Oral contraceptive use and risk of fractures

Introduction: Prior studies have suggested that oral contraceptives (OCs) may be associated with an increased fracture risk. However, the previous studies have only performed a limited adjustment for other potential risk factors. Subjects and Methods: All women with a fracture (n=64,548) in the year 2000 in Denmark served as cases. For each case, three age-matched controls were randomly drawn from the general population (n = 193,641). Exposure was use of OCs between January 1, 1996, and December 31, 2000. Adjustments were made for use of other drugs, pregnancy, prior fracture, other diseases and social variables. Results: In the unadjusted analysis, use of OCs in low dose was associated with a small increase in overall fracture risk. However, upon adjustment, no increase in fracture risk could be demonstrated in any age or dose group. Conclusion: Oral contraceptives are not associated with an increase or a decrease in fracture risk. Any change in fracture risk may be due to confounders. (c) 2006 Elsevier Inc. All rights reserved.