OBJECTIVE: This systematic review aims to gather and appraise existing evidence on the associations between serum vitamin D concentrations during pregnancy and at birth and the development of eczema, wheezing, and RTIs in infants.
DATA SOURCES: PubMed, MEDLINE, ProQuest, Scopus, CINAHL, Cochrane Library and Academic Search Premier databases were searched systematically using specified search terms and keywords.
STUDY SELECTION: Articles on the associations between serum vitamin D concentrations during pregnancy and at birth and eczema, wheezing, and RTIs among infants (1-year-old and younger) published up to 31 March 2019 were identified, screened and retrieved.
RESULTS: From the initial 2678 articles screened, ten met the inclusion criteria and were included in the final analysis. There were mixed and conflicting results with regards to the relationship between maternal and cord blood vitamin D concentrations and the three health outcomes-eczema, wheezing and RTIs-in infants.
CONCLUSION: Current findings revealed no robust and consistent associations between vitamin D status in early life and the risk of developing eczema, wheezing and RTIs in infants. PROSPERO registration no. CRD42018093039.
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: 100 CKD stage 3-4 patients were included in the study. Direct chemiluminesent immunoassay was used to determine the level of serum 25-hydroxyvitamin D. All subjects underwent a carotid ultrasound to measure common carotid artery intima-media thickness (CCA-IMT) and to assess the presence of carotid plaques or significant stenosis (≥50 %). Vitamin D deficiency was defined as serum 25-hydroxyvitamin D vitamin D deficiency and non-deficiency groups did not differ significantly in terms of abnormal CCA-IMT (P = 0.443), carotid plaque (P = 0.349), and carotid stenosis (P = 0.554). No significant correlation between serum 25-hydroxyvitamin D levels and CCA-IMT (P = 0.693) was found. On a backward multiple linear regression model, serum 25-hydroxyvitamin D levels was not associated with CCA-IMT, abnormal CCA-IMT, or plaque presence.
CONCLUSIONS: No important association between serum 25-hydroxyvitamin levels and carotid atherosclerosis was found in CKD patients.
OBJECTIVES: To describe the status and predictors of vitamin D status in healthy Nepalese mothers and infants.
METHODS: 500 randomly selected Nepalese mother and infant pairs were included in a cross-sectional study. Plasma 25(OH)D concentrations were measured by LC-MS/MS and multiple linear regression analyses were used to identify predictors of vitamin D status.
RESULTS: Among the infants, the prevalence of vitamin D insufficiency (25(OH)D <50 nmol/L) and deficiency (<30 nmol/L) were 3.6% and 0.6%, respectively, in contrast to 59.8% and 14.0% among their mothers. Infant 25(OH)D concentrations were negatively associated with infant age and positively associated with maternal vitamin D status and body mass index (BMI), explaining 22% of the variability in 25(OH)D concentration. Global solar radiation, maternal age and BMI predicted maternal 25(OH)D concentration, explaining 9.7% of its variability.
CONCLUSION: Age and maternal vitamin D status are the main predictors of vitamin D status in infants in Bhaktapur, Nepal, who have adequate vitamin D status despite poor vitamin D status in their mothers.
METHODS: This prospective cross-sectional study involved 70 patients with diabetic nephropathy; 40 were categorized into the group with nondeficient serum 25-hydroxyvitamin D levels [25(OH)D >50 nmol/l], whereas 30 patients were categorized to the group with deficient serum 25(OH)D (<50 nmol/l). Microvascular endothelial function was determined using laser Doppler fluximetry and the process of iontophoresis. Acetylcholine and sodium nitroprusside were used to determine endothelium-dependent and independent vasodilatation.
RESULTS: Mean age of patients was 56.7 ± 3.8 years; 50 were men, whereas 20 were women. Mean serum 25(OH)D in the vitamin D-nondeficient group was 69.4 ± 2.9 nmol/l; the level in the vitamin D-deficient group was 42.1 ± 1.3 nmol/l, P < 0.001. Endothelium-dependent vasodilatation was lower in the vitamin D-deficient group compared with the vitamin D-nondeficient group (23.6 ± 2.7 versus 37.3 ± 3.8 arbitrary units, P = 0.004). No significant differences were observed between the two groups in their hsCRP levels, mean age, estimated glomerular filtration rate, systolic blood pressure (SBP) and diastolic blood pressure (DBP) and glycosylated haemoglobin.
CONCLUSION: Microvascular endothelial function was significantly reduced in diabetic nephropathy patients with deficient vitamin D levels compared with those with nondeficient levels.
METHOD: One hundred RA patients and 50 healthy controls, sex- and age-matched, were recruited. Disease Activity Score of 28 joints and Health Assessment Questionnaire scores were assessed. Baseline serum 25(OH)D3 and IL-6 were measured in all subjects. RA patients who were vitamin D deficient were given loading doses of vitamin D3 and repeated assessments were done.
RESULTS: Vitamin D deficiency (<50 nmol/L) was found in 63% of RA patients and 76% of healthy controls. Chinese RA patients and healthy controls had significantly more sufficient 25(OH)D3 levels compared to Malays and Indians (P Vitamin D deficiency is prevalent in Malaysian RA patients. This study suggests that vitamin D is not associated with disease activity or serum IL-6 levels but it may have a role in functional disability in RA patients.
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.
METHODS: A case-control study to examine serum 25- hydroxyvitamin D [25(OH)D] levels in children with and without AD was done. Serum 25-hydroxyvitamin D [25(OH)D] level was measured by immunoassay. AD severity was evaluated using the SCORing Atopic Dermatitis (SCORAD) index.
RESULTS: The serum levels of 25(OH)D, measured in 135 children with AD was not statistically different from 65 children without AD [median (IQR): 25.2ng/mL (15.45) vs 25.9ng/mL (15.87), p=0.616]. However, serum vitamin D levels were significantly lower in children with severe AD compared to those with mild-to-moderate AD [median (IQR): 16.0ng/mL (19.32) vs 26.3ng/mL (15.56), p=0.021]. The odds of having vitamin D deficiency in children with severe AD was 3.82 times that of children with non-severe AD (95% confidence level: 1.13, 12.87).
CONCLUSION: This study suggests that there is an inverse association between vitamin D level and the severity of AD in Malaysian children.
METHOD: This retrospective study involved SLE patients who attended the Rheumatology Clinic at the Hospital Kuala Lumpur from January 2014 to December 2016. Vitamin D was categorised as normal, insufficient or deficient, and the clinical variables were compared across vitamin D categories with chi-squared tests and Pearson correlation coefficient.
RESULTS: We included 216 patients. The mean 25(OH)D concentration was 51.3(Standard Deviation; SD 14.8) nmol/L. Fifty (23.1%) patients had vitamin D deficiency, 120 (55.6%) had vitamin D insufficiency, while 46 (21.3%) had adequate vitamin D levels. There were statistically significant associations between vitamin D status and ethnic group, lupus nephritis and hypertension. No correlations were observed between vitamin D status with SLEDAI score (Pearson correlation coefficient -0.015, p=0.829) as well as SDI score (Pearson correlation coefficient -0.017, p=0.801).
CONCLUSION: SLE patients should be screened for vitamin D concentrations and their levels optimised.