Epidemiology of the rheumatic diseases.

Emerging osteoarthritis studies suggest that certain occupations are associated with a high risk for development of hip and knee osteoarthritis, at least in men. The main activities identified are regular lifting for the hip and knee bending for the knee. Obesity is a well-known risk factor for the knee, and it has been suggested that this risk can be halved by losing weight. Studies of the natural history of knee osteoarthritis suggest that many individuals do not develop osteoarthritis, although precise prognostic indicators are lacking at present. No new etiologic information on rheumatoid arthritis has appeared recently, although hormonal and reproductive factors in women continue to be studied with variable results. Agreement is slowly being reached on how to define vertebral fractures for epidemiologic study, which should produce more consistent results. In a study from Rochester, Minnesota, US incidence rates were produced for clinically diagnosed vertebral fracture (117/100,000) that are similar to hip rates, although they occur at an earlier age. Continued study of risk factors continues to show them to be of little use in screening. In systemic lupus erythematosus, hair dyes have not been confirmed as a risk factor, although there may be a link with domestic pets. There are conflicting data on the roles of obesity and occupational factors in carpal-tunnel syndrome.