Women
have osteoarthritis, the most common form of arthritis, at much higher
rates than men. Experts estimate that almost 27 million people in the
United States have osteoarthritis, and that about 60 percent of them
are women. Before age 55, more men tend to have osteoarthritis, but
after age 55 the number of women with the condition far surpasses the
number of men.
Joints affected by osteoarthritis also tend to
vary by gender, says Alexander Shikhman, MD, PhD, founder of the
Institute for Specialized Medicine in Del Mar, Calif., and medical
director of Restorative Remedies. Men are more prone to experience
arthritis in their hips, while women tend to have it in the knees or
hands, he says.
There are several reasons why these differences occur. They include:
- Biology. Women’s
bodies are designed to give birth, and that means the tendons in their
lower body are more elastic than men’s. “As a result, the joints
probably move around a little more,” says Yusuf Yazici, MD, a
rheumatologist at New York University Hospital for Joint Diseases in
New York. When the joints have less stability, they’re more prone to
injury.
Also, because women’s hips are wider than their
knees, their knee joints are not aligned as straight as men’s, Dr.
Yazici says. The alignment of a woman's body leads to a higher rate of
knee injuries, and injuries can lead to osteoarthritis
later in life. Experts have found that women who play soccer, for
instance, have at least three to four times the number of knee injuries
as men who play soccer, Yazici says.
- Genetics. Osteoarthritis
seems to run in families, and there appears in particular to be a
genetic link among women. Women whose mothers developed osteoarthritis
will probably find that they will develop it in the same joints at
around the same age as she did, Yazici says. Researchers have found
that hand and knee osteoarthritis have specific genetic links.
- Hormones. Researchers
believe that female hormones have an effect on the cartilage that sits
between the bones of the joints and cushions the bones to prevent pain
and allow the joints to move about smoothly. In laboratory studies of
cells that form cartilage, experts have found that the female hormone
estrogen protects cartilage from inflammation, Dr. Shikhman says.
Inflammation can lead to osteoarthritis. But after menopause,
when women’s estrogen levels go down, they lose that protection and may
have a higher risk of developing osteoarthritis even if they are on hormone-replacement therapy (HRT).
A
recent study of 1.3 million women in their 50s found that hormonal and
reproductive factors, such as going through puberty at an early age,
having more children, and taking hormone-replacement therapy, were all
related to whether they had had knee or hip joint replacement surgery, but the researchers don't know what these connections mean.
The
study also found that women who started menstruating at age 11 or
earlier had a 9 to 15 percent higher risk of needing hip and/or knee
replacement surgery as an adult. Additionally, women who used
hormone-replacement therapy after menopause were at significantly
higher risk for hip and knee replacement surgery.
Giving
birth was another risk factor for osteoarthritis found in this study.
Researchers calculated that with each birth, the woman’s risk of
needing knee replacement rose by 8 percent, and for hip replacement by
2 percent.
Although taking birth control pills seemed to have
no effect on osteoarthritis risk, using HRT increased the risk that a
woman would undergo knee replacement by 58 percent, and hip replacement
by 38 percent . Researchers did note, however, that women who take HRT
might be in more frequent contact with their doctors and may have
better health care, which could explain why they were more likely to
have joint replacement surgery.
- Obesity. Statistics show that more women than men are obese or severely obese, and obesity
plays a major role in osteoarthritis, Yazici says. Extra weight puts
more pressure on joints and can cause the cartilage between joints to
wear away faster. With every extra pound you gain, you add three pounds
of pressure to your knees and six pounds of pressure to your hips,
according to the Arthritis Foundation.
Also, women who have
gone through menopause tend to have more belly fat, which puts more
pressure on the lower joints, Shikhman says.
Higher Numbers, but Different Treatment
Although women have osteoarthritis in higher numbers than men, a recent
study found that doctors are less likely to recommend joint replacement
surgery to women who have knee pain, compared to men.
For the
study, which was done in Toronto, researchers sent both men and women
with osteoarthritis of the knee to 67 different family physicians and
orthopedic surgeons. The men were twice as likely to get a
recommendation for knee replacement surgery, the researchers wrote.
The
reason could be that men are seen as being more active than women,
Yazici says. “When you’re not that active, doctors tend to manage your
arthritis more conservatively,” he says. People who play tennis, for
instance, will need the use of their knees more than someone who works
a desk job.
But the real gauge of whether joint replacement
surgery is needed is your pain level, Yazici says: “If you can’t
adequately control pain with oral medications, injections, weight loss,
or physical therapy, that’s the number one indication for having
surgery.”
That's also why it’s important to be open with your
doctor about your level of pain and how often you experience it. Don’t
forget to talk about how you are functioning in daily activities: If
you can’t go up and down stairs or walk more than a block without pain,
let your doctor know. Having a discussion about how pain is affecting
or limiting your life will help you to get the best care possible for
your osteoarthritis.
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