Exposure to harmful substances in the environment, chemicals such as benzene, cigarette smoke and even stress may make people older than their years, according to a new study.
While the birth date on your driver's license can tell you your chronological age, that might mean little in terms of the biological age of your body and cells, researchers said.
A better understanding of the chemicals involved in ageing and biomarkers is needed to measure their effects, they said.
"The rate of physiologic, or molecular, ageing differs between individuals in part because of exposure to 'gerontogens', ie, environmental factors that affect ageing," said Norman Sharpless from the University of North Carolina, Chapel Hill.
"We believe just as an understanding of carcinogens has informed cancer biology, so will an understanding of gerontogens benefit the study of ageing. By identifying and avoiding gerontogens, we will be able to influence ageing and life expectancy at a public health level," said Sharpless.
In the future, blood tests evaluating biomarkers of molecular age might be used to understand differences amongst individuals in ageing rates.
Those tests might measure key pathways involved in the process of cellular senescence or chemical modifications to DNA.
From a public health perspective, cigarette smoke is likely the most important gerontogen, Sharpless said.
Cigarettes are linked with cancers but also with atherosclerosis, pulmonary fibrosis, and other diseases associated with age, researchers said.
UV radiation from the Sun makes us older too, and Sharpless and his colleagues recently showed that chemotherapy treatment is also a strong gerontogen.
With the aid of a mouse model that they developed, his team is prepared to study these gerontogens and others in much greater detail.