Both men and women are known to suffer from osteoarthritis, which is the most common form of arthritis. It is estimated that some 27 million Americans have the disease. Osteoarthritis is significantly more common among men under the age of 45, but after that age, the majority of osteoarthritis cases are in women. Lower-body osteoarthritis - of the knee, ankle, or hip - is more common in younger men, while hand arthritis, for example, is much more common in women, especially over the age of 50.
Why do so many more young men have issues with osteoarthritis than women? According to Patience White, MD, vice president for public health for the Arthritis Foundation and professor of medicine and pediatrics at the George Washington University School of Medicine, many young men with osteoarthritis have had some previous form of trauma to the joints. "When you injure the knee, for example, that requires surgery; such as when you tear cartilage, ligaments, or have other injuries of your knee joint, you are likely to have osteoarthritis in that joint within 10 years," she said. White continued, "Men generally are more involved with high impact sports than women, but in particular sports, like soccer or basketball, women have a high rate of injury as well. As more women are involved with sports and have major injuries to their knees, women are beginning to catch up to men with lower-body osteoarthritis at a young age."
In addition to sports injuries, White said that men tend not to gain as much weight as women early on, another significant risk factor in the development of osteoarthritis. According to White, "Carrying around a baby for nine to 12 months is a significant weight gain," where women often do not lose the weight from pregnancy and do not return to their pre-pregnancy weight. White also said that men often catch up with women in weight gain in their 50s.
Furthermore, research indicates that there could be a hormonal element in a woman's development of osteoarthritis. Estrogen may be a preventative of the breakdown of cartilage, where a decrease in estrogen levels after menopause led to a higher rate of arthritis in the hands. According to the NIH report, "women who take estrogen replacement therapy ... consistently report ... a lower prevalence of osteoarthritis than those women not taking estrogen." White states that there is not enough good evidence to back lower estrogen as a major risk factor for osteoarthritis, but there is a connection between genetics and osteoarthritis. She said that a rise in osteoarthritis cases in post-menopausal women, for example, may not only be based on loss of hormones. Weight, prior injury, and lack of physical activity, calcium, and vitamin-D can result in an increased risk for osteoarthritis. Loss of estrogen is probably not the only reason women have increased osteoarthritis."
However, White was clear about what she felt was the driving force behind increased rates of osteoarthritis: "Weight has become such an issue. For every pound you gain, it is the equivalency of 4 pounds across each knee," she said, "and we are beginning to see an increase of hip and knee arthritis in even younger people."
"Obesity dramatically increases the amount of stress that the weight-bearing joints must carry," Grant Cooper, MD, wrote in a piece for HealthCentral.com. Cooper continued, "Overweight women are four times more likely to develop arthritis... than non-overweight counterparts."
According to a study by Boston University, losing up to 11 pounds could decrease the risk of osteoarthritis by 50 percent in some women. In men, BMI tends to increase until age 50 before leveling off; in women, BMI does not plateau until age 70, aligning with osteoarthritis incidence across gender and age. If the increase in weight in all ages and genders continues, White states this BMI discrepancy will lessen with time.
As individuals live beyond 70 years, osteoarthritis seems to even out between men and women. "In a sense, your body does wear out; however, there are 100 year olds that do not have osteoarthritis," White said. "The effect of having any extra weight is exaggerated over the years if you have a joint that is not aligned correctly." White pointed back to the major risk factors for osteoarthritis -- injury, lack of activity, and weight -- as playing a much bigger role in the development of osteoarthritis in men and women of any age group than that of genetics or hormones. "These three factors have an exponential effect on the development of osteoarthritis."
White is involved in a public health awareness campaign through the Arthritis Foundation, where users can utilize a risk-assessment tool and access great information on osteoarthritis. The main message of FightArthritisPain.org is that movement is the best medicine for your joints; the goal is to help individuals take care of their joint health through education and learning their risk for osteoarthritis. "There is evidence that osteoarthritis pain and disability can be prevented - mention it to your doctor and take action."