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Oral contraceptive use and bone mineral density in premenopausal women: cross-sectional, population-based data from the Canadian Multicentre Osteoporosis Study

Prior JC et al., 2001

CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 165(8), 1023-1029

PMID 11699697 Source

Abstract

Background

Positive and negative effects on bone mineral density (BMD) have been described as a result of the premenopausal use of oral contraceptives (OCs); increased fracture rates have also been reported. This study assessed the relation between OC use and BMD in a population-based, 9-centre, national sample of women aged 25-45 years.

Methods

Premenopausal women who had been enrolled in the Canadian Multicentre Osteoporosis Study were classified as having ever been OC users (> or = 3 months) or as having never been OC users (0 to < 3 months). Data were obtained through extensive questionnaires and measuring of participants' weight, height and the BMD of lumbar vertebrae and the proximal femur.

Results

Of the sample of 524 women, whose mean age was 36.3 (standard deviation [SD] 5.9) years, 454 had used OCs; their mean age when they started using OCs was 19.8 (SD 3.5) years and the mean duration of use was 6.8 (SD 4.8) years. Women who had ever and those who had never used OCs showed no differences in age, age at menarche, parity, current calcium intake, exercise, body mass index (BMI), education, past irregular cycles or amenorrhea. OC users reported more alcohol and cigarette use and more use of medications to create regular cycles. Mean BMD values (adjusted for age, BMI and height) were 0.02-0.04 g/cm2 (that is, 2.3%-3.7%) lower in OC users, and were significantly lower in the spine and trochanter. The BMD of the spine in OC users was 1.03 (SD 0.12) g/cm2 versus 1.07 (SD 0.12) g/cm2 (95% confidence interval [CI] of difference -0.07 to -0.001) in those who had never used OCs. BMD was neither related to the duration of OC use nor to gynecological age at first use. Current and past users had similar BMD values. INTERPRETATION: National, population-based data show lower BMD values for the trochanter and spine in premenopausal women who have used OCs compared with those who have never used OCs.

Topics

Contraception/Comparison > Side Effects > Hormonal ContraceptionBone Health > Osteoporosis Risk > Risk Factors
oral contraceptives bone density premenopausal, birth control pill bone mineral density, hormonal contraception bone health effects, oral contraceptive use bmd loss, oc bone density spine hip, premenopausal bone loss birth control, contraceptive pill long term bone effects, oral contraceptive osteoporosis risk, bmd lower oral contraceptive users, hormonal contraception bone mineral density

Cite this article

Prior, J. C., Kirkland, S. A., Joseph, L., Kreiger, N., Murray, T. M., Hanley, D. A., Adachi, J. D., Vigna, Y. M., Berger, C., Blondeau, L., Jackson, S. A., & Tenenhouse, A. (2001). Oral contraceptive use and bone mineral density in premenopausal women: cross-sectional, population-based data from the Canadian Multicentre Osteoporosis Study. *CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne*, *165*(8), 1023-1029.

Keywords

Absorptiometry, Photon, Adult, Bone Density, Canada, Contraceptives, Oral, Cross-Sectional Studies, Female, Femur, Humans, Logistic Models, Lumbar Vertebrae, Middle Aged, Premenopause, Risk Factors, Surveys and Questionnaires

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