Does Omeprazole Decrease Intestinal Calcium Absorption?

Condition(s) targeted: Osteoporosis; Achlorhydria; GERD; Hip Fracture

Intervention: Omeprazole (Drug)

Phase: Phase 4

Status: Active, not recruiting

Sponsored by: University of Wisconsin, Madison

Official(s) and/or principal investigator(s):
Karen E Hansen, MD, Principal Investigator, Affiliation: Univeristy of Wisconsin School of Medicine and Public Health

The purpose of this study is to measure the effect of omeprazole on intestinal calcium absorption in postmenopausal women. Because older adults frequently take PPI, it is critical to understand the impact of PPI therapy on calcium homeostasis. In this study, I hypothesize that PPI therapy does not alter intestinal calcium absorption in postmenopausal women.

Official title: Does Omeprazole Decrease Intestinal Calcium Absorption?

Study design: Other, Non-Randomized, Open Label, Single Group Assignment

Primary outcome: Change in intestinal calcium absorption after one month of omeprazole therapy

Secondary outcome: The change in bone resorption (urine n-telopeptide) after one month of omeprazole therapy and the month-to-month variability in intestinal calcium absorption.

Detailed description: Existing literature makes it unclear whether PPI therapy truly decreases intestinal calcium absorption. Up to 25 postmenopausal women will participate in this two-month study. The primary study outcome is the change in intestinal calcium absorption following omeprazole therapy. The secondary outcomes include the change in urine n-telopeptide, the month-to-month variability in intestinal calcium absorption and the establishment of a DNA bank for genetic studies of calcium homeostasis.

We will interview women and review their medical records to determine eligibility. Eligible subjects will undergo three GCRC studies. The first 2 studies will determine the monthly variation in calcium absorption, while the 3rd study will occur after taking 40 mg of omeprazole daily for 30 days. Women will present to the GCRC in the early morning and receive an oral and intravenous calcium tracer with breakfast. Over the next 24 hours, we will collect all urine for measurement of its calcium content. During the first or second GCRC stay, we will measure each subject's gastric pH by collecting gastric fluid from a temporary nasogastric tube. In consenting subjects we will collect one tube of blood, isolate its DNA and save it indefinitely within the locked GRECC Drezner Laboratory (5th Floor, VA Hospital) permitting future genetic studies related to calcium homeostasis.

Minimum age: N/A. Maximum age: N/A. Gender(s): Female.

Criteria:

Inclusion Criteria:

- Women at least 5 years past menopause, defined as the last date of menses

Exclusion Criteria:

- Allergy/Intolerance to orange juice

- Allergy/Intolerance to omeprazole or other PPI therapy

- Use of drugs that interact with omeprazole including oral anti-fungal agents,

coumadin, diazepam, phenytoin & tacrolimus

- Use of antacids, PPI or H2-blocker therapy within the past two months

- Intestinal conditions associated with malabsorption or low gastric acid levels

including Crohn's Disease, ulcerative colitis, pernicious anemia, bacterial overgrowth, celiac sprue, chronic diarrhea or use of antibiotics within the past month

- Known Stage 4 or 5 Chronic Kidney Disease, defined as an estimated GFR <30 cc/minute

- Use of medications known to interfere with calcium metabolism, including oral steroids

or anticonvulsants

University of Wisconsin Hospital and Clinics, Madison, Wisconsin 53792, United States

Related publications:

Jacobson BC, Ferris TG, Shea TL, Mahlis EM, Lee TH, Wang TC. Who is using chronic acid suppression therapy and why? Am J Gastroenterol. 2003 Jan;98(1):51-8.

Yang YX, Lewis JD, Epstein S, Metz DC. Long-term proton pump inhibitor therapy and risk of hip fracture. JAMA. 2006 Dec 27;296(24):2947-53.

Vestergaard P, Rejnmark L, Mosekilde L. Proton pump inhibitors, histamine H2 receptor antagonists, and other antacid medications and the risk of fracture. Calcif Tissue Int. 2006 Aug;79(2):76-83. Epub 2006 Aug 15.

Recker RR. Calcium absorption and achlorhydria. N Engl J Med. 1985 Jul 11;313(2):70-3.

Sheikh MS, Santa Ana CA, Nicar MJ, Schiller LR, Fordtran JS. Gastrointestinal absorption of calcium from milk and calcium salts. N Engl J Med. 1987 Aug 27;317(9):532-6.

Serfaty-Lacrosniere C, Wood RJ, Voytko D, Saltzman JR, Pedrosa M, Sepe TE, Russell RR. Hypochlorhydria from short-term omeprazole treatment does not inhibit intestinal absorption of calcium, phosphorus, magnesium or zinc from food in humans. J Am Coll Nutr. 1995 Aug;14(4):364-8.

Heaney RP, Recker RR, Stegman MR, Moy AJ. Calcium absorption in women: relationships to calcium intake, estrogen status, and age. J Bone Miner Res. 1989 Aug;4(4):469-75.

O'Connell MB, Madden DM, Murray AM, Heaney RP, Kerzner LJ. Effects of proton pump inhibitors on calcium carbonate absorption in women: a randomized crossover trial. Am J Med. 2005 Jul;118(7):778-81. No abstract available.

Kassarjian Z, Russell RM. Hypochlorhydria: a factor in nutrition. Annu Rev Nutr. 1989;9:271-85. Review. No abstract available.

Eastell R, Vieira NE, Yergey AL, Riggs BL. One-day test using stable isotopes to measure true fractional calcium absorption. J Bone Miner Res. 1989 Aug;4(4):463-8.

Abrams SA. Using stable isotopes to assess mineral absorption and utilization by children. Am J Clin Nutr. 1999 Dec;70(6):955-64. Review.

Ensrud KE, Duong T, Cauley JA, Heaney RP, Wolf RL, Harris E, Cummings SR. Low fractional calcium absorption increases the risk for hip fracture in women with low calcium intake. Study of Osteoporotic Fractures Research Group. Ann Intern Med. 2000 Mar 7;132(5):345-53.

Starting date: January 2008
Ending date: December 2008
Last updated: June 2, 2008