Oral contraceptive use and risk of fractures.
BACKGROUND
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.


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.


CONCLUSIONS
Oral contraceptives are not associated with an increase or a decrease in fracture risk. Any change in fracture risk may be due to confounders.
Vestergaard
Peter
P
Department of Endocrinology and Metabolism C, Aarhus University Hospital, Aarhus Amtssygehus, DK-8000 Aarhus, Denmark. p-vest@post4.tele.dk
Rejnmark
Lars
L
Mosekilde
Leif
L
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D003276:Contraceptives, Oral / Q000009:adverse effects*; D003718:Denmark / Q000453:epidemiology; D005260:Female; D050723:Fractures, Bone / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors
D003276:Contraceptives, Oral