• Korean Journal of Community Nutrition
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• v.10 no.1
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• pp.79-90
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• 2005

This study was performed to estimate serum 25-hydroxyvitamin D level and to evaluate the relationship between serum 2S-hydroxyvitamin D level and associated factors. The subjects were 61 premenopausal working women aged 30 - 49 y in Busan. The serum 25-hydroxyvitamin D level was measured by radioimmunoassay. Data for physiological characteristics, lifestyle factors, physical activity and nutrient intake were assessed by questionnaire including information about outdoor activity time, daily activity diary and 24 hr recall method. The mean vitamin D intake was 3.12 ug, which corresponded to $62.5\%$ of the Korean RDA. The mean level of serum 25-hydroxyvitamin D was 31.0 ng/mL. Low 25-hydroxyvitamin D (<25 nmol/L) was not found in the subjects. The serum 2S-hydroxyvitamin D level showed positive significant correlations with exercise hours, daily energy expenditure, hours of outdoor activity per weekdays (p < 0.001, P < 0.05, P < 0.05). Exercise hours were found to be the most important determinant of serum 25-hydroxyvitamin D level. Therefore nutritional education for increasing hours of physical activity including indoor and outdoor exercise, is needed for premenopausal working women to increase vitamin D status.

• Journal of Nutrition and Health
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• v.29 no.7
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• pp.758-771
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• 1996

This study attempted to define reference data for the distribution of vitamin d status and to explore the relationship between vitamin D status and related biochemical indices in Korean women. The vitamin D status of 179 Korean women aged from 20 to 75 years was analyzed by using HPLC(High Pressure Liquid Chromatography). Related biochemical indices such as iPTH, alkaline phosphatase, creatinine, albumin, Ca, Mg and P were also measured. The mean serum level of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were s25.8ng/ml and 89.8pg/ml, respectively. Low 25-hydroxyvitamin D (<25nmol/L) was found in 29 subjects(16.5%). There was a significantly progressive decrease in serum 25-hydroxyvitamin D with increasing age(p<0.05). After in their, there was a dramatical reduction in 25-hydroxyvitamin D(p<0.05). It was also significant in post-menopasusal women compared with pre-menopausal women(p<0.000). Serum alkaline phosphatase levels increased significantly with age(p<0.001). Whereas serum calcium and phosphorus levels remained constant with age. Serum 250-hydroxyvitamin D was invesely related to iPTH (p<0.05) and alkaline phophatase (p<0.001).

• Journal of Nutrition and Health
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• v.39 no.7
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• pp.649-660
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• 2006

This study was performed to estimate serum 2S-hydroxyvitamin D (25-OHD) level in wintertime and to evaluate the relationship between serum 25-OHD level and associated factors in 50 premenopausal working women aged 30-49 y in Busan. The serum 25-OHD level was measured by radioimmunoassay. Data for physiological characteristics, lifestyle factors, physical activity and nutrient intake was assessed by questionnaire including information about outdoor activity time, daily activity diary and 24hr recall method. The mean vitamin D intake was $4.24{\mu}g$, which corresponded to 84.9% of the Korean RDA. The mean level of serum 25-OHD was 25.7 ng/mL. Vitamin D deficiency (25-OHD < 7nmol/L) and toxicity $(25-OHD{\geq}75\;nmol/L)$ were not found in the subjects. However, the prevalence of vitamin D insufficiency (25-OHD < 15 nmol/L) and hypovitaminosis D (25-OHD < 30 nmol/L) were 12% and 60% respectively. The serum 25-OHD level showed positive significant correlations with the duration of outdoor activity per weekdays (p < 0.05). Our findings suggest that hypovitaminosis D was common in the subjects in wintertime. So nutritional education for increasing outdoor activities is needed for premenopausal working women to increase vitamin D status in wintertime.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.981-990
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• 1996

To define the risk facots of subclinical vitamin D deficiency in postmenopausal women, circulating serum 25-hydroxyvitamin D levels, known to be the indicator of vitamin D status, were measured and risk faxtors affecting it were investigated in 27 women with low 25-hydoxyvitamin d level(ie, the study group : serum 25-hydroxyvitamin D<10ng/ml) by comparing to 55 age-matched control(the control group) were analyzed. The serum level of 25-hydorxyvitamin D was analyzed by HPLC(High Pressure Liquid Chor-matography) and analyzed biochemical parameter. The following information was obtained by interviews : sociodemographic charateristics, the intake of food containing vitamin D, proxy measure of sunlight exposure(time spent outdoors), and reprocuctive histpry of the subjects. The study group had significantly lower levels of serum calcium, increased levels of iPTH and alkaline phosphatase, Among the dietary determents, energy, protein, fat, calcium, phophorus, and vitamin D intakes were lower in the study group than the normal group. The time spent outdoors in a day was not significantly different between the two groups. However, during the day, a specific time of time spent out doors between 12:00 and 14:00 was significantly lower in the study group. Logistic analysis revealed that vitamin D and calcium intake were more important affecting factors than the time spent outdoors in post menopausal women.

• Nutrition Research and Practice
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• v.16 no.6
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• pp.745-754
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• 2022

BACKGROUND/OBJECTIVES: The incidence of cardiovascular diseases (CVDs) has increased worldwide. Although a low serum vitamin D level is known to be associated with the risk of CVD, the mechanism is not well understood yet. The aim of this study was to determine the relationship of serum 25-hydroxyvitamin D₃ (25[OH]D) with homocysteine and apolipoprotein B (ApoB). SUBJECTS/METHODS: Of 777 subjects recruited from one health promotion center for routine heath exam from January 2010 to December 2016, 518 subjects were included in this study. Serum 25(OH)D, serum homocysteine, and other metabolic parameters including ApoB were analyzed. Simple and partial correlations were carried out after adjustments. Simple linear regression analysis was used for precise correlation of parameters. Multivariate regression analysis was done to know which factor (serum homocysteine or ApoB) was more related to serum 25(OH)D after adjustments. Finally, logarithms of homocysteine concentrations according to tertiles of serum 25(OH)D were compared. RESULTS: After sex and age adjustments, serum 25(OH)D showed negative correlations with serum homocysteine (r' = -0.114) and ApoB (r' = -0.098). In simple linear regression analysis, serum 25(OH)D showed a significant negative correlation with ApoB (P = 0.035). However, in multivariate regression analysis, serum 25(OH)D was significantly associated with serum homocysteine after adjustments (P = 0.022). In addition, serum homocysteine concentration was significantly high in the lowest 25(OH)D group (P = 0.046). CONCLUSION: Serum 25(OH)D concentration showed a stronger negative association with serum homocysteine than with ApoB.

• Journal of Nutrition and Health
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• v.29 no.7
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• pp.747-757
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• 1996

In this study, the serum level of 25-hydroxyvitamin D(25-(OH)D) was measured by high pressure liquid chromatography(HPLC), and factors affecting it were investigated in 72 young adults age ranging from 21 years to 39 years with normal bone density. The mean level of serum 25-(OH)D was 20.0$\pm$6.8ng/ml in males and 26.1$\pm$12.3ng/ml in females, which was significantly higher in females (p<0.01). The serum level of parathyroid hormone(PTH) showed a negative correlation with that of 25-(OH)D(p<0.05). Time spent outdoors in a day correlated positively with the serum level of 25-(OH)D(p<0.01). During the day, a specific time between 12:00 a.m. and 2:00 p.m. showed the most significant correlation with the level of 25-(OH)D(p<0.005). Among the nutrients studied, fat and vitamin D intake were positively correlated with the serum 25-(OH)D level. Stepwise multiple regression analysis showed that the serum level of 25-(OH)D could be fit by vitamin D intake(34.7% explained), serum PTH level (27.3% explained) and the time spent outdoors during the specific time(28.4% explained).1996)

• Journal of Nutrition and Health
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• v.52 no.5
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• pp.465-474
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• 2019

Purpose: This study examined the association between the serum 25-hydroxyvitamin D concentration and the cognitive functions in Korean elderly. Methods: The subjects were 393 adults aged 60 years or older who participated in the Yangpyeong cohort between July 2009 and August 2010. The subjects were classified into deficiency, insufficiency, or adequacy groups according to the serum 25-hydroxyvitamin D concentration diagnostic criteria suggested by the US Institute of Medicine (IOM). The cognitive function was assessed based on the Korean version of the Mini-Mental State Examination (MMSE-KC). The dietary intake was assessed using the quantitative food frequency questionnaire with 106 food items. Results: The proportions of deficiency, insufficiency, or adequacy in serum 25-hydroxyvitamin D were 6.6%, 44.5%, and 48.9%, respectively. The serum 25-hydroxyvitamin D concentration was significantly higher in men than in women and in outdoor workers than in other occupations. The adequacy group had higher MMSE-KC scores than the other two groups, but not to a significant degree. The proportion of cognitive impairment tended to decrease with increasing serum vitamin D concentration to deficiency, insufficiency, and adequacy (p for trend = 0.029). The deficiency group had a 2.28 times higher risk of cognitive impairment than the adequacy group, but the difference was not statistically significant (OR, 2.28; 95% CI, 0.18 ~ 1.07, p for trend = 0.119). Conclusion: The serum vitamin D concentration tended to be associated with the cognitive function in elderly Koreans living in rural areas. To confirm the associations, further longitudinal studies with large samples were required.

• Tuberculosis and Respiratory Diseases
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• v.79 no.3
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• pp.153-157
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• 2016

Background: Vitamin D is known to have diverse effects on various systems in the body. There is evidence to suggest that a link exists between the serum vitamin D status and tuberculosis. The present study was designed to assess the alterations in serum 25-hydroxyvitamin D levels in newly diagnosed sputum acid fast bacilli (AFB) positive pulmonary tuberculosis patients and to study the association, if any, between serum vitamin D levels and different levels of sputum smear positivity. Methods: Serum 25-hydroxyvitamin D levels were estimated in 65 sputum AFB positive pulmonary tuberculosis patients and 65 age and gender-matched healthy controls. Results: The levels of serum 25 hydroxy-vitamin D in tuberculosis patients were not statistically different from the levels of serum 25 hydroxy-vitamin D in healthy controls. However, among patients with pulmonary tuberculosis, there was a significant negative correlation between the levels of serum 25 hydroxy-vitamin D and levels of sputum positivity. Conclusion: Serum vitamin D levels negatively correlates with bacterial load in patients with active pulmonary tuberculosis.

• Korean Journal of Community Nutrition
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• v.19 no.2
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• pp.122-132
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• 2014

Objectives: This study was conducted to investigate the vitamin D status and to determine the association between serum 25-hydroxyvitamin D [25(OH)D] concentrations and consumption frequencies of vitamin D rich foods in Korean adults and older adults. Methods: Subjects were 10,374 adults and 2,792 older adults participating in the 2008-2009 Korea National Health and Nutrition Examination Survey (KNHANES). Consumption frequencies of vitamin D rich foods were estimated by using a qualitative food frequency questionnaire (FFQ). Eleven food items such as beef, egg, mackerel, tuna, yellow corvina, pollack, anchovy, mushroom, milk, yogurt, and ice cream were selected as vitamin D rich foods based on previous research. Results: The proportions of deficiency (< 12 ng/mL), inadequacy (12-20 ng/mL) and sufficiency (${\geq}20ng/mL$) of serum 25(OH)D concentrations from June to November and December to May in adults were 8.8%, 42.3%, 48.8%, and 28.2%, 52.8%, 19.1%, respectively. The proportions of deficiency, inadequacy and sufficiency of serum 25(OH)D concentrations from June to November and December to May in older adults were 10.1%, 32.4%, 57.5%, and 24.1%, 45.4%, 30.5%, respectively. The mean serum 25(OH)D concentrations in adults were positively related to the consumption frequencies of mackerel, anchovy, all fish, milk and milk dairy products. The mean serum 25(OH)D concentrations in older adults were positively related to the consumption frequencies of yellow corvina and negatively related to the consumption frequencies of ice cream. Conclusions: Our results suggest that Korean adults were more deficient in serum 25(OH)D concentrations than older adults. The consumption of vitamin D rich foods may affect vitamin D status in Korean adults. Further studies are required to confirm these findings.

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