DECREASED BONE TURNOVER IN ORAL-CONTRACEPTIVE USERS

Citation
P. Garnero et al., DECREASED BONE TURNOVER IN ORAL-CONTRACEPTIVE USERS, Bone, 16(5), 1995, pp. 499-503
Citations number
39
Categorie Soggetti
Endocrynology & Metabolism
Journal title
BoneACNP
ISSN journal
87563282
Volume
16
Issue
5
Year of publication
1995
Pages
499 - 503
Database
ISI
SICI code
8756-3282(1995)16:5<499:DBTIOU>2.0.ZU;2-Y
Abstract
The objective of this study was to determine the effect of oral contra ceptive pills on bone turnover. The design consisted of a cross-sectio nal analysis of a prospective cohort. There were 52 women taking oral contraceptives and 156 nonuser controls from a large cohort of 1039 he althy women, aged 31-89 years (OFELY study). Most users were taking co mbined oral contraceptives containing 30 mu g ethinyl estradiol and th e mean duration of pill use was 6.7 +/- 6.4 years, Users and nonusers were matched for age [mean age (years): 39.3 +/- 3.5 vs. 40.5 +/- 4.3, range 35-49 years for both]. Main outcome measures included three mar kers of bone formation (serum osteocalcin, bone-specific alkaline phos phatase, and C-terminal propeptide of type I collagen) and two markers of bone resorption that are pyridinoline crosslinked peptides (Crossl aps(TM) and NTX), Users and nonusers did not differ for weight, height , alcohol and tobacco use, dietary calcium intake, parity, exercise ac tivity, body fat and lean composition, and calcium chemistry tests. In pill users all bone formation and resorption markers were decreased c ompared with controls: osteocalcin, 7.7 +/- 2.7 vs. 10.1 +/- 3.1 ng/mL (-24%, p < 0.001); bone-specific alkaline phosphatase, 7.5 +/- 2.3 vs . 8.8 +/- 2.7 ng/mL (-15%, p < 0.003); C-terminal propeptide of type I collagen, 77.2 +/- 93.1 vs. 93.1 +/- 31.9 ng/mL (-17%, p = 0.001); Cr osslaps(TM): 175 +/- 91 vs. 211 +/- 105 mu g/mmol Cr (-17%, p = 0.03); and NTX, 16.2 +/- 5.8 vs. 22.5 +/- 9.4 nmol of bone collagen equivale nt/mmol Cr (-28%, p < 0.001). There was no significant difference in w hole body BMC and BMD, lumbar spine, total hip, and distal radius BMD between oral contraceptive users and controls. Oral contraception is a ssociated with a moderate, but significant, decrease in bone turnover that may have a beneficial influence on bone mass only after prolonged use. However, given the large interindividual variability of bone mes s, such an effect could not be established by this cross-sectional stu dy and a longitudinal design is required.