Although smoking has been shown to have drastic consequences for lifespan and disease progression, new research suggests that not all smokers experience early death, in fact, some manage to survive to extreme ages.

"We identified a set of genetic markers that together seem to promote longevity. What's more, many of these markers are in pathways that were discovered to be important for aging and lifespan in animal models," Morgan Levine, corresponding author of the study, said in a statement. "There is evidence that these genes may facilitate lifespan extension by increasing cellular maintenance and repair. Therefore, even though some individuals are exposed to high levels of biological stressors, like those found in cigarette smoke, their bodies may be better set up to cope with and repair the damage."

For the study, Levine, who is a researcher at UCLA, collected and analyzed data from long-lived smokers. They identified a network of SNPs (a DNA sequence variation occurring commonly within a population) that allow certain individuals to better withstand environmental damage (like smoking) and mitigate damage. Collectively, these SNPs were strongly associated with high survival rates.

The findings suggest that longevity, rather than being entirely determined by environmental factors, may be under the regulation of complex genetic networks which influence stress resistance and genomic stability. Therefore, there is reason to believe that long-lived smokers represent a biologically distinct group, endowed with genetic variants allowing them to respond differentially to environmental stressors.

Genomic instability also happens to be one of the hallmarks of cancer pathogenesis, and so the same genes that may promote survival among smokers may also be important for cancer prevention. This is consistent with the findings of the study, which showed that the genes identified were associated with nearly 11 percent lower cancer prevalence.

The findings are detailed in the Journals of Gerontology: Medical Sciences.