MONDAY, Sept. 29, 2003 (HealthDayNews) -- New research confirms what women all over the world have no doubt been waiting to hear: Wearing high heels does not increase your chances of developing osteoarthritis of the knee.
But beware: The study also confirms that being overweight, especially when you're younger, greatly increases the risk.
According to authors of a study appearing in the October issue of the Journal of Epidemiology and Community Health, about 2.4 percent of people over the age of 55 suffer from osteoarthritis of the knee, in which the joint's cartilage breaks down and causes the bones to rub against each other. By the age of 65, however, the condition is twice as common among women, a discrepancy that has led to much speculation about what different risk factors may be at play.
That speculation has run the gamut from birth control pills to socioeconomic status and, of course, to those uncomfortable-looking pumps that have become more ubiquitous since the end of World War I.
The researchers interviewed 29 women between the ages of 50 and 70 who experienced knee pain and were on a waiting list for knee replacement surgery, as well as 82 women who had no known knee problems.
Each woman was asked about their height and weight at different stages of their life, about previous injuries, occupational activities and use of hormones and birth control pills.
They were also subjected to a grueling series of questions regarding their shoe history: How old were they when they started wearing high heels? How often did they wear them? How high did they go? The women were shown a rogues' gallery of 38 different styles and heights of shoes (front and profile) and life-size pictures of heels and asked to identify their preference. If they had worn any of the shoes, they were asked to divulge whether they wore them for dancing, for social events, or for work.
All of the women reported wearing shoes with heels at least one inch high at some point in their life. Only 7 percent said they had never worn heels as high as two inches, and 36 percent said they had never worn three-inch heels.
Some of the findings were expected: Knee osteoarthritis was associated with previous knee injury, arthritis of the feet, heavy smoking, certain occupational activities and, most importantly, being overweight.
High-heeled shoes, on the other hand, seemed to actually reduce the risk of knee osteoarthritis, although this was probably a statistical aberration.
With regards to weight, a body mass index of 25 or above between the ages of 36 and 40 was most significantly associated with osteoarthritis of the knee.
Certain activities such as lifting and bending also seemed to be associated with the condition.
It's not entirely clear why some people thought that high heels contributed to osteoarthritis. "It was clinical speculation," hypothesizes study author Ray Fitzpatrick, a professor of public health at the University of Oxford in England. "One factor may have been that more women had osteoarthritis than men, but perhaps there was also a nonspecific belief that there's something unnatural about high heels."
Fitzpatrick counsels women (and men, for that matter) to turn their attention to the weight findings.
"We're not the first people to find that, and I think it's now quite clearly the single most preventable risk factor," he states. And by that he means overweight at any age, not just a younger age as was highlighted in this research. "This is a small study, and I wouldn't want you to think that current overweight is less important," Fitzpatrick cautions. "They are of similar importance, current overweight and overweight at an earlier stage."
"Weight is a major issue," confirms Dr. Giles Scuderi, chief of adult knee reconstruction at Beth Israel Medical Center in New York City. "Weight is a major cause of degenerative arthritis of weight-bearing joints."
Oddly, years of regular dancing in three-inch stilettos turned out to have a statistically significant association with knee osteoarthritis but, again, Fitzpatrick urges caution. "I'm not sure that we take that too seriously," he says. "I wouldn't want that to be over-interpreted."
So while scientists still don't know why women have a higher rate of knee osteoarthritis over the age of 65, it's safe to wear Manolo Blahniks at any age and perhaps even when you're dancing. However, there have been no studies done on how likely you are to fall down.
More information
For more on osteoarthritis, visit the Arthritis Foundation or the National Institute of Arthritis and Musculoskeletal and Skin Diseases.
