Probably heart complications. My grandmother on my mother's side died at 60 from that, my grandfather on my mother's side died at 61 from heart failure, and my grandfather on my mother's side had his first heart-attack at age 34 - with 5 subsequent ones over the years. My uncle (on my father's side) had serious heart issues that took him out of work around age 59. Oh, and my mother has heart issues as well. So, yeah, I guess that's the most likely scenario.