Relation between use of antihypertensive medications and risk of breast carcinoma among women ages 65-79 years.

BACKGROUND

Limited data are available regarding the incidence of breast carcinoma among users of relatively recently introduced forms of antihypertensive therapy. Although it has been suggested that women who have taken calcium channel blockers (CCBs) have an increased risk and that women who have taken angiotensin-I-converting enzyme (ACE) inhibitors have a decreased risk, currently, no conclusions can be drawn.

METHODS

A population-based case-control study of women ages 65-79 years was conducted in western Washington State. The responses of 975 women who were diagnosed with invasive breast carcinoma during 1997-1999 were compared with the responses of 1007 women in a control group. Associations between use of different types of antihypertensive medications and breast carcinoma incidence were evaluated using logistic regression.

RESULTS

Overall, women who had ever used CCBs, beta-blockers, or ACE inhibitors did not have an altered risk of breast carcinoma relative to women who had never used antihypertensive medications. Although the use of immediate-release CCBs, thiazide diuretics, and potassium-sparing diuretics was associated with modestly increased risks of breast carcinoma (odds ratio [OR], 1.5; 95% confidence interval [95% CI], 1.0-2.1; OR, 1.4; 95% CI, 1.1-1.8; and OR, 1.6; 95% CI, 1.2-2.1, respectively), the absence of any trend in the size of excess risk with increasing duration or with current versus former use of these agents argues for a cautious interpretation.

CONCLUSIONS

The use of particular types of antihypertensive medications, including immediate-release CCBs and certain diuretics, may increase the risk of breast carcinoma among older women. Additional studies are warranted to clarify these potential associations. Cancer 2003;98:1504-13.