The study of 1,000 women with physical limitations such as trouble walking or performing other daily routines found that those who reported at least two anxiety symptoms at the outset were at greater risk of their disability worsening over the next 3 years.

Frequent anxiety symptoms -- such as feeling nervous, tense, "shaky" or fearful -- were linked to a 41 percent higher risk of deterioration in what researchers refer to as activities of daily living. These include the basic routines of getting out of bed, bathing, dressing and eating.

Women with two or more anxiety symptoms were also more likely to develop problems doing light housework, according to findings published in the Journal of the American Geriatrics Society.

Dr. Gretchen A. Brenes of Wake Forest University School of Medicine in Winston-Salem, North Carolina, led the study.

Brenes and her colleagues followed 1,002 women age 65 or older who started the study with limitations such as difficulty walking more than a short distance, limited mobility in their arms, and problems with bathing and other everyday routines.

The women completed standard measures of anxiety and depression symptoms at the study's start. Nineteen percent said they had frequently had two or more anxiety symptoms over the previous week, and were considered to be suffering from anxiety.

Overall, Brenes and her colleagues found, these women were more likely than their less anxious peers to have worsening problems with daily activities and light housework over the next three years.

This link was independent of depression, which has been implicated in disability, and of any use of medications called benzodiazepines -- sedatives that can have adverse health effects, including raising the risk of falls and bone fractures.

"This study provides evidence that anxiety is associated with the progression of disability in vulnerable older women, independent of several potential confounding factors," the study authors write.

They speculate that anxiety could have direct physical effects that worsen disability. For instance, shakiness or dizziness could make walking or other daily activities too difficult. Anxiety may also be a risk factor for high blood pressure and heart disease, which in turn can exacerbate disability.

"Anxiety is a common yet understudied problem for many older adults," Brenes and her colleagues write.

Clinical trials, they conclude, should look into whether treating anxiety can delay or prevent disability.