Dr. Arnaud Replies

PEDIATRICS ◽  
1977 ◽  
Vol 60 (5) ◽  
pp. 761-761
Author(s):  
Sara B. Arnaud
Keyword(s):  
Vitamin D ◽  
Statistical Analysis ◽  
Vitamin D Deficiency ◽  
Statistical Comparison ◽  
Hydroxyvitamin D ◽  
Number Of Patients ◽  
25 Hydroxyvitamin D ◽  
Deficiency Rickets ◽  
Student’S T ◽  
Student’S T Test

Drs. Giangiacomo and Gleason are quite correct in their criticism that the number of patients with vitamin D deficiency rickets is too small for statistical comparison of the concentration of serum 25-hydroxyvitamin D (25-OH-D) in mild, moderate, and severe rickets. For this reason, we did not attempt this type of statistical comparison (Student's t test). The statistical analysis which supports our conclusion is the calculation of the regression between senim 25-OH-D, ng/ml and the stage of the disease, designated by arbitrary numbers 1, 2, and 3 for mild, moderate, and severe.

Vitamin D3 metabolism in a pig strain with pseudo vitamin D-deficiency rickets, type I

1987 ◽  
Vol 115 (3) ◽  
pp. 345-352 ◽  
Author(s):  
Reinhard Kaune ◽  
Johein Harmeyer
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Type I ◽  
Vitamin D Metabolism ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Before And After ◽  
25 Hydroxyvitamin D ◽  
Deficiency Rickets ◽  
Clinical Healing

Abstract. Vitamin D metabolism was studied in the 'Hannover Pig', a strain which suffers from pseudo vitamin D-deficiency rickets, type I. Animals of this strain are known to be devoid of renal 25-hydroxyvitamin D3-1α-hydroxylase and -24-hydroxylase activities. Pigs with florid rickets and hypocalcaemia were treated with single im injections of 0.25 to 1.25 mg of vitamin D3, doses that have been shown in previous studies to be effective in producing transient healing of rachitic symptoms. The levels of vitamin D3 and its most relevant physiological metabolites in plasma were estimated at intervals before and after this vitamin D3 treatment. Vitamin D3 rose from 14.8 ± 8.1 to 364 ± 190 nmol/l (mean ± sd) 2 to 3 days post injectionem, 25-hydroxyvitamin D3 from 131.0 ± 46.2 to 1068 ± 160 nmol/l within 7 days post injectionem. The 1α,25-dihydroxyvitamin D3 concentration in plasma was elevated from 73.9 ± 25.0 to 281 ± 168 pmol/l 2 to 3 days post injectionem and declined continually from that time. 24R,25-dihydroxyvitamin D3 and 25S,26-dihydroxyvitamin D3 levels after treatment showed different responses in different animals being either elevated or unchanged. Clinical healing of the pigs with these doses of vitamin D3 was attributed to the transient rise of 1α,25-dihydroxyvitamin D3 in plasma. It was assumed that 1α,25-dihydroxyvitamin D3 synthesis takes place under these circumstances in extrarenal tissues.

Prevalence of Vitamin D Deficiency among Patients Attending a General Otolaryngology Clinic in South Auckland

2009 ◽  
Vol 118 (5) ◽  
pp. 326-328 ◽  
Author(s):  
Jim Bartley ◽  
David Reid ◽  
Randall P. Morton
Keyword(s):  
Vitamin D ◽  
Statistical Analysis ◽  
Vitamin D Deficiency ◽  
Prospective Observational Study ◽  
Vitamin D Status ◽  
Hydroxyvitamin D ◽  
Vitamin D Levels ◽  
25 Hydroxyvitamin D ◽  
Relationship Of ◽  
The Relationship

Objectives: We performed a prospective observational study to estimate the prevalence of vitamin D deficiency in patients attending a general otolaryngology clinic in South Auckland, New Zealand. Methods: From July 21, 2008, to August 7, 2008, all new patients presenting to otolaryngology clinics at which one of the authors (D.R.) was present had their vitamin D status assessed by measurement of their plasma 25-hydroxyvitamin D [25(OH)D] level. Results: Of 48 patients, 2% had 25(OH)D levels of 17.5 nmol/L or less (a level associated with osteomalacia), 58% had 25(OH)D levels of 50 nmol/L or less (a level associated with vitamin D deficiency), and 100% had 25(OH)D levels of 80 nmol/L or less. Conclusions: Most of the patients attending a general otolaryngology clinic in South Auckland are vitamin D–deficient. It is unclear whether low vitamin D levels are associated more directly with otolaryngological disorders or skin type, because the small size of this study and the broad range of conditions seen precluded a meaningful statistical analysis. Further research into the relationship of vitamin D to specific otolaryngological presentations is required.

Depressed Serum 25-Hydroxyvitamin D Levels Increase Hospital Stay and Alter Glucose Homeostasis in First-ever Ischemic Stroke

2019 ◽  
Vol 16 (4) ◽  
pp. 340-347
Author(s):  
Yuge Wang ◽  
Yanqiang Wang ◽  
Bingjun Zhang ◽  
Yinyao Lin ◽  
Sha Tan ◽  
...  
Keyword(s):  
Vitamin D ◽  
Ischemic Stroke ◽  
Hospital Stay ◽  
Functional Outcome ◽  
Vitamin D Deficiency ◽  
Glucose Homeostasis ◽  
Clinical Severity ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Deficiency Group

Background and Objective: Vitamin D deficiency is internationally recognized among the potentially modifiable risk factors for ischemic cardio-cerebrovascular diseases. However, the association between vitamin D deficiency and stroke morbidity or mortality remains insufficiently known. Our aim is to investigate their relevance to 25-hydroxyvitamin D [25(OH) D] levels and clinical severity and outcome after 3 months in first-ever ischemic stroke. Methods: Retrospective analysis of 356 consecutive patients in first-ever ischemic stroke between 2013 and 2015. Serum 25(OH) D levels were measured at baseline. Stroke severity was assessed at admission using the National Institutes of Health Stroke Scale (NIHSS) score. Functional outcome after 3 months of onset was evaluated using the modified Rankin scale (mRS). Results: Among the 356 enrolled patients, HbA1c was higher in insufficiency/deficiency group than that in the sufficiency group (6.3 ± 1.7 vs. 5.9 ± 1.1, p =0.015). The hospital stay was longer in insufficiency/deficiency group than that in the sufficiency group (11 (8-17) vs. 9.5 (7-13), p = 0.035). There was a significant inversed trend between serum 25(OH) D levels and hospital stay (OR 0.960, P = 0.031), using logistic regression. Conclusions: 25(OH)D levels are associated with glucose homeostasis, 25(OH) D contributes to increase the length of hospital stay. Low serum 25-OHD level is an independent predictor for hospital stay in first-ever ischemic stroke. Vitamin D deficiency did not predict functional outcome in the span of 3 months.

scholarly journals Association of serum 25-hydroxyvitamin D with metabolic syndrome and type 2 diabetes: a one sample Mendelian randomization study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jing Xiao ◽  
Jingyi Lv ◽  
Shiyu Wang ◽  
Yang Zhou ◽  
Lunwen Chen ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Mendelian Randomization ◽  
Middle Aged ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Randomization Analysis

Abstract Background Vitamin D deficiency has been associated with type 2 diabetes (T2D) and metabolic syndrome (MS) and its components. However, it is unclear whether a low concentration of vitamin D is the cause or consequence of these health conditions. Thus, this study aimed to evaluate the association of vitamin D concentrations and its genetic risk scores (GRSs) with MS and its component diseases, such as T2D, in middle-aged and elderly participants from rural eastern China. Methods A subset of 2393 middle-aged and elderly individuals were selected from 70,458 participants of the Nantong Chronic Diseases Study of 2017–2018 in China. We used two 25-hydroxyvitamin D (25[OH]D) synthesis single-nucleotide polymorphisms (SNPs) (DHCR7-rs12785878 and CYP2R1-rs10741657) and two 25(OH) D metabolism SNPs (GC-rs2282679 and CYP24A1-rs6013897) for creating GRSs, which were used as instrumental variables to assess the effect of genetically lowered 25(OH) D concentrations on MS and T2D based on the Wald ratio. F statistics were used to validate that the four SNPs genetically determined 25(OH) D concentrations. Results Compared to vitamin D sufficient individuals, individuals with vitamin D insufficiency had an odds ratio (OR [95% confidence interval {CI}]) of MS of 1.30 (1.06–1.61) and of T2D of 1.32 (1.08–1.64), individuals with vitamin D deficiency had an ORs (95% CI) of MS of 1.50 (1.24–1.79) and of T2D of 1.47 (1.12–1.80), and those with vitamin D severe deficiency had an ORs (95% CI) of MS of 1.52 (1.29–1.85) and of T2D of 1.54 (1.27–1.85). Mendelian randomization analysis showed a 25-nmol/L decrease in genetically instrumented serum 25(OH) D concentrations using the two synthesis SNPs (DHCR7 and CYP2R1 genes) associated with the risk of T2D and abnormal diastolic blood pressure (DBP) with ORs of 1.10 (95%CI: 1.02–1.45) for T2D and 1.14 (95%CI: 1.03–1.43) for DBP. Conclusions This one sample Mendelian randomization analysis shows genetic evidence for a causal role of lower 25(OH) D concentrations in promoting of T2D and abnormal DBP in middle-aged and elderly participants from rural China.

Serum 25-Hydroxyvitamin D Concentrations and Cardiometabolic Biomarkers in Chinese Rural Population

2021 ◽  
Vol 53 (02) ◽  
pp. 105-111
Author(s):  
Dongdong Zhang ◽  
Cheng Cheng ◽  
Yan Wang ◽  
Yuan Xue ◽  
Yiming Liu ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Rural Population ◽  
Density Lipoprotein ◽  
Cubic Spline ◽  
Lipoprotein Cholesterol ◽  
Linear Regression Models ◽  
Hydroxyvitamin D ◽  
Linear Association ◽  
25 Hydroxyvitamin D

AbstractThere is a paucity of data on the relation between serum 25-hydroxyvitamin D [25(OH)D] concentration and cardiometabolic biomarkers in the Chinese population. To comprehensively and quantitatively examine the association of 25(OH)D and cardiometabolic traits, we conducted a cross-sectional study in the Chinese rural population. Serum 25(OH)D and eight cardiometabolic biomarkers were measured in 1714 individuals from Henan province, China. Scatter plot was used to visualize the distribution and correlation of 25(OH)D and cardiometabolic indicators. Moreover, multivariate linear regressions and restricted cubic spline (RCS) functions were performed to examine the quantitative association between the serum 25(OH)D and cardiometabolic parameters. The median serum 25(OH)D level was 19.94 ng/ml in all participants, with an estimated 50.12% presenting vitamin D deficiency. Serum 25(OH)D level showed significantly modest association with cardiometabolic parameters (p<0.05) except for diastolic blood pressure (r=0.03, p=0.22). Multiple linear regression models showed that 25(OH)D concentration was positively associated with high-density lipoprotein cholesterol (HDL-C) and negatively associated with low-density lipoprotein cholesterol (LDL-C) and fasting serum glucose (GLU). The results of restricted cubic spline models indicated a positively linear association of 25(OH)D with HDL-C (p for overall<0.001, p for nonlinearity=0.191) and a negatively linear association with GLU (p for overall=0.024, p for nonlinearity=0.095). Overall, vitamin D deficiency was very common among Chinese rural population living near the 34 degrees north latitude. Besides, there were significant association between 25(OH)D concentrations and cardiometabolic biomarkers including HDL-C and GLU levels. Future longitudinal studies and randomized trials are warranted to clarify the causal relationship.

scholarly journals Response of the 5′-flanking region of the human 25-hydroxyvitamin D 1α-hydroxylase gene to physiological stimuli using a transgenic mouse model

2005 ◽  
Vol 34 (1) ◽  
pp. 237-245 ◽  
Author(s):  
I Hendrix ◽  
P H Anderson ◽  
J L Omdahl ◽  
B K May ◽  
H A Morris
Keyword(s):  
Gene Expression ◽  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Transgenic Mouse ◽  
Reporter Gene ◽  
Dietary Calcium ◽  
Mrna Levels ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Flanking Region

The enzyme 25-hydroxyvitamin D 1α-hydroxylase, or CYP27B1, is the key enzyme in the two-step activation process of vitamin D to 1,25-dihydroxyvitamin D (1,25D). While a number of regulators of the renal CYP27B1 enzyme activity have been recognized for some years, their underlying molecular mechanisms remain largely unknown, and the DNA regions involved in the in vivo regulation of gene expression by these factors have not been delineated. We have generated a transgenic mouse line that expresses 1501 bp of 5′ flanking region together with 44 bp of 5′ untranslated region of the human CYP27B1 gene fused to the firefly luciferase reporter gene. Animals expressing the luciferase gene demonstrated that both luciferase protein and mRNA for CYP27B1 were localized to proximal convoluted tubule cells of the kidney. In 2-week-old animals, the expression of the transgene and the endogenous CYP27B1 mRNA levels in the kidney were highest and fell with increasing age. Both reporter gene expression and CYP27B1 mRNA levels were downregulated in response to increasing amounts of dietary calcium in a dose-dependent manner. Vitamin D deficiency resulted in an increase in both the reporter gene and CYP27B1 expression. Interestingly, the increase in CYP27B1 mRNA levels was substantially higher than the increase in reporter gene expression, suggesting either that there is a post-transcriptional mechanism that increases the amount of CYP27B1 mRNA or that other regulatory elements are required to maximize the effect of vitamin D deficiency. These findings demonstrate that the 1501 bp 5′ flanking region of the CYP27B1 gene directs expression to the proximal convoluted tubules of the kidney and is responsible for increasing transcriptional activity when dietary calcium and vitamin D levels are depleted. It also responds in the kidney to the physiological regulators of development and ageing.

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