The Relative Influence of Calcium Intake and Vitamin D Status on Serum Parathyroid Hormone and Bone Turnover Biomarkers in a Double-Blind, Placebo-Controlled Parallel Group, Longitudinal Factorial Design

• Published in: The journal of clinical endocrinology and metabolism 2010-07, Vol.95 (7), p.3216-3224
• Main Authors: Aloia, John, Bojadzievski, Trajko, Yusupov, Eleanor, Shahzad, Ghulamullah, Pollack, Simcha, Mikhail, Mageda, Yeh, James
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Aged; Aged, 80 and over; Analysis of Variance; Biological and medical sciences; Biomarkers - blood; Bone Density - drug effects; Calcium - administration & dosage; Calcium - blood; Calcium - urine; Cholecalciferol - administration & dosage; Cholecalciferol - blood; Cholecalciferol - urine; Double-Blind Method; Endocrinopathies; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Humans; Longitudinal Studies; Male; Medical sciences; Middle Aged; Parathyroid Hormone - blood; Patient Selection; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2009-1294

Background: Adequate calcium and vitamin D are needed to maintain calcium balance. Objective: Our objective was to examine the influence of calcium intake and vitamin D exposure separately and their interaction on biomarkers of calcium sufficiency. Design: Healthy men and women, age 20–80 yr, were randomly allocated to four groups: 1) double placebo, 2) calcium (1200 mg daily) plus placebo, 3) vitamin D3 (100 μg) plus placebo, and 4) vitamin D3 and calcium. Fasting serum and urine as well as serum and urine 2 h after a calcium load (600 mg of calcium carbonate) were obtained at baseline and 3 months. Results: Ninety-nine participants were randomized; 78 completed the study. Baseline demographics, protein intake and laboratory studies did not differ among the four groups. Study medication compliance was 90%. Fasting bone turnover markers declined after 3 months only in the two groups given calcium supplements and increased in the vitamin D3 plus placebo calcium group. The calcium load resulted in a decrease in PTH and in bone turnover markers that did not differ among groups. Urinary calcium excretion increased in the combined group. Mean serum 25-hydroxyvitamin D increased from a baseline of 67 (18 sd) nmol/liter to 111 (30 sd) nmol/liter after vitamin D supplementation. Conclusion: Increased habitual calcium intake lowered markers of bone turnover. Acute ingestion of a calcium load lowered PTH and bone turnover markers. Additional intake of 100 μg/d vitamin D3 did not lower PTH or markers of bone turnover. Calcium supplementation lowers markers of bone turnover whereas vitamin D supplementation is without effect.