Theory, methods, and operational results of the Young Women's Health History Study: a study of young-onset breast cancer incidence in Black and White women.
PURPOSE
The etiology of young-onset breast cancer (BC) is poorly understood, despite its greater likelihood of being hormone receptor-negative with a worse prognosis and persistent racial and socioeconomic inequities. We conducted a population-based case-control study of BC among young Black and White women and here discuss the theory that informed our study, exposures collected, study methods, and operational results.


METHODS
Cases were non-Hispanic Black (NHB) and White (NHW) women age 20-49 years with invasive BC in metropolitan Detroit and Los Angeles County SEER registries 2010-2015. Controls were identified through area-based sampling from the U.S. census and frequency matched to cases on study site, race, and age. An eco-social theory of health informed life-course exposures collected from in-person interviews, including socioeconomic, reproductive, and energy balance factors. Measured anthropometry, blood (or saliva), and among cases SEER tumor characteristics and tumor tissue (from a subset of cases) were also collected.


RESULTS
Of 5,309 identified potentially eligible cases, 2,720 sampled participants were screened and 1,812 completed interviews (682 NHB, 1140 NHW; response rate (RR): 60%). Of 24,612 sampled control households 18,612 were rostered, 2,716 participants were sampled and screened, and 1,381 completed interviews (665 NHB, 716 NHW; RR: 53%). Ninety-nine% of participants completed the main interview, 82% provided blood or saliva (75% blood only), and SEER tumor characteristics (including ER, PR and HER2 status) were obtained from 96% of cases.


CONCLUSIONS
Results from the successfully established YWHHS should expand our understanding of young-onset BC etiology overall and by tumor type and identify sources of racial and socioeconomic inequities in BC.
['Velie|Ellen M|EM|http://orcid.org/0000-0001-6865-9715', 'Marcus|Lydia R|LR|http://orcid.org/0000-0003-3748-5921', 'Pathak|Dorothy R|DR|http://orcid.org/0000-0002-5318-3985', 'Hamilton|Ann S|AS|', 'DiGaetano|Ralph|R|', 'Klinger|Ron|R|', 'Gollapudi|Bibi|B|', 'Houang|Richard|R|', 'Carnegie|Nicole|N|', 'Olson|L Karl|LK|', 'Allen|Amani|A|', 'Zhang|Zhenzhen|Z|', 'Modjesk|Denise|D|', 'Norman|Gwendolyn|G|', 'Lucas|Darek R|DR|', 'Gupta|Sapna|S|', 'Rui|Hallgeir|H|', 'Schwartz|Kendra|K|']
D000328:Adult D001741:African Americans D001943:Breast Neoplasms D016022:Case-Control Studies D005260:Female D006801:Humans D015994:Incidence D008875:Middle Aged D044465:Whites D055815:Young Adult
Young-onset breast cancer Breast cancer Life-course Epidemiology Health status disparities Premenopause