Differences In 25OHD Levels Research Articles

6990 Vitamin D Supplementation in Primary Hyperparathyroidism: Effects on 1,25(OH)Vitamin D and FGF23 Levels

Abstract Disclosure: S.G. Pallone: None. M. Ohe: None. L.D. Santos: None. I.O. Nakaguma: None. I.S. Kunii: None. R.E. Silva: None. S.S. Maeda: None. C.M. Brandao: None. J.G. Vieira: None. M. Lazaretti-Castro: None. Background: Primary hyperparathyroidism (PHPT) is a condition characterized by high levels of PTH in the presence of hypercalcemia. Vitamin D deficiency has been associated with more severe presentations. Our aim was to evaluate the effects of Vitamin D supplementation on mineral homeostasis and related hormones in individuals with PHPT compared to controls without PHPT. Materials and methods: Individuals with and without PHPT received 14,000 IU/week of oral vitamin D3 for 12 weeks. At baseline and endpoint, blood samples were collected to measure 1,25(OH)2 vitamin D (1,25(OH)2D), intact Fibroblast Growth Factor 23 (FGF23), 25-hydroxyvitamin D (25OHD), Parathormon (PTH), total calcium (tCa), phosphorus and other biochemical markers. The intact FGF23 was measured using an automated Diasorin LIAISON kit. The 1,25(OH)2D measurement was performed using liquid chromatography and mass spectrometry (LC-MS/MS). Results: 70 PHPT patients and 75 healthy individuals (CTRL) were included, and 55 PHPT and 64 CTRL completed the 12-week protocol. At baseline, tCa, PTH, 1,25(OH)2D, and intact FGF23 concentrations were significantly higher in PHTP, with no difference in 25OHD levels. After the intervention, the 25OHD levels increased significantly in both groups (PHPT: 22.6.9±6.1 to 31.5±6.8; CTRL: 20.3±5.7 to 32.5±6.4 ng/mL, p<0.001). There was significative increase in intact FGF23 levels in both groups (PHPT: 47.9±27.1 to 76.3±33.3; CTRL: 40.5±13.9 to 59.8±19.8 pg/mL, p<0.001). After the vitamin D replacement, the tubular reabsorption of phosphate (TRP) was significantly reduced in both groups (PHPT: 85.0±7.4% to 83.6±7.75% CTRL: 89.5±4.5% to 88.7±4.8%, p=0.031), without changes in serum phosphorus levels, possibly indicating phosphaturic response to the intervention. Moreover, this decrease of TRP was positively correlated to the increment of FGF23 in the PHPT group. A paradoxical decrease in 1,25(OH)2D levels after vitamin D supplementation was observed in both groups (PHPT: 94.8±34.6 to 68.9±25.3; CTRL: 68.7±23.5 to 56.4±20.7 pg/mL, p<0.001). The reduction of 1,25(OH) 2 D was inversely correlated with the elevation of FGF23 in both groups (r=-0.302, p=0.028). In both groups, no changes in tCa were observed (PHPT: from 11.02±0.9 to 11.1±0.8; CTRL: 9.6±0.3 to 9.6±0.3 pg/mL, p=0.153), as the same for urinary calcium (p=0.534) and PTH measurements (p=0.516). Conclusion: The weekly administration of 14,000 IU of Vitamin D3 was safe and the increase in 25OHD after supplementation did not change the serum or urinary calcium levels in adults with and without PHPT. In both groups, it was observed a paradoxical decrease in 1,25(OH)2D levels after supplementation, which was associated with significant increase in intact FGF23 levels. This effect can maybe explain the safety response on calcium levels in face of vitamin D supplementation among PHPT patients. Presentation: 6/2/2024

Pediatric Fractures: Does Vitamin D Play a Role?

Vitamin D (25-OHD) deficiency and insufficiency are reported in about half of all children. The literature on low 25-OHD and pediatric fracture risk presents inconsistent results. This study evaluates the association between pediatric fractures and 25-OHD, parathyroid hormone (PTH), and calcium. This is a prospective case-control study in 2 urban pediatric emergency departments (2014-2017). Patients aged 1 to 17 requiring intravenous access were enrolled. Demographics, nutrition, and activity information were recorded and levels of 25-OHD, calcium, and PTH were measured. Two hundred forty-five subjects were enrolled: 123 fractures and 122 controls. Overall, the mean 25-OHD level was 23ng/mL±8.5: 52 (21%) of patients were 25-OHD sufficient; 193 (79%) were not. Ninety-six percent of patients with lower extremity fractures had low 25-OHD versus 77% of patients with upper extremity fractures (P=0.024). The fracture cohort was younger (P=0.002), included more males (P=0.020), and spent more time playing outdoor sports (P=0.011) than the control cohort. The 25-OHD level (fracture 22.8ng/mL±7.6 vs. nonfracture 23.5ng/mL±9.3, P=0.494) and median calcium level (fracture 9.8mg/dL vs. nonfracture 10.0mg/dL, P=0.054) were similar between cohorts. The median PTH level was higher in the fracture than the control cohort (33 vs. 24.5pg/mL; P<0.0005); PTH was elevated to hyperparathyroidism (>65pg/mL) in 13% of fractures and 2% of controls (P=0.006). Matched subgroup analysis of 81 fracture patients and 81 controls by age, gender, and race showed that PTH was the only variable independently associated with increased odds of fracture (odds ratio=1.10, 95% CI, 1.01-1.19, P=0.021) in a model adjusted for vitamin D sufficiency and time spent playing outdoor sports. Low 25-OHD is common in children with fractures but we found no difference in 25-OHD levels between fracture and nonfracture cohorts. This research can impact evidence-based guidelines on vitamin D level screening and/or supplementation after fracture. Diagnostic level IV-case-control study.

Should We Assess Vitamin D Status in Pediatric Patients With Celiac Disease?

Screening for vitamin D status in celiac disease (CD) has been recommended but the literature provides varying support. We sought to assess the vitamin D status in newly diagnosed children with CD and in a non-CD control population and relate them to vitamin D intake. In a cross-sectional study, serum 25-hydroxyvitamin D (25-OHD) levels were drawn in children with newly diagnosed CD and compared with pediatric outpatients with functional abdominal complaints. Anthropometric data as well as vitamin D intake based on milk and multivitamin ingestion were collected. Thirty-eight newly diagnosed CD patients (10.4 ± 3.0 years old; 50% girls) and 82 controls (11.2 ± 4.2 years old; 58.5% girls) were studied. Both groups were similar except for average daily D intake and BMI. There was no statistical difference in mean 25-OHD levels between CD (26.4 ± 8.0 ng/mL) and controls (23.5 ± 8.2 ng/mL) [P ≤ 0.07]. Both groups had high percentages of suboptimal D status (65.8% CD and 79.3% controls). 25-OHD levels significantly correlated with age (r = -0.262; P < 0.0038) and estimated vitamin D intake (r = 0.361; P < 0.0001). No significant difference in 25-OHD levels was noted between newly diagnosed CD and controls, but inadequate 25-OHD levels were common in both. 25-OHD levels were highly associated with vitamin D intake demonstrating similar vitamin D absorption between patients and controls. As CD is associated with bone disease and D status is frequently low, efforts at optimizing D, such as screening levels at diagnosis need to be conducted.

Current Vitamin D Status in Healthy Japanese Infants and Young Children.

This study aimed to characterize serum 25-hydroxyvitamin D (25OH-D) values among Japanese children aged ≤48 mo. The study included 290 healthy infants and young children aged 0-48 mo (males/females=166/124) living in Shizuoka or Tokyo. The subjects were divided into three groups by age (Low Age: 0-5, Middle Age: 6-15, High Age: 16-48 mo). The vitamin D deficient state was defined as 25OH-D <12 ng/mL, the insufficient state as 12-20 ng/mL, and the sufficient state as >20 ng/mL. The seasonal variation of serum 25OH-D levels was also analyzed. The median serum 25OH-D levels in each group were: Low Age (n=50), 19 ng/mL; Middle Age (n=94), 30 ng/mL; and High Age (n=146), 30 ng/mL. The serum 25OH-D level was significantly lower in the Low Age group than in the other groups (p<0.01). Serum 25OH-D levels in summer and autumn (n=149) were significantly higher than in winter and spring (n=141) (33 vs. 25 ng/mL, p<0.01). In the Low Age group, there was a significant difference in serum 25OH-D levels between breast-fed infants (n=26) and formula-fed or mixed-fed infants (n=19) (12 vs. 32 ng/mL, p<0.01). However, there were no significant differences in 25OH-D levels between the two season classifications in either breast-fed or formula-fed and mixed-fed infants. Although clinical symptoms were not available, more than 75% of the breast-fed infants and 14.6% of infants and young children to whom food had been introduced were defined as having a vitamin D deficient or insufficient state. Breastfeeding seems one of the contributing factor to lower serum 25 OH-D levels among infants ≤5 mo of age.

25-Hydroxyvitamin D and TSH as Risk Factors or Prognostic Markers in Thyroid Carcinoma.

ObjectiveThe increasing incidence of thyroid nodules demands identification of risk factors for malignant disease. Several studies suggested the association of higher TSH levels with cancer, but influence of 25-hydroxyvitamin D (25OHD) is controversial. This study aimed to identify the relationship of thyroid cancer with higher TSH levels and hypovitaminosis D and to evaluate their influence on prognostic characteristics of papillary thyroid carcinomas (PTC).MethodsWe retrospectively evaluated 433 patients submitted to thyroidectomy for thyroid nodules. Patients were categorized according to quartiles of TSH and 25OHD levels. Clinicopathological features were analyzed.ResultsSubjects with thyroid carcinomas were more frequently male and younger compared to those with benign disease. Their median TSH levels were higher and adjusted odds-ratio (OR) for cancer in the highest-quartile of TSH (> 2.4 mUI/mL) was 2.36 (1.36–4.09). Although vitamin D deficiency/insufficiency was prevalent in our cohort (84%), no significant differences in 25OHD levels or quartile distribution were observed between benign and malignant cases. Among 187 patients with PTC, analyses of prognostic features revealed increased risk of lymph nodes metastases for subjects with highest-quartile TSH levels (OR = 3.7, p = 0.029). Decreased 25OHD levels were not overtly associated with poor prognosis in PTC.ConclusionsIn this cross-sectional cohort, higher TSH levels increased the risk of cancer in thyroid nodules and influenced its prognosis, particularly favoring lymph nodes metastases. On the other hand, no association was found between 25OHD levels and thyroid carcinoma risk or prognosis, suggesting that serum 25OHD determination may not contribute to risk assessment workup of thyroid nodules.

Abstract B53: Determinants of serum 25-hydroxyvitamin D levels in African American women in the AMBER Consortium

Abstract Background: African Americans (AAs) are known to have a higher prevalence of vitamin D deficiency than European Americans (EAs). Aside from darker skin pigmentation being a major contributing factor, few studies have investigated determinants of blood levels of 25-hydroxyvitamin D (25OHD) in AA women. Recent evidence suggests that differences in levels between AAs and EAs were largely eliminated after accounting for levels of vitamin D binding protein (VDBP). In the current study, we conducted a comprehensive investigation of associations between genetic and non-genetic factors, including circulating VDBP levels, and serum 25OHD levels in AA and EA women. Study population and methods. Data and biospecimens were examined in the context of the African American Breast Cancer Risk and Epidemiology (AMBER) consortium. For this analysis, levels were measured in 1,756 healthy controls from two case-control studies in AMBER, the Carolina Breast Cancer Study (CBCS) and the Women's Circle of Health Study (WCHS), and included 909 AA and 847 EA women. Blood samples collected at the time of enrollment were used for 25OHD measurement by DiaSorin Liasion immunochemiluminometric assay and VDBP measurement by Assaypro Gc-Globulin ELISA assays. Epidemiological data were collected from questionnaires and harmonized across studies. Genotype data for 25,248 typed and imputed germline variants in vitamin D-related pathways were available as a part of exome genotyping array from AAs in the consortium. Percent of European ancestry in AAs was estimated based on genotype data of ancestry informative markers. Univariate analyses and generalized linear regression analyses were conducted to relate serum 25OHD levels with genetic and non-genetic factors and between AA and EA women. Results: AA women had markedly lower 25OHD levels than EA women (14.2 ng/ml vs. 21.1 ng/ml, p&amp;lt;0.0001), yet had similar levels of VDBP (344 ug/ml vs. 336 ug/ml, p=0.25), which is different from the previous study in AAs showing much lower VDBP levels in AAs than in EAs. Also different is that VDBP levels with were not affected by the two GC polymorphisms rs4588 and rs7041. In AAs, a higher percent of European ancestry was also associated with higher 25OHD levels (p=0.03). Race was the strongest determinant of 25OHD levels, followed by body mass index (BMI), physical activity (walking for exercise), season of blood collection, multivitamin use, dietary vitamin D intake, cigarette smoking and study. Accounting for VDBP levels had little impact on racial difference in 25OHD levels. In analysis of germline variants with serum 25OHD levels, none of the index genome-wide association study (GWAS) variants identified in EAs, including rs2282679 and rs7041 in GC, were significant in AAs in our study. Conclusion: VDBP levels had little impact on notable differences in blood 25OHD levels between AAs and EAs. In addition to race, obesity, season of assessment, and several lifestyle factors were also important determinants of 25OHD levels. Genetic determinants of 25OHD levels in AAs are likely different from those in EAs, which warrants further investigation. Citation Format: Song Yao, Chi-Chen Hong, Ting-Yuan David Cheng, Gary Zirpoli, Stephen A. Haddad, Katherine L. Lunetta, Elisa V. Bandera, Andrew F. Olshan, Julie R. Palmer, Christine B. Ambrosone. Determinants of serum 25-hydroxyvitamin D levels in African American women in the AMBER Consortium. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr B53.

Association between circulating 25-hydroxyvitamin D levels and medication use in patients scheduled for cardiac surgery

Background and aimLow vitamin D status, i.e. circulating 25-hydroxyvitamin D (25OHD) levels <50 nmol/l, is independently associated with increased CVD risk. Medication use may influence 25OHD levels. We therefore investigated the association of circulating 25OHD with medication use in patients scheduled for cardiac surgery. Methods and resultsA total of 11,256 patients were included in this cross-sectional study. We compared 25OHD levels of medication users (18 groups of continuously used and 5 groups of intermittently used medications) with levels of non-users. Moreover, we assessed variables (medications, demographic and clinical parameters) that were independently associated with 25OHD levels <50 nmol/l. The prevalence of 25OHD levels <50 nmol/l was 65.7%. The use of statins and immunosuppressive agents was significantly associated with higher 25OHD levels and lower odds ratios of 25OHD levels <50 nmol/l. The use of ACE-inhibitors, catecholamines and antibiotics was associated with lower 25OHD levels and higher odds ratios of 25OHD levels <50 nmol/l. However, only use of antibiotics, immunosuppressive agents and catecholamines showed clinically relevant differences in 25OHD levels, i.e. differences of more than +4 nmol/l or −4 nmol/l, compared with respective non-users. These medications were prescribed either intermittently (antibiotics, catecholamines) and/or infrequently (<2%; immunosuppressive agents, catecholamines) and/or its causal relationship with circulating 25OHD is questionable (antibiotics). Female sex and blood drawing during wintertime were associated with the highest odds ratios of 25OHD levels <50 nmol/l. ConclusionData indicate that in patients with high cardiovascular risk profile medication use does not substantially contribute to 25OHD levels <50 nmol/l.

Is there an association between periprosthetic joint infection and low vitamin D levels?

Vitamin D is increasingly being recognized as an important mediator of immune function and may have a preventive role in the pathogenesis of periprosthetic joint infection. To the best of our knowledge, no other study has examined possible associations between periprosthetic joint infection and vitamin D deficiency. We investigated the rate of vitamin D deficiency in patients treated for periprosthetic joint infection and whether vitamin D deficiency is independent of other risk factors for vitamin D deficiency in patients with periprosthetic joint infection. Serum 25-hydroxyvitamin D (25OHD) levels of every patient scheduled to receive a total prosthesis either of the hip, knee, or shoulder in the orthopaedic department of the Johannes-Guttenberg-University Hospital in Mainz, Germany (109 patients), were measured after admission. Furthermore, serum 25OHD levels were measured for every patient presenting with periprosthetic joint infection (n = 50) or aseptic loosening of the prosthesis (n = 31) scheduled to undergo revision surgery. The prevalence of normal (> 30 ng/ml), insufficient (20-30 ng/ml), and deficient (<20 ng/ml) 25OHD levels was determined. All tested patient subgroups showed low vitamin D levels. Statistical analysis found no significant difference in vitamin D levels comparing patients with prosthesis and patients with aseptic prosthesis loosening (p = 0.58). Significant differences in 25OHD levels were found comparing patients with periprosthetic joint infection and patients scheduled for primary arthroplasty (p < 0.001). In addition, we found a significant difference (p < 0,001) in 25OHD levels of patients with periprosthetic joint infection compared with patients with aseptic prosthesis loosening. We found a high frequency of vitamin D deficiency in patients being treated by primary arthroplasty and those with aseptic joint prosthetic loosening and periprosthetic joint infection. Vitamin D deficiency was severe in patients with periprosthetic joint infection.

AB0817 Vitamin D serum levels in a cohort of patients with systemic sclerosis: Prevalence, determinants and associations with clinical and biological aspects

BackgroundBesides the genetic background, it is known that environmental factors play an important role in the pathogenesis and activity of autoimmune diseases and vitamin D deficiency has been associated with...

Vitamin D Status in HIV-Infected Patients With and Without Tuberculosis

Tuberculosis (TB) is a leading cause of death in human immunodeficiency virus (HIV)-infected individuals. Efforts to reduce the burden of TB include isoniazid prophylactic therapy (IPT) for latent TB infection (LTBI).1 However, IPT confers a risk of hepatotoxicity and requires at least six months of therapy.2 Therefore, additional strategies to reduce the burden of active TB are needed. Vitamin D supplementation may decrease the progression of LTBI to active TB. Primarily, in vitro studies demonstrate that 1,25-dihydroxyvitamin D (1,25[OH]2D) enhances macrophage function, thereby augmenting immunologic control of mycobacteria.3 The benefit of vitamin D supplementation is suggested by the observation of increased rates of clearance of TB from sputum in HIV-uninfected individuals.4 Vitamin D, however, may have detrimental effects in HIV-infected patients. In vitro, vitamin D depresses cell mediated immune function, 5 which could hasten progression of LTBI to active disease. This may limit vitamin D supplementation as an adjunct for TB control. Given vitamin D’s conflicting mechanisms of action on the immune system, we conducted a study in Botswana, an area of high TB and HIV prevalence,6 to determine if there was evidence for differences in 25-hydroxyvitamin D (25-OHD) levels in HIV-infected individuals with and without active TB. We hypothesized that 25-OHD levels would be significantly lower in HIV-infected individuals with active TB as compared to those without active TB.

Preanalytical, analytical (DiaSorin LIAISON) and clinical variables potentially affecting the 25-OH Vitamin D estimation

BackgroundVitamin D (25-OHD) physiological functions have been expanded beyond traditional bone health, increasing the importance of its estimation in Laboratory Medicine, which renders validation of available methods mandatory. Aims and methodsWe evaluated some preanalytical and analytical aspects of 25-OHD determination and the effects of potentially confounding clinical variables by using the DiaSorin “LIAISON 25-OH Vitamin D TOTAL”. Results25-OHD samples were extremely stable, at least in the short term, without requiring special transport or storage. Precision intervals (CV%) were: within run (7–11%) and total precision (8–11.5%). Mean (SD) recovery was 96 (2)%. The assay was linear on dilution. Comparison with radioimmunoassay (RIA) yielded acceptable correlation (Inter-rater agreement/kappa coefficient=0.94) and clinical equivalence in the interval from 6 to 55ng/mL.The assay was evaluated on a general population (N=476, age: 60±14years, 65 males). The status of 25‐OHD resulted inversely related to parathyroid hormone levels (r=−0.21, p<0.001), and aging (r=−0.17, p<0.001), but not to sex. Levels of 25-OHD were found to be sufficient (≥30ng/mL) only in 54 samples (12%). Marked seasonal 25-OHD variations were observed in 13 subjects (p<0.05). Moreover, a marked seasonal fluctuation was seen in samples collected during the period of February 2010–October 2011 (p≤0.01).Lower 25-OHD concentration was observed in subjects with diabetes (19±9 vs 14±7ng/mL, p<0.01) and hypertension (20±9 vs 17±9ng/mL, p<0.01). Moreover, 25-OHD inversely correlated with BMI (r=−0.25, p<0.001). Conversely, no difference in 25-OHD levels was observed between subjects due to smoking habits and dyslipidemia.In multiple logistic regression models, aging is the only significant independent risk factor for low 25-OHD levels (Odds ratio, 95% confidence intervals: 3.1, 1.3–7.3; p≤0.01). ConclusionsResults confirm the LIAISON 25-OHD assay as a useful tool for 25-OHD estimation in the clinical practice. Lack of vitamin D is common among Italian adults, and appears associated with several cardiovascular risk factors.

Variants in the vitamin D pathway, serum levels of vitamin D, and estrogen receptor negative breast cancer among African-American women: a case-control study

IntroductionAmerican women of African ancestry (AA) are more likely than European Americans (EA) to have estrogen receptor (ER)-negative breast cancer. 25-hydroxyvitamin D (25OHD) is low in AAs, and was associated with ER-negative tumors in EAs. We hypothesized that racial differences in 25OHD levels, as well as in inherited genetic variations, may contribute, in part, to the differences in tumor characteristics.MethodsIn a case (n = 928)-control (n = 843) study of breast cancer in AA and EA women, we measured serum 25OHD levels in controls and tested associations between risk and tag single nucleotide polymorphisms (SNPs) in VDR, CYP24A1 and CYP27B1, particularly by ER status.ResultsMore AAs had severe vitamin D deficiency (< 10 ng/ml) than EAs (34.3% vs 5.9%), with lowest levels among those with the highest African ancestry. Associations for SNPs differed by race. Among AAs, VDR SNP rs2239186, associated with higher serum levels of 25OHD, decreased risk after correction for multiple testing (OR = 0.53, 95% CI = 0.31-0.79, p by permutation = 0.03), but had no effect in EAs. The majority of associations were for ER-negative breast cancer, with seven differential associations between AA and EA women for CYP24A1 (p for interaction < 0.10). SNP rs27622941 was associated with a > twofold increased risk of ER-negative breast cancer among AAs (OR = 2.62, 95% CI = 1.38-4.98), but had no effect in EAs. rs2209314 decreased risk among EAs (OR = 0.38, 95% CI = 0.20-0.73), with no associations in AAs. The increased risk of ER-negative breast cancer in AAs compared to EAs was reduced and became non-significant (OR = 1.20, 95% CI = 0.80-1.79) after adjusting for these two CYP24A1 SNPs.ConclusionsThese data suggest that genetic variants in the vitamin D pathway may be related to the higher prevalence of ER-negative breast cancer in AA women.

Abstract 5603: Common genetic variations in VDR, CYP27B1 and CYP24A1 genes and breast cancer risk in African American and European American women in the Women's Circle of Health Study

Abstract Common single nucleotide polymorphisms (SNPs) in vitamin D receptor (VDR) have been examined with breast cancer risk in populations of European ancestry. Because of the striking differences in vitamin D levels and in SNP linkage disequilibrium (LD) between African Americans (AA) and European Americans (EA), it is hypothesized that associations of VDR SNPs with breast cancer risk may differ by race. A total of 67 multi-population tagSNPs in the VDR, CYP27B1 and CYP24A1 genes were genotyped in 928 breast cancer cases (547 AA and 381 EA) and 843 controls (461 AA and 382 EA) recruited through the Women's Circle of Health Study (WCHS), a case-control study based in New York City and seven counties in New Jersey. Cochran-Armitage test for trend was used for single SNP analysis, and LD block-based haplotype analysis was performed, with multiple comparisons corrected by permutation. In addition, 25-hydroxyvitamin D (25OHD) levels were measured in the banked serum samples from 242 AA and 187 EA healthy women. Four VDR SNPs were associated with breast cancer risk in AA women, and rs2239186 remained significant (p=0.03) after multiple comparison correction. Women with the AG/GG genotype of rs2239186 had a lower risk of breast cancer (OR=0.53, 95% CI=0.35-0.79) than those with the AA genotype, consistent with a three-SNP haplotype carrying the G allele of rs2239186 (OR=0.55, 95% CI=0.38-0.81) in AA women. In EA women, 2 SNPs in the VDR gene and 3 SNPs in the CYP24A1 gene were associated with breast cancer risk. EA women with the TT genotype of the VDR SNP rs11608702 had a significantly increased risk (OR=1.88, 95% CI=1.14-3.09), which were confirmed in an analysis of a two-SNP haplotype carrying the T allele (OR=1.44, 95% CI=1.12-1.85). In addition, a four-SNP haplotype in the CYP24A1 gene was associated with reduced cancer risk in EA women (OR=0.67, 95% CI=0.51-0.88). When stratified by menopausal status, the association of rs7975232 in VDR in EA women was stronger in postmenopausal women (OR=2.24, 95% CI=1.19-4.21); and the association of another VDR SNP rs886441 in AA women was stronger in premenopausal women (OR=2.27, 95% CI=1.32-3.90). Lastly, we found significant differences in 25OHD levels between AA and EA women; the least square mean and standard error were 14.9±0.5 vs 21.4±0.6 ng/mL (p&amp;lt;0.0001), respectively, after adjusting for age, BMI and season of blood collection. Dietary intake of vitamin D helped explain only 3% of the circulating levels. In conclusion, we found different SNPs associated with breast cancer risk between AA and EA women. Our findings support the hypothesis that the role of vitamin D-related genetic variations may be race-specific, possibly due to differences in linkage disequilibrium structure and in endogenous vitamin D levels between the two groups. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5603. doi:10.1158/1538-7445.AM2011-5603

The Effects of Storage Time and Sampling Season on the Stability of Serum 25-Hydroxy Vitamin D and Androstenedione

Knowledge of the stability of serum samples stored in large biobanks is pivotal for reliable assessment of hormone-dependent disease risks. We studied the effects of sample storage time and season of serum sampling on the stability of 25-hydroxy vitamin D (25-OHD) and androstenedione in a stratified random sample of 402 women, using paired sera from the Finnish Maternity Cohort. Serum samples selected were donated between 6 and 24 yr ago. The storage time did not affect serum 25-OHD and androstenedione levels. However, there was a significant mean difference in the 25-OHD levels of sera withdrawn during winter (first sample) vs. during summer (second sample; –18.4 nmol/l, P ≤ 0.001). Also at the individual level, there were significant differences in average 25-OHD levels between individuals with the paired sera taken at winter–winter compared with other alternatives (summer–winter, winter–summer, and summer–summer). The androstenedione levels showed no such differences. Long-term storage does not affect serum 25-OHD and androstenedione levels, but sampling season is an important determinant of 25-OHD levels. Stored serum samples can be used to study disease associations with both hormones. However, sampling season needs to be taken into account for 25-OHD by considering matching and stratification and, if possible, serial sampling.

Does degree of baldness influence vitamin D status?

To determine the association, if any, between male-pattern hair loss (baldness) and serum 25-hydroxyvitamin D (25-OHD) levels. A cross-sectional study of 296 healthy middle-aged and older men. Degree of baldness was independently assessed by two researchers using the Hamilton-Norwood scale and serum 25-OHD was measured in all men. Classification of the degree of baldness by the two researchers showed a high level of agreement (kappa = 0.93). Forty-eight per cent of men had no hair loss or mild frontotemporal recession, 15% had predominant vertex loss, and 37% had significant scalp and vertex loss. After data were adjusted for potential confounding factors - including age, month of 25-OHD measurement, exercise levels, use of sunscreen, skin type and frequency of outdoor hat wearing - no significant differences in 25-OHD levels between these groups was detected (P = 0.60). The degree of baldness does not appear to influence serum 25-OHD levels. The high prevalence of baldness in older men does not explain sex differences in 25-OHD levels. Other novel hypotheses are required to help determine whether baldness serves any physiological purpose.

Correlação entre fotoproteção e concentrações de 25 hidroxi-vitamina D e paratormônio

FUNDAMENTOS- A preocupação com o risco de câncer da pele levou à difusão da fotoproteção em larga escala, e atualmente se discute se haveria, associado a essa recomendação, risco para o desenvolvimento de hipovitaminose D. OBJETIVOS - Avaliar em pacientes orientados para proteção solar, o estado atual de seu estoque de vitamina D. MÉTODOS - Avaliaram-se as concentrações de 25 hidroxivitamina D (25OHD e do hormônio da paratireóide (PTH) em grupos de indivíduos com e sem orientação para fotoproteção, moradores da cidade de São Paulo. RESULTADOS - Encontrou-se diferença significativa entre os níveis de 25OHD, maiores no grupo fotoexposto, 35,4ng/mL [21,86- 72,20], em relação ao fotoprotegido, 29,2ng/mL [23,10-45,80]. Também houve diferença com relação ao PTH, maior no grupo fotoexposto, 29,8pg/mL [18,98-73,94], do que no fotoprotegido, 19,24pg/mL [8,06-66,18]. CONCLUSÕES - Apesar dessas diferenças, não havia indivíduos deficientes de vitamina D nessa amostra, e os níveis de PTH mantiveram- se dentro dos valores de normalidade. A radiação ultravioleta solar do cotidiano foi suficiente para promover uma síntese adequada de 25OHD.

Determinants of vitamin D status in older men living in a subtropical climate

Previously we reported seasonal variation in 25-hydroxyvitamin D (25OHD) levels in postmenopausal women living in a subtropical climate. Because studies have suggested that there are gender differences in 25OHD levels, we sought to determine (1) the levels and determinants of 25OHD in men drawn from the same community, (2) whether seasonal variation of 25OHD occurs in men at this latitude (37 degrees S), and (3) whether these findings were comparable to those we previously observed in postmenopausal women. Cross-sectional study of 378 healthy, middle-aged and older community-dwelling men in Auckland, New Zealand. The mean 25OHD (SD) level was 85 (31) nmol/l. We found significant seasonal variation in 25OHD levels (peak in autumn 103 nmol/l, nadir in spring 59 nmol/l). Vitamin D insufficiency (25OHD <50 nmol/l) was uncommon (prevalence in summer 0-17%, in winter 0-20%). The major determinants of 25OHD were month of blood sampling, fat percentage, physical activity, and serum albumin. Men had higher levels of 25OHD throughout the year than women did, a finding that persisted after adjusting for potential confounding factors. In men and women the determinants of 25OHD were similar. There is significant seasonal variation in 25OHD levels in men living in a subtropical climate. In contrast to postmenopausal women, men have low rates of suboptimal vitamin D status, even in winter. Routine vitamin D supplementation for this population of men is not warranted.

Effect of Underground Working on Vitamin D Levels and Bone Mineral Densities in Coal Miners: A Controlled Study

The aim of this study was to determine the effect of underground working on 25-hydroxyvitamin D (25-OHD) levels and bone mineral density (BMD) values in coal miners. Fifty coal miners working underground and 50 surface workers as controls, matched for age and body mass index, from Zonguldak, Turkey, were recruited to the study. Levels of 25-OHD, biochemical bone markers, and lumbar spine and femur BMD values were measured in all study participants. Lumbar spine and femur BMD values were significantly higher in underground workers compared with surface workers, but there was no significant difference in 25-OHD levels between the two groups. Duration of underground working, age, 25-OHD levels, cigarette consumption and dietary calcium intake were not correlated with BMD values. Underground physical working does not seem to be a significant risk factor for low 25-OHD levels or low BMD values.

14 Phenytoin determination by the substrate-labeled fluorescent immunoassay (SLFIA): R. C. Wong and J. F. Burd, Miles Labs., Inc., Elkhart, IN 46515, U.S.A.

Vitamin D (25-OHD) physiological functions have been expanded beyond traditional bone health, increasing the importance of its estimation in Laboratory Medicine, which renders validation of available methods mandatory.We evaluated some preanalytical and analytical aspects of 25-OHD determination and the effects of potentially confounding clinical variables by using the DiaSorin “LIAISON 25-OH Vitamin D TOTAL”.25-OHD samples were extremely stable, at least in the short term, without requiring special transport or storage. Precision intervals (CV%) were: within run (7–11%) and total precision (8–11.5%). Mean (SD) recovery was 96 (2)%. The assay was linear on dilution. Comparison with radioimmunoassay (RIA) yielded acceptable correlation (Inter-rater agreement/kappa coefficient = 0.94) and clinical equivalence in the interval from 6 to 55 ng/mL.The assay was evaluated on a general population (N = 476, age: 60 ± 14 years, 65 males). The status of 25‐OHD resulted inversely related to parathyroid hormone levels (r = − 0.21, p < 0.001), and aging (r = − 0.17, p < 0.001), but not to sex. Levels of 25-OHD were found to be sufficient (≥ 30 ng/mL) only in 54 samples (12%). Marked seasonal 25-OHD variations were observed in 13 subjects (p < 0.05). Moreover, a marked seasonal fluctuation was seen in samples collected during the period of February 2010–October 2011 (p ≤ 0.01).Lower 25-OHD concentration was observed in subjects with diabetes (19 ± 9 vs 14 ± 7 ng/mL, p < 0.01) and hypertension (20 ± 9 vs 17 ± 9 ng/mL, p < 0.01). Moreover, 25-OHD inversely correlated with BMI (r = − 0.25, p < 0.001). Conversely, no difference in 25-OHD levels was observed between subjects due to smoking habits and dyslipidemia.In multiple logistic regression models, aging is the only significant independent risk factor for low 25-OHD levels (Odds ratio, 95% confidence intervals: 3.1, 1.3–7.3; p ≤ 0.01).Results confirm the LIAISON 25-OHD assay as a useful tool for 25-OHD estimation in the clinical practice. Lack of vitamin D is common among Italian adults, and appears associated with several cardiovascular risk factors.

16 Biochemical evaluation of the nutritional and metabolic status of geriatric subjects: D. Shapcott, S. Hontela, J. Vobecky, Dép. de Pédiatrie and Dép. de Santé communautaire, Centre hospitalier universitaire de Sherbrooke, Québec, J1H 5N4 and Douglas Hospital Centre, Montréal, Québec, H4H 1R3

Vitamin D (25-OHD) physiological functions have been expanded beyond traditional bone health, increasing the importance of its estimation in Laboratory Medicine, which renders validation of available methods mandatory.We evaluated some preanalytical and analytical aspects of 25-OHD determination and the effects of potentially confounding clinical variables by using the DiaSorin “LIAISON 25-OH Vitamin D TOTAL”.25-OHD samples were extremely stable, at least in the short term, without requiring special transport or storage. Precision intervals (CV%) were: within run (7–11%) and total precision (8–11.5%). Mean (SD) recovery was 96 (2)%. The assay was linear on dilution. Comparison with radioimmunoassay (RIA) yielded acceptable correlation (Inter-rater agreement/kappa coefficient = 0.94) and clinical equivalence in the interval from 6 to 55 ng/mL.The assay was evaluated on a general population (N = 476, age: 60 ± 14 years, 65 males). The status of 25‐OHD resulted inversely related to parathyroid hormone levels (r = − 0.21, p < 0.001), and aging (r = − 0.17, p < 0.001), but not to sex. Levels of 25-OHD were found to be sufficient (≥ 30 ng/mL) only in 54 samples (12%). Marked seasonal 25-OHD variations were observed in 13 subjects (p < 0.05). Moreover, a marked seasonal fluctuation was seen in samples collected during the period of February 2010–October 2011 (p ≤ 0.01).Lower 25-OHD concentration was observed in subjects with diabetes (19 ± 9 vs 14 ± 7 ng/mL, p < 0.01) and hypertension (20 ± 9 vs 17 ± 9 ng/mL, p < 0.01). Moreover, 25-OHD inversely correlated with BMI (r = − 0.25, p < 0.001). Conversely, no difference in 25-OHD levels was observed between subjects due to smoking habits and dyslipidemia.In multiple logistic regression models, aging is the only significant independent risk factor for low 25-OHD levels (Odds ratio, 95% confidence intervals: 3.1, 1.3–7.3; p ≤ 0.01).Results confirm the LIAISON 25-OHD assay as a useful tool for 25-OHD estimation in the clinical practice. Lack of vitamin D is common among Italian adults, and appears associated with several cardiovascular risk factors.