No, we are not kidding.
This remarkable piece of junk science comes courtesy of The American Journal of Medicine.
The authors themselves stated that – "the data did not prove smoking leads to low back pain" and also that – "none of the studies were designed to determine if there was a cause and effect relationship". So exactly what was the purpose of this study? If none of the 81 studies they reviewed were designed to determine cause and effect why on Earth was money spent on trying to show something that couldn’t be shown? ie. whether smoking increases the risk of low back pain.
Such is the pot of gold available to tobacco control, even with the prior knowledge that the data they were looking at couldn’t possibly show them what they were seeking, they went ahead and did it anyway and produced a new health scare headline which no doubt ensured their next funding grant from their anti smoking paymasters.