Abstract WP184: Prediction of All-cause and Stroke Mortality by Carotid Intima-Media Thickness in Japanese Urban Cohort: The Suita Study

Abstract

INTRODUCTION: Carotid intima-media thickness (IMT) has been increasingly a subclinical marker for cardiovascular disease (CVD). However, few studies have examined the association between IMT and mortality. We assessed the hypothesis that carotid IMT was a predictor for mortality in a general urban Japanese population. Methods: We studied 5,605 Japanese individuals (mean age 60.1 years, without CVD) who completed a baseline survey and carotid atherosclerosis in the Suita Study, and were then followed for 11.7 years on average. Carotid IMT was evaluated by high-resolution ultrasonography with atherosclerotic indexes of IMT in the common carotid artery (CCA), carotid artery bulb, and internal and external carotid arteries. Mean IMT was defined as the mean of the IMT of the proximal and distal walls for both sides of the CCA at a point 10 mm proximal to the beginning of the dilation of each carotid artery bulb. Max-IMT was defined as the maximum IMT in the entire scanned area. The risks of all-cause mortality across carotid IMT were compared by the use of adjusted Cox proportional-hazards models. Results: In 65,897 person-years of follow-up, we documented 829 all-cause mortality (including 59 strokes, 92 ischemic heart diseases [IHD], and 370 cancers). The adjusted hazard ratios (HRs; 95% confidence intervals, 95% CIs) in the 3rd and 4th quartiles (0.85-0.925 mm and >0.925 mm) of the mean IMT for all-cause mortality were 1.63 (1.02-2.62) and 1.66 (1.03-2.68), respectively, and that in the 4th quartile for CVD mortality was 1.41 (1.01-1.98), compared with the 1st quartile (<0.75 mm). The HR (95% CIs) in the 4th quartile (>1.70 mm) of Max-IMT for all-cause mortality was 1.41 (1.01-1.98) compared with the 1st quartile (<1.0 mm). The adjusted HRs (95% CIs) for all-cause mortality were 2.06 (1.19-3.56) with 0.1 mm increases in mean IMT, and 1.27 (1.16-1.39) in men and 1.27 (1.09-1.47) in women with 0.1 mm increases in Max-IMT. Those for stroke, cerebral infarction, IHD, and cancer mortalities were 1.38 (1.05-1.80), 1.69 (1.18-2.43), 1.49 (1.20-1.86), 1.31 (1.17-1.46) with 0.1 mm increases in Max-IMT, respectively. Conclusions: Carotid IMT, especially Max-IMT is a strong predictor for all-cause, stroke, cerebral infarction, and IHD mortalities in general population.