• 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.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.5
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• pp.713-722
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• 2009

Vitamin D levels have been reported to be associated with diabetes, obesity and metabolic syndrome. There have been studies on the nutritional status of vitamin D in postmenopausal women at Seoul and premenopausal women at Busan, and these studies showed that nearly no relationship between serum vitamin D levels and the obesity index existed. However, there have been no studies that examined about the relationship between serum vitamin D levels and insulin resistance in Korea. In this study, we investigated serum vitamin D levels and the relationship between serum vitamin D levels and insulin resistance (homeostasis model assessment of insulin resistance), obesity index (body mass index, percentage of body fat and waist circumference) in 180 premenopausal women (non-obese women 87.8%, obese women 12.2%) in spring (March~April), fall (September~October) and winter (January~February) at Daejeon. Serum vitamin D levels were lower in winter than in spring-fall, after adjusting for age and the obesity index. The frequency of vitamin D inadequacy (serum vitamin D levels were $\leq$ 20 ng/mL) was 45.5% in winter and, 23.5% in spring-fall, and which showed that vitamin D inadequacy was higher in winter than in spring-fall. Multiple regression analysis showed that serum vitamin D levels had no relationship with the obesity index or insulin resistance. There was no difference in the obesity index or insulin resistance between the vitamin D inadequacy and normal group, and there was no relationship between serum vitamin D levels and the obesity index or insulin resistance in non-obese and obese premenopausal women, respectively. In conclusion, serum vitamin D levels in premenopausal women at Daejeon were lower in winter than in spring-fall, and the frequency of vitamin D inadequacy was higher in winter than in spring-fall. Serum vitamin D levels had no relationship with the obesity index or insulin resistance in premenopausal women, most of whom were not obese.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.5
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• pp.674-682
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• 2014

Four experiments were conducted to investigate the effect of fat-soluble vitamin administration to sows or newborn pigs on plasma vitamin status. In Exp. 1 and 2, a total of 24 and 43 newborn pigs were allotted to control and vitamin treatments (vitamin $D_3$ with variable addition of vitamins A and E) orally or by i.m. injection. In Exp. 3, pigs from Exp. 2 were allotted to 2 treatments (${\alpha}$vitamins $D_3$ and E in drinking water) for 14 d postweaning. In Exp. 4, twenty-four gestating sows were used for 2 treatments (${\pm}injection$ of a vitamin $D_3$/A/E product 2 wk prepartum). In Exp. 1 and 2, when vitamin $D_3$ was administrated orally or by i.m. injection on d 1 of age, pigs had increased plasma 25-hydroxycholecalciferol (25-OH $D_3$) concentration 10 d after administration compared with control pigs (p<0.05). The injectable administration with vitamin $D_3$ and E was able to achieve higher plasma 25-OH $D_3$ (p<0.05) and ${\alpha}$-tocopherol (p<0.05) concentrations than oral administration. At weaning, the pigs in the injection group had higher plasma 25-OH $D_3$ concentration than those in the other groups in both studies (p<0.05). In Exp. 3, water supplementation of vitamin $D_3$ and E postweaning increased plasma 25-OH $D_3$ and ${\alpha}$-tocopherol concentrations at d 14 postweaning (p<0.01). In Exp. 4, when sows were injected with the vitamin $D_3$ product prepartum, serum 25-OH $D_3$ concentrations of sows at farrowing (p<0.01), and in their progeny at birth (p<0.01) and weaning (p<0.05) were increased. These results demonstrated that fat-soluble vitamin administration to newborn pigs increased plasma 25-OH $D_3$ concentration regardless of administration routes and ${\alpha}$-tocopherol concentration by the injectable route, and that water supplementation of vitamin $D_3$ and E to nursery pigs increased plasma 25-OH $D_3$ and ${\alpha}$-tocopherol concentrations. Additionally, injecting sows with vitamin $D_3$ prepartum increased 25-OH $D_3$ in sows and their offspring. If continued research demonstrates that the serum levels of 25-OH $D_3$ are critical in weanling pigs, a variety of means to increase those levels are available to swine producers.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.3
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• pp.292-298
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• 2006

Modification of the diet during childhood and adolescence may be an effective strategy for maximizing the peak bone mass. Many supplementation studies have suggested a positive effect of the increased vitamin D intake on the bone mineral status in the elderly. However to date all studies have been conducted on old men and postmenopausal women. The aim of this study was to examine the effects of vitamin D supplementation on the bone mineral density and bone mineral content in growing rats. Twenty Sprague-Dawley female rats were divided into two groups; Control, and vitamin D supplementation. The bone mineral density(BMD) and bone mineral content(BMC) were measured using PIXImus in the spine and femur. Vitamin D supplementation did not affect the level of weight gain, mean food intake and food efficiency ratio. In addition, vitamin D supplementation had no added effect on the spine and femur BMD, and BMC. There were no significant differences in the spine BMD/weight and BMC/weight between the groups, but the spine BMD/weight and BMC/weight was 11 % higher in the vitamin D supplementation group. The femur BMD/weight and femur BMC/weight were significantly higher in the vitamin D supplementation group 9 weeks after the experiment. These results provide evidence of the beneficial effects of vitamin D supplementation on the BMD during the growth period.

• Nutrition Research and Practice
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• v.13 no.2
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• pp.115-125
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• 2019

BACKGROUND/OBJECTIVES: Vitamin D plays an important role in skeletal growth and maintenance and in the prevention of various diseases. We investigated the relationship between vitamin D intake and bone mineral density (BMD) in Korean adults aged ${\geq}50$ years using the 2009 Korea National Health and Nutrition Examination Survey data. SUBJECTS/METHODS: This study was conducted in 1,808 subjects aged ${\geq}50$ years with BMD data in Korea. Dietary vitamin D levels were assessed by the 24-hour recall method. BMD was measured using dual-energy X-ray absorptiometry. We investigated general characteristics and the association between these characteristics, vitamin D status, and BMD. RESULTS: Vitamin D intake was significantly lower in the osteoporosis group among women (P < 0.05). Among all subjects, the higher the serum 25(OH)D concentration, the higher the whole-body total BMD (WBT-BMD), femoral total hip BMD, and femoral neck BMD (P < 0.01). In the serum vitamin D-deficient group of both the total population and women, serum 25(OH)D concentration was associated with WBT-BMD (P < 0.05). Among women with a calcium intake < 537.74 mg/day, BMD of those with a vitamin D intake > $2.51{\mu}g/day$ (average intake of women) was higher than that of women with a vitamin D intake ${\leq}2.51{\mu}g/day$ (P < 0.001). CONCLUSIONS: Korean adults should increase their BMD by increasing serum 25(OH)D concentration. Furthermore, increasing vitamin D intake could improve BMD, especially in Korean women who consume less calcium than the estimated average requirement.

• Clinical and Experimental Pediatrics
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• v.59 no.7
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• pp.292-297
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• 2016

Purpose: To compare different regimens of vitamin D with respect to its serum increment levels and bone mineral accrual in vitamin D-deficient children. Methods: Children identified as being vitamin D deficient (serum levels<20 ng/mL) were divided into 3 treatment groups by stratified block randomization (group 1, 4,000 IU/day of vitamin D3 plus 50 mg/kg/day calcium for 12 weeks; group 2, 30,000 IU/wk of vitamin D3 plus 50 mg/kg/day calcium for 12 weeks; and group 3, 300,000 IU of vitamin D3 once intramuscularly plus 50 mg/kg/day calcium). After regimen completion, each child received a maintenance dose of 400 IU/day vitamin D3 plus 50 mg/kg/day calcium. Their serum vitamin D level was measured after 3 and 12 months. Total body less head bone mineral concentration (BMC) and total body less head bone mineral density (BMD) were measured after 12 months. Results: The mean increment in serum vitamin D levels from baseline to 3 months was significantly higher in group 3 than in groups 1 and 2, but the levels from 3 to 12 months were almost similar among all 3 groups. There were no significant differences among the 3 groups with respect to percentage increase of BMD and BMC. Conclusion: The injectable form of vitamin D was more efficacious than the oral forms in increasing the serum level to the normal range. All 3 regimens were equally effective in increasing the BMC and BMD. The 400 IU/day maintenance dose was sufficient to keep the serum level within the normal range.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.2
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• pp.125-134
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• 2024

Objective: Vitamin D deficiency is a major problem for human health worldwide. The mechanisms of vitamin D in the male reproductive system are unknown. After coronavirus disease 2019 (COVID-19) vaccines were developed, doubts were raised about their possible effects on male fertility. Based on vitamin D's function in the immune system, its potential role as an adjuvant for COVID-19 vaccines is intriguing. The aims of this study were to assess the effects of vitamin D first on sperm parameters and sex hormones, and then as an immune adjuvant on sperm parameters and sex hormones after study participants had received their second doses of COVID-19 vaccines. Methods: Phase 1 (before the COVID-19 pandemic) included 72 men with idiopathic infertility, and phase 2 had 64 participants who received two doses of COVID-19 vaccines. Both groups were instructed to take 50,000 IU of vitamin D twice monthly for 3 months. Sperm parameters and sex hormones were assessed pre-and post-supplementation. Results: Regular vitamin D intake for 3 months significantly increased the participants' vitamin D levels (p=0.0001). Both phases showed a positive correlation between vitamin D intake and sperm parameters. Vaccination had no negative effects on sperm parameters and sex hormones. Vitamin D was associated with follicle-stimulating hormone (p=0.02) and testosterone (p=0.0001) in phase 2 after treatment. Conclusion: Our results support vitamin D supplementation as an immune adjunct to COVID-19 vaccination for improving sperm parameters and hormone levels. COVID-19 vaccination is not harmful for male fertility potential, and vitamin D is an effective factor for male fertility.

• Osteoporosis and Sarcopenia
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• v.2 no.4
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• pp.228-237
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• 2016

Objective: There has been no prospective study that examined intramuscular injection of high-dose vitamin D in Korean adults. The aim of this study was to assess the efficacy and safety of high-dose vitamin $D_3$ after intramuscular injection in Korean adults with vitamin D deficiency. Method: This study was a 24-week, prospective, multicenter, randomized, double-blind, placebo-controlled trial. A total of 84 subjects ${\geq}19$ and <65 years of age were randomly allocated to either the vitamin $D_3$ or placebo group in a 2:1 ratio. After randomization, a single injection of plain vitamin $D_3$ 200,000 IU or placebo was intramuscularly administered. If serum 25-hydroxyvitamin D (25[OH]D) concentrations were <30 ng/mLon week 12 or thereafter, a repeat injection was administered. Results: After a single intramuscular injection of vitamin $D_3$ to adults with vitamin D deficiency, the proportion of subjects with serum 25(OH)D concentrations ${\geq}30ng/mL$ within 12 weeks was 46.4% in the vitamin $D_3$ group and 3.6% in the placebo group (p<0.0001). The proportion of subjects with serum 25(OH)D concentrations ${\geq}30ng/mL$ within 24 weeks was 73.2% in the vitamin $D_3$ group and 3.6% in the placebo group (p<0.0001). Mean change in serum 25(OH)D concentrations at weeks 12 and 24 after vitamin $D_3$ injection was $12.8{\pm}8.1$ and $21.5{\pm}8.1ng/mL$, respectively, in the vitamin $D_3$ group, with no significant changes in the placebo group. Serum parathyroid hormone concentrations showed a significant decrease in the vitamin $D_3$ group but no change in the placebo group. Conclusion: Intramuscular injection of vitamin $D_3$ 200,000 IU was superior to placebo in terms of its impact on serum 25(OH)D concentrations, and is considered to be safe and effective in Korean adults with vitamin D deficiency.

• Nutrition Research and Practice
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• v.15 no.4
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• pp.492-503
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• 2021

BACKGROUND/OBJECTIVES: Recently, the recommended nutrient intakes (RNI) for vitamin D for Malaysian aged 1-70 yrs has been revised from 5 ㎍/day to 15 ㎍/day. This study is aimed to assess the adequacy of vitamin D intake based on revised RNI and to recommend several dietary strategies to increase total vitamin D intake. SUBJECTS/METHODS: Vitamin D intake from both food and supplement of 217 pregnant women was assessed using a validated food frequency questionnaire. Hypothetical effect of expanded supplementation and food fortifications strategies were modelled using the consumption data. RESULTS: The results revealed that more than half (67.7%) of pregnant women had inadequate vitamin D intake (RNI < 15 ㎍/day). The modelling results demonstrated the potential of universal provision of 10 ㎍/day of multivitamins supplements in increasing vitamin D intake. Moreover, mandatory fortification of both milk and malted drink at single level of 5 ㎍/serving would lead to increase in vitamin D intake of Malaysians, particularly pregnant women. CONCLUSIONS: The outcome of this study can be used as a reference for public health professionals to re-evaluate the existing Malaysian food fortification policies and supplementation recommendation for vitamin D for pregnant women.

• Journal of Hospice and Palliative Care
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• v.18 no.2
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• pp.120-127
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• 2015

Purpose: We aimed to investigate how serum vitamin D levels are related to survival of terminally ill cancer patients. Methods: From May 2012 through June 2013, a retrospective chart review was performed on 96 hospice patients. Univariate and multivariate logistic regression analyses were conducted to identify factors associated with severe vitamin D deficiency and Coxcy and Coxional hazard analyses were used to evaluate effects on survival. Results: The mean vitamin D level in patients was $8.60{\pm}7.16ng/ml$. Vitamin D was severely deficient (<10 ng/ml) in 75 patients (78.2%), deficient (10~20 ng/ml) in 13 patients (13.5%), relatively insufficient (21~29 ng/ml) in five patients (8.3%) and sufficient ((t ng/ml) in three patients (3.1%). Hyperbilirubinemia (${\geq}1.2g/dl$) was the only factor associated with severe vitamin D deficiency according to the multiple logistic regression analysis (Odds ratio, OR=18.48, P<0.05). Although hyperbilirubinemia showed a strong association with survival (Hazard ratio, HR=2.25, P<0.01), no association was found between severe vitamin D deficiency and survival (HR=1.15, P>0.05) in Cox's proportional hazard analysis. Conclusion: Although serum vitamin D levels were severely low in terminally ill cancer patients, we found no association between severe vitamin D deficiency and patient survival.