Does The Act Of Ruling Shorten The Lives Of Monarchs? See ‘Evidence’

The only living national monarchs (in 2017) who were on their country’s thrones during World War 2 are all former monarchs. They are former King Simeon of Bulgaria, former King Michael of Romania and the exiled Dalai Lama of Tibet. So, did the relaxation gotten from not ruling or reigning prolong their life or is it just a rare coincidence?