Hypertension, diuretics and breast cancer risk

Abstract

It is unclear whether hypertension and antihypertensive medication use are associated with breast cancer. In order to examine these associations, we conducted a case-control study among women aged 50-75 years. Breast cancer cases were ascertained via a populationbased cancer registry (n ¼ 523) and controls were ascertained via random-digit-dialing (n ¼ 131). Participants completed a self-administered questionnaire which queried history of hypertension, antihypertensive medication use and risk factors. Unconditional logistic regression was used to estimate the odds ratio (OR) and 95% confidence intervals (CI), adjusted for age, body mass index (BMI), diabetes, smoking, alcohol use, menopausal status, family history of breast or ovarian cancer, age at first full-term pregnancy and education.History of treated hypertension was associated with significant increased risk of breast cancer (OR, 1.77; 95% CI, 1.04-3.03) and this association appeared only in women with BMI X25 kg/m 2 (OR, 2.30; 95% CI, 1.12-4.71). Diuretic use was also associated with elevated breast cancer risk (OR, 1.79; 95% CI, 1.07-3.01). The risk associated with diuretic use increased with duration of use (P for trend, o0.01). Use of other blood pressure medications was not found to be associated with breast cancer risk. These results support a positive association between treated hypertension, diuretic use and breast cancer risk among women aged 50-75 years.

Hypertension and breast cancer: an association revisited?

“…Largent et al 10 also investigated diuretic use, and similar to a recent study by Li et al, 13 found a small but significant association with breast cancer risk. The risks appear small, which in theory could be explained by chance association alone or ascertainment bias (e.g.…”

“…women receiving treatment for hypertension are more likely to be diagnosed with breast cancer as they represent a group in the population receiving regular health care). Largent et al 10 also found that with longer durations of diuretic use, the risk increased whereas Li et al 13 did not. Interestingly, Li et al 13 reported an increased risk only with thiazide and potassiumsparing (plus immediate-release calcium channel blockers) rather than loop diuretics, whereas Largent et al 10 failed to distinguish between the subgroups of diuretic drugs.…”

“…Largent et al 10 also found that with longer durations of diuretic use, the risk increased whereas Li et al 13 did not. Interestingly, Li et al 13 reported an increased risk only with thiazide and potassiumsparing (plus immediate-release calcium channel blockers) rather than loop diuretics, whereas Largent et al 10 failed to distinguish between the subgroups of diuretic drugs. Both studies also fail to mention the incidence if any, of renal cell carcinoma whose association with diuretic treatment has long been scrutinized, with the bulk of evidence pointing towards a positive association.…”

“…Likewise, diuretics could be substituted for other classes of antihypertensive drugs if required, although current recommendations cite diuretics as the first-line treatment for hypertensive patients over 55 years old, and patients from Black ethnic background. 24 In the light of current evidence, the report by Largent et al 10 raises questions but does not deliver firm answers. Although interesting, their findings are largely contrary to the bulk of published evidence, possibly explained away by bias alone and as such, must be viewed with a healthy degree of scepticism until such a time as better designed trials become available.…”

“…[6][7][8] Since then, there have been many studies reporting a putative link between antihypertensive drugs and cancer, with diuretics being the most frequently cited culprit, with renal carcinoma being the most common site-specific cancer. 9 In this issue of the Journal of Human Hypertension, Largent et al 10 describe associations between breast cancer and hypertension, as well as diuretics, in a population-based case-control study. Their study was based on self-administered questionnaires and telephone interviews -rather than clinical observations -and suffers from the inevitable problems of recall bias, as well as an ambiquous definition of antihypertensive drugs and hypertension diagnosis.…”