Hypertension, antihypertensive medication use, and breast cancer risk in the California Teachers Study cohort.
BACKGROUND
We investigated the association between hypertension, antihypertensive (AH) medication use, and breast cancer in a large prospective study, the California Teachers Study (CTS).


METHODS
Information on history of hypertension and lifetime regular use of AH medications was collected from 114,549 women in 1995-1996. Among them, 4,151 invasive breast cancers were diagnosed between 1995 and 2006. Additional information on AH use was collected from 73,742 women in 2000-2001, and 1,714 of these women were subsequently diagnosed with breast cancer. Cox proportional hazards regression was used to estimate relative risks (RR) and 95% confidence intervals (CI) for breast cancer.


RESULTS
Use of AH medication for ≥5 years, when compared with no use, was associated with a modest increased risk of invasive breast cancer (RR = 1.18, 95%CI 1.02-1.36). This increased risk appeared to be confined to estrogen receptor (ER)-positive tumors (RR = 1.21, 95%CI 1.03-1.43) and pre-/peri-menopausal women (RR = 1.58, 95%CI 1.11-2.25).


CONCLUSIONS
Increased risk of invasive breast cancer was observed for long-term (≥5 years) AH use, and this appeared to be confined to ER + breast cancer and younger women.
Largent
Joan A
JA
Department of Epidemiology, College of Health Sciences, University of California Irvine, Irvine, CA 92697-7555, USA. jlargent@uci.edu
Bernstein
Leslie
L
Horn-Ross
Pamela L
PL
Marshall
Sarah F
SF
Neuhausen
Susan
S
Reynolds
Peggy
P
Ursin
Giske
G
Zell
Jason A
JA
Ziogas
Argyrios
A
Anton-Culver
Hoda
H
D000328:Adult; D000367:Age Factors; D000368:Aged; D000959:Antihypertensive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000378:metabolism; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000188:drug therapy*; D008593:Menopause; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011960:Receptors, Estrogen / Q000378:metabolism; D012307:Risk Factors
D000959:Antihypertensive Agents; D011960:Receptors, Estrogen