Objective-With 2.3 million breast cancer survivors in the U.S. today, identification of modifiable factors associated with breast cancer recurrence and survival is increasingly important. Only recently new studies have been designed to examine the impact of lifestyle factors on prognosis, including Pathways, a prospective study of women with breast cancer in Kaiser Permanente Northern California (KPNC).Methods-Pathways aims to examine the effect on recurrence and survival of 1) lifestyle factors such as diet, physical activity, quality of life, and use of alternative therapies and 2) molecular factors such as genetic polymorphisms involved in metabolism of chemotherapeutic agents. Eligibility includes any woman diagnosed with invasive breast cancer within KPNC, no previous diagnosis of other invasive cancer, age 21 years or older, and ability to speak English, Spanish, Cantonese, or Mandarin. Newly-diagnosed patients are identified daily from electronic pathology records and are enrolled within two months of diagnosis. An extensive baseline interview is conducted, blood and saliva samples are collected, and body measurements are taken. Women are followed for lifestyle updates, treatment, and outcomes by self-report and query of KPNC databases.Results-Recruitment began in January 9, 2006, and as of January 16, 2008, 1,539 women have been enrolled along with collection of 1,323 blood samples (86%) and 1,398 saliva samples (91%). Conclusions-ThePathways Study will become a rich resource to examine behavioral and molecular factors and breast cancer prognosis.

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Background: Breast cancer has a complex etiology that includes genetic, biologic, behavioral, environmental, and social factors. Etiologic factors are frequently studied in isolation with adjustment for confounding, mediating, and moderating effects of other factors. A complex systems model approach may present a more comprehensive picture of the multifactorial etiology of breast cancer.Methods: We took a transdisciplinary approach with experts from relevant fields to develop a conceptual model of the etiology of postmenopausal breast cancer. The model incorporated evidence of both the strength of association and the quality of the evidence. We operationalized this conceptual model through a mathematical simulation model with a subset of variables, namely, age, race/ethnicity, age at menarche, age at first birth, age at menopause, obesity, alcohol consumption, income, tobacco use, use of hormone therapy (HT), and BRCA1/2 genotype.Results: In simulating incidence for California in 2000, the separate impact of individual variables was modest, but reduction in HT, increase in the age at menarche, and to a lesser extent reduction in excess BMI >30 kg/m 2 were more substantial.

Objective To examine the association of breastfeeding or its duration with timing of girls’ pubertal onset, and the role of BMI as a mediator in these associations. Methods A population of 1,237 socio-economically and ethnically diverse girls, ages 6–8 years, was recruited across three geographic locations (New York City, Cincinnati, and the San Francisco Bay Area) in a prospective study of predictors of pubertal maturation. Breastfeeding practices were assessed using self-administered questionnaire/interview with the primary caregiver. Girls were seen on at least annual basis to assess breast and pubic hair development. The association of breastfeeding with pubertal timing was estimated using parametric survival analysis while adjusting for body mass index, ethnicity, birth-weight, mother’s education, mother’s menarcheal age, and family income. Results Compared to formula fed girls, those who were mixed-fed or predominantly breastfed showed later onset of breast development (Hazard Ratios 0.90 [95% CI, 0.75–1.09] and 0.74 [95% CI, 0.59–0.94], respectively). Duration of breastfeeding was also directly associated with age at onset of breast development (p trend = 0.008). Associations between breastfeeding and pubic hair onset were not significant. In stratified analysis, the association of breastfeeding and later breast onset was seen in Cincinnati girls only. Conclusion The association between breast feeding and pubertal onset varied by study site. More research is needed about the environments within which breastfeeding takes place in order to better understand whether infant feeding practices are a potentially modifiable risk factor that may influence age at onset of breast development and subsequent risk for disease in adulthood.

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