I think Loneliness is the biggest true killer of older people

Why?

It's because as you get older your friends and relatives all die one by one until maybe you are alone. Even if you are happily married if you are the last one to be alive often that takes you out too. Often people who make it into their 90s when their spouse passes away then they are gone within a year or two also. It's true it depends upon the person but likely if you marry and stay with the same person from your late teens or early twenties it is even more likely that if your significant other goes that you then are soon gone too.

But, it's also true that there are exceptions to everything in life. For example, even though my parents were together I think 39 years my mother lived from 1985 when my Dad passed away until 2008. But, I can't say she was ecstatically happy about still being alive. She just stayed alive but wasn't the same person at all that she was while my Dad was alive.

In life longevity has more to do with adaptability more than any other single factor along with good genetics, a good diet and as many good friends that also have pretty good genetics for longevity too.

Also, you have to be someone that never gives up to face old age ongoing too. The same thing that allows you to be good at camping and survival in the wilderness or sailing a boat through a storm (self discipline) also tends to keep you alive into your 80s, 90s and 100s too. innovation and self discipline tends to help you stay alive longer also.

By God's Grace