Effect of two kinds of different combined oral contraceptives use on bone mineral density in adolescent women.

BACKGROUND

Steroid hormonal contraceptives are highly effective and widely used. Most studies have shown a negative effect of combined oral contraceptives (COCs) on the bone mineral density (BMD) of adolescents. The study was conducted to compare BMD among users of ethinylestradiol/desogestrel, users of ethinylestradiol/cyproterone acetate and nonhormonal control subjects in women aged 16-18 years.

STUDY

DESIGN

The study included 450 women 16-18 years of age. One hundred fifty women were using ethinylestradiol/desogestrel, 150 women were using ethinylestradiol/cyproterone acetate, and 150 women were using nonhormonal contraception as control subjects. BMD ofthe lumbar spine and femoral neck was obtained using dual-energy X-ray absorptiometry, and mean BMD changes in COCs users and nonusers were compared.

RESULTS

At 24 months of treatment, lumbar spine and femoral neck mean BMD values in women (n=127) who used ethinylestradiol/desogestrel were slightly lower compared with baseline, but these effects did not reach statistical significance (p=.837 and p=.630, respectively). The mean lumbar spine and femoral neck BMD values in women (n=134) who used ethinylestradiol/cyproterone acetate were slightly higher compared with baseline, but there was no statistical significance (p=.789 and p=.756, respectively). The increases in mean percent change in lumbar spine and femoral neck BMD in the ethinylestradiol/cyproterone acetate group were less than those in the control group (1.88% vs. 0.30% and 0.98% vs. 0.49%, respectively). There were no significant differences in mean BMD of the lumbar spine and femoral neck between the users of ethinylestradiol/desogestrel or ethinylestradiol/cyproterone acetate and nonusers (p>.05).

CONCLUSION

Our study indicates that 2 years of COCs therapy had no significant effect on bone density in adolescents, but it remains unknown whether therapy longer than 2 years has a significant adverse effect on the attainment of peak bone mass.