Effects Of Vitamin D Deficiency Research Articles

Vitamin D and calcium, together and separately, play roles in female reproductive performance

Vitamin D (VD) deficiency reduces the chances of successful fertilization; however, it remains to be validated whether this effect is dependent or not on calcium. To address this question, we generated several situation using a mouse model in which VD content was either increased or decreased in a normo or hypocalcemia context. After the measurement of serum 25-hydroxyvitamin D2, calcium and phosphorus levels, an analysis was carried out in terms of oocytes maturation as well as reproductive performance. VD overdose, despite the fact that it resulted in an increased number of mature oocytes, reduced developmental competence and offspring survival. VD deficiency (VDD), on the contrary, reduced the number and percentage of mature oocytes, blastocyst rate, as well as fertility rate and offspring survival. Hypo-calcemia when VD levels were normal, had a similar effect than VDD. The effects of VDD were reversed by a diet that corrected calcium level. Therefore, both VD overdose (in a context of normal calcium level) VD deficiency as well as hypo-calcemia have an effect on female reproductive function. In conclusion, although closely related, VD and calcium act in part independently of each other in defining the “optimum” for female reproductive performance.

Maternal and neonatal vitamin D status at birth in black South Africans.

Vitamin D deficiency (VDD) in pregnant women has been associated with adverse pregnancy and neonatal outcomes. 25-hydroxyvitamin D (25(OH)D) levels are affected by numerous factors, including vitamin D intake, skin pigmentation, latitude and season of the year; they therefore vary by race and country. Vitamin D status in pregnant women and their offspring in South Africa (SA) is not well established. To assess vitamin D status by measuring serum 25(OH)D in pregnant black SA women and their offspring in Johannesburg (latitude 26°S) and to assess whether vitamin D status is affected by maternal HIV infection. We prospectively enrolled pregnant women and their healthy neonates, and measured 25(OH)D in maternal and cord blood at delivery. Pregnant women were stratified by their HIV status. Predictors of maternal and neonatal VDD (levels <30 nmol/L) were assessed using multiple logistic regression analysis. A total of 291 pregnant women and their healthy neonates were enrolled over a 21-month period. Mean (standard deviation) maternal and cord blood 25(OH)D levels were 57.0 (29.7) and 41.9 (21.0) nmol/L and the prevalence of VDD was 15.9% and 32.8%, respectively. On average, concentrations of 25(OH)D in cord blood were ~80% of those in the mother. There was no association between cord 25(OH)D and gestational age, but levels were associated with birth weight (p<0.001). There were no differences in maternal or cord blood 25(OH)D levels between those HIV-infected or uninfected. The predictor of VDD in mothers was giving birth in winter (odds ratio (OR) 2.87, 95% confidence interval (CI) 1.47 - 5.61), and in neonates the predictors were maternal age (OR 16.5, 95% CI 1.82 - 149), being born in winter (OR 3.68, 95% CI 2.05 - 6.61), being born by caesarean section (OR 4.92, 95% CI 1.56 - 15.57) and being of low birth weight (OR1.99, 95% CI 1.13 - 3.50). Among black SA women delivering in Johannesburg, about one in six mothers and one in three neonates have 25(OH)D levels indicative of VDD. Maternal HIV status appears not to affect levels of 25(OH)D in either the mother or her neonate. Research on the effects of VDD on the outcomes of pregnancy and the best methods to combat the high prevalence of VDD in women of childbearing age in the SA context is required.

OVERCOMING VITAMIN-D DEFICIENCY IN MALE GYMNASTS DURING PRETEEN YEARS

This paper addresses the issue of vitamin-D deficiency, which is approaching epidemic scale in the Asian countries. Lack of proper nutrition and awareness contributes to this problem. After an explanation of the mechanism of production of vitamin D, the authors list adverse effects of vitamin-D deficiency and propose mandatory testing of vitamin-D deficiency during physical examinations. The remedial measures to overcome this deficiency in the context of preteen male gymnasts include supplements, proper nutrition in the form of sun-ripe fruits and vegetables as well as guarded-graduated sun-exposure. The last two are preferred over supplements as the supplements may produce toxicity if taken in higher doses.

Recurrent pregnancy loss and vitamin D: A review of the literature.

Recurrent pregnancy loss (RPL) affects approximately 1%-2% of reproductive women. Auto- and cellular immune responses seem to be associated with RPL. Vitamin D (VD) has been shown to play a role in the modulation of the immune system. Effects of VD deficiency (VDD) in pregnancy have been associated with preeclampsia, gestational diabetes, fetal growth restriction, preterm labor, and sporadic spontaneous abortion (SA). We systematically reviewed articles that studied women with 2 or more SA and its association with VD. Eleven studies were included. Studies reported a high prevalence of VD insufficiency (VDI) or VDD in women with RPL and suggested that this could be associated with immunological dysregulation and consequently with RPL. Immunological benefits were reported in the peripheral blood of women with RPL after VD exposure. Thus, it is possible to speculate a beneficial role for VD supplementation in RPL. It seems that there are not differences in the vitamin D receptor (VDR) and CYP27B1 expression in endometrium of women with RPL but, in villous and decidual tissues, RPL women seem to have a decreased expression of VDR and, perhaps, a decreased expression of CYP27B1. Further randomized controlled studies are required to investigate the association between VDD or VDI and RPL.

Translating evidence into action: An intervention for increasing vitamin D supplementation in a deficient rehabilitation population

Introduction/Background Inadequate vitamin D is highly prevalent, affecting approximately 42-77% of the general United States population. Vitamin D deficiency (VDD) increases the risk of osteoporosis, falls, and fractures. Acute inpatient rehabilitation patients have several risk factors for VDD, and the adverse effects of VDD may hinder long-term functional gain. Material and method Prospective cohort study, evaluating patients admitted before and after a screening intervention as part of a quality improvement initiative at an academic, freestanding acute inpatient rehabilitation hospital. This study included a convenience sample of patients admitted two months pre-intervention (n = 128), and patients admitted two months post-intervention (n = 129). Providers obtained a routine serum vitamin D level on admission (universal screening), then utilized a standard supplementation protocol. Vitamin D insufficiency (VDI) was defined as a 25-hydroxyvitamin D (25(OH)D) level of 20–29.9 ng/mL, and VDD as Results Pre-intervention, 10.2% of patients were screened for VDD, with 23.1% found to be VDI and 46.2% VDD. Post-intervention, 89.9% of patients were screened, with 31.9% found to be VDI and 47.4% VDD. Pre-intervention, 88.9% of all screened patients were on vitamin D supplementation at discharge versus 75.0% post-intervention. In both uni- and multivariate analyses, we found increased risk of VDD was significantly associated with African American race (OR 7.3, 95% CI, 1.56–34.2, P = 0.12) and age younger than 65 (OR 13.6, 95% CI, 2.5–73.8, P = 0.002). Diagnoses in the “other neurologic” category were associated with decreased risk of VDD (OR 0.01, 95% CI, 0.001–0.193, P = 0.002). Conclusion Given the high prevalence of VDD in an acute inpatient rehabilitation hospital, a routine screening and standardized supplementation protocol may be a good practice to improve quality of care.

Tenofovir-Linked Hyperparathyroidism Is Independently Associated With the Presence of Vitamin D Deficiency

To determine patient and treatment characteristics associated with vitamin D deficiency (VDD) in an UK inner city HIV-1-positive adult cohort. Two hundred twenty-seven HIV-positive patients attending prospectively for routine blood tests in winter had serum 25-hydroxyvitamin D and parathyroid hormone (PTH) concentrations and other routine chemistry measured. Those with and without VDD were defined as having serum 25-hydroxyvitamin D concentrations <50 nmol/L and >75 nmol/L, respectively. Characteristics were compared between patients with and without VDD. The effects of VDD, tenofovir use, and their interaction on chemical measures were investigated. VDD was found in 57% (131 of 227) of patients. Independent associations included nonwhite ethnicity [adjusted odds ratio (95% confidence interval): 7.40 (2.52 to 21.7)], higher random blood glucose [2.38 (1.24 to 4.57) per mmol/L], higher estimated glomerular filtration rate [eGFR: 1.04 (1.01 to 1.06)], and higher PTH [1.19 (1.00 to 1.42)]. PTH was higher in those receiving tenofovir (median 7.2 pmol/L) than other patients (4.3; P < 0.001) overall, but high PTH with tenofovir occurred only in the context of VDD. Tenofovir use was not associated with serum creatinine or eGFR overall but interacted with vitamin D status (P = 0.05 and P = 0.08, respectively), being linked to somewhat higher creatinine and lower eGFR among patients without VDD but higher eGFR in VDD patients. 25(OH) VDD is associated with tenofovir-linked hyperparathyroidism and also with higher eGFR.

Distribution and properties of Ca2+-ATPase, phytase, and alkaline phosphatase in isolated enterocytes from normal and vitamin D-deficient rats.

The effects of vitamin D-deficiency and repletion on the distribution and activities of Ca2+-ATPase, phytase, and alkaline phosphatase in intact epithelial cells isolated from different regions of the villi and the crypts of the rat jejunum were studied. Similar distribution patterns of activities were found for the three enzymes. In all cases, the enzyme levels were the highest at the villus tip and gradually declined to low activities in the crypt. The Kms were very different between cells in the crypt base and those at the villus tip, the highest Kms being found in the crypt. The activities of these enzymes were reduced in the entire length of the villus in vitamin D-deficient rats. Recovery of the enzymatic levels was observed on vitamin D repletion, but at different rates. Total recovery of activity of Ca2+-ATPase, phytase, and alkaline phosphatase was observed after 18, 24, and 36 hours, respectively, after a single dose of 6.5 nmol (2.5 micrograms) vitamin D3. Enzymatic activities in the crypt cells were not affected by vitamin D3 treatment. These data suggest that Ca2+-ATPase, phytase, and alkaline phosphatase may be distinct entities, and that their activities in the crypt cells may not be vitamin D-dependent.