Oral Contraceptives and Bone Mineral Density

In a recent study of adolescent females with anorexia nervosa (AN) or eating disorder not otherwise specified (EDNOS), use of oral contraceptives did not have a significant effect on lumbosacral spine or hip bone mineral density (J Adolesc Health 2006;39:819).

Dr. G.R. Strokosh and colleagues designed a randomized, double-blind, placebo-controlled study of 112 females 11 to 17 years of age with EDNOS or AN to determine if oral contraceptives could affect bone mineral density. The girls were randomized equally to treatment with a triphasic oral contraceptive containing norgestimate, 180-250 mcg (NGM group) or to treatment with ethinyl estradiol, 35 mcg (EE group), or to a placebo. At the end of the 6th cycle of treatment, there was a significant increase in the mean BMD of the lumbosacral spine in the NGM/EE group compared with placebo; however, by the 13th cycle, the difference was no longer significant. There was no significant difference in change in hip BMD among the three groups.