['To determine the effect of oral contraceptive pill (OCP) use during adolescence on peak bone mass.', 'Longitudinal observational study.', 'Academic clinical research center.', "Sixty-two non-Hispanic, white females in The Penn State Young Women's Health Study, who were studied for 8 years during ages 12-20.", 'There were 28 OCP users, who used OCPs for a minimum of 6 months and were still using at age 20, and 34 nonusers who had never used OCPs.', 'Total body bone, dedicated hip bone, and body composition measurements were made by dual-energy roentgenogram absorptiometry.', 'The OCP users and nonusers did not differ at entry in anthropometric, body composition, or total body bone measurements. By age 20, the average duration of OCP use by the user group was 22 months. At age 20, the groups remained indistinguishable in anthropometric, body composition, total body, and hip bone measures, and in age of menarche and sports exercise scores.'] Does oral contraceptive use by teenage women affect peak bone mass : a longitudinal study?