• Nutrition Research and Practice
• /
• v.9 no.2
• /
• pp.158-164
• /
• 2015

BACKGROUND/OBJECTIVES: Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS: A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and $1,25(OH)_2D$ levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml. RESULTS: Mean 25(OH)D and $1,25(OH)_2D$ levels were $13.5{\pm}5.8ng/ml$ and $20.6{\pm}11.8pg/ml$, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (${\geq}30ng/ml$) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise. CONCLUSIONS: Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.

• Clinical and Experimental Pediatrics
• /
• v.54 no.7
• /
• pp.298-303
• /
• 2011

Purpose: To evaluate the clinical characteristics of vitamin D deficiency and its association with iron deficiency anemia (IDA). Methods: A total of 171 children aged less than two years underwent 25-hydroxyvitamin $D_3$ tests between January 2007 and July 2009. The study was classified into two groups: normal and vitamin D insufficiency, by their vitamin 25-hydroxyvitamin $D_3$ levels. Results: In total, 120 children were in the normal group (mean age, body weight and heights $12.5{\pm}7.0$, $9.3{\pm}0.9$ kg and $76.8{\pm}1.1$ cm), and 51 children in the vitamin D insufficiency group ($9.9{\pm}5.4$ months, $9.0{\pm}0.9$ kg and $75.1{\pm}0.9$ cm). Vitamin D insufficiency was most commonly diagnosed in the spring (44%). The proportion of complete breast-feeding was higher in the insufficiency (92%), and 25.5% of the children in the deficient group also experienced IDA compared that 12% of normal group. Ten children in the insufficiency group experienced bony changes. Six children received calcitriol medication in the normal group, in whom the mean vitamin 25-hydroxyvitamin $D_3$ level increased from $39.6{\pm}14.6$ ng/mL (pre-medication) to $41.8{\pm}17.2$ ng/mL (post-medication), and 13 in the insufficiency group, in whom the mean vitamin 25-hydroxyvitamin $D_3$ increased from $20.7{\pm}7.0$ ng/mL to a mean post-treatment level of $43.7{\pm}23.8$ ng/mL. Conclusion: This study demonstrated that approximately 30% of children aged ${\leq}2$ years experienced vitamin D insufficiency associated with subclinical rickets. Many children also experienced concurrent IDA. Guidelines for vitamin D supplement in such children must therefore be established.

• Journal of Nutrition and Health
• /
• v.47 no.5
• /
• pp.321-329
• /
• 2014

Purpose: The aim of this study was to determine the relationship between serum concentrations of 25-hydroxyvitamin D [25(OH)D] and chronic obstructive pulmonary disease (COPD) prevalence. Methods: The analysis was performed using data from the Fifth Korean National Health and Nutrition Examination Survey, a cross-sectional survey of the Korean civilian population conducted from 2010 to 2012. The analyses were restricted to males who were 40 years of age and above. Complex sample multiple logistic regression analyses were used to examine the associations of COPD prevalence with 25(OH)D and other factors. Results: $FEV_1/FEV_6$ varied significantly with smoking status, age, household income, education level, occupation, body mass index (BMI), and physical activity (p < 0.05). In univariate analysis, smoking status, BMI, household income, education level, and occupation showed association with COPD (p < 0.05), but vitamin D was not associated with COPD (p = 0.078). However, when adjusted with smoking status, household income, education level, occupation, BMI, age, and smoking index, the lowest quartile of 25(OH)D showed OR 1.643 (95% CI 1.161-2.236) compared to 3rd quartile (p = 0.024). Conclusion: A significant relationship was observed between serum concentration of 25(OH)D and COPD.

• Proceedings of the Korean Nutrition Society Conference
• /
• 1995.11b
• /
• pp.54-54
• /
• 1995

• Proceedings of the Korean Nutrition Society Conference
• /
• 1996.06b
• /
• pp.46-46
• /
• 1996

• Proceedings of the Korean Nutrition Society Conference
• /
• 1996.11b
• /
• pp.43-43
• /
• 1996

• Clinical and Experimental Pediatrics
• /
• v.58 no.3
• /
• pp.96-101
• /
• 2015

Purpose: Atopic dermatitis (AD) is a chronic inflammatory relapsing skin disorder. Vitamin D plays a pivotal role in the development of AD, and interleukin (IL) 31 is known to be related to pruritus in AD. The aim of our study was to determine whether 25-hydroxyvitamin D (25(OH)D) levels are related to IL-31 levels or to the severity of AD. Methods: We enrolled 91 children with AD and 32 control subjects without history or symptoms of allergic diseases. Blood was drawn to evaluate complete blood cell count, total eosinophil count (TEC), and total IgE, specific IgE to common allergens, 25(OH)D, and IL-31 levels. Serum 25(OH)D and IL-31 levels were measured using high-performance liquid chromatography and enzyme-linked immunosorbent assay, respectively. The scoring atopic dermatitis (SCORAD) index was used to evaluate the severity of AD. Results: The mean 25(OH)D level was significantly lower in the AD group than in the control group; 25(OH)D decreased greatly in the moderate and severe AD groups compared with the mild AD group. Children with atopic sensitization showed significantly lower 25(OH)D levels than nonatopic children. However, serum IL-31 levels were not related to AD group, SCORAD index, or 25(OH)D levels. The SCORAD index was inversely correlated with serum 25(OH)D level and positively correlated with TECs and total IgE levels. Children with moderate and severe AD had significantly higher TECs than children with mild AD. Conclusion: Vitamin D is related to the severity of AD independently of IL-31.

• Nutrition Research and Practice
• /
• v.13 no.6
• /
• pp.498-508
• /
• 2019

BACKGROUND/OBJECTIVES: Lower circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with a higher risk of hypertension (HTN); however, it remains unclear whether the relationship is causal. We aimed to evaluate the causal effects of circulating 25(OH)D levels on the prevalence of HTN in the Korean population using the Mendelian randomization (MR) approach. SUBJECTS/METHODS: Epidemiological data, serum 25(OH)D data, and genomic DNA biospecimens were obtained from 2,591 participants, a subset of the study population in the Korea National Health and Nutrition Survey 2011-2012. Five 25(OH)D-related single nucleotide polymorphisms (SNPs; DHCR7 rs12785878, CYP2R1 rs10741657, CYP2R1 rs12794714, CYP24A1 rs6013897, and GC rs2282679), identified a priori from genome-wide association studies, were used as instrument variables (IVs) for serum 25(OH)D levels. In the MR analysis, we performed IV analyses using the two-stage least squares method. RESULTS: In the observational analysis, circulating 25(OH)D levels were found to be inversely associated with the HTN prevalence in ordinary least squares models (odds ratio: 0.97, 95% confidence interval: 0.96, 0.99) after adjusting for the potential confounders. There were differences in the circulating 25(OH)D levels across genotypes of individual SNPs. In the MR analysis, using individual SNPs as IVs, 25(OH)D levels were not associated with the HTN prevalence. CONCLUSIONS: We found no association between genetically determined circulating 25(OH)D levels and HTN in Korean adults. Our results are listed owing to the relatively small sample size and possible weak instrument bias; therefore, further studies are needed to confirm these results.

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

• Korean Journal of Poultry Science
• /
• v.19 no.4
• /
• pp.217-225
• /
• 1992

This research was carried out to determine the 25-Hydroxyvitamin $D_3$[25(OH)$D_3$] content in liver of broiler Hubbard chicks fed vitamin VD-deficient diet for 31 days in a subdued light room and exposed to UVB light (maximum intensity at 297nm) with dose of 0.204 or 0.408 mJ/$\textrm{cm}^2$(30 or 60 min irradiation) . The lipid in liver collected at 0~138 hr after irradiation was extracted by chloroform-methanol(2：1, v /v) and 25(OH)$D_3$ fraction was separated by Sep-Pak silica cartridge. The 25(OH)$D_3$ concentration was measured by normal phase HPLC. The negative control chicks Presented 25(OH)D$_3$17.5 ng/g liver. When 0.204mJ/$\textrm{cm}^2$ was treated to whole body of chicks, the 25(OH)$D_3$ level was increased to 37.8 ng/g at 12 hr after irradiation, the peak concentration, 40.5 ng /g was appeared at the time of 86 hr, and decreasing trend was shown thereafter until 138 hr, the final time in this study. When 0.408 mJ/$\textrm{cm}^2$ was applied, the 25(OH)$D_3$ content was 36.7 ng /g liver at 12 hr, 61.4 ng/g(maximum value ) was appeared at 42 hr, and 39.5 ng /g at 138 hr. The increased absolute amounts in liver 25(OH)$D_3$ were 23 and 43.9 ng/g as chicks were exposed to UVB light with dose of 0.204 and 0.408mJ/$\textrm{cm}^2$, respectively. Consequently, it was found that when double dose of UVB light was irradiated to the chicks, their liver samples produced nearly double 25(OH)$D_3$ at 42 hr after exposure, and the peak value was presented earlier by 24 hr than that in the low dose treatment.