We document racial trends in chronic conditions among older men between 1910 and 2004. The 1910 black arteriosclerosis rate was six times higher than the white 2004 rate and more than two times higher than the 2004 black rate. We argue that blacks' greater lifelong burden of infection led to high arteriosclerosis rates in 1910. Infectious disease, especially respiratory infections at older ages and rheumatic fever and syphilis at younger ages, predicted arteriosclerosis in 1910, suggesting that arteriosclerosis has an infectious cause. Additional risk factors for arteriosclerosis were being born in the second relative to the fourth quarter, consistent with studies implying that atherogenesis begins in utero, and a low body mass index, consistent with an infectious disease origin of arteriosclerosis.