The effect of oral contraceptives on lumbar bone density in premenopausal women.

The lumbar spine bone mineral densities of 15 premenopausal females ranging in age from 20-35 years and taking oral dosages of 50 mcg or less of estrogen were measured using dual photon absorptiometry bone scans. A group of 15 women who had never taken oral contraceptives (OCs) matched for age weight and height were also scanned and served as controls. All subjects completed a medical questionnaire regarding menstrual history dietary habits physical activity and family history of bone disease. Review of dietary histories revealed that all participants maintained good dietary habits with adequate intake of vitamins minerals and nutrients. There was no difference in the reported caloric intake or physical activity levels between the 2 groups. Analysis of the bone mineral data revealed that there were no significant differences in the lumbar bone mineral content central density or bone mineral density measurements between the OC user and the control group. There were also no differences in the house mineral data based upon whether or not the subject supplemented her diet with calcium. In this group of women studied the duration of OC use (up to 84 months) did not appear to have a significant measurable effect upon the bone mineral density parameters. (authors)