There are so many factors that lead to disease. Genes are a huge determinant. In my own family: grandmother, cancer, grandfather ,cancer, my mother had two different cancers, my sister has breast cancer and my brother has a blood cancer.
My mother was slim and exercised her whole life and believed in healthy eating
Sometimes childhood diseases affect your health in adulthood.
I know someone with post-polio syndrome. Thankfully we have vaccines today.
We live far longer today because of medicine. And this is coming from someone with a deep-seated fear of drugs and doctors!