There are several new health hazards associated with smoking. High chances of developing lung cancer, cardiac diseases and diabetes are some of the well-known side effects of smoking. A new study has revealed that smoking causes chromosomal damage and speeds up aging. The risk of damage can be reduced by quitting the habit.

In the study, researchers analyzed data from around 500,000 people from the U.K. Biobank and found that smoking shortens telomeres in the white blood cells, the length of which determines the rate of aging and ability to repair cells.

Telomeres are repetitive DNA sequences that act as protective caps at the chromosomal ends, similar to how plastic tips on shoelaces prevent them from unraveling. With each cell replication, telomeres gradually shorten until they reach a length when cell division is not possible, resulting in tissue aging.

"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. In other words, smoking can accelerate the process of aging, while quitting may considerably decrease the related risk," Dr. Siyu Dai, who presented the study at the European Respiratory Society International Congress in Milan, Italy, said in a news release.

Previous studies have shown that smoking affects the length of telomeres in white blood cells but, they did not quantify the effect of cigarette smoking with the shortening of telomeres.

In the latest study, researchers evaluated if the participants were current smokers, previous smokers, or had never smoked, the level of their addiction to smoking, and the quantity of cigarettes smoked. Using blood tests, they also measured the telomere lengths in the participants.

The study used Mendelian randomization, which uses the variations in inherited genes to understand how modifiable environmental factors can cause or affect a disease or health condition.

"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. Among people who used to smoke, there was a trend toward 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," Dr. Dai said.

Researchers hope the findings will prompt increased support and treatment options for individuals planning to quit the habit.

"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 create a smoke-free environment for the next generation," Dr. Dai added.