title: Myocardial infarction and use of low-dose oral contraceptives: a pooled analysis of 2 US studies.
abstract: BACKGROUND
  Population-based case-control studies to assess the relationship of low-dose oral contraceptive (OC) use with myocardial infarction (MI) were performed at 2 sites in the United States (California and Washington state). The purpose of the present study was to estimate risk of MI in relation to use of low-dose OCs in a pooled analysis combining results from the 2 sites.
  
  
  RESULTS
  The study included as cases women aged 18 to 44 years with incident MI who had no prior history of ischemic heart disease or cerebrovascular disease. Women in the case and control groups were interviewed in person regarding OC use and cardiovascular risk factors. The analysis included 271 MI cases and 993 controls. Compared with noncurrent users, the adjusted pooled odds ratio for MI in current OC users was 0.94 (95% CI, 0.44, 2.20) after adjustment for major risk factors and sociodemographic factors. Compared with never users, the adjusted pooled odds ratio for MI was 0.56 (0.21, 1.49) in current OC users and 0.54 (0.31, 0.95) in past OC users. Among past OC users, duration and recency of use were unrelated to MI risk as was current hormone replacement therapy. There was no evidence of interaction between OC use and age, presence of cardiovascular risk factors (hypercholesterolemia, hypertension, diabetes), obesity, or smoking.
  
  
  CONCLUSIONS
  We conclude that low-dose OCs as used in these populations are safe with respect to risk of MI in women.
authors.affiliation: From the Division of Research, Kaiser Permanente Medical Care Program, Northern California, Oakland, CA 94611, USA. sxs@dor.kaiser.org
authors.forename: S
authors.initials: S
authors.lastname: Sidney
authors.forename: D S
authors.initials: DS
authors.lastname: Siscovick
authors.forename: D B
authors.initials: DB
authors.lastname: Petitti
authors.forename: S M
authors.initials: SM
authors.lastname: Schwartz
authors.forename: C P
authors.initials: CP
authors.lastname: Quesenberry
authors.forename: B M
authors.initials: BM
authors.lastname: Psaty
authors.forename: T E
authors.initials: TE
authors.lastname: Raghunathan
authors.forename: J
authors.initials: J
authors.lastname: Kelaghan
authors.forename: T D
authors.initials: TD
authors.lastname: Koepsell
mesh_terms: D000293:Adolescent; D000328:Adult; D003276:Contraceptives, Oral / Q000008:administration & dosage* / Q000009:adverse effects*; D003327:Coronary Disease / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D009203:Myocardial Infarction / Q000453:epidemiology*; D012307:Risk Factors
chemical_list: D003276:Contraceptives, Oral