Serum Vitamin D Concentrations,Time to Pregnancy,and Pregnancy Outcomes among Preconception Couples: A Cohort Study in Shanghai,China

Background: The role of vitamin D in reproductive health is still unclear. This study aimed to assess the effect of serum 25-hydroxyvitamin D (25(OH)D), among preconception couples, on fecundity, and the associations between 25(OH)D concentrations before and during pregnancy, and pregnancy outcomes. Methods: 200 preconception couples attempting to conceive were recruited and were followed-up until childbirth. Time to pregnancy was collected via telephone every two months or obtained via a questionnaire during pregnancy. Blood samples were collected to measure serum 25(OH)D levels from both partners at enrollment and from women during the second and third trimester of pregnancy. Results: Couples had higher conception rates within six months (adjusted odds ratio (aOR): 3.72, 95% CI: 1.16, 11.9) and reduced time to pregnancy (adjusted fecundability ratio (aFR): 1.50, 95% CI: 1.01, 2.23) if male partners had sufficient 25(OH)D compared with insufficient 25(OH)D. Compared to pregnant women with insufficient 25(OH)D in the third trimester of pregnancy, sufficient 25(OH)D was associated with reduced odds of anemia (OR: 0.22, 95% CI: 0.06, 0.82), longer gestational age (β: 0.53, 95% CI: 0.04, 1.01) and newborns’ higher ponderal index (β: 0.10, 95% CI: 0.01, 0.19). Conclusions: Sufficient serum 25(OH)D levels among preconception men or during pregnancy were associated with better reproductive health.     

Total 25(OH)D Concentration Moderates the Association between Caffeine Consumption and the Alkaline Phosphatase Level in Pregnant Women

The evidence as to whether caffeine consumption is beneficial or harmful to human health has been mixed. This study aimed to examine the effect of 25-hydroxyvitamin D (25(OH)D) concentration on the association between caffeine consumption and mineral metabolism in pregnant women. This is a cross-sectional study involving pregnant women at their 25th to 35th gestational week recruited at antenatal clinics in the period of July 2019 to December 2020. Peripheral blood samples were collected to determine their total 25(OH)D, albumin, alkaline phosphatase (ALP), calcium, phosphate, and ferritin level in serum. Questionnaires on demographics and dietary intake were also administered. Among 181 pregnant women recruited (Average age = 32.9 years), 50 (27.6%) of them were found to be vitamin D insufficient (25(OH)D concentration < 75 nmol/L), and 131 (72.4%) were vitamin D sufficient (25(OH)D concentration ≥ 75 nmol/L). Adjusted regression models identified an association between higher caffeine intake and lower ALP level only among vitamin D-sufficient pregnant women (β = −0.24, p = 0.006), but not in those with insufficient vitamin D (β = −0.02, p = 0.912). The findings provide new insights into 25(OH)D concentration as a potential modifier of the health effects of caffeine consumption during pregnancy.     

Prenatal Vitamin D Levels in Maternal Sera and Offspring Specific Learning Disorders

Recent evidence has suggested potential harmful effects of vitamin D deficiency during pregnancy on offspring brain development, for example, elevated risks for neuropsychiatric disorders. Findings on general cognition and academic achievement are mixed, and no studies have examined the effect of prenatal 25-hydroxyvitamin D (25(OH)D) levels on diagnosed specific learning disorders, which was the aim of this study. We examined a nested case–control sample from the source cohort of all singleton-born children in Finland between 1996 and 1997 (n = 115,730). A total of 1607 cases with specific learning disorders (mean age at diagnosis: 9.9 years) and 1607 matched controls were identified from Finnish nationwide registers. Maternal 25(OH)D levels were analyzed from serum samples collected during the first trimester of pregnancy and stored in a national biobank. Conditional logistic regression was used to test the association between maternal 25(OH)D and offspring specific learning disorders. There were no significant associations between maternal 25(OH)D levels and specific learning disorders when vitamin D was examined as a log-transformed continuous variable (adjusted OR 0.98, 95% CI 0.82–1.18, p = 0.84) or as a categorical variable (25(OH)D < 30 nmol/L: adjusted OR 1.03, 95% CI 0.83–1.28, p = 0.77 compared to levels of >50 nmol/L), nor when it was divided into quintiles (adjusted OR for the lowest quintile 1.00, 95% CI 0.78–1.28, p = 0.99 compared to the highest quintile). This study found no association between low maternal 25(OH)D in early pregnancy and offspring specific learning disorders.     

High Prevalence of Vitamin D Deficiency in Infertile Women Referring for Assisted Reproduction

A comprehensive analysis of the vitamin D status of infertile women is the first step in understanding hypovitaminosis impact on reproductive potential. We sought to determine vitamin D profiles of women attending an infertility center and to investigate non-dietary determinants of vitamin D status in this population. In this cross-sectional analysis, a cohort of 1072 women (mean age ± standard deviation 36.3 ± 4.4 years) attending an academic infertility center was used to examine serum 25-hydroxy-vitamin D (25(OH)D) levels in relation to demographic characteristics, seasons and general health risk factors. Both unadjusted and adjusted levels of serum 25(OH)D were examined. Median 25(OH)D concentration was below 30 ng/mL for 89% of the entire year. Over the whole year, 6.5% of patients had 25(OH)D levels ≤10 ng/mL, 40.1% ≤20 ng/mL, and 77.4% ≤30 ng/mL. Global solar radiation was weakly correlated with 25(OH)D levels. At multivariable analysis, 25(OH)D levels were inversely associated with BMI; conversely, 25(OH)D levels were positively associated with height and endometriosis history. Serum 25(OH)D levels are highly deficient in women seeking medical help for couple’s infertility. Levels are significantly associated with body composition, seasonal modifications and causes of infertility. Importantly, this deficiency status may last during pregnancy with more severe consequences.     

乌市水区新生儿脐血与孕母血维生素D水平的相关性及其影响因素

目的了解新生儿脐带血与孕母妊娠末期血维生素D水平的相关性,探讨影响新生儿脐血维生素D水平的相关因素。方法对自2015年11月-2016年3月冬季收住的112例新生儿脐血及其中40例的孕母产前静脉血采用化学发光法测定维生素D值,进行相关性分析。结果 112例新生儿脐血25(OH)D平均水平为(6.75±3.59)ng/ml,新生儿维生素D均处于缺乏状态,中、重度维生素D缺乏新生儿占85.7%。40例孕母血25(OH)D平均水平与新生儿血25(OH)D水平呈显著正相关(r=0.86,P0.001);孕妇的民族、孕期补钙时间、海产品摄入次数与孕妇文化程度等对新生儿维生素D水平的影响有统计学意义;孕妇不同孕周、工作类型、户外活动时间、孕期是否抽筋及新生儿胎产次、胎儿性别、出生方式等对新生儿维生素D水平的影响无统计学意义(P0.05)。结论冬季出生的新生儿维生素D缺乏严重,与孕妇妊娠末期静脉血维生素D水平显著相关。冬季应给予孕晚期孕妇补充足量维生素D,以提高新生儿维生素D水平。     

Exercise: A Possibly Effective Way to Improve Vitamin D Nutritional Status

Vitamin D deficiency has become a widespread public health problem owing to its potential adverse health effects. Generally, the nutritional status of vitamin D depends on sunlight exposure and dietary or supplementary intake. However, recent studies have found that exercise can influence circulating 25(OH)D levels; although, the results have been inconclusive. In this review, we focused on the effect of exercise on circulating vitamin D metabolites and their possible mechanisms. We found that endurance exercise can significantly increase serum 25(OH)D levels in vitamin D-deficient people but has no significant effect on vitamin D-sufficient people. This benefit has not been observed with resistance training. Only chronic endurance exercise training can significantly increase serum 1,25(OH)₂D, and the effect may be sex-dependent. Exercise may influence 25(OH)D levels in the circulation by regulating either the vitamin D metabolites stored in tissues or the utilization by target tissues. The effects of exercise on 25(OH)D levels in the circulation may be dependent on many factors, such as the vitamin D nutritional status, exercise type and intensity, and sex. Therefore, further research on the effects and mechanisms of exercise on vitamin D metabolites is required.     

母孕期维生素D水平与婴儿体格生长的相关性研究

目的 探讨母孕期维生素D水平与婴儿体格生长的相关性。方法 检测孕晚期孕妇血清和新生儿脐血的25-(OH)D;并测量出生时、3、6、8月龄婴儿的体格生长指标及3、6、8月龄胫骨超声骨强度。结果 223例孕母血清25-(OH)D水平为(50.7±18.5)nmol/L,与婴儿体格生长指标无相关性;孕母与新生儿25-(OH)D水平呈正相关,并存在季节差异。结论 孕期维生素D水平与婴儿体格生长无相关性。     

Vitamin D-Related Risk Factors for Maternal Morbidity during Pregnancy: A Systematic Review

Vitamin D has well-defined classical functions related to metabolism and bone health but also has non-classical effects that may influence pregnancy. Maternal morbidity remains a significant health care concern worldwide, despite efforts to improve maternal health. Nutritional deficiencies of vitamin D during pregnancy are related to adverse pregnancy outcomes, but the evidence base is difficult to navigate. The primary purpose of this review is to map the evidence on the effects of deficiencies of vitamin D on pregnancy outcome and the dosage used in such studies. A systematic search was performed for studies on vitamin D status during pregnancy and maternal outcomes. A total of 50 studies came from PubMed, 15 studies came from Cochrane, and 150 studies came from Embase, for a total of 215 articles. After screening, 34 were identified as candidate studies for inclusion. Finally, 28 articles met the inclusion criteria, which originated from 15 countries. The studies included 14 original research studies and 13 review studies conducted between 2012 and 2021. This review was finally limited to the 14 original studies. This systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, and the quality and strength of the evidence was evaluated using the Navigation Guide Systematic Review Methodology (SING). We found evidence that supports the idea that supplementary vitamin D for pregnant women is important for reducing the risk of gestational diabetes, hypertension, preeclampsia, early labor, and other complications. The data retrieved from this review are consistent with the hypothesis that adequate vitamin D levels might contribute to a healthy pregnancy.     

A Narrative Review of the Evidence for Variations in Serum 25-Hydroxyvitamin D Concentration Thresholds for Optimal Health

Vitamin D₃ has many important health benefits. Unfortunately, these benefits are not widely known among health care personnel and the general public. As a result, most of the world’s population has serum 25-hydroxyvitamin D (25(OH)D) concentrations far below optimal values. This narrative review examines the evidence for the major causes of death including cardiovascular disease, hypertension, cancer, type 2 diabetes mellitus, and COVID-19 with regard to sub-optimal 25(OH)D concentrations. Evidence for the beneficial effects comes from a variety of approaches including ecological and observational studies, studies of mechanisms, and Mendelian randomization studies. Although randomized controlled trials (RCTs) are generally considered the strongest form of evidence for pharmaceutical drugs, the study designs and the conduct of RCTs performed for vitamin D have mostly been flawed for the following reasons: they have been based on vitamin D dose rather than on baseline and achieved 25(OH)D concentrations; they have involved participants with 25(OH)D concentrations above the population mean; they have given low vitamin D doses; and they have permitted other sources of vitamin D. Thus, the strongest evidence generally comes from the other types of studies. The general finding is that optimal 25(OH)D concentrations to support health and wellbeing are above 30 ng/mL (75 nmol/L) for cardiovascular disease and all-cause mortality rate, whereas the thresholds for several other outcomes appear to range up to 40 or 50 ng/mL. The most efficient way to achieve these concentrations is through vitamin D supplementation. Although additional studies are warranted, raising serum 25(OH)D concentrations to optimal concentrations will result in a significant reduction in preventable illness and death.     

Vitamin D in pregnancy and lactation: maternal, fetal, and neonatal outcomes from human and animal studies

During pregnancy and lactation, mothers require significant amounts of calcium to pass on to the developing fetus and suckling neonate, respectively. Given the dependence of adult calcium concentrations and bone metabolism on vitamin D, one might anticipate that vitamin D sufficiency would be even more critical during pregnancy and lactation. However, maternal adaptations during pregnancy and lactation and fetal adaptations provide the necessary calcium relatively independently of vitamin D status. It is the vitamin D-deficient or insufficient neonate who is at risk of problems, including hypocalcemia and rickets. Due to poor penetrance of vitamin D and 25-hydroxyvitamin D [25(OH)D] into milk, exclusively breastfed infants are at higher risk of vitamin D deficiency than are formula-fed infants. Dosing recommendations for women during pregnancy and lactation might be best directed toward ensuring that the neonate is vitamin D-sufficient and that this sufficiency is maintained during infancy and beyond. A dose of vitamin D that provides 25(OH)D sufficiency in the mother during pregnancy should provide normal cord blood concentrations of 25(OH)D. Research has shown that during lactation, supplements administered directly to the infant can easily achieve vitamin D sufficiency; the mother needs much higher doses (100 mug or 4000 IU per day) to achieve adult-normal 25(OH)D concentrations in her exclusively breastfed infant. In addition, the relation (if any) of vitamin D insufficiency in the fetus or neonate to long-term nonskeletal outcomes such as type 1 diabetes and other chronic diseases needs to be investigated.     

Vitamin D metabolism in the hooded seal (Cystophora cristata)

Fish-eating mammals, such as seals, appear to ingest levels of vitamin D that are toxic to most mammals. To determine how seals cope with high vitamin D intakes, the metabolism of tritiated cholecalciferol ([3H]D3) was investigated in hooded seal (Cystophora cristata) pups during their postweaning fast and pups and adults consuming herring alone or supplemented with 400,000 iu D3 daily. [3H]D3 was metabolized to 25-[3H]OHD3 and 24,25-[3H](OH)2D3. 1,25-[3H](OH)2D3 was not detected, but plasma levels of 1,25-(OH)2D were similar to those in other mammals and were not affected by vitamin D intake. Plasma vitamin D, 25-OHD and 24,25-(OH)2D increased with vitamin D intake, but 25-OHD did not increase to the extent seen in other mammals. The supplemented seals showed no evidence of toxicity. Levels of 24,25-(OH)2D were higher in the unsupplemented seals (4 to 33 ng/mL) than reported in other mammals with similar 25-OHD levels and did not decrease with 25-OHD. High levels of 24,25-(OH)2D relative to 25-OHD have also been found in hooded seals in the wild. The half-lives of vitamin D, 25-OHD and 24,25-(OH)2D were shorter than those reported for most other mammals. Increased conversion of 25-OHD to 24,25-(OH)2D and a high capacity for vitamin D storage in their large blubber mass appeared to be factors in the resistance of seals to vitamin D toxicity.     

Health impacts of vitamin D: are we getting enough?

Increasingly, scientists are debating whether photochemical synthesis of vitamin D in Western countries is adequate, and whether dietary intakes can plug the gap between endogenous vitamin D production and requirements, particularly in young and older populations. The debate is driven by the plethora of evidence suggesting that, in addition to its important role in maintaining bone health, vitamin D may be involved in ameliorating cell ageing and preventing cardiovascular disease, diabetes, immune dysfunction and some cancers. Observational evidence from different populations suggests a significant degree of vitamin D insufficiency, often defined as plasma 25-hydroxyvitamin D [25(OH)D] <25 nmol/l. Some experts have argued that daily intakes up to 40 µg/day may be needed to ensure a desirable vitamin D status, even after accounting for sun exposure. However, there is presently no consensus on the most appropriate vitamin D status for maintaining bone health and preventing chronic disease. In addition, the UK has not set a vitamin D recommendation for most adults under 65 years. Given the plethora of information about vitamin D and bone health, this article reviews evidence for a link between vitamin D and other aspects of health. In conclusion, three actions are suggested: (1) agreement on optimal plasma 25(OH)D levels for health; (2) a debate on whether UK dietary recommendations need revision; and (3) better promotion of dietary vitamin D via food sources and, for certain groups, supplements.     

Associations between Maternal Selenium Status and Cord Serum Vitamin D Levels: A Birth Cohort Study in Wuhan,China

Serum selenium (Se) has been reported to be associated with serum 25-hydroxyvitamin D [25(OH)D], but epidemiological findings are limited in pregnant women. We aimed to assess the associations between maternal urinary Se concentrations and cord serum 25(OH)D levels. We measured urinary concentrations of Se in the first, second, and third trimesters and cord serum 25(OH)D of 1695 mother-infant pairs from a prospective cohort study in Wuhan, China. The results showed that each doubling of urinary Se concentrations in the first, second, third trimester, and whole pregnancy (average SG-adjusted concentrations across three trimesters) were associated with 8.76% (95% confidence interval (CI): 4.30%, 13.41%), 15.44% (95% CI: 9.18%, 22.06%), 11.84% (95% CI: 6.09%, 17.89%), and 21.14% (95% CI: 8.69%, 35.02%) increases in 25(OH)D levels. Newborns whose mothers with low (<10 μg/L) or medium (10.92–14.34 μg/L) tertiles of urinary Se concentrations in whole pregnancy were more likely to be vitamin D deficient (<20 ng/mL) compared with those with the highest tertile (>14.34 μg/L). Our study provides evidence that maternal Se levels were positively associated with cord serum vitamin D status.     

Vitamin D Supplementation during Pregnancy: An Evidence Analysis Center Systematic Review and Meta-Analysis

BackgroundGiven the high rates of vitamin D deficiency among pregnant women and possible effects on offspring health, a systematic review on this topic was conducted to help inform future practice guidelines.ObjectiveTo evaluate associations between maternal vitamin D supplementation, maternal 25-hydroxyvitamin D (25(OH)D) concentrations, and health outcomes.MethodsA PubMed literature search was conducted to identify studies that examined the health effects of vitamin D supplementation during pregnancy on maternal and infant health outcomes published from 2000 to 2016. Among 976 identified publications, 20 randomized clinical trials met the inclusion criteria. The initial search was extended to include five studies published between July 2016 and September 2018.Main outcome measuresMaternal and infant 25(OH)D concentrations, gestational diabetes, preeclampsia or gestational hypertension, cesarean section, maternal parathyroid hormone and calcium concentrations, and infant gestational age, birth weight, and birth length.Statistical analysesMean differences, odds ratios, and 95% CIs were calculated, only for the initial search, using separate random-effects meta-analyses for each outcome.ResultsEvidence was good or strong that maternal vitamin D supplementation significantly increased maternal (13 studies, n=18, mean difference, 14.1 ng/mL [35.2 nmol/L]; 95% CI=9.6-18.6 ng/mL [24.0-46.4 nmol/L]) and infant (nine studies, n=12; 9.7, 5.2, 14.2 ng/mL [24.2, 12.9, 35.5 nmol/L]) 25(OH)D concentrations, although heterogeneity was significant (I²=95.9% and I²=97.4, respectively, P<0.001). Evidence was fair that vitamin D supplementation significantly decreases maternal homeostatic model assessment-insulin resistance (five studies, n=7; −1.1, −1.5, −0.7) and increases infant birth weight (nine studies, n=11, 114.2, 63.4, 165.1 g), both had insignificant heterogeneity. A null effect of maternal supplementation on other maternal (preeclampsia, cesarean section) and infant (gestational age, birth length) outcomes was found.ConclusionsResults show vitamin D supplementation during pregnancy improves maternal and infant 25(OH)D concentrations and may play a role in maternal insulin resistance and fetal growth. To further inform practice and policies on the amount of vitamin D, which supports a healthy pregnancy, high quality dose-response randomized clinical trials, which assess pregnancy-specific 25(OH)D thresholds, and appropriately powered clinical outcomes are needed.     

Season,dietary factors,and physical activity modify 25-hydroxyvitamin D concentration during pregnancy

Purpose

The objectives of this cross-sectional study were to define maternal and umbilical cord blood (UCB) 25-hydroxyvitamin D (25(OH)D) to characterize maternal factors modifying 25(OH)D during pregnancy and predict UCB 25(OH)D in two subgroups with Declined [Δ25(OH)D?<0 nmol/l] and Increased [Δ25(OH)D?>0 nmol/l] 25(OH)D concentration.

Methods

A complete dataset was available from 584 women. 25(OH)D was determined at gestational weeks 6–13 and in UCB. Baseline characteristics were collected retrospectively using questionnaires. Δ25(OH)D was calculated as UCB 25(OH)D?early pregnancy 25(OH)D. Dietary patterns were generated with principal component analysis. Multivariate regression models were applied.

Results

Vitamin D deficiency was scarce, since only 1% had 25(OH)D concentration?<50 nmol/l both in early pregnancy and in UCB. Shared positive predictors of UCB 25(OH)D in the subgroups of Declined and Increased, were early pregnancy 25(OH)D (P?<?0.001) and supplemental vitamin D intake (P?<?0.04). For the Increased subgroup summer season at delivery (P?=?0.001) and “sandwich and dairy” dietary pattern characterized with frequent consumption of vitamin D fortified margarine and milk products (P?=?0.009) were positive predictors of UCB 25(OH)D. Physical activity (P?=?0.041) and maternal education (P?=?0.004) were additional positive predictors in the Declined group

Conclusions

Maternal and newborn vitamin D status was sufficient, thus public health policies in Finland have been successful. The key modifiable maternal determinants for 25(OH)D during pregnancy, and of the newborn, were supplemental vitamin D intake, frequent consumption of vitamin D fortified foods, and physical activity.

     

冬季早期婴儿维生素D营养状况观察

目的 观察早期婴儿维生素D营养状况,为合理地补充维生素D提供依据。方法 以我国北方地区冬季出生的72例婴儿为研究对象,自生后15 d起口服维生素D补充剂,满月起逐月询问生活史和体检。于出生及4月龄时分别采集脐血和静脉血,测定血清25-(OH)D、钙、磷和碱性磷酸酶浓度。结果 脐血25-(OH)D平均水平(21.91±5.75)nmol/L,72例(100.0%)维生素D缺乏;婴儿4月龄时血清25-(OH)D平均水平(108.12±45.30)nmol/L,10例(13.9%)维生素D缺乏。血清25-(OH)D平均水平在每日摄入维生素D 200 U~组升至(112.37±37.98)nmol/L,在400 U~组升至(133.97±34.93)nmol/L。但维生素D不足和缺乏者在每日摄入维生素D 200 U~组6例(23.1%),400 U~组仅2例(7.1%)。新生儿及婴儿血钙、磷、碱性磷酸酶水平均正常。结论 北方地区冬季新生儿普遍存在维生素D缺乏,生后尽早补充可以显著改善维生素D营养状况。每日补充200 U维生素D可显著提高早期婴儿血清25-(OH)D水平;若要达到维生素D营养充足,至少补充400 U维生素D。     

Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency: implications for establishing a new effective dietary intake recommendation for vitamin D

It has been more than 3 decades since the first assay assessing circulating 25-hydroxyvitamin D [25(OH)D] in human subjects was performed and led to the definition of "normal" nutritional vitamin D status, i.e., vitamin D sufficiency. Sampling human subjects, who appear to be free from disease, and assessing "normal" circulating 25(OH)D levels based on a Gaussian distribution of these values is now considered to be a grossly inaccurate method of identifying the normal range. Several factors contribute to the inaccuracy of this approach, including race, lifestyle habits, sunscreen usage, age, latitude, and inappropriately low dietary intake recommendations for vitamin D. The current adult recommendations for vitamin D, 200-600 IU/d, are very inadequate when one considers that a 10-15 min whole-body exposure to peak summer sun will generate and release up to 20,000 IU vitamin D-3 into the circulation. We are now able to better identify sufficient circulating 25(OH)D levels through the use of specific biomarkers that appropriately increase or decrease with changes in 25(OH)D levels; these include intact parathyroid hormone, calcium absorption, and bone mineral density. Using these functional indicators, several studies have more accurately defined vitamin D deficiency as circulating levels of 25(OH)D < or = 80 nmol or 32 microg/L. Recent studies reveal that current dietary recommendations for adults are not sufficient to maintain circulating 25(OH)D levels at or above this level, especially in pregnancy and lactation.     

纯母乳喂养小婴儿及其母亲维生素D水平相关性研究

目的 分析出生28~42 d出现佝偻病临床表现的纯母乳喂养儿的血清维生素D水平及与其母亲血维生素D水平的相关性,为预防婴儿早期营养性佝偻病的发生提供理论依据。方法 对2016年4月-2017年10月来西北妇女儿童医院儿童保健科正常体检的年龄为28~42 d、并且表现有佝偻病早期症状和(或)体征的119例纯母乳喂养儿及其母亲静脉血25-羟维生素D[25-(OH)D]进行相关性分析。结果 119例母亲血25-(OH)D＞30 ng/ml者15例(12.61%),≤30 ng/ml者104例(87.39%);孕期平均每日补充维生素D≥400 U的母亲19例,血25-(OH)D中位数为28.8 ng/ml,每日补充维生素D＜400 U母亲100例,血25-(OH)D中位数为16.1 ng/ml,两组血25-(OH)D差异有统计学意义(P<0.05);在119例婴儿中补充和未补充维生素D组的婴儿血25-(OH)D中位数分别为20.0 ng/ml和9.5 ng/ml,两者差异有统计学意义(P<0.05);婴儿血25-(OH)D与其母亲血清25-(OH)D水平呈正相关(r=0.349,P<0.01)。婴儿血25-(OH)D水平(＞20 ng/ml和≤20 ng/ml)与其出现佝偻病的症状、体征之间无统计学意义。结论 婴儿及其母亲维生素D整体处于不足水平,两者之间维生素D水平存在相关性。婴儿血25-(OH)D＞20 ng/ml并没有降低其发生营养性佝偻病的风险。建议母亲孕期应积极补充维生素D,同时提倡从新生儿一出生即开始补充维生素D,预防婴儿早期营养性佝偻病的发生。     

西安地区新生儿维生素D水平及影响因素分析

目的调查西安地区(北纬34°)新生儿维生素D水平,并分析其影响因素。方法选取2018年10月至2019年10月在西安交通大学第一附属医院新生儿科住院,生后48小时内入院且生命体征平稳的161例新生儿为研究对象。检测新生儿生后48小时内血清25-羟维生素D[25(OH)D]水平,并分析性别、胎龄、出生季节,母亲年龄、分娩方式、妊娠胎数,以及母亲孕晚期维生素D补充剂量对新生儿血清25(OH)D水平的影响。结果新生儿血清25(OH)D平均水平为12.20(9.10,17.30)ng/mL,维生素D缺乏、不足和充足的发生率分别为65.84%、15.53%和18.63%。单胎新生儿血清25(OH)D水平显著高于双胎新生儿(Z=-1.967,P<0.05)。秋季出生的新生儿血清25(OH)D水平显著高于春季出生的新生儿(H=-2.726,P<0.05)。与母亲孕晚期补充维生素D剂量<600IU/d相比,母亲孕晚期补充维生素D剂量≥600IU/d新生儿血清25(OH)D水平显著增高(Z=-3.968,P<0.05),维生素D缺乏发生率显著降低(χ^2=8.003,P<0.017)。经Logistic回归分析显示,母亲孕晚期补充维生素D剂量<600IU/d是新生儿维生素D缺乏的危险因素(OR=2.481,95%CI:1.023~6.008,P<0.001)。结论西安地区新生儿维生素D缺乏发生率较高;胎数、出生季节和母亲孕期维生素D补充剂量是新生儿维生素D水平的影响因素。     

无锡市足月新生儿维生素D水平及适宜补充剂量的研究

目的 分析无锡市新生儿维生素D(VD)的营养状况及其影响因素,为制定适合本地区的新生儿VD补充方案提供科学依据。方法 选取2015年3月-2018年3月入住无锡市人民医院新生儿科的足月、母乳喂养、日龄≤7 d的新生儿347例,检测其血清25-(OH)D基础水平,其中血清25-(OH)D≤50 nmol/L的新生儿随机分为两组,分别给予400 U/d或800 U/d VD口服,6周后复查。同时对其母亲一般信息及孕期补充VD情况等展开问卷调查。结果 VD缺乏、VD不足和VD充足的比例分别为91.07%、8.07%和0.86%。夏秋季出生的患儿血清25-(OH)D水平较冬春季出生的患儿高(t=-3.467,P<0.05)。6周后复查发现,总体患儿血清25-(OH)D平均值较前上升,VD缺乏者比例下降(χ²=118.235、163.196,P＜0.05)。 新生儿血清25-(OH)D水平与母亲孕期是否补充充足的钙剂、VD存在一定的相关性(r=0.116,P=0.043)。结论 无锡地区足月新生儿VD普遍缺乏,建议根据母亲孕期VD补充情况,可以将早期足月新生儿VD补充剂量调整为400~800 U/d,持续6周。