Biochemistry, Anatomy & Lifestyle Explain Why more Women Suffer from Arthritis.
Titles in bookstores remind us that women think, behave and feel differently than men. Even in health, diseases in women manifest and progress uniquely, and the effectiveness of medications varies. Scientific research informs us that women are also more vulnerable to arthritis. Such differences may be due to hormonal, genetic, biomechanical, and lifestyle differences between genders, contributing to disparities in men and women’s treatments. Understanding these gender-specific differences will help us treat women’s arthritis more effectively.
Cartilage is the tough, slippery tissue covering the ends of long bones. As we move our bodies and go about daily activities, healthy cartilage permits bones to smoothly and painlessly glide over each other.
In patients with arthritis, particularly osteoarthritis (AH-stee-oh-ar-THREYE-tis), the cartilage is worn away, causing the underlying bones to grind against each other, driving the pain.
X-ray of a woman’s knee showing signs of severe arthritis (left). Knee on the right appears normal. Women generally have wider hips resulting in the thigh bone making a larger “Q” angle at the knee, causing higher stresses in the cartilage.
In the very common knee osteoarthritis, walking can be very painful, and attended by swelling and stiffness. Arthritis also affects hips, hands, shoulders and spine. Cartilage breakdown can be due to normal wear and tear brought on by aging, or due to a previous injury to the joint.
Arthritis is widespread among U.S. adults and is the second most common diagnosis after chronic heart disease. The United States Center for Disease Control (CDC) reports that 46 million adults in the United States, representing 21% of the adult population, have arthritis (just over 1 in 5 adults). As the population ages, arthritis is expected to affect an estimated 67 million adults in the U.S. by 2030. Arthritis affects all races, and its risk increases with age. Compared to men, women bear a higher burden with 61% of all arthritis cases.
Osteoarthritis makes up more than half of all arthritis cases. Other forms include rheumatoid arthritis and gout. Not only do more women have arthritis, women are also more likely to suffer limitations in their day-to-day living, including difficulty climbing stairs, sleeping and walking.
Projected Prevalence of Arthritis in Women (pink) and Men (blue); From: Hootman & Helmick, Arthritis & Rheum (2006).
Women have Distinct Biochemical Profiles
Research indicates that hormonal differences may be one reason why women’s joints are susceptible to injury. Estrogen (es-tro-jen) is a key hormone, which makes women, women. Among other functions, estrogen protects cartilage in joints and increases production of its two important building blocks: collagen (KAHL-uh-jen) and proteoglycans (PRO-tee-uh-GLY-kanz). After menopause, there is a steep drop-off in a woman’s protective estrogen level, leaving joints deprived of these strengthening molecules. Day-to-day stress on the knee, along with repeated bumps and bruises can now make joints prone to long-term damage and osteoarthritis.
Growth factors promote tissue regrowth and are important in repairing the damage that occurs from daily activities. Scientific research indicates that levels of growth factors are significantly decreased in women with severe osteoarthritis. Women thus have a lower ability to repair soft tissue damage and end up with more severe cartilage damage.
Women Get More Knee Injuries
Researchers suggest that during athletic activities, women tend to favor their quadriceps muscles in the front of the thigh to stabilize the knee, instead of the stronger hamstring and gluteal muscles that support the back of the thigh. Especially during strenuous activities, this over reliance on the quadriceps, strains knee ligaments (fibrous bands connecting bones) leaving them more vulnerable to injury and tearing. Not surprisingly, compared to male athletes, female athletes are at a two to ten times greater risk of injuring their anterior cruciate ligament (ACL) – an important tissue band that controls knee joint motion. With a torn ACL, the knee can become unstable during day-to-day activities and lead to a higher risk of osteoarthritis.
Anatomic Differences May Lead to Arthritis
Anatomical differences in women’s hips and knees may also explain the increased severity of osteoarthritis in women. Women tend to have wider hips, so the femur (thighbone) reaches the knee at a larger angle (called the Q-angle) than in men (see x-ray above). Thus parts of the quadriceps muscles, which extend the knee, tend to pull the kneecap away from the centerline of the body, leading to eccentric wear of the kneecap and pain during climbing stairs.
There are other bone-related differences in women. For example, the femur is narrower and the kneecap (patella) is thinner in women, and more prone to cartilage wear and tear.
Delaying the Effects of Arthritis
There are a number of safe and effective ways to prevent or delay the impact of arthritis. These consist of improving joint flexibility with exercises such as yoga or Pilates, increasing physical exercise and losing excess weight. These have been shown to decrease arthritis pain and lessen associated disability. Medical treatment of osteoarthritis typically includes over-the-counter pain medications and muscle strengthening exercises. Dietary supplements may also be effective. If arthritis continues to be disabling, the last option is a surgical replacement of the joint.
Although women and men’s knees differ significantly, few treatments take such differences into account. As we continue to learn about the effect of specific hormones and anatomy on women’s arthritis, more targeted therapies can be used to improve the lives and alleviate the symptoms of our mothers, spouses and daughters.
cross-posted from my article on Aches & Joints
From our Archives: Try Simple Exercises at Home
Selected Resources on the Web:
- Arthritis at the Center for Disease Control
- Osteoarthritis at the National Institutes of Health