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This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: clinchem.2004.043828v1 51/4/778    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Riedel, B. Articles by Schneede, J. Search for Related Content PubMed PubMed Citation Articles by Riedel, B. Articles by Schneede, J. Related Collections Nutrition Evidence Based Laboratory Medicine and Test Utilization

Effects of Oral Contraceptives and Hormone Replacement Therapy on Markers of Cobalamin Status

¹ Laboratory of Clinical Biochemistry, Section of Clinical Pharmacology, and² Department of Pediatrics, Haukeland University Hospital, Bergen, Norway;³ Locus for Homocysteine and Related Vitamins, University of Bergen, Bergen, Norway

^aaddress correspondence to this author at: Laboratory of Clinical Biochemistry, Section of Clinical Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway; fax 47-55-97-4605, e-mail bettina.marie.riedel@helse-bergen.no

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Low serum concentrations of vitamin B₁₂ (cobalamin) have been observed in users of oral contraceptives (OCs) (1), in women during pregnancy (2), and in men treated with high doses of ethinylestradiol for prostate cancer (3). Similar effects of hormone replacement therapy (HRT) have been noticed by some (4) but not all investigators (5).

Serum cobalamin has low diagnostic accuracy as a marker of vitamin B₁₂ status (6). Because of the long-term consequences of cobalamin deficiency [see Ref. (7) for a review], it is important to investigate whether decreased total cobalamin in OC or HRT users is associated with other evidence of impaired cobalamin status, such as increased plasma concentrations of methylmalonic acid (MMA) and total homocysteine (tHcy) and decreased plasma concentrations of holo-transcobalamin (holoTC) (8).

We performed a cross-sectional study on 264 female healthcare students and workers. All participants gave written informed consent, and the study was approved by the Regional Ethical Committee and by the Norwegian Social Science Data Services. Study groups were OC users (n = 54) and controls (n = 81; age range, 18–40 years) and HRT users (n = 51) and controls (n = 78; age range, 41–65 years). The most frequently used OCs were triphasic combination tablets containing the synthetic estrogen ethinylestradiol and the progestogens levonorgestrel or drospirenon [Trinordiol^TM (Wyeth-Lederle) or Trionetta^TM or Yasmin^TM (Schering AG)]. The most commonly used HRTs were either tibolone (Livial^TM; Organon) or the naturally occurring estradiol in combination with the progestogen noretisterone (Trisekvens^TM, Kliogest^TM, or Activelle^TM; Novo Nordisk A/S). We did not collect data on menstrual cycle or menopause. Detailed characteristics of the study population are given in Table 1 of the Data Supplement that accompanies the online version of . . . [Full Text of this Article]

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				D J. Bakker, L. T W de Jong-van den Berg, and M R. Fokkema Controlled study on folate status following folic acid supplementation and discontinuation in women of child-bearing age Ann Clin Biochem, May 1, 2009; 46(3): 231 - 234. [Abstract] [Full Text] [PDF]

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				H. Refsum, C. Johnston, A. B. Guttormsen, and E. Nexo Holotranscobalamin and Total Transcobalamin in Human Plasma: Determination, Determinants, and Reference Values in Healthy Adults Clin. Chem., January 1, 2006; 52(1): 129 - 137. [Abstract] [Full Text] [PDF]