Schedule of taking calcium supplement and the risk of nephrolithiasis.

What Was Tested

This randomized controlled trial looks at Calcium, Dietary.

Therefore, this study was performed to compare calcium bioavailability and the risk of calcium oxalate stone formation for calcium supplement taken with meal vs. taken at bedtime.

Activity product for calcium oxalate was determined to assess the risk of calcium oxalate stone formation.

Why It Was Studied

Variation in the timing of calcium supplement may affect gastrointestinal absorption of both calcium and oxalate differently and may associate with variable risk of calcium oxalate nephrolithiasis.

There are few human studies addressing specifically the appropriate time for taking calcium supplement.

Who Took Part

By PubMed's age tags, the people studied were adults, men only.

Thirty-two healthy male navy privates, 22.7 +/- 1.9 years old (mean +/- SD), who had normal renal function (serum creatinine less than 150 umol/L) and no history of renal stone, participated in the study.

The subjects were randomly allocated into two groups of 16 each.

How the Study Was Run

The design is described as randomized and crossover.

Random assignment meant chance, not the researchers, decided who got Calcium, Dietary and who got the comparison, which limits bias.

In the crossover set-up each of the participants took both Calcium, Dietary and the comparison in turn, acting as their own control.

The diet was controlled throughout the study.

Twenty-four-hour urine collections for the determination of urinary constituents were obtained at baseline and after taking both regimens of calcium supplement.

What Was Measured

Variation in the timing of calcium supplement may affect gastrointestinal absorption of both calcium and oxalate differently and may associate with variable risk of calcium oxalate nephrolithiasis.

Topics PubMed links to this paper include Biological Availability, Calcium, Calcium Oxalate, Calcium, Dietary, Citric Acid, Kidney Calculi and Oxalic Acid.

What This Means in Plain Language

The paper is a randomized and crossover study of Calcium, Dietary.

Its findings take up roughly 6 sentences of the abstract and are left out here on purpose; the source paper is the place to read them.

The publication is from 2004 (Kidney international), a journal based in United States.

More context: all human trials.