Why are some people crippled by colds, while others seem to never get sick? A new study suggests the answer could lie in our telomeres, the DNA "caps" at the end of our chromosomes that protect our genetic information from damage. Each time a cell divides, its telomeres shorten -- and short telomeres have been associated with aging and age-related diseases.
Researchers from Carnegie Mellon University found that the telomere length within immune cells seems to be associated with risk of infection by a cold-causing virus for people as young as 22 years. And the strength of the association only gets stronger with age.
"Our work suggests the possibility that telomere length is a relatively consistent marker across the life span and that it can start predicting disease susceptibility in young adulthood," study researcher Sheldon Cohen, a psychologist at the university, said in a statement.
The study, published in the Journal of the American Medical Association, included 152 people between ages 18 and 55 whose white blood cell telomeres were measured for length (shorter telomeres are associated with aging, and a higher risk of death and illnesses that are more common in older age, like some cancers, dementia and heart disease). Then they were all exposed to the rhinovirus, a virus responsible for the common cold.
An association was found between white blood cell telomere length and susceptibility to the virus. Specifically, the shorter the telomere, the more likely a person was to be infected by the rhinovirus. However, the researchers didn't find an association in people ages 18 to 21 -- they only found the association in those ages 22 and older.
Researchers also found a particularly strong association between telomere length of the CD8CD28- T-cytolytic cell and susceptibility to the cold virus.
However, the researchers cautioned that the findings are still preliminary and more study is needed to explain what processes are occurring. Another caveat: one of the researchers is a cofounder of a telomere measurement company.
Past research in telomeres has shown that their length could also be affected by stress. A study in the journal PLoS ONE shows that people who experience high levels of stress from work are more likely to have short telomeres, and another study in the same journal also showed that phobic anxieties (fear of social situations, spiders, and the like) might also be associated with short telomeres.