I wouldn't be surprised if 5 cigarettes a day mightn't have some salubrious effects long-term, depending on the personality of the smoker / imaginary demons defused and the like. We'll never get believable stats on that, of course.
Clearly - few.. smoke only 5/day. (I've met a very-few who smoke only one after dinner, \ufffd l\ufffd cigar.)