Common environmental toxins — such as benzene and cigarette smoke — are linked to premature aging.

In a new study published in the journal Trends in Molecular Medicine, researchers from the University of North Carolina-Chapel Hill report environmental toxins and stress may explain why some people fare better than others as they grow older, the Newsmax Health reported.

"The rate of physiologic, or molecular, aging differs between individuals in part because of exposure to 'gerontogens,' i.e., environmental factors that affect aging," lead researcher Norman Sharpless told the Medical Xpress Website.

"We believe just as an understanding of carcinogens has informed cancer biology, so will an understanding of gerontogens benefit the study of aging. By identifying and avoiding gerontogens, we will be able to influence aging and life expectancy at a public health level."

Sharpless's research raises the intriguing possibility that doctors may one day use blood tests to assess biomarkers of their patients' "molecular age." Such tests might measure key factors in health and DNA.

Tobacco smoke is likely the most important gerontogen, Sharpless said, noting cigarettes are linked with cancers, heart conditions, and other age-related diseases. UV radiation from the sun makes us older too, and Sharpless has found that chemotherapy treatment is also a strong gerontogen.