PMID- 12160467
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20240314
IS  - 1472-6874 (Electronic)
IS  - 1472-6874 (Linking)
VI  - 2
IP  - 1
DP  - 2002 Aug 5
TI  - Oral contraceptive use before first birth and risk of breast cancer: a case 
      control study.
PG  - 9
AB  - BACKGROUND: The aim of this study was first, to investigate whether women 
      starting oral contraceptive (OC) use at a young age and before first birth have 
      an increased risk for breast cancer and second, to report difficulties 
      encountered in studying long-term health impacts of medical technologies. 
      METHODS: Breast cancers occurring up until 1997 among 37153 Helsinki students 
      born between 1946 and 1960 were identified by record linkage from the Finnish 
      Cancer Registry; for each cancer case, five age-matched random controls were 
      picked from the same student population. Those who had used the Helsinki Student 
      Health Service (HSHS) at least three times (150 cases and 316 controls) form the 
      final study subjects. Data on OC use and background characteristics were 
      collected from patient records, and data on live births were derived from the 
      population register. Odds ratios (OR) were adjusted for number of births, smoking 
      and sports activity. RESULTS: Compared to the few non-users, OC users had a 
      higher risk of breast cancer: the adjusted OR was 2.1 (95% confidence interval 
      1.1-4.2). Among OC users, no statistically significant differences in risk of 
      breast cancer were found in regard to starting age or first birth, but small 
      numbers made confidence intervals wide. Even though we had chosen students to be 
      our study group, the population turned out to be unsuitable to answer our 
      research question: most women had started their OC use old (at the age of 20 or 
      later) and there were very few unexposed (almost all had used OC and before their 
      first birth). CONCLUSIONS: Because adoption of the modern pattern of OC use was 
      not common among students, it is unlikely that the impact of early and extended 
      OC use can be studied before 2010, when women born in the 1960s are 40 to 50 
      years old.
FAU - Hemminki, Elina
AU  - Hemminki E
AD  - National Research and Development Center for Welfare and Health, Health Services 
      Research, Helsinki, Finland. elina.hemminki@stakes.fi
FAU - Luostarinen, Tapio
AU  - Luostarinen T
FAU - Pukkala, Eero
AU  - Pukkala E
FAU - Apter, Dan
AU  - Apter D
FAU - Hakulinen, Timo
AU  - Hakulinen T
LA  - eng
PT  - Journal Article
DEP - 20020805
PL  - England
TA  - BMC Womens Health
JT  - BMC women's health
JID - 101088690
PMC - PMC122097
EDAT- 2002/08/06 10:00
MHDA- 2002/08/06 10:01
PMCR- 2002/08/05
CRDT- 2002/08/06 10:00
PHST- 2002/01/30 00:00 [received]
PHST- 2002/08/05 00:00 [accepted]
PHST- 2002/08/06 10:00 [pubmed]
PHST- 2002/08/06 10:01 [medline]
PHST- 2002/08/06 10:00 [entrez]
PHST- 2002/08/05 00:00 [pmc-release]
AID - 1472-6874-2-9 [pii]
AID - 10.1186/1472-6874-2-9 [doi]
PST - epublish
SO  - BMC Womens Health. 2002 Aug 5;2(1):9. doi: 10.1186/1472-6874-2-9.