Project description:BackgroundVitamin D deficiency or insufficiency is thought to be common among pregnant women. Vitamin D supplementation during pregnancy has been suggested as an intervention to protect against adverse gestational outcomes.ObjectivesTo examine whether supplements with vitamin D alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.Search methodsWe searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2011), the International Clinical Trials Registry Platform (ICTRP) (31 October 2011), the Networked Digital Library of Theses and Dissertations (28 October 2011) and also contacted relevant organisations (8 April 2011).Selection criteriaRandomised and quasi-randomised trials with randomisation at either individual or cluster level, evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy.Data collection and analysisTwo review authors independently i) assessed the eligibility of studies against the inclusion criteria ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Data were checked for accuracy.Main resultsThe search strategy identified 34 potentially eligible references. We included six trials assessing a total of 1023 women, excluded eight studies, and 10 studies are still ongoing. Five trials involving 623 women compared the effects of vitamin D alone versus no supplementation/placebo and one trial with 400 women compared the effects of vitamin D and calcium versus no supplementation.Only one trial with 400 women reported on pre-eclampsia: women who received 1200 IU vitamin D along with 375 mg of elemental calcium per day were as likely to develop pre-eclampsia as women who received no supplementation (average risk ratio (RR) 0.67; 95% confidence interval (CI) 0.33 to 1.35). Data from four trials involving 414 women consistently show that women who received vitamin D supplements had higher concentrations of vitamin D in serum at term than those women who received no intervention or a placebo; however the magnitude of the response was highly heterogenous. Data from three trials involving 463 women suggest that women who receive vitamin D supplements during pregnancy less frequently had a baby with a birthweight below 2500 grams than those women receiving no treatment or placebo; statistical significance was borderline (RR 0.48; 95% CI 0.23 to 1.01).In terms of other conditions, there were no significant differences in adverse side effects including nephritic syndrome (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women); stillbirths (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women) or neonatal deaths (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women) between women who received vitamin D supplements in comparison with women who received no treatment or placebo. No studies reported on preterm birth, maternal death, admission to neonatal intensive care unit/special nursery or Apgar scores.Authors' conclusionsVitamin D supplementation in a single or continued dose during pregnancy increases serum vitamin D concentrations as measured by 25-hydroxyvitamin D at term. The clinical significance of this finding and the potential use of this intervention as a part of routine antenatal care are yet to be determined as the number of high quality trials and outcomes reported is too limited to draw conclusions on its usefulness and safety. Further rigorous randomised trials are required to evaluate the role of vitamin D supplementation in pregnancy.
Project description:The effect of maternal multivitamin supplementation on breast milk vitamin B12 concentrations has not been examined in Tanzania, where the prevalence of maternal plasma B12 insufficiency is 25.6%. Multivitamins (containing 50 µg vitamin B12) or placebo were provided during pregnancy and in the postpartum period. Breast milk samples were collected at or around six weeks postpartum from 491 participants in a trial of multivitamins (NCT00197548). Linear and logistic regression models were used to examine the effect of supplements on vitamin B12 concentration in milk and its associations with other variables including potential confounders. Median vitamin B12 concentration in breast milk was 206 pmol/L and 70% of women had levels indicating inadequacy (<310 pmol/L). Multivitamin supplements did not significantly reduce the odds of inadequate vitamin B12 in breast milk, suggesting suboptimal absorption. A single unit increase in maternal hemoglobin at six weeks was associated with 18% lower odds of inadequate vitamin B12 in breast milk. Participants with higher BMI at baseline had double the odds of having inadequate vitamin B12 than the reference group (<22 kg/m2). Trials to determine the optimal dose, route, and duration of supplementation to improve maternal B12 status in Sub-Saharan Africa are of utmost importance.
Project description:Objective To analyze the related factors of the postpartum thyroid function in women with overt hypothyroidism (OH)/subclinical hypothyroidism (SCH) and explore the effects of vitamin D categories. Methods Thyroid hormones, thyroid autoantibody, and serum 25OHD levels were continuously recorded from the first trimester of pregnancy (T1) to the 12th postpartum month. Logistic regression analysis and Cox regression analysis were used to screen the related factors of postpartum thyroid function, and the Latent Class Growth Model was performed to analyze the trajectory characteristics of serum 25OHD levels. Results Totally, 252 pregnant women with OH/SCH were enrolled in the study. In the 12th month postpartum, 36.5% of the patients improved thyroid function, 37.3% continued hypothyroidism, and 26.2% developed thyroid dysfunction. Vitamin D sufficiency, positive TPOAb, and positive TgAb in T1 were independent prognostic factors of postpartum thyroid function. Vitamin D sufficiency in T1 was illustrated as an independent factor of the improved postpartum thyroid function, but the protective effect for the developed postpartum thyroid dysfunction was only confirmed in TPOAb-positive patients. Cox regression analysis further confirmed the effects of vitamin D categories. Notably, the high-level 25OHD trajectory during pregnancy and postpartum could predict improved postpartum thyroid function and decrease the risk of developed postpartum thyroid dysfunction. Conclusion Appropriate vitamin D nutrition during pregnancy and postpartum may be beneficial to postpartum thyroid function.
Project description:Although vitamin C supplements were consumed for health maintenance and fatigue recovery, the effects of high doses of vitamin C supplement remains controversial. Our study performed the effects of 100 mg and 2,000 mg vitamin C supplements on plasma and urinary vitamin C concentration in Korean women. Twenty-four women completed the 4 weeks intervention. Anthropometric data, plasma and urinary vitamin C concentrations, superoxide dismutase activity, thiobarbituric acid reactive substance (TBARS) level, and fatigue severity scale (FSS) were collected, and the statistical analyses compared between- and within-group findings at pre- and post-intervention. Concentrations of vitamin C in plasma and urinary excretion were significantly increased with 100 mg and 2,000 mg of vitamin C supplementation (p < 0.050). TBARS level was decreased significantly with 2,000 mg of vitamin C supplementation (p < 0.050). In addition, FSS was declined significantly in 100 mg of vitamin C supplementation group (p < 0.050). Our result showed that vitamin C supplementation of either 100 mg or 2,000 mg led to an increase in vitamin C concentrations in plasma and vitamin urinary excretion but not statistically significant among groups. TBARS level was decreased in 2,000 mg and FSS was decreased in 100 mg of vitamin C supplementation in Korean women. We suppose that additional clinical trial is needed to examine the effects of vitamin C supplements for a wide range of doses on plasma and urinary vitamin C concentrations in Korean.
Project description:ContextSerum 25-hydroxyvitamin D (25OHD) is lower in women with darker skin color. Is it due to lower skin production, lower absorption, or different metabolism of vitamin D?ObjectivesThe objective of the study was to measure the effect of vitamin D3 on serum 25OHD and serum PTH in older African American women with vitamin D insufficiency and the serum 25OHD 20 ng/mL or less (<50 nmol/L). The results can be used to estimate the Recommended Dietary Allowance (RDA).Design and settingThis was a randomized, double-blind placebo trial at Creighton University Medical Center and Indiana University Medical Center.ParticipantsParticipants were 110 healthy older African American women.InterventionsThe intervention consisted of participants randomly assigned to placebo, vitamin D3 400, 800, 1600, 2400, 3200, 4000, or 4800 IU daily; calcium supplements were given to maintain total calcium intake of 1200-1400 mg/d.Main outcome measurementsChange in serum 25OHD and serum PTH levels at 12 months was measured.ResultsMean baseline serum 25OHD was 13 ng/mL (33 nmol/L). On 4800 IU, serum 25OHD averaged 50 ng/mL (125 nmol/L) compared with 47 ng/mL (117 nmol/L) in Caucasian women. Serum PTH at 12 months decreased significantly (P = .008) when related to serum 25OHD but not dose. Hypercalcemia occurred in 7% and hypercalciuria in 15%. Events were unrelated to vitamin D dose.ConclusionVitamin D3 800 IU increased serum 25OHD greater than 20 ng/mL (>50 nmol/L) in 97.5% of the African American women just as it did in the Caucasian women, and therefore, the RDA is the same for both groups. Because absorption and metabolism of oral vitamin D absorption is similar in both groups, lower levels of serum 25OHD in African Americans must be due to lower production of vitamin D in skin.
Project description:Subclinical mastitis is common in HIV-infected women and is a risk factor for mother-to-child transmission of HIV. The purpose of this study was to examine the effect of vitamin supplementation [vitamin A + ?-carotene, multivitamins (B complex, C, and E), or multivitamins, including vitamin A + ?-carotene] on the risk of subclinical mastitis during the first 2 y postpartum among HIV-infected women. The study was a randomized, placebo-controlled, clinical trial including 674 HIV-infected, antiretroviral naïve Tanzanian women who were recruited during pregnancy and followed-up after delivery. Breast milk samples were obtained approximately every 3 mo. Any subclinical mastitis was defined as a ratio of the sodium to potassium (Na:K) breast milk concentrations > 0.6 and further classified as either moderate (Na:K ? 0.6 and ? 1) or severe (Na:K > 1.0). Fifty-eight percent of women had at least 1 episode of any subclinical mastitis. Women assigned to multivitamins (B complex, C, and E) had a 33% greater risk of any subclinical mastitis (P = 0.005) and a 75% greater risk of severe subclinical mastitis (P = 0.0006) than women who received the placebo. Vitamin A + ?-carotene also increased the risk of severe subclinical mastitis by 45% (P = 0.03). Among women with CD4+ T-cell counts ? 350 cells/?L, multivitamin intake resulted in a 49% increased risk of any subclinical mastitis (P = 0.006); by contrast, there were no treatment effects among women with CD4+ T-cell counts < 350 cells/?L (P- interaction for treatment × CD4+ T-cell count = 0.10). Supplementation of HIV-infected women with vitamins increased the risk of subclinical mastitis.
Project description:This study compared serum cholecalciferol and 25-hydroxyvitamin D (25(OH)D) concentrations over four weeks in healthy, non-pregnant, non-lactating females aged 18-40 years, who were randomized to oral cholecalciferol 5000 international units (IU) daily for 28 days or a single dose of 150?000?IU. The study was conducted in Rochester, MN in March and April of 2010. We found no difference in mean 25(OH)D between treatment groups on study day 0 or day 28 (P=0.14 and 0.28, respectively). The daily group had 11 more days of detectable serum cholecalciferol than the single-dose group (P<0.001). There was no difference observed in cholecalciferol area under the curve (AUC28) between groups (P=0.49). However, the single-dose group had a significantly greater mean 25(OH)D AUC28 compared with the daily group (P<0.001).
Project description:BackgroundVitamin D is important to maternal, fetal, and infant health, but quality data on vitamin D status in low- and middle-income countries and response to cholecalciferol supplementation in pregnancy are sparse.ObjectiveWe characterized vitamin D status and vitamin D metabolite change across pregnancy and in response to cholecalciferol supplementation in rural Gambia.MethodsThis study was a secondary analysis of samples collected in a 4-arm trial of maternal nutritional supplementation [iron folic acid (FeFol); multiple micronutrients (MMN); protein energy (PE) as lipid-based supplement; PE + MMN]; MMN included 10 μg/d cholecalciferol. Plasma 25-hydroxycholecalciferol [25(OH)D3], 24,25-dihydroxycholecalciferol [24,25(OH)2D3], and C3-epimer-25-hydroxycholecalciferol [3-epi-25(OH)D3] were measured by LC-MS/MS in 863 women [aged 30 ± 7 y (mean ± SD)] in early pregnancy (presupplementation) and late pregnancy, (gestational age 14 ± 3 and 30 ± 1 wk). Changes in 25(OH)D3 and vitamin D metabolite concentrations and associations with pregnancy stage and maternal age and anthropometry were tested.ResultsEarly pregnancy 25(OH)D3 concentration was 70 ± 15 nmol/L and increased according to pregnancy stage (82 ± 18 and 87 ± 17 nmol/L in the FeFol and PE-arms) and to cholecalciferol supplementation (95 ± 19 and 90 ± 20 nmol/L in the MMN and PE + MMN-arms) (P < 0.0001). There was no difference between supplemented groups. Early pregnancy 25(OH)D3 was positively associated with maternal age and gestational age. Change in 25(OH)D3 was negatively associated with late pregnancy, but not early pregnancy, triceps skinfold thickness. The pattern of change of 24,25(OH)2D3 mirrored that of 25(OH)D3 and appeared to flatten as pregnancy progressed, whereas 3-epi-25(OH)D3 concentration increased across pregnancy.ConclusionThis study provides important data on the vitamin D status of a large cohort of healthy pregnant women in rural Africa. Without supplementation, vitamin D status increased during pregnancy, demonstrating that pregnancy stage should be considered when assessing vitamin D status. Nutritionally relevant cholecalciferol supplementation further increased vitamin D status. These data are relevant to the development of fortification and supplementation policies in pregnant women in West Africa.
Project description:UNLABELLED: Vitamin K mediates the synthesis of proteins regulating bone metabolism. We have tested whether high vitamin K(2) intake promotes bone mineral density and bone strength. Results showed that K(2) improved BMC and femoral neck width, but not DXA-BMD. Hence high vitamin K(2) intake may contribute to preventing postmenopausal bone loss. INTRODUCTION: Vitamin K is involved in the synthesis of several proteins in bone. The importance of K vitamins for optimal bone health has been suggested by population-based studies, but intervention studies with DXA-BMD as a clinical endpoint have shown contradicting results. Unlike BMC, DXA-BMD does not take into account the geometry (size, thickness) of bone, which has an independent contribution to bone strength and fracture risk. Here we have tested whether BMC and femoral neck width are affected by high vitamin K intake. METHODS: A randomized clinical intervention study among 325 postmenopausal women receiving either placebo or 45 mg/day of vitamin K(2) (MK-4, menatetrenone) during three years. BMC and hip geometry were assessed by DXA. Bone strength indices were calculated from DXA-BMD, femoral neck width (FNW) and hip axis length (HAL). RESULTS: K(2) did not affect the DXA-BMD, but BMC and the FNW had increased relative to placebo. In the K(2)-treated group hip bone strength remained unchanged during the 3-year intervention period, whereas in the placebo group bone strength decreased significantly. CONCLUSIONS: Vitamin K(2) helps maintaining bone strength at the site of the femoral neck in postmenopausal women by improving BMC and FNW, whereas it has little effect on DXA-BMD.