Why osteoarthritis is more common in women

Intermountain Healthcare May 16, Osteoarthritis: Why the Odds are Stacked Against Women Women get arthritis later than men — but when they do get it, it hurts more. More men get arthritis before the age of 55, but women then catch up quickly and overtake men in numbers.

And women with arthritis consistently report higher pain scores than men. Arthritis tends to affect different joints in women than men. Men get more arthritis in their hip joints; women in their hands and knees. Hormones play a role too. Estrogen helps keep inflammation in check, which is why younger women have less arthritis than men — but when levels plummet with menopause, arthritis often arrives.

Researchers are currently trying to tease out other complicated findings regarding how hormones shape arthritis risk, with apparent connections between age of puberty, childbearing and the use of hormone replacement therapy.

Extra weight means more arthritis. Obesity is more common in women than men. Excess weight puts pressure on the knee joints, eroding cartilage and therefore raising arthritis risk. For the new study, researchers set out to investigate whether there were differences in this information between men and women with osteoarthritis OA.

Study co-author Dr. For the study, the team analyzed samples of synovial fluid taken from the knees of men and women both with and without OA. The researchers focused on the exosomes of synovial fluid, which are vesicles within the fluid that carry small molecules called microRNAs miRNAs. These regulate gene expression. Specifically, they found that the synovial fluid of men showed 69 downregulated and 45 upregulated miRNAs, while the the synovial fluid of women had 91 downregulated and 53 upregulated miRNAs.

This microRNA activity was associated with 70 altered biological processes among women, compared with approximately 50 altered biological processes among men. Interestingly, the researchers found that women were more likely than men to show a deactivation or alteration of miRNAs that are important for estrogen signaling and collagen production. The team notes that lower estrogen levels — which normally arise as a result of menopause — are associated with a greater production of bone-destroying cells.

What is more, studies have linked hormone replacement therapy , which boosts estrogen levels, with a lower risk of OA. Taking this information into account, the researchers believe that their findings indicate that estrogen influences miRNA levels within the exosomes of synovial fluid. Further confirming their theory, the researchers found that blocking estrogen availability in exosomes using aromatase inhibitors led to a reduction in miRNAs.

Additionally, the study may have shed light on a cause of OA in both sexes. While the researchers are unable to explain the exact role of MiRp in OA, they believe that it may be involved in cartilage degeneration, which is the root cause of the disease. Based on this finding, Dr. Hunter and colleagues plan to conduct further studies, which will investigate the effects of MiRp inhibition on OA development. Incidence and risk factors for clinically diagnosed knee, hip and hand osteoarthritis: influences of age, gender and osteoarthritis affecting other joints.

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