METHODS: The Web of Science, Scopus, PubMed/Medline, Embase, and Google Scholar databases were searched for all available observational studies that reported the risk of venous thromboembolism (VTE) based on serum vitamin D levels categories. The search was performed up to March 2020.
RESULTS: Seven studies were included. The overall analysis showed a significantly increased risk of VTE in subjects with low levels of serum vitamin D compared with those with normal vitamin D levels (RR = 1.34; 95% CI: 1.07-1.69; P = 0.011). In a sensitivity analysis, we did not observe a significant effect of any individual study on the combined effect sizes. Nevertheless, significant heterogeneity was present among the studies (Cochrane Q test, p = 0.018, I2 = 61%). In the stratified analysis, low vitamin D levels were positively associated with an increased risk of VTE in prospective population-based studies (RR = 1.31; 95% CI: 1.06-1.61; P = 0.010) and in subjects below 60 years old (RR = 1.28; 95% CI: 1.07-1.54; P = 0.060).
CONCLUSION: our systematic review and meta-analysis showed that a low serum vitamin D level was indeed associated with an increased risk of VTE.
DESIGN: Cross-sectional.
SETTING: Jakarta, Indonesia and Kuala Lumpur, Malaysia.
PARTICIPANTS: A convenience sample of 504 non-pregnant women 18-40 years.
MAIN MEASURES: Plasma 25-hydroxyvitamin D and PTH.
RESULTS: The mean 25-hydroxyvitamin D concentration was 48 nmol/l. Less than 1% of women had a 25-hydroxyvitamin D concentration indicative of vitamin D deficiency (<17.5 nmol/l); whereas, over 60% of women had a 25-hydroxyvitamin D concentration indicative of insufficiency (<50 nmol/l). We estimate that 52 nmol/l was the threshold concentration for plasma 25-hydroxyvitamin D above which no further suppression of PTH occurred. Below and above this concentration the slopes of the regression lines were -0.18 (different from 0; P=0.003) and -0.01 (P=0.775), respectively. The relation between vitamin D status and parathyroid hormone concentration did not differ between women with low, medium or high calcium intakes (P=0.611); however, even in the highest tertile of calcium intake, mean calcium intake was only 657 mg/d.
CONCLUSION: On the basis of maximal suppression of PTH we estimate an optimal 25-hydroxyvitamin D concentration of approximately 50 nmol/l. Many women had a 25-hydroxyvitamin D below this concentration and may benefit from improved vitamin D status.
METHODS: We searched the Medline, Embase, Cochrane Library and Scopus databases from inception until March 2015 for studies meeting the following criteria: (1) RCT with adult participants, (2) vitamin D administration alone, (3) studies that quantified EF using commonly applied methods including ultrasound, plethysmography, applanation tonometry and laser Doppler.
RESULTS: Sixteen articles reporting data for 1177 participants were included. Study duration ranged from 4 to 52 weeks. The effect of vitamin D on EF was not significant (SMD: 0.08, 95 % CI -0.06, 0.22, p = 0.28). Subgroup analysis showed a significant improvement of EF in diabetic subjects (SMD: 0.31, 95 % CI 0.05, 0.57, p = 0.02). A non-significant trend was found for diastolic blood pressure (β = 0.02; p = 0.07) and BMI (β = 0.05; p = 0.06).
CONCLUSIONS: Vitamin D supplementation did not improve EF. The significant effect of vitamin D in diabetics and a tendency for an association with BMI may indicate a role of excess adiposity and insulin resistance in modulating the effects of vitamin D on vascular function. This remains to be tested in future studies.
METHODS: Chinese and Malay men (n = 382) aged 20 years or above residing in the Klang Valley, Malaysia were recruited. Their fasting blood was collected for serum testosterone, sex hormone-binding globulin (SHBG) and 25-hydroxyvitamin D (25(OH)D) assays. Relationship between 25(OH)D and testosterone levels was analyzed using multiple regression analysis. Testosterone and SHBG levels among subjects with different vitamin D status were compared using univariate analysis. Confounders such as age, ethnicity and body mass index (BMI) were adjusted.
RESULTS: 25(OH)D was significantly and positively associated with total testosterone and SHBG levels before and after adjustment for age and ethnicity (p vitamin D deficiency to those with optimal level (p 0.05).
CONCLUSION: 25(OH)D is significantly associated with total testosterone and SHBG in Malaysian men but this association is BMI-dependent.
METHODS: Cross-sectional study in Malaysian children with CLD. Factors affecting serum vitamin D level (definition: deficient vitamin D intake was 715 ± 562 units/day. Thirteen (22%) patients had at least one clinical signs of rickets. Seventeen (29%) had serum bilirubin level ≥ 34 μmol/L. Eight (14%) children were deficient in vitamin D, eight (14%) were vitamin D-insufficient and 43 (73%) were sufficient. As compared with children with serum bilirubin <34 μmol/L, those with serum bilirubin ≥34 μmol/L were more likely to have rickets (24% vs. 65%; P vitamin D level (86.0 ± 54.9 nmol/L vs. 65.4 ± 48.2 nmol/L; P = 0.05) despite being given a significantly higher vitamin D dose (608 ± 571 vs. 970 ± 543 units/day; P = 0.008). The proportion of children with either deficient or insufficient vitamin D status was significantly higher in children with bilirubin level ≥34 μmol/L than in children <34 μmol/L (47% vs. 19%; P = 0.028).
CONCLUSION: Vitamin D deficiency and insufficiency is common in children with CLD in a tropical country. Regular monitoring of vitamin D status and screening for metabolic bone disease in all children with CLD is recommended. Higher dose of oral supplement or parenteral route should be considered, especially in those with bilirubin ≥34 μmol/L.
METHODS: This cross-sectional study was conducted among 555 (164 men, 391 women) Orang Asli adults aged 18-65 years of Jah Hut sub-tribe in Krau Wildlife Reserve (KWR), Peninsular Malaysia. Demographic and socio-economic information were obtained using interviewer-administered questionnaire. Participants were also assessed for serum 25-hydroxyvitamin D (25(OH)D) concentration, adiposity indices (BMI, WC, WHtR, WHR, %BF) and lipid parameters (TC, LDL-C, HDL-C, TG). Data were analyzed using binary logistic regression via SPSS.
RESULTS: The prevalence of suboptimal 25(OH)D concentration was 26.3%, comprising 24.9% insufficiency (50 to <75 nmol/L) and 1.4% deficiency (<50 nmol/L). While men (14-30.5%) were associated with a more proatherogenic lipid profile than women (6.1-14.3%), more women were with central obesity (M: 19.5-46.3%; F: 34.5-49.1%) and suboptimal (<75 nmol/L) vitamin D status (M: 11.6%; F: 32.4%). While suboptimal 25(OH)D concentration was significantly associated with higher odds of at-risk LDL-C (p < 0.01) and obesity (WC, WHtR) (p < 0.05) in men, no significant association was observed for women. Nonetheless, it should be noted that there were only 19 men with suboptimal (<75 nmol/L) vitamin D status.
CONCLUSIONS: While suboptimal vitamin D status was relatively low in Orang Asli adults, the prevalence of obesity and undesirable serum lipids were relatively high. The sex-specific associations between vitamin D status with adiposity indices and serum lipids warrant further investigation.
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 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.
OBJECTIVE: To determine the prevalence and potential risk factors of vitamin D deficiency and insufficiency among Malaysian children with spina bifida.
SETTING: Four Malaysian tertiary hospitals.
METHODS: Children with spina bifida were assessed for potential demographic, disease severity and lifestyle risk factors for vitamin D deficiency and insufficiency. Blood for 25-hydroxy vitamin D (25(OH)D) was taken. Vitamin D deficiency was defined as 25(OH)D levels ≤ 37.5 nmol/L and insufficiency as 37.6-50 nmol/L.
RESULTS: Eighty children aged 2-18 years (42 males) participated in the study. Vitamin D levels ranged from 14 to 105 nmol/L (mean 52.8, SD 19.1). Vitamin D deficiency was identified in 18 (22.5%) and insufficiency in 26 (32.5%) children. Logistic regression analysis showed that skin exposure to sunlight ≤ 21% body surface area (OR: 6.2, CI 1.7-22.9) and duration of sun exposure ≤ 35 min/day (OR: 4.0, CI 1.2-14.1) were significant risk factors for vitamin D deficiency and insufficiency, respectively.
CONCLUSIONS: Over half (55%) of Malaysian children with spina bifida seen in urban tertiary hospitals have vitamin D insufficiency and deficiency. Lifestyle sun exposure behaviours were risk factors for vitamin D deficiency and insufficiency.
DESIGN: This is a cross-sectional study among Form 1 (year 7) students from 15 schools selected using a stratified random sampling design. Information regarding sociodemographic characteristics, clinical data and environmental factors was collected and blood samples were taken for total vitamin D. Descriptive and multivariable logistic regression was performed on the data.
SETTING: National secondary schools in Peninsular Malaysia.
PARTICIPANTS: 1361 students (mean age 12.9±0.3 years) (61.4% girls) completed the consent forms and participated in this study. Students with a chronic health condition and/or who could not understand the questionnaires due to lack of literacy were excluded.
MAIN OUTCOME MEASURES: Vitamin D status was determined through measurement of sera 25-hydroxyvitamin D (25(OH)D). Body mass index (BMI) was classified according to International Obesity Task Force (IOTF) criteria. Self-reported physical activity levels were assessed using the validated Malay version of the Physical Activity Questionnaire for Older Children (PAQ-C).
RESULTS: Deficiency in vitamin D was seen in 78.9% of the participants. The deficiency was significantly higher in girls (92.6%, p<0.001), Indian adolescents (88.6%, p<0.001) and urban-living adolescents (88.8%, p<0.001). Females (OR=8.98; 95% CI 6.48 to 12.45), adolescents with wider waist circumference (OR=2.64; 95% CI 1.65 to 4.25) and in urban areas had higher risks (OR=3.57; 95% CI 2.54 to 5.02) of being vitamin D deficient.
CONCLUSIONS: The study shows a high prevalence of vitamin D deficiency among young adolescents. Main risk factors are gender, ethnicity, place of residence and obesity.