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Smoking cigarettes accelerates aging by speeding up the genetic clock

New research has confirmed that smoking cigarettes greatly accelerates the aging process. The findings were recently presented at the European Respiratory Society International Congress in Milan by Dr. Siyu Dai. He is an assistant professor in the School of Clinical Medicine at Hangzhou Normal University.

Telomere shortening 

“Our study shows that smoking status and cigarette quantity can result in the shortening of leucocyte telomere length, which is an indicator of tissue self-repair, regeneration and aging,” explained Dr. Dai. “In other words, smoking can accelerate the process of aging, while quitting may considerably decrease the related risk.”

To understand the significance of this revelation, it is necessary to understand the function of telomeres. They serve a protective role that is similar to the plastic or metal caps that prevent shoelaces from fraying.

Aging progression 

Comprising lengths of repetitive DNA sequences, telomeres shield the ends of our chromosomes. But with every cell division, these telomeres undergo minor shortening. 

When they become too short, the cell’s ability to divide is compromised. This leads to cellular death – an intrinsic part of the aging progression. 

Focus of the study 

There has been speculation that telomere length in white blood cells, or leucocytes, is linked to smoking. However, the current study is the first to explore the link between smoking status, quantity of cigarette consumption, and telomere shortening.

In collaboration with her colleague Dr. Feng Chen, Dr. Dai extracted and analyzed a staggering amount of genetic and health-related data from UK Biobank. In particular, the researchers focused on data from 472,174 UK Biobank participants and 113 SNPs.

Mendelian randomization

The team’s methodology, known as Mendelian randomization, is particularly significant. This approach leverages genetic variations, or SNPs (single nucleotide polymorphisms), inherited from our forebears to infer causal relationships between exposure to modifiable factors (like smoking) and health conditions (like shortened leucocyte telomeres). 

The strength of this method lies in its ability to avoid the interference of other potential factors. This offers a clearer picture of causality.

What the researchers discovered 

“We found that current smoking status was statistically significantly associated with shorter leucocyte telomere length, whereas previous smokers and people who had never smoked didn’t show significantly shorter leucocyte telomere length,” said Dr Dai.

“Among people who used to smoke, there was a trend towards shorter telomere length, but this was not statistically significant. People who smoked the greater number of cigarettes had significantly shorter leucocyte telomere length.” 

“In summary, smoking may cause the shortening of leucocyte telomere length, and the more cigarettes smoked, the stronger the shortening effect.”

Telomere length and disease

Dr. Dai noted that in recent years, observational studies have linked shortened leucocyte telomere length with many diseases. These include cardiovascular disease, diabetes and muscle loss. 

“This means that the effect of smoking on telomere length probably plays a critical role in these diseases, although more research is needed to understand the underlying mechanisms.”

“Our study adds to the evidence that smoking causes aging. As there are clear health benefits of smoking cessation, it is time to include cessation support as well as treatment into daily clinical management to help us to create a smoke-free environment for the next generation.”

Future research on smoking cigarettes

Dr Dai and Dr Chen will carry out further research to validate the current findings. They also plan to further investigate the effect of passive smoke exposure on tissue self-repair, regeneration and aging. In particular, they will explore the way that it could affect children.

Significance of the study

Professor Jonathan Grigg, Chair of the European Respiratory Society Tobacco Control Committee, who was not involved with this research, commented: 

“This study addresses the question whether smoking affects telomere lengths. Telomeres protect the ends of chromosomes. If telomeres become short, cells can no longer divide successfully, and they die.”

“Dr Dai and her colleagues, in a study of half a million adults, show a clear association between smoking and reduced telomere length. This study applied Mendelian randomization, a well-known method for providing good levels of evidence and being able to show causal relationships, to support previous, observational studies suggesting that smoking causes aging, while quitting may reverse this effect.” 

“It will be interesting to see what the researchers have found in relation to the effects of passive smoking on telomere length.”

More about telomeres

Our cells contain the intricate blueprint of life: DNA. As vital as this molecule is, it’s the tiny end caps called telomeres that play a crucial role in maintaining DNA’s health and stability.

What are telomeres?

Imagine the plastic tips on the end of your shoelaces. They prevent the laces from fraying, ensuring longevity and functionality. In a similar way, telomeres act as protective caps at the ends of our DNA strands, safeguarding our genetic information.

The role of telomeres in aging and cell division

Every time a cell divides, its DNA replicates. But each replication shaves a little bit off the telomeres. Over time, as telomeres shorten, they send signals to the cell to stop dividing. This process plays a part in aging, as cells lose their ability to divide and repair tissue.

Telomerase: The protector of telomeres

Nature, recognizing the importance of telomeres, has a backup system: the enzyme telomerase. This enzyme helps rebuild telomeres, allowing cells to keep dividing for a longer time. While most of our cells don’t produce much telomerase after birth, some cells, like stem cells, do, ensuring they can continually regenerate.

Telomeres and health implications

Short telomeres link to several age-related diseases, including certain forms of cancer, heart disease, and osteoporosis. Stress, poor diet, and lack of exercise can accelerate telomere shortening, underscoring the importance of a healthy lifestyle.

The future of telomere research

Researchers believe that understanding telomeres can unlock treatments for aging and associated diseases. By manipulating telomerase or developing treatments that affect telomere length, we might someday extend the lifespan of cells and combat age-related illnesses.

In conclusion, telomeres serve as guardians of our DNA, playing an essential role in cell aging and health. As research continues, these small DNA end caps might hold the key to longer, healthier lives.

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