Factors Influencing the Urinary Excretion of Calcium.  I. In Normal Persons1

Knapp, Elizabeth L.

doi:10.1172/jci101797

Cited by 160 publications

(61 citation statements)

References 15 publications

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“…In HV, the fractional intestinal absorption of phosphorus and calcium was, respectively, 65% and 20%. These figures are consistent with literature data [21,28,29,30,31]. In CKD patients, the fractional intestinal absorption of calcium was drastically decreased and amounted to less than 3% in patients with CKD stage 4.…”

Section: Discussionsupporting

confidence: 92%

Evidence in Favor of a Severely Impaired Net Intestinal Calcium Absorption in Patients with (Early-Stage) Chronic Kidney Disease

Viaene¹,

Meijers²,

Vanrenterghem³

et al. 2012

Am J Nephrol

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Introduction: Calcium and phosphorus are essential to many vital physiological processes. Little is known about the net and fractional intestinal absorption of calcium and phosphorus in patients with chronic kidney disease (CKD) and their clinical and hormonal determinants. Methods: Blood and 24-hour urine samples were collected in 20 healthy volunteers (HV) and 72 stable CKD stage 1–4 patients and analyzed for parameters of mineral metabolism including calcidiol, calcitriol, and parathyroid hormone (PTH). Dietary intake was assessed by dietary history. Results: The 24-hour urinary calcium excretion, as opposed to the phosphorus excretion, showed a stepwise decrease across CKD stages (median of 219, 84, 40, and 22 mg/day in HV and patients with CKD stages 1–2, 3 and 4, respectively). Younger age, high serum calcitriol, and high estimated GFR were associated with a high 24-hour urinary calcium excretion. High serum calcitriol levels and dietary phosphorus intake were associated with a high 24-hour urinary phosphorus excretion. The fractional intestinal calcium absorption, as estimated by the urinary-to-ingested calcium ratio, decreased across CKD stages. Conclusions: The 24-hour urinary excretion of calcium, as opposed to phosphorus, is markedly decreased in CKD, even in early-stage disease. This is partly explained by low calcitriol levels and older age. Assuming a neutral calcium balance at the time of urine collection, we infer that net intestinal calcium absorption may be severely impaired in CKD.

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Section: Discussionsupporting

confidence: 92%

Evidence in Favor of a Severely Impaired Net Intestinal Calcium Absorption in Patients with (Early-Stage) Chronic Kidney Disease

Viaene¹,

Meijers²,

Vanrenterghem³

et al. 2012

Am J Nephrol

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“…It is well documented that Ca intake is correlated with urinary Ca excretion in adults [19,20]. In this study a positive relationship between Ca intake and excretion was found (r = 0.29; p = 0.05).…”

Section: Discussionsupporting

confidence: 66%

Effects of Calcium and Phosphorus Intake and Excretion on Bone Density in Postmenopausal Women in Hermosillo, Mexico

Mendez‐Estrada¹,

Gomez²,

Lopez³

et al. 2002

Ann Nutr Metab

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Calcium (Ca) is important in bone formation and as aging progresses, bone loss gradually occurs. With the onset of menopause, reduced estrogen levels and insufficient Ca in the diet often create serious problems with fractures. Since little is known about the diet and other factors related to risk factors in postmenopausal women in northern Mexico, it was the objective of this study to determine the effects of dietary Ca and phosphorus (P) and their excretion, anthropometric measurements, and blood serum estradiol on bone density in women aged 45–63 years. No studies are available on the dietary intake of Ca and P and the effects on bone mineral density (BMD) in postmenopausal women in northern Mexico, so this study reports some of the first data on this population. Women with an average age of 55 years showed a positive relation of Ca intake and Ca excretion, however, dietary intake of Ca and P had no relation to bone density. Age, urinary Ca, Ca/creatinine and years of postmenopause had the highest negative correlation. Weight and body mass index had a positive correlation with BMD in the forearm and heel. Only 15% of the women met the recommendation of 1,500 mg/day of Ca. A high Ca/creatinine ratio has been proposed to indicate excess Ca excretion and subsequent bone density loss. Thirty-five percent of the women exceed the Ca/creatinine indicator of >0.16. In this study, 1% of the subjects were classified as osteoporotic and 37% as osteopenic.

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“…Urinary calcium is related to calcium intake but the relationship is not close [121]. It has been estimated that 2-7% of an increment in dietary calcium appears in the urine [175,180].…”

Section: Dietary Intake O F Sodium Calcium and Magnesiummentioning

confidence: 99%

The Hormonal and Non-Hormonal Control of Renal Excretion of Calcium and Magnesium

Massry¹,

Jw²

1973

Nephron

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This report reviews the various hormonal and non-hormonal factors involving the renal handling of calcium and magnesium and the effect of these factors on the relationship between the excretions of these divalent ions and that of sodium. Among the factors discussed are: (1) extracellular volume expansion, (2) renal vasodilatation, (3) changes in glomerular filtration rate, Parathyroid hormone (4) hypercalcemia and hypermagnesemia, (5) diuretics, (6) phosphate depletion and loading, (7) alterations in acid base balance, (8) diet, (9) fasting, (10) activity, (11) diurnal variation, and (12) various hormones including parathyroid hormone, calcitonin, vitamin D, growth hormone, thyroid hormone, and adrenal steroids.

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Factors Influencing the Urinary Excretion of Calcium. I. In Normal Persons1

Cited by 160 publications

References 15 publications

Evidence in Favor of a Severely Impaired Net Intestinal Calcium Absorption in Patients with (Early-Stage) Chronic Kidney Disease

Evidence in Favor of a Severely Impaired Net Intestinal Calcium Absorption in Patients with (Early-Stage) Chronic Kidney Disease

Effects of Calcium and Phosphorus Intake and Excretion on Bone Density in Postmenopausal Women in Hermosillo, Mexico

The Hormonal and Non-Hormonal Control of Renal Excretion of Calcium and Magnesium

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