TUESDAY, Feb. 19 (HealthDay News) -- Some people seem to catch a cold every few weeks while others appear immune. Now a preliminary study suggests that the protective "caps" on your chromosomes could partly explain the mystery.
The study, reported in the Feb. 20 issue of the Journal of the American Medical Association, found that healthy young adults were more prone to catching a cold when their immune system cells had relatively short telomeres.
Telomeres are lengths of DNA that sit at the ends of your chromosomes. Think of them like the plastic caps at the ends of a shoelace: Telomeres help keep your chromosomes -- which carry your genes -- from fraying and sticking together.
As people age, their telomeres gradually get shorter, and research has linked shorter telomere length to older adults' risks of developing and dying from infections, cancer and heart disease.
"But there's been very little known about telomere length in young people, certainly in relation to health," said Sheldon Cohen, a professor of psychology at Carnegie Mellon University in Pittsburgh who led the new study.
Because colds and other respiratory infections are the most common health woe in younger people, Cohen's team decided to see whether telomere length mattered in their risk of developing a cold.
The researchers recruited 152 healthy 18- to 55-year-olds, and measured telomere length in the volunteers' T cells -- immune system cells that fight off infection. They then exposed the men and women to a cold virus via nasal drops, and quarantined them in a hotel to be monitored.
Over the next five days, 22 percent of the volunteers developed cold symptoms, and the odds were higher among those with shorter telomeres in a particular subtype of T cell. Of the one-third with the shortest telomeres, 26 percent became sick, versus 13 percent among the one-third with the longest telom
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