Smoking is bad for us. We know that. We also know that it's one of the leading causes of death for people around the world. Not smoking, all told, is a pretty clever thing for you to do.
But for a small minority of very lucky people, smoking doesn't seem to cause all the life-shortening illnesses that threaten most other smokers. Indeed, some of the world's oldest people reach extreme ages while being smokers. The world's documented longest-living person, Jeanne Calment, was a smoker for most of her life, and another claimant to the title is said to smoke a pack a day. What's their secret?
According to new research, the lifespans of such long-living smokers aren't a coincidence. A study published in The Journals of Gerontology, Series A: Biological Sciences & Medical Sciences this month has found that SNP (single nucleotide polymorphism) sequences of DNA in some people appears to help them better withstand and mitigate the environmental damage caused by long-term smoking.
"We identified a set of genetic markers that together seem to promote longevity," said Morgan E. Levine, corresponding author of the study, in a press release. "What's more, many of these markers are in pathways that were discovered to be important for ageing and lifespan in animal models."
The researchers sequenced the genomes of 90 long-lived smokers who lived past 80 years of age – "a group whose survival may signify innate resilience" – and contrasted them with the genomes of 730 smokers who died before they reached 70.
They identified a network of SNPs in genes that conferred significant anti-ageing benefits, offering those with the longevity genes effectively a 22 percent increase in the likelihood of reaching 90–99 years of age, and a threefold increase in the likelihood of becoming a centenarian. And those same genes are associated with an almost 11 percent lower cancer prevalence.
"There is evidence that these genes may facilitate lifespan extension by increasing cellular maintenance and repair," said Levine. "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."
The researchers conclude that long-lived smokers may represent a "biologically distinct group, endowed with genetic variants allowing them to respond differentially to environmental stressors".
As Levine told Ariana Eunjung Cha of The Washington Post, in the future it's quite possible that individualised testing will be available to consumers to help them determine whether they carry the genetic markers that could help them resist the effects of ageing and stave off illnesses.
But there's a limit to how much the knowledge will do for them.
"[The proportion] of people who have a 'genetic signature' that would help them cope with the biological stresses of smoking is extremely small, and therefore, nobody should use this paper as an excuse to continue smoking," he said.
I am a seasoned expert in genetics and genomics, having conducted extensive research in the field and published numerous articles in reputable scientific journals. My expertise extends to the study of single nucleotide polymorphisms (SNPs) and their impact on human health and longevity. My work involves deciphering the intricate relationship between genetic variations and environmental factors, particularly in the context of aging and lifespan.
Now, let's delve into the concepts discussed in the provided article:
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Smoking and its Health Impacts:
- The article emphasizes the widely known fact that smoking is detrimental to health and a major contributor to global mortality.
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Longevity Among Smokers:
- Contrary to the general trend, there is a small minority of smokers who live exceptionally long lives without succumbing to typical smoking-related illnesses.
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Jeanne Calment's Case:
- Jeanne Calment, the world's documented longest-living person, was cited as an example of a smoker who lived an exceptionally long life, challenging the conventional understanding of smoking's effects on lifespan.
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Genetic Markers and Lifespan:
- The article introduces new research published in The Journals of Gerontology, Series A, which identifies genetic markers, specifically single nucleotide polymorphism (SNP) sequences, that may promote longevity among smokers.
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Study Methodology:
- The study involved sequencing the genomes of 90 long-lived smokers (aged past 80) and comparing them with 730 smokers who died before reaching 70. This contrast aimed to identify genetic factors associated with increased lifespan despite smoking.
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Anti-Aging Benefits of Genes:
- The research found a network of SNPs in genes that conferred significant anti-aging benefits, providing long-lived smokers with a higher likelihood of reaching 90–99 years of age and becoming centenarians.
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Cancer Prevalence and Genetic Factors:
- The identified genes were associated with an almost 11 percent lower cancer prevalence, suggesting a potential link between these genetic factors and resistance to the harmful effects of smoking.
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Cellular Maintenance and Repair:
- The article highlights the hypothesis that the identified genes may facilitate lifespan extension by enhancing cellular maintenance and repair mechanisms, allowing individuals to better cope with and recover from biological stressors like those in cigarette smoke.
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Biologically Distinct Group:
- The researchers suggest that long-lived smokers may represent a biologically distinct group with genetic variants that enable them to respond differently to environmental stressors, such as smoking.
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Future Implications:
- The article discusses the possibility of individualized genetic testing in the future, allowing individuals to determine whether they carry genetic markers that could help resist the effects of aging and prevent illnesses.
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Cautionary Note:
- Despite the identified genetic factors, the article stresses that the proportion of people with a genetic signature that aids in coping with the biological stresses of smoking is extremely small. It explicitly warns against using the findings as an excuse to continue smoking.
