scholarly journals Effects of Above Average Summer Sun Exposure on Serum 25-Hydroxyvitamin D and Calcium Absorption

2002 ◽  
Vol 87 (11) ◽  
pp. 4952-4956 ◽  
Author(s):  
M. Janet Barger-Lux ◽  
Robert P. Heaney
Keyword(s):  
Calcium Absorption ◽  
Sun Exposure ◽  
Urinary Calcium ◽  
Seasonal Difference ◽  
Interquartile Range ◽  
Late Winter ◽  
Calcium Excretion ◽  
Creatinine Ratio ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D

Abstract The purpose of this study was to examine the effects of summer sun exposure on serum 25-hydroxyvitamin D [25(OH)D], calcium absorption fraction, and urinary calcium excretion. Subjects were 30 healthy men who had just completed a summer season of extended outdoor activity (e.g. landscaping, construction work, farming, or recreation). Twenty-six subjects completed both visits: after summer sun exposure and again approximately 175 d later, after winter sun deprivation. We characterized each subject’s sun exposure by locale, schedule, and usual attire. At both visits we measured serum 25(OH)D, fasting urinary calcium to creatinine ratio, and calcium absorption fraction. Median serum 25(OH)D decreased from 122 nmol/liter in late summer to 74 nmol/liter in late winter. The median seasonal difference of 49 nmol/liter (interquartile range, 29–67) was highly significant (P < 0.0001). However, we found only a trivial, nonsignificant seasonal difference in calcium absorption fraction and no change in fasting urinary calcium to creatinine ratio. Findings from earlier work indicate that our subjects’ sun exposure was equivalent in 25(OH)D production to extended oral dosing with 70 μg/d vitamin D3 (interquartile range, 41–96) or, equivalently, 2800 IU/d (interquartile range, 1640–3840). Despite this input, at the late winter visit, 25(OH)D was less than 50 nmol/liter in 3 subjects and less than 75 nmol/liter in 15 subjects.

scholarly journals Combined vitamin D and calcium supplementation in vitamin D inadequate patients with urolithiasis: Impact on hypercalciuria and de novo stone formation

2015 ◽  
Vol 9 (11-12) ◽  
pp. 403 ◽  
Author(s):  
Charles Hesswani ◽  
Yasser A Noureldin ◽  
Mohamed A Elkoushy ◽  
Sero Andonian
Keyword(s):  
Vitamin D ◽  
De Novo ◽  
Stone Formation ◽  
Calcium Supplementation ◽  
Urinary Calcium ◽  
Urinary Calcium Excretion ◽  
Calcium Excretion ◽  
Hydroxyvitamin D ◽  
History Of ◽  
25 Hydroxyvitamin D

<p><strong>ABSTRACT </strong></p><p><strong>Introduction</strong>: We examined the effect of combined vitamin D and calcium supplementation (VDCS) on urinary calcium excretion and de novo stone formation in vitamin D inadequate (VDI) urolithiasis patients.</p><p><strong>Methods</strong>: We retrospectively reviewed the data of VDI patients (serum 25-hydroxyvitamin D&lt;75 nmol/L) followed at a tertiary stone centre between September 2009 and December 2014. VDI patients with history of urolithiasis, who were placed on VDCS for abnormal bone mineral density or hyperoxaliuria, were included. Hypercalciuric patients and patients on thiazide diuretics were excluded. Metabolic stone workup and two 24-hour urine collections were performed before and after VDCS.</p><p><strong> Results</strong>: In total, we inculded 34 patients, with a mean age of 54.8 years and a mean body mass index of 25.7 kg/m2. After VDCS, there was a significant increase in the mean serum 25-hydroxyvitamin D (52.0 vs. 66.4 nmol/L, p&lt;0.001) and the mean urinary calcium excretion (3.80 vs. 5.64 mmol/d, p&lt;0.001). Eight (23.5%) patients developed de novo hypercalciuria. After a median follow-up of 39 (range: 7-60) months, 50% of hypercalciuric patients developed stones compared with 11.5% of non-hypercalciuric patients (p=0.038).</p><p><strong>Conclusion</strong>: This study showed a significant effect of combined VDCS on mean urinary calcium excretion, de novo hypercalciuria, and stone development in VDI patients with history of urolithiasis. Therefore, VDI urolithiasis patients receiving VDCS are advised to have monitoring with 24-hour urine collections and imaging studies. Although small, the sample size is good enough to validate the statistical outcomes. Prospective studies are needed to confirm these results.</p>

Seasonal Variation in Vitamin D Status in Elite Athletes: A Longitudinal Study

2017 ◽  
Vol 27 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Evelien Backx ◽  
Cindy van der Avoort ◽  
Michael Tieland ◽  
Kamiel Maase ◽  
Arie Kies ◽  
...  
Keyword(s):  
Vitamin D ◽  
Elite Athletes ◽  
Sun Exposure ◽  
Late Winter ◽  
Vitamin D Status ◽  
Seasonal Fluctuations ◽  
Hydroxyvitamin D ◽  
Vitamin D Intake ◽  
25 Hydroxyvitamin D ◽  
Insight Into

Studies monitoring vitamin D status in athletes are seldom conducted for a period of 12 months or longer, thereby lacking insight into seasonal fluctuations. The objective of the current study was to identify seasonal changes in total 25-hydroxyvitamin D (25(OH)D) concentration throughout the year. Fifty-two, mainly Caucasian athletes with a sufficient 25(OH)D concentration (>75 nmol/L) in June were included in this study. Serum 25(OH)D concentration was measured every three months (June, September, December, March, June). In addition, vitamin D intake and sun exposure were assessed by questionnaires at the same time points. Highest total 25(OH)D concentrations were found at the end of summer (113 ± 26 nmol/L), whereas lowest concentrations were observed at the end of winter (78 ± 30 nmol/L). Although all athletes had a sufficient 25(OH)D concentration at the start of the study, nearly 20% of the athletes were deficient (<50 nmol/L) in late winter.

scholarly journals Comparison of Vitamin D and 25-Hydroxyvitamin D Concentrations in Human Breast Milk between 1989 and 2016–2017

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 573
Author(s):  
Naoko Tsugawa ◽  
Mayu Nishino ◽  
Akiko Kuwabara ◽  
Honami Ogasawara ◽  
Maya Kamao ◽  
...  
Keyword(s):  
Vitamin D ◽  
Breast Milk ◽  
Sun Exposure ◽  
Stepwise Multiple Regression ◽  
Human Breast Milk ◽  
Vitamin D Status ◽  
Human Breast ◽  
Hydroxyvitamin D ◽  
Lactating Mothers ◽  
25 Hydroxyvitamin D

Background: Breast milk is considered the optimal source of nutrition during infancy. Although the vitamin D concentration in human breast milk is generally considered poor for infants, vitamin D in breast milk is an important source for exclusively breastfed infants. Increases in vitamin D insufficiency and deficiency in lactating mothers may reduce vitamin D concentrations in breast milk. This study aimed to compare vitamin D and 25-hydroxyvitamin D (25OHD) concentrations in breast milk collected in 1989 and 2016–2017 and simultaneously analyze them with liquid chromatography-tandem mass spectrometry (LC-MS/MS); the association between the lifestyle of recent lactating mothers (2016–2017) and vitamin D status in human breast milk was also evaluated. Method: Lactating mothers were recruited from three regions of Japan in 1989 (n = 72) and 2016–2017 (n = 90), and milk from 3–4 months was collected in summer and winter. The samples were strictly sealed and stored at −80℃ until measurement. Breast milk vitamin D and 25OHD concentrations were analyzed by LC-MS/MS. Vitamin D intake, sun exposure, and sunscreen use of the lactating mothers in 2016–2017 were assessed. Results: Both vitamin D and 25OHD concentrations in breast milk were higher in the summer regardless of the survey year. Significantly lower vitamin D and 25OHD concentrations were observed in 2016–2017 compared with 1989 in summer, but no survey year difference was observed in winter. The stepwise multiple regression analyses identified season, daily outdoor activity, and suntan in the last 12 months as independent factors associated with vitamin D3 concentrations. Conclusion: The results suggest that low vitamin D status in recent lactating mothers may have decreased vitamin D and 25OHD concentrations in breast milk compared with the 1980s. These results are helpful for developing public health strategies to improve vitamin D status in lactating mothers and infants.

Adolescents with anorexia nervosa have decreased calcium absorption and increased urinary calcium excretion

1991 ◽  
Vol 12 (2) ◽  
pp. 171
Author(s):  
Steven A. Abrams ◽  
Tomas J. Silber ◽  
Nora V. Esteban ◽  
Nancy E. Vieira ◽  
Mansoud Majd ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Calcium Absorption ◽  
Urinary Calcium ◽  
Urinary Calcium Excretion ◽  
Calcium Excretion

Hematuria and Hypercalciuria in Children With Diabetes Mellitus

PEDIATRICS ◽  
1987 ◽  
Vol 79 (5) ◽  
pp. 756-759
Author(s):  
John I. Malone ◽  
Saul Lowitt ◽  
John A. Duncan ◽  
Shirish C. Shah
Keyword(s):  
Diabetes Mellitus ◽  
Type I Diabetes ◽  
Large Population ◽  
Unknown Origin ◽  
Urinary Calcium ◽  
Calcium Excretion ◽  
Type I ◽  
Creatinine Ratio ◽  
Diabetic Children ◽  
Nondiabetic Control

Hematuria of unknown origin occurs in 30% of patients with diabetic nephropathy. In nondiabetic persons, hematuria may be caused by hypercalciuria with or without nephrolithiasis. Eight children with type I diabetes mellitus, hematuria, and hypercalciuria were observed in our clinic during a 1-year period. Two of these also had evidence of renal papillary necrosis. To assess the importance of hypercalciuria in the pathogenesis of hematuria in children with diabetes mellitus, we measured urinary calcium excretion in a large population of such patients. The calcium to creatinine ratio in the urine of diabetic children (0.21 ± 0.01) was greater than that of nondiabetic children (0.12 ± 0.01). A calcium to creatinine ratio of 0.28 was established as the upper limit of normal in our nondiabetic population, and 27% of the diabetic children were hypercalciuric on this basis. The diabetic children with hypercalciuria also had hyperphosphaturia and a urinary CaHPO4.2H2O molar ion product three times that found in the nondiabetic control population. These data suggest that many children with diabetes are at risk for renal damage due to hypercalciuria. Because hypercalciuria is more common in diabetic than nondiabetic children, it may play a previously unrecognized role in the renal disease associated with diabetes mellitus.

Effect of alcohol ingestion on bone and mineral metabolism in rats

1980 ◽  
Vol 238 (6) ◽  
pp. E507-E510 ◽  
Author(s):  
D. T. Baran ◽  
S. L. Teitelbaum ◽  
M. A. Bergfeld ◽  
G. Parker ◽  
E. M. Cruvant ◽  
...  
Keyword(s):  
Mineral Metabolism ◽  
Serum Levels ◽  
Urinary Calcium ◽  
Alcohol Ingestion ◽  
Ethanol Administration ◽  
Calcium Excretion ◽  
Hydroxyvitamin D ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Circulating Levels

Chronic ethanol administration to growing rats for 56 days resulted in circulating levels of 140 mg/dl, approximating concentrations that characterize alcoholic intoxication in man. This degree of alcohol ingestion, although without gross or histological effect on the liver or testicles, was attended by decreased trabecular bone volume despite a normal rate of skeletal mineralization as measured by time-spaced tetracycline labeling. Concomitant serum levels of calcium, phosphate, magnesium, creatinine, glutamic oxalacetic transaminase, alkaline phosphatase, testosterone, and 25-hydroxyvitamin D were normal. Although alcohol treatment was associated with a significant decrease in urinary calcium excretion, it had no effect on phosphate excretion nor on its renal tubular reabsorption. The data reveal that circulating levels of alcohol that do not result in hepatic or testicular injury are toxic for bone.

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