Risk factors for early age at breast cancer onset : The COSA program population-based study

• Published in: Anticancer research Vol. 27; no. 2; pp. 1087 - 1094
• Main Authors: DELORT, Laetitia, KWIATKOWSKI, Fabrice, CHALABI, Nasséra, SATIH, Samir, BIGNON, Yves-Jean, BERNARD-GALLON, Dominique J
• Format: Journal Article
• Language: English
• Published: Attiki International Institute of Anticancer Research 01.03.2007
• Subjects: Adult; Aged; Analysis of Variance; Anthropometry; Biological and medical sciences; Breast Neoplasms - epidemiology; Breast Neoplasms - etiology; Female; France - epidemiology; Gynecology. Andrology. Obstetrics; Humans; Mammary gland diseases; Medical sciences; Middle Aged; Multivariate Analysis; Reproduction; Risk Factors; Tumors; France; Human; risk factors; Program; Lactation; early onset; Oral administration; Breast cancer; Malignant tumor; Epidemiology; Mammary gland diseases; Cancerology; oral contraceptive use; Age of onset; Risk factor; Early; Contraceptive
• ISSN: 0250-7005; 1791-7530

Breast cancer is the most frequent cancer in women in western countries. A number of risk factors are now known, but the etiology of the disease is not fully understood. The aim of this study was to determine the effects of reproductive, anthropometric and environmental factors on cancer onset. 934 women who developed a non-hereditary breast cancer were recruited from different hospitals in the Auvergne region (France) and completed a questionnaire. The use of oral contraceptives (OC) increased the risk of early cancer development (odds ratio = 1.84, 95% confidence interval = 1.38-2.44). The age at first OC use appeared to be a major factor since the risk decreased when OC use was after the age of 23 years (odds ratio = 0.52, 95% confidence interval = 0.34-0.79). A duration of breast-feeding greater than 26 weeks decreased the risk of early cancer development (odds ratio = 0.62, 95% confidence interval = 0.39-0.97). No overall association was found with anthropometric or lifestyle factors and early age at breast cancer onset. OC use, age at first OC use and lactation were significantly associated with an early age at breast cancer onset. Thus, a number of "risk factors" could be considered as "early onset risk factors".