which PTH plateaued. The bone turnover markers P1NP and CTX inversely correlated with age but were not different between ethnic groups. CTX and P1NP exhibited good correlation, however, there was no significant correlation between 25-OHD(3) or PTH concentrations and the bone turnover markers P1NP and CTX.

CONCLUSIONS

Healthy women in Singapore have a high prevalence of vitamin D insufficiency. Vitamin D insufficiency was more prevalent in Malays and Indians compared to Chinese.

Double burden of undernutrition and overnutrition in Vietnam in 2011: results of the SEANUTS study in 0·5-11-year-old children

The Vietnamese South East Asian Nutrition Survey (SEANUTS), a cross-sectional study, was undertaken to assess the nutritional status in a nationally representative sample of children aged 0·5-11·9 years. A multi-stage cluster-randomised sampling method was used to recruit 2872 children. Anthropometric measurements included weight, height, mid-upper arm circumference, and waist and hip circumferences. Blood biochemistry involved analyses of Hb, serum ferritin, and vitamins A and D. Dietary intake was assessed using a 24 h recall questionnaire, and nutrient intakes were compared with the Vietnamese RDA. In children aged < 5 years, approximately 14% were stunted, 8·6% underweight and 4·4% thin. A higher prevalence of stunting (15·6%) and underweight (22·2%) was observed in school-aged children. Undernutrition was more prevalent in rural areas than in urban areas. In contrast, almost 29% of the urban children were either overweight or obese when compared with 4% of the overweight children and 1·6% of the obese children in rural areas. A higher percentage of children in the age group 0·5-1·9 years and residing in rural areas had low Hb levels than those in the age group 2·0-5·9 years and residing in urban areas. In children aged 6-11 years, a small percentage had low Hb (11-14%) and vitamin A (5-10%) levels, but almost half the children (48-53%) had vitamin D insufficiency. Food consumption data indicated that the children did not meet the RDA for energy, protein, Fe, vitamin A, vitamin B1 and vitamin C. Results from the SEANUTS highlight the double burden of malnutrition in Vietnam. Information from the SEANUTS can serve as an input for targeted policy development, planning and development of nutrition programmes.

Vitamin D insufficiency and deficiency with stages of chronic kidney disease in an Asian population

Background

Vitamin D insufficiency is associated with proteinuria and could be a risk factor for end-stage renal disease (ESRD). However, few studies have examined the significance of vitamin D insufficiency as a contributing factor for the development of ESRD in the Asian chronic kidney disease (CKD) population.

Methods

Authors examined the relationship between vitamin D status and the staging of CKD using data from an outpatient clinic-based screening in 2,895 Thai CKD patients. Serum levels of 25-hydroxyvitamin D were analyzed according to CKD stages. Vitamin D deficiency and insufficiency were defined as a serum 25-hydroxyvitamin D concentration < 10 ng/mL and 10–30 ng/mL, respectively.

Results

The mean (SD) 25-hydroxyvitamin D levels were significantly lower according to severity of renal impairment (CKD stage 3a: 27.84±14.03 ng/mL, CKD stage 3b: 25.86±11.14 ng/mL, CKD stage 4: 24.09±11.65 and CKD stage 5: 20.82±9.86 ng/mL, p<0.001). The prevalence of vitamin D deficiency/insufficiency was from CKD stage 3a, 3b, 4 to 5, 66.6%, 70.9%, 74.6%, and 84.7% (p<0.001). The odds ratio (95% CI) of vitamin D insufficiency/deficiency (serum 25-hydroxyvitamin D ≤ 30 ng/mL) and vitamin D deficiency (serum 25-hydroxyvitamin D < 10 ng/mL) for developing ESRD, after adjustment for age, gender, hemoglobin, serum albumin, calcium, phosphate and alkaline phosphatase were 2.19 (95% CI 1.07 to 4.48) and 16.76 (95% CI 4.89 to 57.49), respectively.

Conclusion

This study demonstrates that 25-hydroxyvitamin D insufficiency and deficiency are more common and associated with the level of kidney function in the Thai CKD population especially advanced stage of CKD.

A systematic review of vitamin D status in populations worldwide

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

An analysis of the association between the vitamin D pathway and serum 25-hydroxyvitamin D levels in a healthy Chinese population

Vitamin D deficiency has been recognized as a major public health issue worldwide. Recent studies have indicated that genetic factors might play an important role in determining serum 25-hydroxyvitamin D [25(OH)D] levels in Caucasians and African Americans. However, the genes that contribute to the variation in serum 25(OH)D levels in Chinese are unknown. In this study, we screened 15 key genes within the vitamin D metabolic pathway using 96 single-nucleotide polymorphism (SNP) markers in a group of 2897 unrelated healthy Chinese subjects. Significant confounding factors that may influence the variability in serum 25(OH)D levels were used as covariates for association analyses. An association test for quantitative traits was performed to evaluate the association between candidate genes and serum 25(OH)D levels. In the present study, variants and/or haplotypes in GC, CYP2R1, and DHCR7/NADSYN1 were identified as being associated with 25(OH)D levels. Participants with three or four risk alleles of the two variants (GC-rs4588 and CYP2R1-rs10766197) had an increased chance of presenting with a 25(OH)D concentration lower than 20 ng/mL (odds ratio 2.121, 95% confidence interval 1.586-2.836, p = 6.1 × 10(-8) ) compared with those lacking the risk alleles. Each additional copy of a risk allele was significantly associated with a 0.12-fold decrease in the log-25(OH)D concentration (p = 3.7 × 10(-12) ). Haplotype TGA of GC rs705117-rs2282679-rs1491710, haplotype GAGTAC of GC rs842999-rs705120-rs222040-rs4588-rs7041-rs10488854, haplotype CA of GC rs1155563-rs222029, and haplotype AAGA of CYP2R1 rs7936142-rs12794714-rs2060793-rs16930609 were genetic risk factors toward a lower 25(OH)D concentration. In contrast, haplotype TGGGCCC of DHCR7/NADSYN1 rs1790349-rs7122671-rs1790329-rs11606033-rs2276360-rs1629220-rs2282618 were genetic protective factors. The results suggest that the GC, CYP2R1, and DHCR7/NADSYN1 genes might contribute to variability in the serum 25(OH)D levels in a healthy Chinese population in Shanghai. These markers could be used as tools in Mendelian randomization analyses of vitamin D, and they could potentially be drug targets in the Chinese population in Shanghai.

Hypovitaminosis D and mild hypocalcaemia are highly prevalent among young Vietnamese children and women and related to low dietary intake

Introduction

In many developing countries including Vietnam, data are lacking on vitamin D and calcium deficiencies whereas those deficiencies can play an important role in the development of bone health and possibly non-communicable diseases. The purpose of this study was to determine the overall prevalence of vitamin D and calcium deficiencies in women and young children and their nutritional related risk factors.

Methods

A cross-sectional study conducted among 595 women of reproductive age and 532 children <5 years from 19 provinces of Vietnam. For each individual, data concerning daily diet, socioeconomic group, anthropometric status were obtained, and plasma concentrations of calcium and vitamin D were measured.

Results

The prevalence of hypovitaminosis D status was very high, with the prevalence of vitamin D deficiency (25(OH)D<30 nmol/L) and insufficiency (25(OH)D between 30–49.9 nmol/L) being 17% and 40% in women and 21% and 37% in children, respectively. Using more liberal cut-off of 75 nmol/L, approximately 90% of the women and children were classified as having hypovitaminosis D. Overweight/obese women had a 2 times lower risk (OR = 0.46, [0.24–0.90]) for vitamin D deficiency than non-overweight and non-obese women. No participant had severe calcium deficiency but moderate and mild hypocalcaemia (plasma calcium concentrations between 1.15-0.9 mmol/L for mild deficiency and between 0.9-0.8 mmol/L for moderate deficiency) affected respectively 14% and 83% of the women with 97% of the children having mild hypocalcaemia. Women and children consumed about 1% of the Institute of Medicine (IOM) recommended nutrient intake (RNI) for vitamin D and less than 43% of the RNI for calcium.

Conclusion

Our study suggests that calcium and vitamin D deficiencies represent a major public health concern in Vietnam. Thus, actions to improve the vitamin D and calcium status of the Vietnamese population should be considered.

Awareness regarding the importance of calcium and vitamin D among the undergraduate pharmacy students in Bangladesh

Background

Calcium and vitamin D are two important micronutrients required for maintaining proper bone health. Previous works intended to determine the status of these micronutrients in local population have reported that the people in Bangladesh are at high risk of calcium insufficiency and hypovitaminosis D related health complications. Lack of awareness and insufficient knowledge of the essentiality of these two nutrients are assumed to cause this problem in Bangladesh. The present study was designed and conducted to establish a basic understanding on the level of gap of knowledge and awareness among pharmacy students at undergraduate level in Bangladesh.

Findings

A total of 713 students of Bachelor of Pharmacy course participated in the study. The students were asked about basic idea related to calcium and vitamin D and the disorders due to their deficiency, name of common foods containing calcium and vitamin D, their perception regarding the essentiality of the said nutrients etc. It was found that most of the students were familiar with the importance of calcium (98.9%) and vitamin D (99.3%) in bone health. 82.2% students know about the term osteoporosis. Unfortunately, 10.7% and 18.8% students failed to mention at least one food that is rich in calcium and vitamin D, respectively. Most of the students got familiar about the nutrients from their teachers (48.9%) and textbooks (32.8%).

Conclusion

Being a student of pharmacy, the students should have more comprehensive knowledge about calcium and vitamin D. The present study indicates that the pharmacy students have lack of knowledge about calcium and vitamin D and thus it can be clearly predicted that the condition of general people may be worse.

Vitamin D deficiency in northern Vietnam: prevalence, risk factors and associations with bone mineral density

PURPOSE

Vitamin D deficiency has been linked to osteoporosis and also to the risk of cancer, autoimmune disorders and cardiovascular diseases. This study sought to determine the prevalence of, and risk factors for, vitamin D deficiency and its relationship with bone mineral density (BMD) in a Vietnamese population.

METHODS

This cross-sectional study involved 269 women and 222 men aged 13-83 years, who were randomly selected from urban and rural areas in northern Vietnam. Serum concentrations of 25-hydroxy-vitamin D [25(OH)D] and parathyroid hormone (PTH) were measured by electrochemiluminescence immunoassay. Vitamin D deficiency was defined as serum 25(OH)D levels below 20 ng/mL. BMD was measured by dual X-ray absorptiometry.

RESULTS

The prevalence of vitamin D deficiency in women was 30%, almost two-fold higher than in men (16%). Significant predictors of vitamin D deficiency in women were urban residency (p<0.01) and age less than 30 years (p<0.01), whereas use of contraceptive pills was protective (p<0.01). In men, winter season was the only significant predictor of vitamin D deficiency (p<0.01). In multiple linear regression analysis, serum levels of 25(OH)D were positively associated with BMD in both women (p<0.001) and men (p<0.001).

CONCLUSIONS

These data suggest that the prevalence of vitamin D deficiency is high in the Vietnamese population, and that part of this prevalence could be explained by low exposure to sunlight (urban residency and winter season). The high prevalence of vitamin D deficiency should raise the awareness of potentially important health issues such as osteoporosis within the Vietnamese society.

High prevalence of vitamin D insufficiency in China: relationship with the levels of parathyroid hormone and markers of bone turnover

There is a lack of large-scale studies on vitamin D status and its relationship to parathyroid hormone (PTH) and bone turnover markers in adults living in Shanghai. The objectives were to determine the prevalence of vitamin D insufficiency in Shanghai and to investigate the relationship of 25(OH)D with parathyroid function and bone turnover markers. This cross-sectional study involved 649 men and 1939 women aged 20–89 years who were randomly sampled in Shanghai. Serum concentrations of 25(OH)D, PTH, albumin, and bone turnover markers were measured. During the winter season, the prevalence of vitamin D insufficiency (<30 ng/mL) was 84% in males and 89% in females. The prevalence of vitamin D deficiency (<20 ng/mL) was 30% in males and 46% in females. With increasing serum 25(OH)D concentrations categorized as <10, 10–20, 20–30, and ≥30 ng/mL, the mean PTH and bone turnover markers levels gradually decreasd in both sexes (p<0.001). There was an inverse relationship between the serum 25(OH)D and PTH concentrations in both genders, but no threshold of 25(OH)D at which PTH levels plateaued was observed. There were modest but significantly inverse relationships between the levels of 25(OH)D and bone turnover markers, but no plateau was observed for serum 25(OH)D levels up to 40 ng/mL.

A global representation of vitamin D status in healthy populations

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

High prevalence of vitamin D deficiency among healthy Saudi Arabian men: relationship to bone mineral density, parathyroid hormone, bone turnover markers, and lifestyle factors

SUMMARY

In this cross-sectional study, the prevalence of vitamin D deficiency [serum 25-hydroxyvitamin D (25(OH)D) <50 nmol/L] was 87.8% among Saudi Arabian men. There was a linear inverse relationship between serum 25(OH)D and intact parathyroid hormone (PTH) levels, but without a threshold of 25(OH)D at which intact PTH values plateaued.

INTRODUCTION

Vitamin D insufficiency and/or deficiency has now reached epidemic proportions and has been linked to low bone mineral density (BMD), some lifestyle factors, and obesity in adults. This relationship is not well documented in Saudi Arabian men. This study examines the relationship between vitamin D status, intact parathyroid hormone (intact PTH), and lifestyle factors among Saudi Arabian men.

METHODS

This cross-sectional study involved 834 men aged 20-74 years living in Jeddah area who were randomly selected and medically examined. Men had their BMD (lumbar spine (L1-L4) and neck femur), 25(OH)D, intact PTH, and other parameters measured according to detailed inclusion criteria.

RESULTS

Deficiency (25(OH)D<50 nmol/L) and insufficiency (≥50-75 nmol/L) were present in 87.8% and 9.7%, respectively. Deficiency was common among older and obese men with no education and sedentary lifestyle sampled during summer and spring. Serum 25(OH)D showed an inverse linear relationship with intact PTH, but there was no threshold of serum 25(OH)D at which PTH levels plateaued. There was a positive correlation between BMD values at both lumbar spine (L1-L4) (P < 0.023) and neck femur (P < 0.036) and serum 25(OH)D levels, respectively.

CONCLUSIONS

Functionally significant vitamin D deficiency affects BMD and bone turnover markers among Saudi Arabian men and is largely attributed to older age, obesity, sedentary lifestyle, no education, poor exposure to sunlight, smoking, and poor dietary vitamin D supplementation. The data suggest that an increase in PTH cannot be used as a marker for vitamin D deficiency.

Vitamin D status of pregnant and non-pregnant women of reproductive age living in Hanoi City and the Hai Duong province of Vietnam

Vitamin D insufficiency during pregnancy has been associated with a number of adverse outcomes for both mother and child. Vitamin D insufficiency has been well described in many populations of both pregnant and non-pregnant women of childbearing age, but there is a lack of data on women living in South-East Asia. We measured plasma 25-hydroxyvitamin D in a representative sample of pregnant (n=64) and non-pregnant (n=477) women (15-49 years) living in Hanoi City (n=270) and rural Hai Duong Province (n=271) in northern Vietnam. Mean 25-hydroxyvitamin D (95% confidence interval) concentration was 81 (79, 84)nmolL(-1) . Mean 25-hydroxyvitamin D concentration differed between urban and rural (78 vs. 85nmolL(-1) ; P=0.016), farming and non-farming (89 vs. 77nmolL(-1) ; P<0.001) but not pregnant and non-pregnant or older vs. younger women. Only one woman had a 25-hydroxyvitamin D less than 25nmolL(-1) , a concentration indicative of vitamin D deficiency. Of the women, 7% and 48% of the women were vitamin D insufficient based on cut-offs for plasma 25-hydroxyvitamin D of 50 and 75nmolL(-1) , respectively. Mean plasma 25-hydroxyvitamin D concentrations of these Vietnamese women were much higher than those reported in other studies of pregnant and non-pregnant women in the region.

High prevalence of vitamin D insufficiency and its association with obesity and metabolic syndrome among Malay adults in Kuala Lumpur, Malaysia

BACKGROUND

Vitamin D status, as indicated by 25-hydroxyvitamin D is inversely associated with adiposity, glucose homeostasis, lipid profiles, and blood pressure along with its classic role in calcium homeostasis and bone metabolism. It is also shown to be inversely associated with metabolic syndrome and cardiovascular diseases in western populations. However, evidence from the Asian population is limited. Therefore, we aim to study the prevalence of vitamin D insufficiency (< 50 nmol/L) and the association of 25-hydroxyvitamin D with metabolic risk factors among an existing Malay cohort in Kuala Lumpur.

METHODS

This is an analytical cross sectional study. A total of 380 subjects were sampled and their vitamins D status (25-hydroxyvitamin D), fasting blood glucose, full lipid profile were assessed using venous blood. Systolic and diastolic blood pressure, weight, height and waist circumference were measured following standard protocols. Socio-demographic data such as sex, age, smoking status etc were also collected. Data was analysed using t-test, chi-square test, General Linear Model and multiple logistic regression.

RESULTS

Females made up 58% of the sample. The mean age of respondents was 48.5 (SD 5.2) years. Females had significantly lower mean Vitamin D levels (36.2; 95% CI: 34.5, 38.0 nmol/L) compared to males (56.2; 95% CI: 53.2, 59.2 nmol/L). Approximately 41% and 87% of males and females respectively had insufficient (< 50 nmol/L) levels of 25-hydroxyvitamin D (p < 0.001). The prevalence of Metabolic Syndrome for the whole sample was 38.4 (95% CI: 33.5, 43.3)%. In the multivariate model (adjusted for age, sex, abdominal obesity, HDL-cholesterol, diastolic blood pressure), insufficient Vitamin D status was significantly associated with 1-year age increments (OR: 0.93; 95% CI: 0.88, 0.98), being female (OR: 8.68; 95% CI: 5.08, 14.83) and abdominal obesity (OR: 2.57; 95% CI: 1.51, 4.39). Respondents with insufficient vitamin D were found to have higher odds of having Metabolic Syndrome (OR: 1.73; 95% CI: 1.02, 2.92) after adjusting for age and sex.

CONCLUSIONS

Our results highlight the high prevalence of vitamin D insufficiency among Malay adults in Kuala Lumpur. Vitamin D insufficiency is independently associated with younger age, female sex and greater abdominal obesity. Vitamin D insufficiency is also associated with Metabolic Syndrome.

Relationship between vitamin D, parathyroid hormone, and bone health

CONTEXT

There is a controversy regarding the definition of vitamin D insufficiency as it relates to bone health.

OBJECTIVE

The objective of the study was to examine the evidence for a threshold value of serum 25-hydroxyvitamin D (25OHD) that defines vitamin D insufficiency as it relates to bone health.

DESIGN AND PARTICIPANTS

This was a cross-sectional analysis of baseline data in 488 elderly Caucasian women, mean age 71 yr, combined with a literature review of 70 studies on the relationship of serum PTH to serum 25OHD.

SETTING

The study was conducted in independent-living women in the midwest United States.

MAIN OUTCOME MEASURE

The relationship between serum 25OHD, serum PTH, and serum osteocalcin and 24-h urine N-telopeptides was evaluated.

RESULTS

Serum PTH was inversely correlated with serum 25OHD (r = -0.256, P < 0.0005), but no threshold as defined by suppression of serum PTH was found within the serum 25OHD range 6-60 ng/ml (15-150 nmol/liter). However, in contrast, there was a threshold for bone markers, serum osteocalcin and urine N-telopeptides, that increased only below a serum 25OHD of approximately 18 ng/ml (45 nmol/liter). Calcium absorption was not correlated with serum PTH and serum 25OHD, and no threshold was found. A literature review of 70 studies generally showed a threshold for serum PTH with increasing serum 25OHD, but there was no consistency in the threshold level of serum 25OHD that varied from 10 to 50 ng/ml (25-125 nmol/liter).

CONCLUSIONS

Vitamin D insufficiency should be defined as serum 25OHD less than 20 ng/ml (50 nmol/liter) as it relates to bone.

Serum 25-hydroxyvitamin D, bone mineral density, and non-vertebral fracture risk in community-dwelling older men: results from Mr. Os, Hong Kong

The study examined vitamin D status in relation to bone mineral density (BMD) and fracture risk in older Chinese men. Vitamin D deficiency was uncommon in this sample. Higher serum vitamin D level was associated with higher baseline BMD, but was not associated with bone loss or fracture risk.

PURPOSE

Vitamin D status in relation to bone health and fracture risk in Asian men is unknown. This study examined how vitamin D status was associated with BMD and fracture risk in Chinese men.

METHODS

The study consisted of a cross-sectional and longitudinal design (the 4-year follow-up). Subjects included 939 and 712 men aged 65 year and older for cross-sectional analysis and longitudinal analysis, respectively. Baseline serum 25-hydroxyvitamin D (25OHD) was measured by a competitive radioimmunoassay kit. Baseline and 4-year percentage change in BMD at total hip, spine, and femoral neck was examined by dual-energy X-ray absorptiometry. Data on incident non-vertebral fractures and hip fractures in 4 years were collected. Data were collected for confounding factors: demographics, smoking, alcohol use, body mass index, physical activity, diet, season of blood measurement, and serum parathyroid hormone level. Multivariate regression analyses were performed with adjustments for confounding factors.

RESULTS

A total of 94.1% of this sample had serum 25OHD at 50 nmol/L and over. After adjustment for potential confounding factors, higher serum 25OHD level was associated with higher baseline BMD at all measured sites. No association was observed between serum 25OHD level and percentage change in BMD or risk of non-vertebral fracture or hip fracture after adjustment for confounding factors.

CONCLUSIONS

Vitamin D deficiency was not common in this sample of Chinese men. Higher serum 25OHD level was associated with higher BMD at cross-sectional level. There was no association between serum 25OHD level and bone loss or fracture risk.

An Asian viewpoint on the use of vitamin D and calcium in osteoporosis treatment: physician and patient attitudes and beliefs

BACKGROUND

Osteoporosis treatment guidelines recommend calcium and vitamin D supplementation for both prevention as well as treatment, however, compliance with these guidelines is often unsatisfactory. This study investigated the opinion of Asian physicians and Asian patients regarding vitamin D and calcium and patients' use of both.

METHODS

Physicians selected from Malaysia, Taiwan, Philippines, Korea and Singapore were asked to grade the significance of vitamin D and calcium in the treatment of osteoporosis and their patients' use of these supplements. In addition, physicians recruited seven eligible osteoporotic women to answer a questionnaire to determine their use of vitamin D and calcium, and their attitudes and beliefs regarding these supplements.

RESULTS

In total, 237 physicians and 1463 osteoporosis patients completed the questionnaire. The results revealed that 22% of physicians in Malaysia, 12% in Taiwan, 72% in the Philippines, 50% in Korea and 24% in Singapore rated the importance of vitamin D supplementation as being extremely important. For calcium, 27% of physicians in Malaysia, 30% in Taiwan, 80% in the Philippines, 50% in Korea and 38% in Singapore rated the importance as being extremely important. Forty-three percent of patients in Malaysia, 38% in Taiwan, 73% in the Philippines, 35% in Korea and 39% in Singapore rated the importance of vitamin D as being extremely important. For calcium, 69% of patients in Malaysia, 58% in Taiwan, 90% in the Philippines, 70% in Korea and 55% in Singapore rated the importance as being extremely important. In addition, results of the patient questionnaire revealed that only a very small number regularly took both supplements. In addition, the results indicated that, with the exception of patients from the Philippines, the majority of patients had no or infrequent discussion with their physician about vitamin D and calcium.

CONCLUSIONS

There is generally suboptimal appreciation by both physicians and patients of the importance of vitamin D and calcium for maintenance of bone health as reflected in the low number of patients who reported regularly taking these supplements. Recognition of this problem should translate to appropriate action to improve education for both physicians and patients, with a goal to increase use of these supplements among Asian patients with osteoporosis.

Association between vitamin D insufficiency and tuberculosis in a Vietnamese population

Background

Recent in vitro evidence suggests a link between vitamin D status and the risk of tuberculosis (TB). This study sought to examine the association between vitamin D status, parathyroid hormone (PTH) and the risk of TB in a Vietnamese population.

Methods

The study was designed as a matched case-control study, which involved 166 TB patients (113 men and 53 women), who were age-and-sex matched with 219 controls (113 men and 106 women). The average age of men and women was 49 and 50, respectively. TB was diagnosed by the presence of acid-fast bacilli on smears from sputum, and the isolation of M. tuberculosis. All patients were hospitalized for treatment in a TB specialist hospital. Controls were randomly drawn from the general community within the Ho Chi Minh, Vietnam. 25-hydroxyvitamin D [25(OH)D] and PTH was measured prior to treatment by an electrochemiluminescence immunoassay (ECLIA) on a Roche Elecsys. A serum level of 25(OH)D below 30 ng/mL was deemed to be vitamin D insufficient.

Results

The prevalence of vitamin D insufficiency was 35.4% in men with TB and 19.5% in controls (P = 0.01). In women, there were no significant differences in serum 25(OH)D and serum PTH levels between TB patients and controls. The prevalence of vitamin D insufficiency in women with TB (45.3%) was not significantly different from those without TB (47.6%; P = 0.91). However, in both genders, serum calcium levels in TB patients were significantly lower than in non-TB individuals. Smoking (odds ratio [OR] 1.25; 95% confidence interval [CI] 1.10 - 14.7), reduced 25(OH)D (OR per standard deviation [SD]: 1.14; 95% CI 1.07 - 10.7) and increased PTH (OR per SD 1.13; 95% CI 1.05 - 10.4) were independently associated with increased risk of TB in men.

Conclusion

These results suggest that vitamin D insufficiency was a risk factor for tuberculosis in men, but not in women. However, it remains to be established whether the association is a causal relationship.