Length of telomere unaffected by smoking: study

A new study has surprised the medical world, finding that smoking does not shorten the length of telomeres – a marker at the end of our chromosomes that is widely accepted as an indicator of aging.

This suggests that adult telomere length should be considered as a static biomarker that changes relatively little in adult life.

The meta-analysis of 18 previously collected datasets led by researchers from Newcastle University is published in the Royal Society Journal Open Science aujourd & # 39; hui.

The researchers chose to focus on smoking simply because there is more data on the associations between smoking and telomere length than for any other unhealthy behavior.

The study confirms that, while smokers actually have shorter telomeres (as many studies have shown before), it is important to note that there is no indication that telomeres are shortening faster in smokers than non-smokers, contrary to what one would predict if smoking causes shortening of the telomere. The findings suggest that smoking is not responsible for the shorter telomeres observed in adult smokers.

Professor Melissa Bateson of the Faculty of Medical Sciences at the University of Newcastle, who led the study, said, "The importance of this study is that it forces us to rethink the value of telomere length as a reading of how our current lifestyles affect our body.We do not dispute the abundant evidence that smoking is bad for you, but simply the evidence that telomere length is a good way to assess the biological damage caused by smoking and possibly, by extension, by other unhealthy behaviors. "

This raises the question of why do smokers have shorter telomeres? The team of international researchers suggests that a plausible answer to this question is that telomere shortening and smoking are made more likely by a third variable, possibly exposure to various forms of depression. adversity at the beginning of life, such as physical and psychological violence. The University of Newcastle team is continuing its research in this area.

This discovery modifies prior scientific knowledge on telomere length, a recognized biomarker of increased morbidity and reduced longevity. It was previously thought that telomere length dynamically responded to current adult behavior, shortening further when we engage in unhealthy activities such as smoking and perhaps lengthening in response to healthier behaviors. However, this study suggests that the length of adult telomeres should be reinterpreted as a static biomarker that changes relatively little during adult life.

Method

Data were included in 18 longitudinal studies covering 10 countries and four continents. The study was made possible through international collaboration among researchers involved in all of these original studies, making their data available for further analysis. The combined dataset is the largest of its kind and includes data from 12,579 adults (4,678 current and 7,901 non-smokers). The average age of participants ranges from 26 to 80 years old.

The change in telomere length of participants was measured over a follow-up period of approximately 8.6 years, using telomere length measurements in blood samples collected at the beginning and end of this period .

Professor Bateson added, "For the scientific community, this means that measuring changes in adult telomere length may be less useful than expected in identifying harmful behaviors and monitoring the consequences of these changes.

"More generally, the results highlight the need for caution when interpreting correlational data.The fact that two variables correlate does not mean that one variable causes the other."