Burden of subclinical cardiovascular disease in "metabolically benign" and "at-risk" overweight and obese women: The Study of Women's Health Across the Nation (SWAN)

Background: Metabolically benign obese individuals have a 10-year cardiovascular disease (CVD) risk comparable to healthy normal weight individuals. However, the burden of subclinical CVD among metabolically benign obese is not well known. Methods: In cross-sectional analyses of 475 mid-life women, we compared common carotid artery intima media thickness (CCA-IMT), aortic pulse wave velocity (aPWV) and coronary (CAC) and aortic calcification (AC) among three groups: healthy normal weight, metabolically benign overweight/obese (<3 metabolic syndrome components/elevated CRP), and at-risk overweight/obese (≥3 metabolic syndrome components/elevated CRP). Results: The mean (SD) CCA-IMT and aPWV were lowest in the normal weight group (n= 145), followed by the benign overweight/obese (n= 260) and at-risk overweight/obese (n= 70) groups [CCA-IMT: 0.64 (0.08) vs. 0.68 (0.09) vs. 0.73 (0.13) mm, p<. 0.001; aPWV: 731.0 (176.4) vs. 809.9 (182.3) vs. 875.7 (228.8) cm/s, p<. 0.001]. Similar results were found for the frequency (%) of women with increased CAC and AC [CAC: 13 (9%) vs. 53(20%) vs. 28(40%), p<. 0.001; AC: 47(32%) vs. 130 (50%) vs. 55(79%), p<. 0.001]. These differences remained significant after multivariable adjustment. Further adjustment for BMI attenuated the statistical significance of differences in aPWV and calcification between benign and at-risk overweight/obese women, but had little effect on the magnitude of these differences. Conclusions: Metabolically benign overweight/obese women have a significantly greater subclinical CVD burden than normal weight women, despite published data finding similar CVD event rates between the two groups. Prospective studies tracking the progression of subclinical atherosclerosis to clinical CVD in these women are needed.