I think the question is stupid. though, if i had to choose a behavior that is considered a sin that when committed by a person would also increase the chances of that person dying, I would have to say murder. When a person kills someone they put themselves at risk of being killed by another person out of revenge or they risk being killed by the death penalty. The second most deadly sin would probably be promiscuity or the act of premarital sex. Promiscuity, probably not as much now but in the age before condoms, was a very risky act, increasing a person's odds of catching an STD.
I think in some cases my answer shows that religion deems sin what decreases the odds of life expectancy, and not that any particular religion is true.
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