Incidence rates vary among the autoimmune diseases, with estimates ranging from prevalence rates less than 5 per 100,000 (e.g. chronic active hepatitis, uveitis) to more than 500 per 100,000 (Grave disease, rheumatoid arthritis, thyroiditis). At least 85% of thyroiditis, systemic sclerosis, systemic lupus erythematosus, and Sjögren disease patients are female. Although most diseases can occur at any age, some diseases primarily occur in childhood and adolescence (e.g. type 1 diabetes), in the mid-adult years (e.g. myasthenia gravis, multiple sclerosis), or among older adults (e.g. rheumatoid arthritis, primary systemic vasculitis).