• Clinical and Experimental Pediatrics
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• v.58 no.11
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• pp.427-433
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• 2015

Purpose: We investigated the vitamin D status of preterm infants to determine the incidence of vitamin D deficiency. Methods: A total of 278 preterm infants delivered at Kyungpook National University Hospital between January 2013 and May 2015 were enrolled. The serum concentrations of calcium, phosphorous, alkaline phosphatase, and 25-hydroxyvitamin D (25-OHD) were measured at birth. We collected maternal and neonatal data such as maternal gestational diabetes, premature rupture of membranes, maternal preeclampsia, birth date, gestational age, and birth weight. Results: Mean gestational age was $33^{+5}{\pm}2^{+2}$ weeks of gestation and mean 25-OHD concentrations were $10.7{\pm}6.4ng/mL$. The incidence of vitamin D deficiency was 91.7%, and 51.1% of preterm infants were classified as having severe vitamin D deficiency (25-OHD<10 ng/mL). The serum 25-OHD concentrations did not correlate with gestational age. There were no significant differences in serum 25-OHD concentrations or incidence of severe vitamin D deficiency among early, moderate, and late preterm infants. The risk of severe vitamin D deficiency in twin preterm infants was significantly higher than that in singletons (odds ratio, 1.993; 95% confidence interval [CI], 1.137-3.494, P=0.016). In the fall, the incidence of severe vitamin D deficiency decreased 0.46 times compared to that in winter (95% CI, 0.227-0.901; P=0.024). Conclusion: Most of preterm infants (98.9%) had vitamin D insufficiency and half of them were severely vitamin D deficient. Younger gestational age did not increase the risk of vitamin D deficiency, but gestational number was associated with severe vitamin D deficiency.

• Nutrition Research and Practice
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• v.7 no.6
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• pp.495-502
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• 2013

Recent studies suggest that vitamin D deficiency and cardiometabolic disorders are becoming increasingly more prevalent across multiple populations. However, there is a lack of comprehensive data for Korean adults. We investigated the vitamin D status, the prevalence of vitamin D deficiency and its association with metabolic syndrome (MS) risk in Korean adults aged 20 years or older. The study subjects (n = 18,305) were individuals who participated in the Korean National Health Examination and Nutrition Survey (KNHANES) in 2008-2010. Vitamin D status (25-hydroxyvitamin D [25(OH)D]) was categorized as < 20, 21-29, and ${\geq}$ 30 ng/mL, which are the cut-off points for deficiency, insufficiency and normal limits. A wide variety of cardiometabolic risk factors were compared according to the vitamin D status. Vitamin D deficiency was found in 53.9% of men and 70.5% of women. Mean BMI, systolic BP, HbA1c and low density lipoprotein cholesterol (LDL-C) were highest in the vitamin D deficiency group in both genders. Further, the MS was most prevalent in the vitamin D deficiency group in both genders (12.3%, P = 0.002 in men and 9.2%, P < 0.001 in women). Compared to the vitamin D normal group, the adjusted odds ratio (ORs) (95% confidence interval [95% CI]) for MS in the vitamin D deficiency group were 1.46 (1.05-2.02) in men and 1.60 (1.21-2.11) in women, after adjusting for confounding variables. In conclusion, Vitamin D deficiency is a very common health problem in Korean adults and is independently associated with the increasing risk of MS.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.133-137
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• 2010

Purpose: The main function of vitamin D is the mineralization of the brain by increase of calcium and phosphorus, in case it is insufficient in children, lime deposition on cartilage cannot occur so it leads to rachitis, and in adults, it leads to osteomalacia or osteoporosis. It is also strongly believed in the academic world that vitamin D can restrict the growth of cancer cells and prevent heart diseases, which is also somewhat proven in epidemiological researches. While the right density of vitamin D is still being studied, 20-32 ng/mL is believed to be the most ideal density. Therefore, I wanted analyze how much density of 25-Hydroxyvitamin D3 that Koreans possess. Materials and Methods: From February 20th, 2008 to April 21st, 2009, the collection of 2800 serums, from medical examination treated subjects by Neodin Medical Institute, have been tested. The targets were tested by 25-Hydroxyvitamin D (125I Kit: Diasorin, USA), and were analyzed by dividing into many different categories (gender, age, season, region). Results: The average density of male were 20 ng/mL, female 17.08 ng/mL. Per age groups, the density of males were as follows: 10~20-18 ng/mL, 21~30-17 ng/mL, 31~40-19 ng/mL, 41~50-21 ng/mL, 51~60-22 ng/mL, 61~70-22 ng/mL, 71~80-22 ng/mL and 81~90-19.9 ng/mL. Average density of females per age groups, were as follows: 10~20-16 ng/mL, 20~30-15.26 ng/mL, 30~40-16 ng/mL, 40~50-17 ng/mL, 50~60-19 ng/mL, 60~70-19 ng/mL, 70~80-19 ng/mL, and 80~90-17 ng/mL. Per seasons, From December to May, the subjects showed the density of 15.97 ng/mL, while from June to November, it showed 21.60 ng/mL. On density of males from January to April regionally, Seoul+Gyeonggi-Do-15.52 ng/mL, Gangwon-Do-15.33 ng/mL, Choongchung-Do-18.03 ng/mL, Jeonla-Do-18.68 ng/mL, Gyungsang-Do-18.76 ng/mL and Cheju Do-21.23 ng/mL. Conclusions: The vitamin D of Koreans is has been insufficient compared to the suggested amount. Ultraviolet rays, which is the main source of vitamin D is critical, therefore it is suggested that more outdoor activities can definitely help.

• Nutrition Research and Practice
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• v.10 no.3
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• pp.328-335
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• 2016

BACKGROUND/OBJECTIVES: Vitamin D plays an important role in the etiology of gestational diabetes mellitus (GDM). This study evaluated the effect of vitamin D supplementation on metabolic indices and hs-C-reactive protein (CRP) levels in GDM patients. SUBJECTS/METHODS: The study was a randomized, placebo-controlled, double-blinded clinical trial. Seventy-six pregnant women with GDM and gestational age between 24-28 weeks were assigned to receive four oral treatments consisting of 50,000 IU of vitamin $D_3$ (n = 38) or placebo (n = 38) once every 2 weeks for 2 months. Fasting blood glucose (FG), insulin, HbA1c, 25-hydroxyvitamin D, lipid profile, hs-CRP, and homeostasis model assessment-insulin resistance (HOMA-IR) were measured before and after treatment. Independent and paired t-tests were used to determine intra- and intergroup differences, respectively. ANCOVA was used to assess the effects of vitamin D supplementation on biochemical parameters. RESULTS: Compared with the placebo group, in the vitamin D group, the serum level of 25-hydroxyvitamin D increased (19.15 vs. -0.40 ng/ml; P < 0.01) and that of FG (-4.72 vs. 5.27 mg/dl; P = 0.01) as well as HbA1c (-0.18% vs. 0.17%; P = 0.02) decreased. Improvements in the lipid profiles were observed in the vitamin D group, but without statistical significance. Significant increases in concentrations of hs-CRP, FG, HbA1c, total cholesterol, and LDL cholesterol were observed in the placebo group. No significant change in fasting insulin and HOMA-IR was observed in either group. CONCLUSIONS: In GDM patients, vitamin D supplementation improved FG and HbA1c but had no significant effects on lipid profile or hs-CRP.

• Nutritional Sciences
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• v.8 no.2
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• pp.111-117
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• 2005

It has been more than three decades since the first assay assessing circulating 25 (OH)D in human subjects was performed That publication as well as several that followed it defined 'normal' nutritional vitamin D status in human populations. Recently, the wisdom by which 'normal' circulating 25 (OH)D levels in human subjects were assigned in the past has come under question. It appears that sampling human subjects, who appear to be free from disease, and assessing 'normal' circulating 25 (OH)D levels by plotting a Gaussian distribution is grossly inaccurate. There are many reasons why this method is inaccurate, including race, lifestyle habits, sunscreen usage, age, latitude, and inappropriately low dietary recommendations for vitamin D. For instance, a 400 IU/day. AI for vitamin D is insignificant when one considers that a 10-15 minute whole body exposure to peak summer sun will generate and release up to 20,000 IU vitamin $D_3$ into the circulation. Recent studies, which orally administered up to 10,000 IU/day vitamin $D_3$ to human subjects for several months, have successfully elevated circulating 25 (OH)D levels to those observed in individuals from sun-rich environments. Further, we are now able to accurately assess sufficient circulating 25 (OH)D levels utilizing specific biomarkers instead of guessing what an adequate level is. These biomarkers include intact parathyroid hormone (PTH), calcium absorption, bone mineral density (BMD), insulin resistance and pancreatic beta cell function. Using the data from these biomarkers, vitamin D deficiency should be defined as circulating levels of 25 (OH)D$\leq$30 ng/mL. In certain cases, such as pregnancy and lactation, significantly higher circulating 25 (OH)D levels would almost certainly be beneficial to both the mother and recipient fetus/infant.

• Proceedings of the Korean Nutrition Society Conference
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• 2004.11a
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• pp.22-33
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• 2004

It has been more than three decades since the first assay assessing circulating 25(OH)D in human subjects was performed. That publication as well as several that followed it defined 'normal' nutritional vitamin D status in human populations. Recently, the wisdom by which 'normal' circulating 25(OH)D levels in human subjects were assigned in the past has come under question. It appears that sampling human subjects, who appear to be free from disease, and assessing 'normal' circulating 25(OH)D levels by plotting a Gaussian distribution is grossly inaccurate. There are many reasons why this method is inaccurate, including race, lifestyle habits, sunscreen usage, age, latitude, and inappropriately low dietary recommendations for vitamin D. For instance, a 400IU/day. AI for vitamin D is insignificant when one considers that a 10-15 minute whole body exposure to peak summer sun will generate and release up to 20,000 IU vitamin $D_3$ into the circulation. Recent studies, which orally administered up to 10,000 IU/day vitamin $D_3$ to human subjects for several months, have successfully elevated circulating 25(OH)D levels to those observed in individuals from sun-rich environments. Further, we are now able to accurately assess sufficient circulating 25(OH)D levels utilizing specific biomarkers instead of guessing what an adequate level is. These biomarkers include intact parathyroid hormone (PTH), calcium absorption, bone mineral density (BMD), insulin resistance and pancreatic beta cell function. Using the data from these biomarkers, vitamin D deficiency should be defined as circulating levels of $25(OH)D{\leq}30ng/mL$. In certain cases, such as pregnancy and lactation, significantly higher circulating 25(OH)D levels would almost certainly be beneficial to both the mother and recipient fetus/infant.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.3
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• pp.125-131
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• 2019

Objective: To investigate serum 25-hydroxyl vitamin D (25(OH)D) and vitamin D-binding protein (VDBP) concentrations in women with endometriosis according to the severity of disease. Methods: Women with mild endometriosis (n = 9) and advanced endometriosis (n = 7), as well as healthy controls (n = 16), were enrolled in this observational study. Serum total 25(OH)D concentrations were analyzed using the Elecsys vitamin D total kit with the Cobas e602 module. Concentrations of bioavailable and free 25(OH)D were calculated. Concentrations of VDBP were measured using the Human Vitamin D BP Quantikine ELISA kit. Variables were tested for normality and homoscedasticity using the Shapiro-Wilk test and Leven F test, respectively. Correlation analysis was used to identify the variables related to total 25(OH)D and VDBP levels. To assess the effects of total 25(OH)D and VDBP levels in the three groups, multivariate generalized additive modeling (GAM) was performed. Results: Gravidity and parity were significantly different across the three groups. Erythrocyte sedimentation rate (ESR) and CA-125 levels increased as a function of endometriosis severity, respectively (p= 0.051, p= 0.004). The correlation analysis showed that total 25(OH)D levels were positively correlated with gravidity (r = 0.59, p< 0.001) and parity (r = 0.51, p< 0.003). Multivariate GAM showed no significant relationship of total 25(OH)D levels with EMT severity after adjusting for gravidity and ESR. However, the coefficient of total 25(OH)D levels with gravidity was significant (1.87; 95% confidence interval, 0.12-3.63; p= 0.040). Conclusion: These results indicate that vitamin D and VDBP levels were not associated with the severity of endometriosis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.303-311
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• 2018

The aim of this study was to investigate vitamin D status and factors associated with vitamin D deficiency among Koreans in their using Korean National Health and Nutrition Examination Survey (KNHANES) V. The subjects were 1,837 people who were 20-29 years old. The data were analyzed by ${\chi}^2$ test and multiple logistic regression analysis using weighted composite sample analysis. Vitamin D deficiency was reveled in 84.2% of subjects; 88.6% of women and 79.4% of men showed deficiency. In the multiple logistic regression analysis, the risk for vitamin D deficiency was higher in women (OR 1.84; 95% CI 1.31-2.56), non-married (OR 2.12; 95% CI 1.41-3.19), poor subjective health status (OR 1.94; 95% CI 1.16-3.25), and in the absence of moderate to vigorous physical activity (OR 3.38; 95% CI 1.85-6.16). Continued research on vitamin D levels at this time is needed since vitamin D deficiency among Koreans in their twenties will exacerbate health problems, both individually and socially. In addition, vitamin D has been shown to be closely related to time of exposure to sunlight and physical activity. Therefore, it is thought that long-term and planned efforts should be made at the national level, such as establishing schools and workplaces in which those in their twenties can perform outdoor activities and moderate to vigorous physical activity.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.5
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• pp.397-402
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• 2014

Microglia are activated by inflammatory and pathophysiological stimuli in neurodegenerative diseases, and activated microglia induce neuronal damage by releasing cytotoxic factors like nitric oxide (NO). Activated microglia synthesize a significant amount of vitamin $D_3$ in the rat brain, and vitamin $D_3$ has an inhibitory effect on activated microglia. To investigate the possible role of vitamin $D_3$ as a negative regulator of activated microglia, we examined the effect of 25-hydroxyvitamin $D_3$ on NO production of lipopolysaccharide (LPS)-stimulated microglia. Treatment with LPS increased the production of NO in primary cultured and BV2 microglial cells. Treatment with 25-hydroxyvitamin $D_3$ inhibited the generation of NO in LPS-activated primary microglia and BV2 cells. In addition to NO production, expression of 1-${\alpha}$-hydroxylase and the vitamin D receptor (VDR) was also upregulated in LPS-stimulated primary and BV2 microglia. When BV2 cells were transfected with 1-${\alpha}$-hydroxylase siRNA or VDR siRNA, the inhibitory effect of 25-hydroxyvitamin $D_3$ on activated BV2 cells was suppressed. 25-Hydroxyvitamin $D_3$ also inhibited the increased phosphorylation of p38 seen in LPS-activated BV2 cells, and this inhibition was blocked by VDR siRNA. The present study shows that 25-hydroxyvitamin $D_3$ inhibits NO production in LPS-activated microglia through the mediation of LPS-induced 1-${\alpha}$-hydroxylase. This study also shows that the inhibitory effect of 25-hydroxyvitamin $D_3$ on NO production might be exerted by inhibiting LPS-induced phosphorylation of p38 through the mediation of VDR signaling. These results suggest that vitamin $D_3$ might have an important role in the negative regulation of microglial activation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.231-242
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• 2019

The aim of this study was the relationship between smoking, alcohol drinking and vitamin D level among Korean adults using data from the '6th(2013-2014) Korean National Health and Nutrition Examination Survey'. The data used in this study were analyzed for 3,565 people who were over the age of 19 ages and checked vitamin D level and consumption frequencies of vitamin D rich foods among 15,568 respondents to the '6th(2013-2014) Korean National Health and Nutrition Examination Survey'. The subjects were divided into four groups: None group(non-smoking and non-alcohol drinking), smoking only group, alcohol drinking only group and both group (smoking and alcohol drinking). The mean serum vitamin D level of the subjects was $16.5{\pm}0.20ng/mL$ and 73.5% of vitamin D levels were insufficient and deficiency. The results from hierarchical multiple logistic regression showed that the Odds ratio for insufficient vitamin D due to smoking and alcohol drinking were significantly higher in the smoking only group 2.281(95% CI 1.080-4.817)times and both group 1.356(95% CI 1.010-1.922)times than none group. Our results showed the relationship between smoking, alcohol drinking and vitamin D level was significant in Korean adults. Future studies, such as a more systematic cohort study investigating the relationship between smoking, alcohol drinking and vitamin D level may be helpful in confirming the causal relationship between smoking, alcohol drinking and vitamin D level.