FNDC5 and atherosclerosis: Notably, Remuzgo-Martínez and colleagues evaluated the degree of subclinical atherosclerosis in a large cohort of 725 patients with axial spondyloarthritis, identifying how low levels of irisin are associated with a high atherogenic index (AI > 4), calculated as a ratio between total cholesterol and high-density lipoprotein cholesterol (HDL-C) and carotid plaques [70].