Body Size and Serum 25 Hydroxy Vitamin D Response to Oral Supplements in Healthy Older Adults

Background: Vitamin D insufficiency is prevalent in the northeast United States. Since vitamin D insufficiency is readily amenable to supplementation, it is important to understand what factors are associated with serum 25 hydroxy vitamin D (25(OH)D) response to vitamin D supplementation.

Objective: In this study we examined the association of serum 25(OH)D response to vitamin D supplementation with body size in a population of elderly subjects.

Methods: 257 healthy, ambulatory men and women 65 years of age or older were randomly assigned to treatment with either 700 IU/day (17.5 μg/d) of supplemental vitamin D₃ and 500 mg/day (12.5 mmol/d) of supplemental calcium, or to placebo.

Results: In multivariate regression analyses, after adjusting for baseline 25(OH)D, season, and sex, we found change in 25(OH)D to be inversely associated with baseline BMI (p = 0.01) in subjects treated with supplements for one year. Change in 25(OH)D was also negatively associated with other baseline anthropometric measurements in these subjects.

Conclusion: Our study implies that body size should be taken into account when estimating the amount of vitamin D intake needed to raise 25(OH)D to the desired level.     

健康学龄前351名儿童25-羟维生素D水平及影响因素

目的 了解上海市学龄前儿童的维生素D水平并分析其影响因素,为防治该地区维生素D缺乏提供理论依据。方法 随机抽取上海市浦东新区3家幼儿园共351名3～6岁学龄前儿童(男:185名,女:166名),采用液相色谱串联质谱法(LC-MS/MS)测定测血清25-羟维生素 D[25-(OH)D]水平,并通过标准问卷获得相关影响因素数据。结果 受试学龄前儿童血清25-羟维生素 D[25-(OH)D]的平均水平为(28.14±6.70) ng/ml。维生素D缺乏[25-(OH)D＜20 ng/ml]为35例(10.0％),维生素D适宜水平(20～100 ng/ml)为316例(90.0%)。多因素分析结果显示维生素D制剂补充频率低及大年龄组(≥6岁)是学龄前儿童25-(OH)D缺乏的高危因素(P＜0.05)。结论 年龄和维生素D制剂补充与学龄前儿童维生素D水平明显相关,大年龄组(≥6岁)儿童维生素D制剂补充率相对较低。针对目前学龄前儿童仍存在维生素D缺乏的情况,应该加强儿童保健的科普教育,结合个体情况提高维生素D的补充率,同时增加儿童户外活动,促进学龄前儿童健康。     

健康学龄前351名儿童25-羟维生素D水平及影响因素

目的 了解上海市学龄前儿童的维生素D水平并分析其影响因素,为防治该地区维生素D缺乏提供理论依据。方法 随机抽取上海市浦东新区3家幼儿园共351名3～6岁学龄前儿童(男:185名,女:166名),采用液相色谱串联质谱法(LC-MS/MS)测定测血清25-羟维生素 D[25-(OH)D]水平,并通过标准问卷获得相关影响因素数据。结果 受试学龄前儿童血清25-羟维生素 D[25-(OH)D]的平均水平为(28.14±6.70) ng/ml。维生素D缺乏[25-(OH)D＜20 ng/ml]为35例(10.0％),维生素D适宜水平(20～100 ng/ml)为316例(90.0%)。多因素分析结果显示维生素D制剂补充频率低及大年龄组(≥6岁)是学龄前儿童25-(OH)D缺乏的高危因素(P＜0.05)。结论 年龄和维生素D制剂补充与学龄前儿童维生素D水平明显相关,大年龄组(≥6岁)儿童维生素D制剂补充率相对较低。针对目前学龄前儿童仍存在维生素D缺乏的情况,应该加强儿童保健的科普教育,结合个体情况提高维生素D的补充率,同时增加儿童户外活动,促进学龄前儿童健康。     

Association between serum 25-hydroxyvitamin D levels and adiposity measurements in the general Korean population

BACKGROUND/OBJECTIVES

Obesity, which is a known risk factor for many chronic diseases, has also been associated with vitamin D deficiency. This study explored the relationship between serum 25-hydroxy-vitamin D [25(OH)D] concentrations and adiposity measures in a general Korean population using the most recent, nationally representative survey data.

SUBJECTS/METHODS

The study sample consisted of 4,771 Korean adults (≥ 19 years) who participated in the fifth Korean National Health and Nutrition Examination Surveys. Serum 25(OH)D was determined by radioimmunoassay. Body mass index (BMI), waist circumference (WC) and total body fat content were measured as adiposity measurements. Total body fat content was measured by dual-energy X-ray absorptiometry.

RESULTS

The serum 25(OH)D level was significantly higher in men than in women. Serum 25(OH)D concentration was positively correlated with energy intake, and it was negatively correlated with total body fat content (P < 0.0001) and percentage body fat (P < 0.0001) after adjustment for age in both sexes, while was inversely correlated with BMI only in women. In multivariable regression analysis, serum 25(OH)D was inversely associated with the total body fat content after adjustment for age, BMI, education, region, smoking, alcohol consumption, physical activity, and energy intake only in men (P = 0.0047). However, the serum 25(OH)D concentration was not associated with WC or BMI, indicators of adiposity after adjustment for potential risk factors.

CONCLUSIONS

Serum 25(OH)D concentration was independently associated with the total body fat content in a general Korean population, but it may be not associated with the indicators for estimating adiposity, such as WC or BMI.     

Effect of Selected Factors on the Serum 25(OH)D Concentration in Women Treated for Breast Cancer

Maintaining an optimal vitamin D concentration reduces the risk of recurrence and extends survival time in patients after breast cancer treatment. Data on vitamin D deficiency among Polish women after breast cancer therapy are limited. Thus, the aim of the study was the analysis of vitamin D status in post-mastectomy patients, considering such factors as seasons, social habits, vitamin D supplementation and its measurements. The study involved 94 women after breast cancer treatment. Serum vitamin D concentration was measured, and a questionnaire, gathering demographic and clinical data regarding cancer, diet, exposure to sun radiation, and knowledge of recommendations on vitamin D supplementation, was delivered twice, in both winter and in summer. The control group consisted of 94 age-matched women with no oncological history. In women after breast cancer treatment, 25-hydroxyvitamin D (25(OH)D) deficiency was much more frequent than in the general population. Only about half of the patients supplemented vitamin D at the beginning of the study. After the first test and the issuing of recommendations on vitamin D supplementation, the percentage of vitamin D supplemented patients increased by about 30% in study groups. The average dose of supplement also increased. None of the women that were not supplementing vitamin D and were tested again in winter had optimal 25(OH)D concentration. It was concluded that vitamin deficiency is common in women treated for breast cancer. Medical advising about vitamin D supplementation and monitoring of 25(OH)D concentration should be improved.     

Vitamin D Status in Malaysian Men and Its Associated Factors

Vitamin D insufficiency is a global health problem. The data on vitamin D status in Malaysian men is insufficient. This study aimed to investigate vitamin D status among Chinese and Malay men in Malaysia and its associating factors. A cross-sectional study was conducted on 383 men aged 20 years and above, residing in Klang Valley, Malaysia. Their age, ethnicity, body anthropometry and calcaneal speed of sound (SOS) were recorded. Their fasting blood was collected for serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid (PTH), total calcium and inorganic phosphate assays. Vitamin D deficiency was defined as a serum 25(OH)D level <30 nmol/L and insufficiency as a serum 25(OH)D level between 30 and 50 nmol/L. The overall prevalence of vitamin D deficiency was 0.5%, and insufficiency was 22.7%. Vitamin D deficiency and insufficiency were more prevalent in the Malays compared to the Chinese. Being Chinese, older in age, having lower body mass index (BMI) and a high physical activity status were associated significantly with a higher serum 25(OH)D level (p < 0.05). The serum PTH level was inversely associated with the serum 25(OH)D level (p < 0.05). As a conclusion, a significant proportion of Malaysian men have vitamin D insufficiency, although deficiency is uncommon. Steps should be taken to correct the vitamin D status of these men.     

泸州市儿童血清25－羟维生素 D 水平调查分析

目的：调查暑期儿童血清25－羟维生素D[25（OH）D]水平,为合理补充维生素D提供科学依据。方法选取2015年7-8月间在泸州医学院附属医院儿童保健科门诊常规体检的1～16岁儿童670名为研究对象,采用化学发光法检测儿童血清25（OH）D,以体质量指数（BMI）将研究对象分为肥胖组、超重组及正常组。结果儿童25（OH）D总体水平为28．48±10．40 ng／mL,缺乏及不足率高达60．30％,＞7～16岁组、1～3岁组及＞3～7岁组儿童25（OH）D水平差异具有统计学意义,其中1～3岁组最高,＞7～16岁组最低,组间比较有统计学意义（F＝77．218,P＜0．05）。肥胖组、超重组儿童25（OH）D水平缺乏率明显高于正常儿童组（χ2值分别为6．94、7．12,均P＜0．05）;城区儿童25（OH）D水平明显低于农村儿童（t＝－9．128,P＜0．05）。 BMI与25（OH）D呈负相关（r＝－0．242,P＜0．05）。结论泸州市儿童血清25（OH）D总体不足;儿童BMI与25－羟维生素D呈负相关;城区儿童血清25（OH）D总体水平偏低。应加强血清25（OH）D检测,尤其肥胖儿童及城区居住儿童,积极予以合理的维生素D补充并加强对此类儿童的随访观察。     

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。     

Applying Machine Learning to Determine 25(OH)D Threshold Levels Using Data from the AMATERASU Vitamin D Supplementation Trial in Patients with Digestive Tract Cancer

Some controversy remains on thresholds for deficiency or sufficiency of serum 25-hydroxyvitamin D (25(OH)D) levels. Moreover, 25(OH)D levels sufficient for bone health might differ from those required for cancer survival. This study aimed to explore these 25(OH)D threshold levels by applying the machine learning method of multivariable adaptive regression splines (MARS) in post hoc analyses using data from the AMATERASU trial, which randomly assigned Japanese patients with digestive tract cancer to receive vitamin D or placebo supplementation. Using MARS, threshold 25(OH)D levels were estimated as 17 ng/mL for calcium and 29 ng/mL for parathyroid hormone (PTH). Vitamin D supplementation increased calcium levels in patients with baseline 25(OH)D levels ≤17 ng/mL, suggesting deficiency for bone health, but not in those >17 ng/mL. Vitamin D supplementation improved 5-year relapse-free survival (RFS) compared with placebo in patients with intermediate 25(OH)D levels (18–28 ng/mL): vitamin D, 84% vs. placebo, 71%; hazard ratio, 0.49; 95% confidence interval, 0.25–0.96; p = 0.04. In contrast, vitamin D supplementation did not improve 5-year RFS among patients with low (≤17 ng/mL) or with high (≥29 ng/mL) 25(OH)D levels. MARS might be a reliable method with the potential to eliminate guesswork in the estimation of threshold values of biomarkers.     

Serum 25(OH)D response to vitamin D3 supplementation: A meta-regression analysis

ObjectiveThe aim of this study was to review factors that influence serum 25(OH)D when patients are given vitamin D supplements.MethodsFrom a comprehensive search of all randomized controlled clinical trials with vitamin D₃ supplementation available on PubMed up to November 2011, we selected 33 with 43 treatment arms that included at least 30 adult participants. The achieved pooled mean difference (PMD) and 95% confidence intervals (CIs) were calculated using the random-effects models. Meta-regression and subgroup analyses were performed for prespecified factors, including dose, duration, baseline serum 25(OH)D, and age.ResultsWith a mean baseline serum 25(OH)D of 50.4 nmol/L, PMD was 37 nmol/L (95% CI, 33–41) with significant heterogeneity among studies. Dose (slope: 0.006; P < 0.001), trial duration (slope: 0.21; P < 0.001), baseline serum 25(OH)D (slope: −0.19; P < 0.001), and age (slope: 0.42; P < 0.001) independently influenced vitamin D response. Similar results were found in studies with a mean baseline serum 25(OH)D <50 nmol/L. In subgroup analyses, the PMD was higher with doses ≥800 IU/d (39.3 nmol/L) after 6 to 12 mo (41.7 nmol/L), with baseline 25(OH)D <50 nmol/L (39.6 nmol/L), and in adults aged >80 y (40.5 nmol/L).ConclusionThis meta regression indicates that a higher increase in serum levels of 25(OH)D in adults is found with a dose of ≥800 IU/d, after at least 6 to 12 mo, and even when baseline 25(OH)D is low and in adults >80 y.     

The Importance of Dose,Frequency and Duration of Vitamin D Supplementation for Plasma 25-Hydroxyvitamin D

The importance of dose, frequency and duration of vitamin D supplementation for plasma 25(OH)D levels is not well described and rarely reported for supplementation that exceeds 2000 IU per day. The objective is to examine dose, frequency and duration of supplementation in relation to plasma 25(OH)D in a large population-based sample. We accessed data on 2714 volunteers that contributed to 4224 visits and applied multilevel regression. Compared to not using supplements, a minimum regimen of 1000–2000 IU once or twice per week for one month was not effective in raising 25(OH)D. Compared to this minimum regimen, higher doses of 2000–3000, 3000–4000, and 5000 IU or more were associated with a 7.49, 13.19 and 30.22 nmol/L 25(OH)D increase, respectively; frequencies of three to four, five to six and seven times/week were associated with a 5.44, 16.52 and 30.69 nmol/L increase, respectively; and supplementation of five months or longer was associated with an increase of 6.68 nmol/L (p < 0.01 for all). Age, body weight, physical activity, smoking, and self-rated health were significantly associated with 25(OH)D. Whereas dose, frequency and duration of supplementation are important to healthy subjects committed to optimizing their nutritional status, to the design of clinical trials, individual characteristics and lifestyle contribute substantially to 25(OH)D.     

Vitamin D Status Is Associated with Modifiable Lifestyle Factors in Pre-Adolescent Children Living in Urban Kuala Lumpur,Malaysia

Studies on vitamin D status and its determinants in growing children in countries with ample sunshine such as Malaysia have been limited. The aim of our study was to determine factors associated with serum 25(OH)D concentrations such as lifestyle, dietary intake, anthropometry, and body composition in 243 pre-adolescent Malaysian children from low-income families living in Kuala Lumpur. This cross-sectional study measured bone density and body composition using dual-energy X-ray absorptiometry (DXA), while serum 25(OH)D was measured using LC–MS/MS. Time spent outdoors, body surface area exposed to sunlight, dietary intake, and physical activity level were assessed using questionnaires. Multiple linear regression and stepwise analysis were performed to identify significant predictors for serum 25(OH)D. About 69.4% had 25(OH)D < 50 nmol/L, and 18.9% were vitamin-D-deficient with 25(OH)D < 30 nmol/L. Girls had a nine-fold higher prevalence of vitamin D deficiency than boys. Body surface area exposed to sunlight, Sun Index, and fat mass were significant predictors of 25(OH)D concentrations in this population. Modifiable lifestyle factors such as sun exposure and reducing obesity are important public health guidance to ensure optimal vitamin D status in these children.     

687例儿童血清25羟维生素D检测与影响因素分析

目的 了解神木市儿童血清25羟维生素D[25-(OH)D]水平,寻找影响因素并评价危险程度,为防治该地区维生素D(VD)缺乏提供理论依据。方法 选取2016年1月-2017年12月在神木市医院儿童保健科健康查体儿童共687例。采用化学发光免疫法测定血清25-(OH)D水平并分析影响因素。结果 共收集687例健康儿童血清VD,最高值为96.9 ng/ml,最低值为2 ng/ml,平均水平为(32.59±13.14)ng/ml,其中VD缺乏120例(17.5%),VD不足169例(24.6%),VD适宜398例(57.9%),无VD过量及中毒。单因素分析结果显示,VD水平与年龄、季节、每天户外活动时间、曾添加过VD、持续服用VD时间、近三月是否添加VD相关(P<0.05)。进一步Logistic回归分析显示,户外活动时间[在30 min与2 h之间(OR=0.43,95%CI:0.22~0.84,P=0.03)、持续服用VD时间在3月~1年之间(OR=0.12,95%CI:0.05~0.28,P<0.001)是影响VD水平的因素。结论 户外活动时间、持续服用VD时间是VD缺乏的保护性因素。VD缺乏重在预防,应加强健康宣教。     

Changes in Vitamin D Supplement Use and Baseline Plasma 25-Hydroxyvitamin D Concentration Predict 5-y Change in Concentration in Postmenopausal Women

Few studies have prospectively examined predictors of change in plasma concentrations of 25-hydroxyvitamin D [25(OH)D]. We sought to determine the predictors of 5-y change in 25(OH)D. Plasma 25(OH)D concentrations were assessed at baseline (1997-2000) and 5 y later (2002-2005) in 668 postmenopausal women enrolled in the Osteoporosis and Periodontal Disease Study. Baseline and changes in demographic, dietary, lifestyle, and health-related factors were tested as predictors of change in 25(OH)D concentrations by using multivariable linear regression. The mean 5-y change in 25(OH)D (mean ± SD) was 7.7 ± 0.7 nmol/L (P < 0.001). In our predictive model (n = 643), predictors explained 31% of the variance in change in 25(OH)D concentrations and included baseline 25(OH)D, baseline and change in vitamin D supplementation and physical activity, change in season of blood draw, BMI, whole-body T score, and baseline hormone therapy use. Baseline 25(OH)D and change in vitamin D supplementation explained the most variation (25%) in 25(OH)D. Exploratory analyses showed a borderline significant interaction between tertiles of baseline 25(OH)D and change in vitamin D supplementation over time (P = 0.06). The greatest mean increase in 25(OH)D (22.9 ± 16.8 nmol/L), with adjustment for other statistically significant predictors, occurred in women whose baseline 25(OH)D concentration was ≤51.0 nmol/L (tertile 1) and who increased supplementation use over time. These results confirm the importance of supplementation in increasing 25(OH)D concentrations in aging women, even after other statistically significant predictors are controlled for. These data also suggest that this is especially true among aging women with inadequate 25(OH)D (e.g., <50 nmol/L).     

郑州中原区小学儿童1000例血清25羟维生素D水平调查及影响因素分析

目的调查郑州中原区小学儿童血清25羟维生素D水平并探讨分析影响儿童维生素D水平的因素。方法采用多阶段分层整群随机抽样的方法选取郑州中原区小学的1000例儿童作为本次研究对象,所有儿童均行血清25(OH)D水平检测。比较不同年龄段、不同性别、不同体质量的儿童维生素D水平情况,并采用多因素Logistic回归分析维生素D水平的影响因素。结果1000例儿童中,血清25(OH)D水平的平均值为(70.15±8.96)nmol/L,其中维生素D不足占比最高,为56.20%,其次是维生素D充足,占比为30.30%,维生素D缺乏占比最低,为13.50%;6~9岁儿童的血清25(OH)D水平显著高于10~12岁儿童,且6~9岁儿童的维生素D缺乏或不足人数占比(66.98%)显著少于10~12岁儿童(74.52%),差异均有统计学意义(P<0.05);男童的血清25(OH)D水平显著高于女童,且男童的维生素D缺乏或不足人数占比(66.82%)显著少于女童(75.22%),差异均有统计学意义(P<0.05);正常儿童的血清25(OH)D水平显著高于超重儿童和肥胖儿童,超重儿童的血清25(OH)D水平显著高于肥胖儿童,正常儿童的维生素D缺乏或不足人数占比显著少于超重儿童和肥胖儿童,超重儿童的维生素D缺乏或不足人数占比显著少于肥胖儿童,差异均有统计学意义(P<0.05);多因素Logistic回归分析结果显示,BMI、年龄、日照辐射、饮食均是维生素D水平的重要影响因素。结论郑州中原区小学部分儿童存在维生素D不足或缺乏,相关工作者应予以重视,加强儿童的维生素D补充。     

儿童青少年身体脂肪分布与维生素D营养状况的关联研究

目的探讨儿童身体脂肪分布与维生素D营养状况的关系。方法研究对象来自“儿童青少年心血管与骨健康促进项目”2017年北京基线调查。采用多重线性回归和无序多分类logistic回归分析BMI、全身体脂肪质量指数(FMI)、躯干脂肪质量指数(TFMI)、四肢脂肪质量指数(AFMI)和内脏脂肪面积(VFA)与维生素D水平及营养状况的关系。结果共纳入11960名儿童[年龄(11.0±3.3)岁,男童占49.7%]进行分析,血清25(OH)D水平为(35.0±11.9)nmol/L,维生素D缺乏率为37.2%。BMI、FMI、TFMI和AFMI与维生素D的关联性具有性别差异(交互P<0.05),在男童中呈负相关(BMI:β=-0.56;FMI:β=-0.59;TFMI:β=-0.60;AFMI:β=-0.59;均P<0.05),在女童中关联无统计学意义(均P>0.05)。VFA与维生素D缺乏和不足风险在男女童中均呈正相关,VFA每增加1个标准差,维生素D缺乏和不足的患病风险均增加17%(95%CI:9%~25%)。结论儿童内脏脂肪水平越高维生素D水平越低,腹型肥胖儿童和体脂肪过多的男童是维生素D缺乏防控的重点人群。     

Vitamin D Intake May Reduce SARS-CoV-2 Infection Morbidity in Health Care Workers

In the last 2 years, observational studies have shown that a low 25-hydroxyvitamin D (25(OH)D) level affected the severity of infection with the novel coronavirus (COVID-19). This study aimed to analyze the potential effect of vitamin D supplementation in reducing SARS-CoV-2 infection morbidity and severity in health care workers. Of 128 health care workers, 91 (consisting of 38 medical doctors (42%), 38 nurses (42%), and 15 medical attendants (16%)) were randomized into two groups receiving vitamin D supplementation. Participants of group I (n = 45) received water-soluble cholecalciferol at a dose of 50,000 IU/week for 2 consecutive weeks, followed by 5000 IU/day for the rest of the study. Participants of group II (n = 46) received water-soluble cholecalciferol at a dose of 2000 IU/day. For both groups, treatment lasted 3 months. Baseline serum 25(OH)D level in health care workers varied from 3.0 to 65.1 ng/mL (median, 17.7 (interquartile range, 12.2; 24.7) ng/mL). Vitamin D deficiency, insufficiency, and normal vitamin D status were diagnosed in 60%, 30%, and 10%, respectively. Only 78 subjects completed the study. Vitamin D supplementation was associated with an increase in serum 25(OH)D level, but only intake of 5000 IU/day was accompanied by normalization of serum 25(OH)D level, which occurred in 53% of cases. Neither vitamin D intake nor vitamin D deficiency/insufficiency were associated with a decrease in SARS-CoV-2 morbidity (odds ratio = 2.27; 95% confidence interval, 0.72 to 7.12). However, subjects receiving high-dose vitamin D had only asymptomatic SARS-CoV-2 in 10 (26%) cases; at the same time, participants who received 2000 IU/day showed twice as many SARS-CoV-2 cases, with mild clinical features in half of them.     

不同剂量维生素D补充在早产儿中的应用研究

目的 评估不同剂量维生素D补充对胎龄≤34周早产儿出院时维生素D水平的影响,为早产儿生后合理补充维生素D提供依据。方法 选择2019年1月—2020年6月在博罗县妇幼保健计划生育服务中心出生的胎龄≤34周早产儿67例,在完全肠内喂养后开始口服维生素D,并随机分为维生素D低剂量组(n=32)和高剂量组(n=35),比较两组患儿出院时25(OH)D水平、维生素D缺乏/不足的比例及相关不良反应发生率。结果 两组患儿出生时脐带血25(OH)D水平、维生素D缺乏/不足发生率比较,差异无统计学意义(P＞0.05);出院时高剂量组血清25(OH)D水平明显高于低剂量组、维生素D缺乏/不足发生率明显低于低剂量组(t=2.872、χ²=4.189,P＜0.05),但高剂量组出院时维生素D缺乏/不足发生率仍为28.6%。结论 对于胎龄≤34周的早产儿,给予补充维生素D 800 U/d可明显改善患儿出院时维生素D缺乏或不足的情况,但对于胎龄更小、出生体重更低的超低出生体重儿,可能需要更大剂量的维生素D补充。     

Associations between Body Composition and Vitamin D Status in Children with Overweight and Obesity Participating in a 1-Year Lifestyle Intervention

Background: To examine associations between body composition and vitamin D status in children participating in a lifestyle intervention. Methods: Children (6–12 y, n = 101) with a body mass index (BMI)-for-age >85th percentile were randomized to six dietitian-led behavior counselling sessions or no intervention. Plasma 25-hydroxyvitamin D (25(OH)D), anthropometry, and body composition using dual-energy X-ray absorptiometry were assessed every 3 months for 1 year. For each anthropometry variable (z-scores), tertiles were created to test for differences in 25(OH)D over time (tertile-by-time), and for changes in the z-score (loss, maintain, gain)-by-time, and according to fat patterning (android vs. gynoid) using mixed effects models. Results: The baseline plasma 25(OH)D was 62.2 nmol/L (95%CI: 58.7–65.7), and none < 30 nmol/L. At 6 mo, children with gynoid fat patterning had higher 25(OH)D concentrations than in those with android fat patterning (64.5 ± 1.1 nmol/L vs. 50.4 ± 1.0 nmol/L, p < 0.003, Cohen’s f = 0.20). Children with the lowest lean mass index z-score at 9 mo had higher plasma 25(OH)D concentrations than children with the highest z-score at baseline, 3 mo, and 6 mo (p < 0.05, Cohen’s f = 0.20). No other significant differences were observed. Conclusion: In this longitudinal study, vitamin D deficiency was not present in children 6–12 y of age with obesity. Reductions in adiposity did not alter the vitamin D status.     

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.