Risk factor clustering in the insulin resistance syndrome and its relationship to cardiovascular disease in postmenopausal White, Black, Hispanic, and Asian/Pacific Islander women

The aim of this study was to examine how major components of the insulin resistance (IR) syndrome relate to each other and to cardiovascular disease (CVD) in postmenopausal women in 4 ethnic groups. Baseline data from the Women's Health Initiative (WHI) on 3,083 50- to 79-year-old women (1,635 white, 802 black, 390 Hispanic, and 256 Asian/Pacific Islander) were examined. Participants underwent a personal interview and a physical examination, blood samples were drawn, and a detailed cardiovascular history was ascertained. Factor analysis was used to assess the clustering and interdependence of groups of CVD-related IR syndrome variables. Four factors were identified. An obesity factor included IR in all groups and had a significant association with CVD in white (P = .0001) and Hispanic (P = .0024) women. A dyslipidemia factor (high-density lipoprotein [HDL], triglycerides, and HDL₂: total HDL ratio) also included insulin and IR and was significantly correlated with CVD in black (P = .0006) and Hispanic (P = .0217) women and had a borderline association in white women (P = .068). Total and low-density lipoprotein (LDL) cholesterol did not relate to CVD in any group. Blood pressure was related weakly to CVD in white women (P = .0434) and Strongly in black women (P = .0095). Components of the IR syndrome appear to be associated with CVD in postmenopausal women, although the magnitude of these relationships differed by ethnicity.