Do otterbox and a silicone phone pocket affect iPhone battery?

On my iPhone 7 (bought about two months ago), I have an otterbox defender and a silicone phone pocket on it. Recently, I noticed the battery life has been noticeably shorter and I wanted to know if the case + silicon pocket is to blame, or if this is just normal. I've heard things about heavy cases causing the battery to overheat which lighten shorten battery life, but I don't know if this would be enough to do that.

Unless it contains lights of some sort,
a case has No connection with power consumption.