Purpose
The metabolic syndrome (MetS, clustering of elevated blood pressure, triglycerides and glucose, reduced high-density lipoprotein cholesterol (HDL-C), abdominal obesity) has been associated with increased breast cancer risk, but less is known about its association with mammographic breast density, a strong risk factor for breast cancer.
Methods
We collected data on risk factors, body size and blood pressure via in-person interviews and examinations, and measured glucose, triglycerides, and HDL-C from dried blood spots from women recruited through a mammography screening clinic (n=373; 68% Hispanic, 17% African American; 63% foreign born). We performed linear regression models to examine the associations of each MetS component and the MetS cluster (≥ 3 components) with percent density and dense breast area, measured using a computer-assisted technique and Cumulus software.
Results
About 45% of women had the MetS, with the prevalence of the individual components ranging from 68% for abdominal obesity to 33% for elevated triglycerides. The prevalence of the MetS increased with higher body mass index (BMI) and postmenopausal status, but did not vary substantially by ethnicity, immigrant generational status, parity, age at menarche or alcohol consumption. Low HDL-C (< 50 mg/dL), but not the MetS cluster or the other MetS components, was associated with larger dense breast area after adjusting for age, BMI, fasting time, and educational attainment (β=8.77, 95% CI=2.39, 15.14). The MetS and its individual components were not associated with BMI-adjusted percent density.
Conclusions
HDL-C alone may have an influence on dense breast tissue that is independent of BMI, and may be in the same direction as its association with breast cancer risk.