Effect of two combinations of low-dose oral contraceptives on adolescent bone mass: A clinical trial with 2 years follow-up.

INTRODUCTION

Most contraceptive combinations can interfere with the processes of bone formation and resorption.

AIM: The aim of this study was to evaluate the effect of 2 combinations of low-dose oral hormonal contraceptives (20 µg ethinyl estradiol [EE]/150 mg desogestrel [COC1] or 30 µg EE/3 mg drospirenone [COC2]) on bone mass acquisition in adolescents over 2 years by means of bone densitometry and measurement of biomarkers of bone remodeling.

METHODS

Parallel-group, non-randomized controlled clinical trial of 127 adolescents divided into a control group and 2 groups receiving either COC1 or COC2. The participants were submitted to anthropometric assessment and evaluation of secondary sexual characteristics (Tanner criteria) and bone age. Bone densitometry by dual-energy X-ray absorptiometry and measurement of bone biomarkers (bone alkaline phosphatase, osteocalcin, and C-terminal telopeptide) were performed at baseline and after 24 months.

RESULTS

No significant differences in the variables analyzed were observed between COC1 or COC2 users and the control group at baseline. After 24 months, non-users had incorporated more bone mass (content and density) than either group of contraceptive users. This negative impact was more pronounced in the COC2 group than in the COC1 group. A significant reduction in the percentage values of bone alkaline phosphatase and osteocalcin was observed in users of oral contraceptives.

CONCLUSION

Bone mass acquisition was compromised in adolescent users of combined hormonal contraceptives. The negative impact was more pronounced in adolescents using contraceptives that contain 30 µg EE/3 mg drospirenone.