Variance In Vitamin Research Articles

Hormonal status and bone turnover in adolescents with polycystic ovarian syndrome

Background: Problems with hormonal changes and the related variations in bone turnover in adolescents with polycystic ovarian syndrome (PCOS) have been of interest in terms of providing these patients with an opportunity to receive a prophylactic and precision-based treatment aiming to prevent early onset of osteoporosis. Materials and methods: Prospective comparative clinical trial—‘case-control’ type in Bulgarian populace of 36 female patients with PCOS and 42 healthy controls aged 12 to 18. The study protocol included a general section of anthropometric patient data, clinical section–including general and Ob/Gyn Medical History, ultrasound exam of the lesser pelvis and a lab section examining the serum levels of Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), estradiol, Anti-Müllerian hormone (AMH) and bone turnover markers–osteocalcin and β-CrossLaps (bCTX), as well as Vitamin D. Results: A statistically significant high serum levels of the gonadotropic hormones were observed (LH — p < 0.001 и FSH — p = 0.017), AMH (p < 0.001) in patients with PCOS compared to the controls, while the estradiol (p = 0.043) and osteocalcin (p < 0.001) levels displayed a statistically significant lower values in patients with PCOS compared to the control group. AMH can be utilized as a surrogate marker for diagnosing patients with PCOS where the marker shows sensitivity — 94% and specificity — 69% with threshold value (cut-off) at ≥5.95 ng/mL (area under the curve 0.854, p < 0.001). Significant variance in Vitamin D serum levels between the two groups was not detected. Conclusion: Despite the hormonal characteristic of normogonadotropic normogonadism in adolescent patients with PCOS, the significantly lower values of osteocalcin demonstrated suppressed bone metabolism–bone formation, in particular–compared to the healthy controls, which can be interpreted as increased risk of insufficient bone accretion and risk of early onset of osteoporosis later in life.

Prospective Evaluation of Vitamin D Levels and Stress Injury in Collegiate Female Long-Distance Runners

Category:Lesser Toes, Midfoot/Forefoot, SportsIntroduction/Purpose:The incidence of stress injury in female runners is reported in up to 21% of competitive runners, with female runners at higher risk for stress injury than men. Bone metabolism is closely linked with vitamin D, which may play a role in the high prevalence of stress fractures in female runners. Although runners who train outdoors in the southeastern US have adequate vitamin D levels, no study to date has evaluated runners in northeastern US. The aim of the study was to prospectively evaluate the relationship between 25-OH vitamin D serum levels and the incidence of stress injury in a cohort of collegiate competitive long-distance runners.Methods:101 female collegiate runners from 7 Northeastern US colleges competing in varsity cross country were enrolled. Surveys were collected from all the study participants at the start of the fall cross country season reviewing demographics, weekly mileage, and medical history, including previous stress fracture incidence. Additionally, baseline (“summer”) serum 25-hydroxy vitamin D levels were obtained. Subjects insufficient in vitamin D (<30ng/mL) were supplemented with cholecalciferol (D3) 50,000 units weekly for 8 weeks and 2,000 units daily for an additional 1 month. In subjects with vitamin D insufficiency, repeat labs were performed at 3 months and repeat surveys distributed. To account for variation in season and geographical location, all subjects underwent repeat vitamin D labs at 6 months (”winter”). Fisher’s exact test was used to determine whether vitamin D levels were correlated with incidence of stress fracture.Results:91/101 (90%) subjects with mean BMI of 20.5 and average age of 20 years completed all study requirements. The mean summer and winter vitamin D serum levels were 64.0 ng/mL (SD 16.6; range 28.9-112.9) and 45.0 ng/mL (SD 13.8; range 20.1- 90.6), respectively. One subject (1%) in the summer and 9 subjects (10%) in the winter were supplemented for vitamin D insufficiency. 7/10 (70%) insufficient subjects and 28/81 (35%) vitamin D sufficient subjects reported a stress fracture during the study period. Patients that had an insufficient vitamin D result were significantly more likely to have a stress fracture during the study period (p=0.041; Table 1). The mean change in vitamin D level from summer to winter was -19.7 (SD 14.4; range -60.5- 60.7).Conclusion:The high rate of stress fractures in this cohort of collegiate female long-distance runners is greater than previously reported. Runners who are vitamin D insufficient are at a higher risk to incur a stress fracture. The results of the study also highlight the considerable seasonal variance in vitamin D levels amongst female collegiate long-distance runners in the northeastern US. Further study is needed to determine whether vitamin D supplementation reduces the risk of stress fractures.

Half the Genetic Variance in Vitamin D Concentration is Shared with Skin Colour and Sun Exposure Genes.

This study assessed the heritability of 25 hydroxyvitamin D3 (25(OH)D3) in a large twin cohort and the shared effect of sun exposure and skin colour on 25(OH)D3 variance. Study participants included 1604 twin pairs and their siblings (n = 4020). Twin correlations for 25(OH)D3 concentration were rMZ=0.79 (584 pairs) and rDZ = 0.52 (1020 pairs) consistent with an average h2 = 0.50 throughout the year. Significant phenotypic and genetic seasonal fluctuation was observed in 25(OH)D3 concentrations with heritability decreasing during the winter (h2 = 0.37) compared to summer (h2 = 0.62). Skin colour (measured both ordinally and quantitatively) and self-reported sun exposure were found to significantly affect 25(OH)D3 concentration. Twins with olive/dark skin had significantly lower 25(OH)D3 concentrations than those with fair/pale skin and multivariate genetic analysis showed that approximately half of the total additive genetic variation in 25(OH)D3 results from genes whose primary influence is on skin colour and sun exposure. Additionally, 37% of the total variance was attributed to shared environmental effects on vitamin D, skin colour and sun exposure measures. These results support a moderate estimate of vitamin D heritability and suggest significant influence of season, skin colour and sun exposure on the genetic variance.

Vitamin D deficiency in a European inflammatory bowel disease inception cohort: an Epi-IBD study.

Serum vitamin D level is commonly low in patients with inflammatory bowel disease (IBD). Although there is a growing body of evidence that links low vitamin D level to certain aspects of IBD such as disease activity and quality of life, data on its prevalence and how it varies across disease phenotype, smoking status and treatment groups are still missing. Patients diagnosed with IBD between 2010 and 2011 were recruited. Demographic data and serum vitamin D levels were collected. Variance of vitamin D level was then assessed across different treatment groups, disease phenotype, disease activity and quality of life scores. A total of 238 (55.9% male) patients were included. Overall, 79% of the patients had either insufficient or deficient levels of vitamin D at diagnosis. Patients needing corticosteroid treatment at 1 year had significantly lower vitamin D levels at diagnosis (median 36.0 nmol/l) (P=0.035). Harvey-Bradshaw Index (P=0.0001) and Simple Clinical Colitis Activity Index scores (P=0.0001) were significantly lower in patients with higher vitamin D level. Serum vitamin D level correlated significantly with SIBQ score (P=0.0001) and with multiple components of SF12. Smokers at diagnosis had the lowest vitamin D levels (vitamin D: 34 nmol/l; P=0.053). This study demonstrates the high prevalence of low vitamin D levels in treatment-naive European IBD populations. Furthermore, it demonstrates the presence of low vitamin D levels in patients with IBD who smoke.

Common Genetic Variants Influence Circulating Vitamin D Levels in Inflammatory Bowel Diseases.

The accuracy and utility of electronic health record (EHR)-derived phenotypes in replicating genotype-phenotype relationships have been infrequently examined. Low circulating vitamin D levels are associated with severe outcomes in inflammatory bowel disease (IBD); however, the genetic basis for vitamin D insufficiency in this population has not been examined previously. We compared the accuracy of physician-assigned phenotypes in a large prospective IBD registry to that identified by an EHR algorithm incorporating codified and structured data. Genotyping for IBD risk alleles was performed on the Immunochip and a genetic risk score calculated and compared between EHR-defined patients and those in the registry. Additionally, 4 vitamin D risk alleles were genotyped and serum 25-hydroxy vitamin D [25(OH)D] levels compared across genotypes. A total of 1131 patients captured by our EHR algorithm were also included in our prospective registry (656 Crohn's disease, 475 ulcerative colitis). The overall genetic risk score for Crohn's disease (P = 0.13) and ulcerative colitis (P = 0.32) was similar between EHR-defined patients and a prospective registry. Three of the 4 vitamin D risk alleles were associated with low vitamin D levels in patients with IBD and contributed an additional 3% of the variance explained. Vitamin D genetic risk score did not predict normalization of vitamin D levels. EHR cohorts form valuable data sources for examining genotype-phenotype relationships. Vitamin D risk alleles explain 3% of the variance in vitamin D levels in patients with IBD.

Determinants of vitamin D status in healthy men and women aged 40–80 years

ObjectivesTo determine the contribution of life style and health related factors on vitamin D status in middle-aged and older men and women. Study designA cross-sectional single-center study in 400 male subjects (40–80 years) and 402 postmenopausal female subjects (56–73 years), conducted in a University Medical Center in the central part of the Netherlands (52 degrees northern latitude). Main outcome measuresMedical history, vitamin D, calcium and alcohol intake, physical activity, Body Mass Index, Blood pressure, smoking, total fat body mass and total lean body mass were measured using DEXA. Laboratory analysis included 25-hydroxyvitamin D (25OHD) and sex hormones. ResultsThirty-six percent of men and 51% of women had 25OHD less than 50nmol/L. In summertime men had significant higher 25OHD as compared to women (81.5 vs 53.3nmol/L, P=.000) but this difference disappeared come winter. In a saturated model, male gender (B=.16, P=.008), and season (summer vs winter B=.30, P=.000) remained statistically significant. In men, physical activity and season explained 21% of the variance. In women, household physical activity (B=.13, P=.03), sport physical activity (B=.02, P=.02) and estradiol (B=−.003, P=.048) remained in the model,. ConclusionIn healthy middle-aged and older men and postmenopausal women, male gender and season were important predictors of vitamin D status. In men, physically activity and season, explained 21% of the variance in vitamin D status. In women, physical activity and estradiol explained 9.3% of the variance in vitamin D.

Can a Model Predictive of Vitamin D Status Be Developed From Common Laboratory Tests and Demographic Parameters?

Vitamin D deficiency is highly prevalent and has been linked to increased morbidity and mortality. There has been an increase in testing for vitamin D with a concomitant increase in costs. While individual factors are significantly linked to vitamin D status, prior studies have not yielded a model predictive of vitamin D status or 25(OH)D levels. The purpose of this investigation was to determine if a prediction model of vitamin D could be developed using extensive demographic data and laboratory parameters. Patient data from 6 Veterans Administration Medical Centers were extracted from medical charts. For the 14,920 available patients, several factors including triglyceride level, race, total cholesterol, body mass index, calcium level, and number of missed appointments were significantly linked to vitamin D status. However, these variables accounted for less than 15% of the variance in vitamin D levels. While the variables correctly classified vitamin D deficiency status for 71% of patients, only 33% of those who were actually deficient were correctly identified as deficient. Given the failure to find a sufficiently predictive model for vitamin D deficiency, we propose that there is no substitute for laboratory testing of 25(OH)D levels. A baseline vitamin D 3 daily replacement of 1000-2000 IU initially with further modification based on biannual testing appears to factor in the wide variation in dose response observed with vitamin D replacement and is especially important in high-risk groups such as ethnic minorities.

Abstract 3736: Correlates of vitamin D: A measurement pilot study

Abstract Vitamin D has protective effects for colorectal cancer and possible benefits for breast and ovarian cancers yet the determinants of vitamin D status are not fully understood. This study measured sun exposure, sun protection, diet, body mass index, and skin color and correlated them with serum 25(OH)D to understand better the impact of these factors on vitamin D status. Women (n=28) ages 18-30 residing in Hawaii attended small group sessions where they completed questionnaires about diet, supplement use, and skin type and had skin color measured by reflectance spectrophotometry. Participants wore polysulphone dosimeters mounted on wristbands, photographed clothing outfits and kept daily diaries for the 7 days before their blood draw. Results: Participants were, on average, 24.6 (3.3) years old, had BMI of 23.6 (range 17.7 – 34.7), consumed 308 IU vitamin D daily (range 10 – 1202), used sunscreen on 12% of their body (range 0 to 44%), were 44% covered by clothing (range 22 – 79%), received 2.3 standard erythemal doses (range .1 to 5.9) of UVB and had 34.7 ng/mL of 25(OH)D3 (range 17.7 – 90.5). Personal UVB dose accounted for 22% of the variance in 25(OH)D, and the addition of clothing and sunscreen coverage increased the R2 value to 0.33. Skin color and diet were not associated with 25(OH)D. While BMI was showed an association 25(OH)D, it did not improve the model and was inversely related to UVB exposure. While the measured sun-related variables were useful for predicting 25(OH)D, the majority of variance in vitamin D status is unexplained. More research is needed to understand how this hormone is regulated in the body. 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 3736. doi:10.1158/1538-7445.AM2011-3736

Vitamin A levels in HIV/AIDS.

To study the correlation of vitamin A concentrations in patients with AIDS, HIV positive symptom free and HIV negative symptom free men and women. A cross-sectional study. Male and female volunteers aged between 15 and 60 years willing to undergo an HIV-test. Participants came from different backgrounds within the city of Ndola. Some were urban while others were peri-urban dwellers. They were included in the study only if they were willing to undergo the HIV test regardless of their place of residence. After obtaining consent blood samples were taken from the participants using needle and syringe. Whole blood was used to measure haematological indices while serum was used to measure vitamin A concentrations and HIV status. One hundred and thirty five participants were recruited for the study. Vitamin A was analysed in eighty seven HIV negative symptom free, forty one HIV-positive symptom free and seven AIDS cases. There was a significant difference (p < 0.05) in the variance of vitamin A levels in the three groups. Vitamin A deficiency is defined as blood concentrations below 30 micrograms/dl. Using this cut-off point, the Odds Ratio for deficiency if HIV-positive was found to be 6.3 (2.5, 16.7 p < 0.0001). The Odds Ratio for HIV and serum vitamin A deficiency was approximately the same for males and females. There was a modest correlation between vitamin A concentrations and haemoglobin (r = 0.34, 95% CI 0.18, 0.48, p < 0.0001). Vitamin A concentration is lowered in HIV infection. The depletion of vitamin A seems to increase with progression of the infection leading to AIDS disease. Whether regular supplementation of vitamin A to the HIV infected individual can lead to a delayed progression to AIDS needs to be explored.