AGE AT MENOPAUSE AND BREAST-CANCER - ESTIMATION OF FLOATING ABSOLUTE RISKS

Citation
C. Braga et al., AGE AT MENOPAUSE AND BREAST-CANCER - ESTIMATION OF FLOATING ABSOLUTE RISKS, Breast, 7(1), 1998, pp. 27-32
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oncology,"Obsetric & Gynecology
Journal title
BreastACNP
ISSN journal
0960-9776
Volume
7
Issue
1
Year of publication
1998
Pages
27 - 32
Database
ISI
SICI code
0960-9776(1998)7:1<27:AAMAB->2.0.ZU;2-S
Abstract
Late menopause is consistently related to breast cancer risk, but dire ct comparison of the modifying effects of type of menopause and of tim e factors across studies has been made difficult by the heterogeneity in the choice of the reference category, and in the definition of post menopausal status. These effects were investigated in the absence of a n arbitrary baseline category by computing floating absolute risks (FA Rs). Pooled data from two case-control studies conducted between 1983 and 1994 in major teaching and general hospitals of six Italian centre s were used. Participants were 3576 postmenopausal women with incident , histologically confirmed breast cancer: and 3578 postmenopausal cont rols admitted to hospital for acute, non-neoplastic, non-hormonal, non -gynaecological conditions. When all types of menopause were considere d together, FARs were 0.49 for <35 years, 0.81 for 35-39 years, 0.82 f or 40-44 years, 0.88 for 45-47 years, 1.02 for 48-50 years, 1.23 for 5 1-53 years and 1.24 for 54-56 years, with a significant linear trend. The same pattern was seen in women reporting a natural menopause, with FAR of 0.14 for women with menopause when aged <35 years versus 1.20 for those with menopause at 54-56 years (ratio between extreme FAR est imates = 8.6). No trend emerged in the overall surgical menopause grou p (including hysterectomy alone or with monolateral oophorectomy, and bilateral oophorectomy). However, when women reporting a bilateral oop horectomy were selected, a significant linear trend was observed. No h eterogeneity emerged when risks were evaluated in strata of age at dia gnosis/interview. Thus, using a unique large dataset and an innovative method of analysis, this study documented an over 8-fold ratio of ris ks between extreme categories of age at menopause, but no evidence of a latency period before the establishment of an effect of age at menop ause.