Hypertension and the Risk of Breast Cancer in Chilean Women: a Case-control Study

Abstract

Background: Breast cancer is the most common cancer in women worldwide. Although different metabolic factors have been implicated in breast cancer development, the relationship between hypertension and breast cancer has not been elucidated. Aim: To evaluate hypertension as a risk factor for breast cancer in Chilean women of low and middle socio-economic status. Methods: We conducted an age-matched (1:1) case-control study in 3 hospitals in Santiago, Chile. Breast cancer cases (n=170) were histopathologically confirmed. Controls had been classified as Breast Imaging Reporting and Data System I (negative) or II (benign findings) within 6 months of recruitment. Blood pressure was measured using a mercury sphygmomanometer and standardized procedures. We used 2 hypertension cut-off points: blood pressures of ≥140/90 mmHg and ≥130/85 mmHg. Fasting insulin and glucose levels were assessed, and anthropometric, sociodemographic, and behavioral information were collected. Odds ratios and 95% confidence intervals were estimated for the entire sample and restricted to postmenopausal women using multivariable conditional logistic regression models. Results: Hypertension (≥140/90 mmHg) was significantly higher in cases (37.1%) than controls (17.1%) for the entire sample and in postmenopausal pairs (44.0% compared to 23.8%). In crude and adjusted models, hypertensive women had a 4-fold increased risk of breast cancer (adjusted odds ratio: 4.2; 95% confidence interval: 1.8; 9.6) compared to non-hypertensive women in the entire sample. We found a similar association in the postmenopausal group (adjusted odds ratio: 2.8; 95% confidence interval: 1.1; 7.4). A significant effect was also observed when hypertension was defined as blood pressure of ≥130/85 mmHg. Conclusion: A significant association was found between hypertension and breast cancer over the entire sample and when restricted to postmenopausal women. Hypertension is highly prevalent in Latin America and may be a modifiable risk factor for breast cancer; therefore, a small association between hypertension and breast cancer may have broad implications.

Risk factors of breast cancer and knowledge about the disease: an integrative revision of Latin American studies

“…Therefore, increased and decreased educational level may be associated in distinct ways with reproductive and lifestyle-related risk factors in rural regions and urbanized centres. This argument was supported by the fact that regression modelling revealed several independent reproductive and lifestyle-related risk factors, whereas increased educational level was not identified as an independent variable 34,40 .…”

“…In contrast, three authors identified increased educational level as risk factor (Chart 2) 34,36,40 . Decreased educational level may explain increased risk of non-participation on screening programs and BSE in three out of four studies (Chart 2) 22,29,50 .…”

“…This argument cannot explain the results of Inamuru et al, who compared in a case-control study several reproductive risk factors among women from rural regions and urbanized centres of Mid-western Brazil (Chart 2) 37 : Additionally, the authors of this study also identified lower income and decreased educational level as risk factors for women living in rural areas (Chart 2) 37 . In contrast, two studies from Mexico and Chile that identified higher educational level as risk factor were based on data obtained from hospitals of urban centres (Chart 2) 34,40 . The third study that identified higher educational level as risk factor was based on a large data set of BC mortality rates and selected socioeconomic and health care indicators in Brazil 36 .…”

“…Risk factors were subdivided into four main categories: Lifestyle-related, reproductive, socio economic and environmental risk factors, respectively, a category of history of BC (Chart 2). Several authors have analysed risk factors of all four categories 30,34,37,38,[40][41][42] . Two studies performed in Uruguay for example, included a broad range of different risk factors 41,42 .…”

Clinical Safety of Chemotherapy for Elderly Cancer Patients Complicated with Hypertension

“…The coexistence of hypertension and cancer in China is also common, and both hypertension and cancer incidence rates have been reported to increase with age (JanssenHeijnen et al, 1998;Yancik et al, 1998;Yancik et al, 2001;López-Encuentra et al, 2002;Janssen-Heijnen et al, 2004). Hypertension is reported regularly in cancer patients, with estimates of hypertension approaching 40% in cancer populations (Havlik et al, 1994;Satariano et al, 1994;Yancik et al, 2001;Ko et al, 2002;Piccirillo et al, 2004;Tammemagi et al, 2005;Smith et al, 2008;Pereira et al, 2012;Choi et al, 2013). The reported hypertension prevalence is even higher in elderly patients (Satariano et al, 1994;Yancik et al, 2004;Smith et al, 2008).…”