Risk factors for breast cancer in a population with high incidence rates.
BACKGROUND
This report examines generally recognized breast cancer risk factors and years of residence in Marin County, California, an area with high breast cancer incidence and mortality rates.


METHODS
Eligible women who were residents of Marin County diagnosed with breast cancer in 1997-99 and women without breast cancer obtained through random digit dialing, frequency-matched by cases' age at diagnosis and ethnicity, participated in either full in-person or abbreviated telephone interviews.


RESULTS
In multivariate analyses, 285 cases were statistically significantly more likely than 286 controls to report being premenopausal, never to have used birth control pills, a lower highest lifetime body mass index, four or more mammograms in 1990-94, beginning drinking after the age of 21, on average drinking two or more drinks per day, the highest quartile of pack-years of cigarette smoking and having been raised in an organized religion. Cases and controls did not significantly differ with regard to having a first-degree relative with breast cancer, a history of benign breast biopsy, previous radiation treatment, age at menarche, parity, use of hormone replacement therapy, age of first living in Marin County, or total years lived in Marin County. Results for several factors differed for women aged under 50 years or 50 years and over.


CONCLUSIONS
Despite similar distributions of several known breast cancer risk factors, case-control differences in alcohol consumption suggest that risk in this high-risk population might be modifiable. Intensive study of this or other areas of similarly high incidence might reveal other important risk factors proximate to diagnosis.
Wrensch
Margaret
M
University of California, San Francisco, California, USA. wrensch@itsa.ucsf.edu
Chew
Terri
T
Farren
Georgianna
G
Barlow
Janice
J
Belli
Flavia
F
Clarke
Christina
C
Erdmann
Christine A
CA
Lee
Marion
M
Moghadassi
Michelle
M
Peskin-Mentzer
Roni
R
Quesenberry
Charles P
CP
Souders-Mason
Virginia
V
Spence
Linda
L
Suzuki
Marisa
M
Gould
Mary
M
D000428:Alcohol Drinking; D001943:Breast Neoplasms / Q000453:epidemiology*; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D015999:Multivariate Analysis; D012067:Religion; D012307:Risk Factors; D012907:Smoking; D012959:Socioeconomic Factors; D013997:Time Factors