A link has been discovered between biological aging and the risk of developing many age-related diseases – including multiple sclerosis, heart disease, and various cancers, according to a new study by a team of scientists at the University of Leicester.

The study involved 14 centers spanning 8 nations collaborating as part of the ENGAGE Consortium. The findings were published in the journal Nature Genetics.

The scientists examined a feature of chromosomes called telomeres. Telomeres are found at the end of chromosomes – the strands of DNA inside the nucleus of cells. The telomeres shrink each time a cell divides to form new cells, until they achieve a crucial short length – sending the cells into an inactive state where they eventually die.

As people age, telomeres shorten, however, each person is born with different telomere lengths and the rate at which they shorten can fluctuate. The speed with which telomeres break down is a calculation of “biological aging”.

Professor Nilesh Samani, British Heart Foundation Professor of Cardiology at the University of Leicester and Director of the National Institute for Health Research (NIHR) Leicester Cardiovascular Biomedical Research Unit, who led the project, explained:

“Although heart disease and cancers are more common as one gets older, not everyone gets them – and some people get them at an earlier age. It has been suspected that the occurrence of these diseases may in part be related to some people “biologically” ageing more quickly than others.”

The researchers calculated telomere lengths in more than 48,000 people and viewed their DNA, finding seven genetic variants that were linked to telomere length. Next, they wanted to find out whether these genetic variants also impacted risk of different diseases.

DNA cannot be altered by environmental or lifestyle factors, therefore, an association of these genetic variants which influence telomere length with a disease, also reveals a causal association between telomere length and that disease.

The investigators established that the variants were linked to many types of cancers, including colorectal cancer, in addition to other diseases such as multiple sclerosis and celiac disease.

Surprisingly, the authors showed that in aggregate, the seven variants were also linked to coronary artery disease – which potentially leads to heart attacks.

Professor Samani added:

“These are really exciting findings. We had previous evidence that shorter telomere lengths are associated with increased risk of coronary artery disease but were not sure whether this association was causal or not. This research strongly suggests that biological ageing plays an important role in causing coronary artery disease, the commonest cause of death in the world. This provides a novel way of looking at the disease and at least partly explains why some patients develop it early and others don’t develop it at all even if they carry other risk factors.”

The authors point out that these findings are significant and could lead to a number of health advantages. They note there is a long road ahead before clinical application can become a reality. However, there are experimental models where extending telomere length has been seen to slow down, and in some instances, completely alter age-related changes in some organs.

In a separate study released last year, scientists discovered a link between attentional state and length of telomeres. The study found those who experienced more mind wandering had shorter telomeres, while those who reported longer concentration spans had longer telomeres.

Last month, an experiment using mice revealed that with decreased caloric intake, they developed longer telomeres and reduced their incidence of cancer

Written by Kelly Fitzgerald