THURSDAY, Feb. 3 (HealthDay News) -- Women coping with peripheral arterial disease (PAD) in the legs appear to lose mobility faster than men, new research reveals.

PAD is marked by narrowing and blockages of the peripheral arteries, usually those in the legs and pelvis. The most common symptoms are pain, cramping and tiredness in the leg or hip muscles when walking or climbing stairs -- symptoms that go away during rest.

"The bottom line is that among those with lower extremity PAD, women have faster declines in mobility and functional performance compared to men," said study author Mary M. McDermott, a professor of medicine in the department of medicine at the Northwestern University Feinberg School of Medicine in Chicago.

"This may be related to gender differences in calf muscle, as women tend to have less calf muscle compared to men," McDermott added.

She and her colleagues report their findinsg in the Feb. 8 issue of the Journal of the American College of Cardiology.

Both the researchers and the American Heart Association note that an estimated 8 million American men and women are affected by lower extremity PAD, with disease prevalence being split about equally across genders.

To examine whether disease progression differs among men and women, between 2002 and 2009 McDermott and her team tracked the progress of 380 male and female patients with PAD of the legs in the Chicago area.

All the participants were 59 and older. Over a four-year period, annual mobility assessments were conducted during which each patient was asked to complete a quarter mile, six-minute walk, as well as a four-minute speed test, to observe the development of disability. Changes in calf muscle measurements and characteristics were also noted, alongside knee extension strength.

Overall, the research team determined that after adjusting for age, women fared more poorly than men over the course of the study.

As the study period unfolded, they noted that women ended up walking less per week and had more difficulty walking the quarter-mile. Specifically, female PAD patients who had initially been able to complete a continuous six-minute quarter-mile walk were 2.3 times as likely as men to lose that ability by year four.

Women were also more likely to undergo a decline in unassisted mobility at a faster rate, year-to-year, than men, and were 1.9 times as likely to develop mobility disability (defined as being unable to continuously walk a quarter mile or ascend and descend a single flight of stairs without help).

Women also experienced a faster drop than men in the speed with which they could walk unassisted. And although women experienced less of an annual decline in calf muscle area and isometric knee extension strength than men, they also had generally smaller calf muscles, lower calf muscle density, and less overall knee extension strength to begin with.

The authors concluded that female PAD patients suffer faster rates of functional decline than their male counterparts.

They noted, however, that women generally started out the study with worse mobility than men, and that their faster loss of mobility might in the end be traced to the initial disadvantage women have in terms of weaker calf muscles and poorer leg strength. Viewed in reverse, the greater lower extremity "muscle reserves" typical of men may actually help protect them against the mobility ravages of PAD.

"This has not been reported before in people with PAD," McDermott noted. "So I was somewhat surprised. But there is some data in people without PAD that also shows this gender phenomenon. So it may be that because women live longer, they have more opportunity to experience these declines than men."

Regardless, McDermott stressed that the observations could have important implications for treatment protocols. Further research will help determine whether interventions to increase calf muscle area and leg strength in women with PAD in the legs can help slow a decline in mobility, she and her colleagues noted.

The researchers did not report any conflicts of interest.

For his part, Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, said that the findings underscore the importance of timely intervention among PAD patients, regardless of gender.

"Men or women with peripheral arterial disease have four to five times the risk of heart attack or stroke," he noted. "Left untreated, peripheral arterial disease can lead to amputation."

"Treatment of peripheral artery disease," he added, "focuses on preventing further progression of the disease, including lifestyle changes, exercise programs, and specific medications to reduce the risk of heart attacks and stroke as well as to slow the progression or even reverse symptoms of peripheral artery disease."

This study, he concluded, "highlights the need for aggressive treatment of peripheral artery disease in both women and men".

More information

For more on PAD, visit the American Heart Association.