Abstract P369: Relation of Breast Arterial Calcification With Ankle Brachial Index

Abstract

Presence of breast arterial calcification (BAC) has been shown to be independently associated with increased risk of subclinical cardiovascular disease (CVD), angiographically-defined coronary disease and with incident coronary heart disease, stroke and heart failure. However, a relationship between BAC and peripheral vascular disease has not been established. The ankle brachial index (ABI) is an indicator of the severity of peripheral arterial disease (PAD) that predicts future CVD risk. We utilized cross-sectional data collected at the baseline examination (2012-15) of the MultIethNic Study of BrEast ARterial Calcium Gradation and CardioVAscular Disease (MINERVA Study), a cohort study of 5,145 post-menopausal women who were members of the Kaiser Permanente Medical Care Program of Northern California (KPNC) who were free of clinical CVD at baseline. Presence and gradation (in mg of calcium mass) of BAC in digital mammograms was ascertained with a validated densitometry method. ABI, the average of two ankle systolic pressure readings divided by the average of two brachial systolic pressure readings, was measured by trained and certified personnel after a ten-minute rest. A total of 3,693 women had complete data on all variables of interest; their mean (SD) age was 66 (4) years and 64% were white, 12% African-American, 14% Asian, 9% Latina and 1% mixed or other. While 28.2% presented with any detectable BAC (i.e., BAC mass > 0 mg), 5.4% had an ABI < 0.90. Three women had ABI>1.40 and were excluded from analyses (none had BAC>0). Prevalence of ABI < 0.90 was 4.8% (27/2,653) in women with BAC=0 and 6.9% (72/1,040) in women with any detectable BAC. The Odds Ratio of ABI<0.90 associated with any BAC was 1.39 (95% CI, 1.03-1.89) in a model adjusting for age and race/ethnicity, and was 1.38 (95% CI, 1.02-1.88) in a model with further adjustment for BMI, smoking status, diabetes, hypertension, LDL cholesterol, HDL cholesterol and hs-CRP. However, among women with any detectable BAC, standardized log_BAC mass (mg) was not significantly associated in bivariate linear regression analysis with ABI (slope=-0.0030 [SE=0.0031]; p=0.32). Our study demonstrates (for the first time) an independent association between presence of BAC and ABI indicative of PAD, with no apparent linear dose-response relationship.