A link has been found between the shortening of telomeres and the risk of early death or heart attack.
Research carried out by researchers at the University of Copenhagen backed up previous speculation on the subject while also providing physicians with a theory of testing the cellular health of a person.
Using around 20,000 Danes for the research, experts isolated each person's DNA to examine their specific telomere length, which highlights cellular ageing.
Telomeres shorten over the duration of a person's life, while they can also be affected by lifestyle choices like obesity and smoking.
Borge Nordestgaard, clinical professor of genetic epidemiology at the Faculty of Health and Medical Sciences at the institute, explained that the risk of having a heart attack or early death is increased when telomeres are found to be shortened.
"That smoking and obesity increases the risk of heart disease has been known for a while. We have now shown, as has been speculated, that the increased risk is directly related to the shortening of the protective telomeres – so you can say that smoking and obesity ages the body on a cellular level, just as surely as the passing of time," he added.
Mr Nordestgaard went on to say that any future studies will be able to reveal the actual molecular mechanism which will show why short telomere length causes heart attacks.
According to the NHS, around 111,000 people have a heart attack every year in England, with many of those that lead to death being preventable.
It added that some of the risk factors of a heart attack are smoking, enjoying a high-fat diet and being obese.
The research, which is titled 'Short telomere length, myocardial infarction, ischemic heart disease, and early death' will be published in next month's issue of the journal Arteriosclerosis, Thrombosis and Vascular Biology.