Blood pressure is a common cause. I nearly failed exactly 12 months ago as my BP was about 158, just under the 160 limit. For me though, I know this is not a true reflection of my normal BP and I was able to show the doc regular records of my BP which is normally around 135 !
CG !
P.S. Just let my Class 1 lapse to Class 2 priviledges as I am not flying commercially !! Not suer I can be bothered to renew iot any time soon !!