Changes in the incidence and prevalence of rheumatoid arthritis in England and Wales, 1970-1982.

Data from the Second and Third National Studies of Morbidity Statistics from General Practice, conducted from 1970 to 1972 and 1981 to 1982, respectively, by the General Practice Research Unit of the Royal College of General Practitioners, were analyzed to estimate morbidity rates of RA and examine changes in these rates over time. The age-adjusted annual incidence of RA in females fell from 3.3 to 2.6 cases per 1,000 person-years from 1970 to 1972 and 1980 to 1981; there was no change observed in males. Over the same time interval, there was a rise in age-adjusted period prevalence of RA in both sexes from 6.4 to 7.5 per 1,000 and 2.8 to 3.5 per 1,000 in females and males, respectively. These data, which should be interpreted with caution, confirm a decline in incidence of RA in females and demonstrate an increase in prevalence of RA in both sexes over the past decade.