Birth Characteristics and Breast Cancer in Young Women
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Currently, only about 50% of breast cancer can be explained by known risk factors. Most of these risk factors are related to exposures to estrogens during adult life. Very little, however, is known about how factors experienced earlier in life affect later breast cancer risk. Recently, one line of inquiry has focused on the role that prenatal exposures to maternal estrogens may play in breast cancer etiology. These exposures, which occur during a period when breast tissue may be especially susceptible to environmental insults, can be several-fold higher than those experienced during normal non-pregnant adult life. Another burgeoning area of interest is the influence of socioeconomic status (SES) and geographic location on breast cancer risk. While both adult SES and geographic location are well-established predictors of breast cancer risk, they are not well understood. Similar to other known breast cancer risk factors, almost nothing is known about how these factors experienced during early life affect subsequent risk of breast cancer.
 
 
 
 
 
 
 
 This study aims to evaluate if certain birth characteristics that are considered to be markers for high levels of in utero estrogen exposures are related to breast cancer risk in young women. It also aims to investigate whether young women whose mothers were living in high SES areas at the time of their birth have a different breast cancer risk than women whose mothers were living in low SES areas. Finally, this study seeks to investigate whether there are geographic differences in breast cancer rates based on maternal residence at birth similar to those observed based on residence at diagnosis.
 
 
 
 
 
 
 
 All cases of invasive breast cancer diagnosed in California 1988-2002 among women born in California 1960 or later will be identified from the California Cancer Registry. Cases will be linked to their birth records and data on birth characteristics as well as maternal address at birth will be extracted from their birth records. Using historical U.S. Census data, neighborhood SES and region at birth will be assigned to all cases. The distribution of these factors among the cases will then be compared to two comparison groups (controls). One control group will consist of randomly selected females born in the same year as the cases. The other control group will consist of other non-hormonally and non-smoking related cancers diagnosed in California women of the same age as the cases. Statistical models will be used to see if any of these characteristics are more common among the breast cancer cases than among either control group.
 
 
 
 
 
 
 
 This study is the first of its kind to incorporate early life environmental factors such as SES and region of birth with a study of prenatal factors and breast cancer risk. Furthermore, the large and ethnically diverse California population will allow us to evaluate some of the more rare birth characteristics and to examine potentially different effects among different racial/ethnic groups.