Women are affected by rheumatic diseases more often than men. The most common condition that affects the joints, osteoarthritis, is found more frequently in women than in men, and it is more disabling in women.

A woman's bone structure is different than a man's, especially in the knees, such that weight and impact cause degeneration of the knee faster in a woman than in a man. Osteoarthritis of the hand is also more common in women, and although a definitive cause has not been identified, genetic influences could be an important factor.

• Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) occur twice as often in women as in men.
• Sjogren's syndrome occurs 10 times more often in women than it does in men.
• Myopathies occur two to three times more frequently in women than men.

Rheumatic diseases called spondyloarthritis do affect men than women. Although the reasons for this are not known for certain, possible contributing factors include:

• The expression of a disease appears to be different in men than in women.
• Male hormones appear to suppress the immune system, while female hormones stimulate it.
• Some effects of rheumatic disease are related to the dose of hormones. Opposite effects may occur depending on the dose. The natural rise and fall in female hormones during the menstrual cycle and pregnancy, after giving birth, at menopause and while using oral contraceptives and hormone replacement therapy (HRT) also influences susceptibility to certain diseases.
• Genetic factors might further interfere with the roles of sex hormones in certain individuals who have these diseases.