The impact of oral contraceptive use on bone mineral density
M. Sojáková (1), J. Payer (2), M. Borovský(1), Z. Killinger (2), E.
Stenová (2), P. Hrúziková (2), P. Ondrejka (2)
First Department of Obstetrics and Gynaecology, Faculty of Medicine,
Comenius University, Bratislava, Slovak Republic (1); First Department of
Internal Medicine, Faculty of Medicine, Comenius University, Bratislava, Slovak
Republic (2)
Objectives: The aim of this pilot, cross-sectional study was to
determine the influence of oral contraceptives (OC) on bone mineral density (BMD)
in pre-menopausal women, to evaluate the relation between BMD and body mass
index, and to analyze the role of potential risk factors of osteoporosis in
women with normal and decreased BMD.
Design and Methods: Fifty healthy young pre-menopausal women enrolled
into the study were divided in two groups according to the use of OC pills.
Group A (N=30) had used OC formulations containing 30 µg ethinylestradiol for
more then two years. Group B (N=20) had never used OC pills. To be eligible
women have had no personal history of chronic diseases potentially affecting
bone metabolism. All subjects underwent BMD evaluation at lumbar spine (L1-L4)
and total femur using dual x-ray absorptiometry (Hologic, Delphi). Potential
risk factors of decreased BMD were determined by a detailed questionnaire and an
interview. Statistical evaluation employed Kruskal-Wallis analysis.
Results: There were no significant differences in age, weight, body
mass index, parity, smoking status, current calcium intake, personal and family
history of fractures, and the regular use of drugs influencing bone metabolisms
in both investigated groups. The mean age of women when they started using OC
was 20.6 (range 17–25) years and the mean duration of OC use ranged between 2–7
years. No significant differences in mean lumbar spine BMD and mean total femur
BMD were determined between women who never used OC and current users of OC
pills. The mean lumbar spine and total femur BMD values significantly paralleled
body mass index in both investigated groups (P .05). Although patients with
decreased BMD values did not differ with respect to use of OC pills, they were
less likely to be involved in regular physical activity in leisure time (P=
.04).
Conclusion: Use of OC pills containing 30 µg ethinylestradiol in
healthy young women did not influence BMD at lumbar spine and total femur. There
was a significant association between body mass index and BMD in both
investigated groups. A significant correlation was found between normal and
decreased BMD values and regular physical activity in leisure time irrespective
of the use of OC.
