Adult ; China ; epidemiology ; Humans ; Male ; Middle Aged ; Sunlight ; Vitamin D ; blood ; Vitamin D Deficiency ; epidemiology

Objective: To explore current vitamin D status and influential factors of vitamin D deficiency and insufficiency among children under 7 years of age in 11 provinces, autonomous regions or municipalities of China. Methods: According to the "province-city-hospital" sampling technical route, a total of 1 531 healthy children under 7 years of age were sampled from 11 provinces, autonomous regions or municipalities in China by the cluster random sampling method from November 2020 to November 2021. The demographic information, family conditions, behavior and living habits and feeding behaviors were collected using unified questionnaire. Serum 25-hydroxyvitamin D(25(OH)D) levels were measured by liquid chromatography-tandem mass spectrometry. Serum 25(OH)D<30 nmol/L was considered deficient and 30-50 nmol/L was considered insufficient. With 25(OH)D≤50 nmol/L as the dependent variable, multivariate Logistic regression was applied to analyze the association between vitamin D deficiency and insufficiency and potential influential factors. Results: The prevalence of vitamin D deficiency and insufficiency among children under 7 years of age in 11 provinces, autonomous regions or municipalities of China was 14.0% (215/1 531), 3.8% (25/664) and 21.9% (190/867) in 0-<3 and 3-<7 of age years, respectively. Compared to children aged 0-<3 years, children aged 3-<7 years had a 2.6-fold increased risk of vitamin D deficiency and insufficiency (OR=3.60, 95%CI 1.93-6.72, P<0.001). Frequent sunlight exposure (OR=0.46, 95%CI 0.29-0.73, P=0.001), vitamin D supplementation (sometimes, OR=0.33, 95%CI 0.21-0.51, P<0.001; daily, OR=0.20, 95%CI 0.11-0.36, P<0.001) and infant formula intake(4-7 times per weeks, OR=0.43, 95%CI 0.28-0.68, P<0.001) were protective factors for vitamin D deficiency and insufficiency. Conclusion: Vitamin D deficiency and insufficiency are common among children under 7 years of age in 11 provinces, autonomous regions or municipalities of China, which is affected by age, sunlight exposure, vitamin D supplementation and infant formula intake.
Child ; China/epidemiology* ; Cross-Sectional Studies ; Humans ; Infant ; Vitamin D ; Vitamin D Deficiency/epidemiology* ; Vitamins

Humans ; Infant ; Prevalence ; Risk Factors ; Vitamin D Deficiency/epidemiology*

BACKGROUND: Determining the concentration profiles of serum 25-hydroxyvitamin D (25OHD) may aid in the clinical diagnosis and treatment of vitamin D deficiency. To date, the standardized liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been used for accurate and precise determination of 25-hydroxyvitamin D levels. Here, we evaluated the performance of the recently developed and introduced PerkinElmer Vitamin D kit and compared the measurements obtained by RIA and LC-MS/MS methods. METHODS: We evaluated the accuracy, precision, linearity, lower limit of quantification (LLOQ), recovery, and carry-over of the MSMS Vitamin D kit. Clinical specimens from 80 patients were used for the comparison between the MSMS Vitamin D kit (PerkinElmer, USA) and the RIA kit (DiaSorin, USA). RESULTS: The MSMS Vitamin D kit was found to produce intra-assay and inter-assay coefficients of variation (CVs) of less than 6% for precision and showed a bias of less than 5%. The MSMS Vitamin D kit displayed linearity within the range for total vitamin D levels of 4.5-150 ng/mL, and the lower limit of quantification for 25OHD was 0.38 ng/mL. The RIA measurements of 25OHD showed a correlation of y=0.9931x+0.2216 (r2=0.74) with the LC-MS/MS values. CONCLUSIONS: The LC-MS/MS assay of 25OHD3 and 25OHD2 showed excellent performance when using the MSMS Vitamin D kit and in terms of 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) derivatization. Further, the results obtained were well correlated with those obtained using the RIA method. Thus, assays using the MSMS Vitamin D kit are considered as more standardized, and they enable quicker and more accurate analysis and help reduce inter-laboratory variation than that by other existing methods.
25-Hydroxyvitamin D 2 ; Bias (Epidemiology) ; Calcifediol ; Humans ; Mass Spectrometry ; Tandem Mass Spectrometry ; Triazoles ; Vitamin D ; Vitamin D Deficiency ; Vitamins

OBJECTIVETo evaluate the endogenous vitamin D level and its correlation with bone mineral density (BMD) in children under 7 years old.

METHODSTotally 6 838 children who visited the Growth and Development Clinic due to "growth retardation, night terrors, hyperhidrosis, and dysphoria" were enrolled in the study. Serum 25-hydroxyvitamin D [25(OH)D] level was measured by chemiluminescence, whereas individual BMD was measured by quantitative ultrasound.

RESULTSAmong all subjects, serum 25(OH)D level was 34 ± 14 ng/mL, and the Z value of BMD was -0.49 ± 0.54. With increasing age, serum 25(OH)D level and BMD decreased gradually (P<0.01), and the detection rates for vitamin D deficiency and low BMD increased gradually (P<0.01). Compared with those with sufficient vitamin D, children with vitamin D deficiency had a significantly lower BMD (P<0.01) and a significantly higher detection rate for low BMD (P<0.01). 25-(OH)D level showed a positive linear correlation with BMD in children with vitamin D deficiency (P<0.01).

CONCLUSIONSPreschool and school-age children have severer vitamin D deficiency than infants. Vitamin D level may be correlated with BMD within a certain range.

Bone Density ; Child ; Child, Preschool ; Humans ; Infant ; Infant, Newborn ; Vitamin D ; analogs & derivatives ; blood ; Vitamin D Deficiency ; epidemiology

OBJECTIVETo investigate the difference in serum 25(OH)D level between children with bloodstream infection and healthy children.

METHODSA case-control study was conducted among 60 children with bloodstream infection who were hospitalized between January 2010 and December 2013 and had positive results of two blood cultures. Meanwhile, 60 aged-matched healthy children who underwent physical examination during the same period of time were enrolled as the healthy control group. Chemiluminescence was applied to measure the serum 25(OH)D level, and the constituent ratios of children with different serum 25(OH)D levels were compared between the two groups.

RESULTSThe bloodstream infection group had a significantly lower serum 25(OH)D level than the healthy control group (P<0.01). Compared with the healthy control group, the bloodstream group had significantly lower constituent ratios of children with normal Vitamin D level (8% vs 35%) or vitamin D insufficiency (22% vs 43%) (P<0.05). Compared with the healthy control group, the bloodstream group had significantly higher constituent ratios of children with vitamin D deficiency (42% vs 13%) or severely vitamin D deficiency (28% vs 8%) (P<0.01).

CONCLUSIONSVitamin D insufficiency prevails among children, and children with bloodstream infection have a significantly lower serum 25(OH)D level than healthy children.

Case-Control Studies ; Child, Preschool ; Female ; Humans ; Male ; Sepsis ; blood ; Vitamin D ; analogs & derivatives ; blood ; Vitamin D Deficiency ; epidemiology

Vitamin D plays an important role in bone metabolism and maintaining bone health. Recently, new evidence has revealed that vitamin D affects chronic diseases such as autoimmune diseases, cardiovascular diseases and certain cancers. The aim of this study was to evaluate the vitamin D status and the prevalence of vitamin D deficiency in an urban Korean population. This study included 8,976 participants (3,587 men and 5,389 women) aged 50 yr and older. Serum 25(OH)D level was measured by chemiluminescent microparticle immunoassay. The prevalence of vitamin D deficiency [25(OH)D < 20 ng/mL] was 59.7% and 86.5% in men and women, respectively. The prevalence of vitamin D deficiency increased significantly with age in men, but not in women and it decreased from April to July, more prominently in men than in women. These results suggest that sun exposure, intake of vitamin D supplement, and regular physical activities is recommended in an urban Koreans, especially in women.
Aged ; Aging ; Bone and Bones/metabolism ; Female ; Humans ; Male ; Middle Aged ; Prevalence ; Republic of Korea/epidemiology ; Risk Factors ; Sex Factors ; Vitamin D/*blood ; Vitamin D Deficiency/blood/*epidemiology

OBJECTIVETo investigate the association between vitamin D deficiency and risk of gestational diabetes mellitus (GDM) in pregnant Chinese women.

METHODSA nested case-control study was conducted. Clinical and biochemical data were analyzed for 200 subjects with GDM and 200 subjects with normal glucose tolerance (NGT).

RESULTSThe median (interquartile range) serum 25-hydroxyvitamin D (25OHD) levels were 22.39 (17.67, 29.38) and 25.86 (19.09, 34.88) nmol/L in the GDM and NGT groups, respectively. Rates of 25OHD deficiency or insufficiency were significantly higher in the GDM group than in the NGT group. Subjects with 25OHD levels <25 nmol/L had a 1.8-fold higher risk of GDM compared with subjects with higher vitamin D levels. In the GDM group, serum 25OHD was independently associated with HbA1c and insulin resistance after adjusting for confounding factors. In the NGT group, serum 25OHD was independently associated with fasting plasma glucose and systolic blood pressure after adjusting for maternal age and other confounding factors.

CONCLUSION25OHD insufficiency is very common in Chinese women. Low 25OHD status may be associated with insulin resistance and act as a risk factor for GDM.

Adult ; Asian Continental Ancestry Group ; Diabetes, Gestational ; blood ; epidemiology ; Female ; Humans ; Pregnancy ; Vitamin D ; analogs & derivatives ; blood ; Vitamin D Deficiency ; blood ; epidemiology

Brain ; physiology ; Child ; Dyssomnias ; drug therapy ; epidemiology ; etiology ; Humans ; Infant ; Sleep ; drug effects ; Vitamin D ; administration & dosage ; analogs & derivatives ; blood ; Vitamin D Deficiency ; complications ; drug therapy ; epidemiology

Adult ; Body Mass Index ; Cross-Sectional Studies ; Diabetes Mellitus, Type 2/epidemiology* ; Humans ; Obesity/epidemiology* ; Vitamin D ; Vitamin D Deficiency ; Vitamins ; Waist Circumference