I never build health care units for this reason only as battle medics. I also never build the graveyard or mausoleum either too expensive. Still my 4 biggest cities skyrockets to 60-70 population in the late classical era while the biggest AI city in the world is around 30-40 population. (deity diff.) Disease is too easy to control in my opinion and has too little bad effects; but they still need to be spread more out.