High levels of anxiety might really make you age faster, a new study suggests.

The study found a link between a common form of anxiety called phobic anxiety - an unreasonable fear of certain situations, such as crowds, heights or the outside world - and shorter telomeres in middle-aged and older women. Telomeres are caps on the ends of chromosomes that protect the genetic material from damage.

"Many people wonder about whether - and how - stress can make us age faster," said study researcher Dr. Olivia Okereke, a psychiatrist at Brigham and Women's Hospital in Boston. "This study is notable for showing a connection between a common form of psychological stress - phobic anxiety - and a plausible mechanism for premature aging," Okereke said.

Telomeres generally shorten as we age, and among people of the same age, shortened telomeres have been linked to an increased risk of cancers, heart disease, dementia and overall risk of death.

However, the researchers emphasized that the study only shows an association, not a cause-effect link, and it's possible that people with shorter telomeres are generally prone to experiencing more stress. Studies that follow people forward over time are needed to confirm the findings.

Okereke and colleagues analyzed information from 5,243 women ages 42 to 69 years, who took part in the Nurses' Health Study. To measure participants' levels of phobic anxiety, researchers looked at their answers to questions such as "Do you have an unreasonable fear of being in enclosed spaces?" and "Do you feel panicky in crowds?"

The researchers found a link between high scores on the questionnaire and shorter telomeres.

The difference in telomere lengths between women who were highly phobic and those who were not was similar to what would be expected between women about six years apart in age.

The findings held even after the researchers accounted for factors that might influence the length of telomeres, such as participants' smoking, body mass indexes, physical activity levels and the age of participants' fathers when their children were born. [See Men Who Delay Fatherhood May Extend Grandkids' Lives ]

The researchers noted they did not take into account whether participants experienced depression, which may have affected the results.