Reproductive factors and breast cancer in New Zealand
Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand. International Journal of Cancer
(Impact Factor: 5.09).
04/1998; 76(2):182-8. DOI: 10.1002/(SICI)1097-0215(19980413)76:23.0.CO;2-T
A national population-based case-control study was used to assess the influence on breast cancer risk of reproductive factors and the possibility of an interaction with age at diagnosis. A total of 891 women aged 25 to 54 with a first diagnosis of breast cancer, and 1864 control subjects, randomly selected from the electoral rolls, were interviewed. There was a declining risk of breast cancer with increasing age at menarche (p = 0.06), the strongest effect being seen in women aged less than 40. Parous women had a 27% lower risk of breast cancer than nulliparous women, a reduced risk being evident in all but the youngest age group. A falling risk of breast cancer with rising parity was clear only in women diagnosed when aged at least 45 years. Breast cancer risk tended to fall amongst parous women with increasing duration of breastfeeding (p = 0.14); the association was most apparent in the youngest women, while those over 40 years at diagnosis showed no clear negative trend. There was no association of breast cancer risk with age at first full-term pregnancy, time since last full-term pregnancy, abortion (spontaneous or induced), abortion before first full-term pregnancy, or ability to conceive, and there was no trend in risk with age at natural menopause. Women in the highest category of body mass index at age 20 had the lowest risk of breast cancer in the age group studied. When each reproductive factor was formally tested for effect modification by age at diagnosis, the interaction term in logistic models approached statistical significance only for parity (p = 0.07).
Available from: Ali Montazeri
- "However, in the present study no association with parity emerged when multivariate analysis was performed. Evidence suggests that there is an interaction between marital status and parity , supporting a 'dual effect' of parity on breast cancer risk with pregnancy. Studies have shown that interactions between age, family history of breast cancer and parity might exist . "
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ABSTRACT: Iranian breast cancer patients are relatively younger than their Western counterparts. The objective of the present study was to investigate risk factors for breast cancer in Iranian women.
A case-control study was conducted from April 1997 to April 1998 in Tehran, Iran. Demographical data and risk factor related information were collected using a short structured questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived from logistic regression analysis.
In all, 286 women with breast cancer and 249 control women were interviewed. In multivariate analysis, only marital status (never married: OR 4.24, 95% CI 1.70-10.57 [P = 0.002]; widowed/divorced: OR 1.71, 95% CI 1.05-2.68 [P = 0.03]) and family history (positive family history of breast cancer: OR 2.95, 95% CI 1.15-7.59 [P = 0.02]) were associated with significantly increased risk for breast cancer.
The findings of the present study suggest that family history and marital status may have an impact on the incidence of breast cancer in Iranian women.
Available from: tobias-lib.ub.uni-tuebingen.de
Available from: acta.uta.fi
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