Reproductive factors and breast cancer: A case-control study in tertiary care hospital of North India

BACKGROUND: Clinical, animal, and epidemiological studies have clearly demonstrated that cancer is a hormonally mediated disease and several factors that influence hormonal status or are markers of change in hormonal status have been shown to be associated with the risk of breast cancer. AIMS: To identify the association of various reproductive factors with breast cancer. SETTINGS AND DESIGN: A hospital-based, matched, case-control study. MATERIALS AND METHODS: Three hundred and twenty newly diagnosed breast cancer cases and three hundred and twenty normal healthy individuals constituted the study population. The subjects in the control group were matched individually with the cases for their age +/- 2 years and socioeconomic status. A pre-tested, semi-structured questionnaire was administered to each individual to collect information on identification data, socio-demographic profile, and reproductive factors. STATISTICAL ANALYSIS USED: The Chi-square test and unpaired t-test were used. The conditional univariate logistic regression analysis (unadjusted odds ratio and confidence intervals) was used to calculate the significance level of each variable followed by multivariate regression analysis. RESULTS AND CONCLUSIONS: The cases had a lower mean age at menarche, higher age at marriage, higher mean age at last child birth, lower mean duration of breastfeeding, higher number of abortions, late age at menopause, history of oral contraceptive pills, and a family history of breast cancer as compared to the controls. The results of the present study revealed a strong association of reproductive factors with breast cancer in the Indian population.