Association of ISI with all-cause mortality as modeled by cubic spline, adjusted for age, sex, race, and study site, among 3,138 participants in the CHS. Ticks on the x-axis represent the distribution of ISI observations. Association of ISI with all-cause mortality as modeled by cubic spline, adjusted for age, sex, race, and study site, among 3,138 participants in the CHS. Ticks on the x-axis represent the distribution of ISI observations. (A high-quality color representation of this figure is available in the online issue.) Ian H. de Boer et al. Dia Care 2012;35:1355-1360 ©2012 by American Diabetes Association