• Journal of Nutrition and Health
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• v.56 no.1
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• pp.1-11
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• 2023

Purpose: Obesity is associated with alterations in vitamin D metabolism and elevation of parathyroid hormone (PTH). Increased PTH level in obesity is likely one of the factors contributing to the dysregulation of vitamin D metabolism. We investigated the effects of lowering the PTH level in high-fat diet-induced obese mice on vitamin D metabolism. Methods: Five-week-old male C57BL/6N mice were fed either with control (10% energy as fat) or high-fat (60% energy as fat) diets ad libitum for 12 weeks, and vehicle or cinacalcet HCl (30 ㎍/g body weight) was gavaged daily during the final week of the experiment. The following groups were studied: CON (control diet + vehicle), HFD (high-fat diet + vehicle), and HFD-CIN (high-fat diet + cinacalcet HCl). PTH, 1,25-dihydroxyvitamin D (1,25[OH]₂D), 25-hydroxyvitamin D (25[OH]D), calcium, and phosphate levels in circulation, and the expression of genes related to vitamin D metabolism in the liver and kidneys were determined. Results: Renal 1α-hydroxylase expression in the HFD group was higher than that in the CON group despite the lack of a difference in the PTH levels between the 2 groups. The plasma PTH level in the HFD-CIN group was 60% lower than that in the HFD group (p < 0.05). In parallel, the HFD-CIN group had lower adipose tissue amount (9% lower), renal 1α-hydroxylase expression (48% lower), and plasma 1,25(OH)₂D concentration (38% lower) than the HFD group. Conclusion: Lowering the PTH levels in high-fat diet-induced obese mice recovered the expression of renal 1α-hydroxylase and might be associated with lower amounts of white adipose tissue.

• Clinical and Experimental Pediatrics
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• v.61 no.3
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• pp.90-94
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• 2018

Purpose: The present study aimed to determine the relationship between serum 25-hydroxyvitamin D (25(OH)D) level and Urinary tract infections (UTIs) in children. Methods: In this case-control study, 70 children with UTI (case group) were compared with 70 healthy children (control group) in terms of serum 25(OH)D levels. The children were between 1 month and 12 years of age. Serum 25(OH)D levels were measured using enzyme-linked immunosorbent assay (ELISA). The results were analyzed and compared between both groups. Results: Among 70 children with UTI (case group), 5 children (7.2%) were male and 65 (92.8%) were female. Among the healthy children (control group), 9 (12.8%) and 61 children (87.2%) were male and female, respectively (P=0.39). The $mean{\pm}standard$ deviation of age in the case and control groups were $53.2{\pm}35.6$ and $36.1{\pm}60.2months$, respectively (P=0.24). The mean level of serum 25(OH)D in the case group was significantly higher than that of the control group ($20.4{\pm}8.6ng/mL$ vs. $16.9{\pm}7.4ng/mL$, P=0.01) Conclusion: This study showed that there was a relationship between serum 25(OH)D levels and UTI in children. It seems that 25(OH)D plays a role in the pathogenesis of UTI.

• Journal of Veterinary Science
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• v.24 no.2
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• pp.32.1-32.10
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• 2023

Background: The association between vitamin D and canine keratoconjunctivitis sicca (KCS) has not been investigated in dogs. Objectives: To investigate the association of serum 25-hydroxyvitamin D [25(OH)D] concentrations with Schirmer tear test 1 (STT-1) and tear film breakup time (TFBUT) in dogs. Methods: Sixty-one clinically healthy, client-owned dogs were enrolled. STT-1 and TFBUT were measured in 122 (61dogs) and 82 (41 dogs out of total 61 dogs) eyes, respectively. Serum 25(OH)D concentrations were evaluated by quantitative chemiluminescent immunoassay. The dogs were classified into 6 groups according to the evaluations (STT-1: group 1, normal [≥ 15 mm/min] in both eyes; group 2, normal in one eye and abnormal [< 15 mm/min] in the fellow eye; group 3, abnormal in both eyes; TFBUT: group 4, normal [≥ 20 sec] in both eyes; group 5, normal in one eye and abnormal [< 20 sec] in the fellow eye; group 6, abnormal in both eyes). Results: STT-1 was positively correlated with TFBUT (p < 0.001). Among the STT-1 groups, the mean serum 25(OH)D concentration in group 1 was significantly higher than in groups 2 and 3 with positive correlation (p < 0.001). However, there were no significant differences among the TFBUT groups 4, 5, and 6. Conclusions: In dogs, it was found that serum 25(OH)D concentrations had a greater effect on quantitative KCS than qualitative KCS. Therefore, it is considered that measurement of serum 25(OH)D concentration could be included in the diagnostic tests in canine quantitative KCS patients.

• Journal of the Health Care and Life Science
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• v.9 no.1
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• pp.161-167
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• 2021

The present study was conducted to assess the association between serum ferritin and 25-hydroxyvitamin D [25(OH)D] and metabolic syndrome (MetS) in Korean women. The data of a total of 9,256 adults (4,196 premenopausal women and 4,340 postmenopausal women) aged ≥ 20 years from the Fifth Korean National Health and Nutrition Examination Survey (KNHANES V) (2010-2012) were analyzed. The key study results were as follows: First, in women without MetS, after adjusting for related variables (age, smoking, alcohol consumption, regular exercise, SBP, DBP, WM, TC, TGs, HDL-C, FPG, Hb, Hct, and Fe), vitamin D status was positively associated with serum ferritin levels (premenopausal, p < 0.001; postmenopausal, p = 0.027). Second, in women with MetS, after adjusting for related variables, vitamin D status was not associated with serum ferritin levels (premenopausal, p = 0.739; postmenopausal, p = 0.278). In conclusions, vitamin D status was positively associated with serum ferritin levels in women without MetS but not in women with MetS.

• Korean Journal of Poultry Science
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• v.21 no.3
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• pp.157-168
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• 1994

This study was carried out to elucidate the time course variation of vitamin $D_{3}$ (V$D_{3}$) and 25-hydroxyvitamin $D_{3}$ [25(OH)$D_{3}$] contents in the liver and skeleton of 3-wk old broiler chicks when treated with different UV irradiation procedure. Day-old Hubbard chicks were fed vitamin D deficient diet for 3 wk and exposed to medium wave ultraviolet(UVB) light with different irradiation procedures. Procedure I was 30 min continuous irradiation(O.204 mJ /$cm^{2}$) and Procedure II was three seperate 10 min irradiation with 12 h intervals, and Procedure III was three seperate 10 min irradiation with 24 h intervals. The liver and skeleton samples were collected at 10 different times between 0000~2400 h after the last irradiation. The V$D_{3}$ and 25(OH)$D_{3}$ fractions wereseparated by Sep-Pak silica cartridge and the concentrations were determined by normal phase HPLC. The mean content of V$D_{3}$ in the liver of the birds treated by Procedure II was 6.68 ng /g, which was higher than 5.60 and 5.30 ng /g from Procedure I and Ill, respectively(P<.O5). With regard to the effect of elapsed time after UVB irradiation on the V$D_{3}$ concentration of the liver, 96 h treatment showed the highest value(13.08 ng/g)(P<.05). There was a significant(P$D_{3}$ were significantly(P$D_{3}$ in the skeleton of tibia and femur, there were no significant differences among Procedure I, II and III, but significant differences were found among those from various elapsed time after irradiation, The highest value was shown at 96 h(O.99 ng /g) treatment, and interaction between irradiation procedure and elapsed time was not significant. With regard to the mean content of 25(OH)$D_{3}$ in bone, the Procedure II(18.79 ng /g) and III(17.73 ng /g) showed higher values than Procedure I did (P<.05), and the 12 h elapsed time showed the highest value(31.17 ng /g) among 10 treatments (P<.05), however, there was no significant interaction between exposing procedure and elapsed time. In conclusion, the Procedure II would he more desirable than Procedure I or III to produce more V$D_{3}$ and 25(OH)$D_{3}$ in the liver and skeleton of birds by exposing to the UVB light. Also, it was verified that 25(OH)$D_{3}$ increases more quickly than V$D_{3}$ in both tissues tested and is utilized more quickly to recover from the rickets of chicks.

• 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.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.5983-5986
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• 2015

Background: Serum 25-hydroxyvitamin D insufficiency is very common in Pakistan and is often related to inferior prognosis in some cancers but limited data exist for hematopoietic malignancies. This study was conducted to determine the vitamin D insufficiency in B-chronic lymphoid leukemia (CLL) cases at the time of presentation and its possible correlation with clinical staging, hematological parameters and biochemical markers. Materials and Methods: This descriptive cross sectional study was carried at Liaquat National Hospital from January 2011 to June 2013. Sixty patients with B-chronic lymphoid leukemia were enrolled. Complete blood count, vitamin D levels, serum urea, creatinine, uric acid and LDH levels were assessed. Data were compiled and analyzed using SPSS version 21. Results: Out of 60 patients, 42 (70%) were male and 18 (30%) were female. Mean age was $59.0{\pm}9.2years$. The frequency of vitamin D insufficiency was found to be 56.7%. Overall insufficiency was more frequently seen in male gender (40%). Vitamin D insufficiency demonstrated a positive association with low lactate dehydrogenase levels (P=0.005). No links were established with age, clinical stage, hematological and other biochemical markers. Conclusions: Vitamin D insufficiency is high compared with Western studies. Whether normalization of vitamin D insufficiency in deficient B-CLL patients could improve the clinical outcome or delay disease progression will require further studies.

• Clinical and Experimental Pediatrics
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• v.54 no.2
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• pp.51-54
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• 2011

Vitamin D is present in two forms, ergocalciferol (vitamin $D_2$) produced by plants and cholecalciferol (vitamin $D_3$) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 $[1,25(OH)_2D]$, plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of $1,25(OH)_2D$ from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the $1{\alpha}$-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D $1{\alpha}$-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of $1,25(OH)_2D$ despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human $1{\alpha}$-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and $1{\alpha}$-hydroxylase mutations with clinical findings.

• Nutrition Research and Practice
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• v.15 no.sup1
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• pp.32-40
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• 2021

BACKGROUND/OBJECTIVES: Considering the high number of deaths from coronavirus disease 2019 (COVID-19) in Latin American countries, together with multiple factors that increase the prevalence of vitamin D deficiency, we aimed to determine 25-hydroxyvitamin D (25[OH]D) levels and its association with mortality in patients with critical COVID-19. SUBJECTS/METHODS: This was a prospective observational study including adult patients with critical COVID-19. Data, including clinical characteristics and 25(OH)D levels measured at the time of intensive care unit admission, were collected. All patients were followed until hospital discharge or in-hospital death. The patients were divided into those surviving and deceased patient groups, and univariate and multivariate logistic regression analyses were performed to determine independent predictors of in hospital mortality. RESULTS: The entire cohort comprised 94 patients with critical COVID-19 (males, 59.6%; median age, 61.5 years). The median 25(OH)D level was 12.7 ng/mL, and 15 (16%) and 79 (84%) patients had vitamin D insufficiency and vitamin D deficiency, respectively. The median serum 25(OH)D level was significantly lower in deceased patients compared with surviving (12.1 vs. 18.7 ng/mL, P < 0.001). Vitamin D deficiency was present in 100% of the deceased patients. Multivariate logistic regression analysis revealed that age, body mass index, other risk factors, and 25(OH)D level were independent predictors of mortality. CONCLUSIONS: Vitamin D deficiency was present in 84% of critical COVID-19 patients. Serum 25(OH)D was independently associated with mortality in critical patients with COVID-19.