INCIDENCE OF RHEUMATOID-ARTHRITIS IN CENTRAL MASSACHUSETTS

Objective. To determine whether there is a secular decline in the inci dence of rheumatoid arthritis (RA), as has been suggested by previous studies. Methods. In the absence of comprehensive data in the United S tates population, we estimated RA incidence in a health maintenance or ganization population from 1987 through 1990 and compared the rates wi th those in an earlier, similarly performed study from Rochester, Minn esota, which covered the years 1950 through 1974. RA estimates were ba sed on our review of medical records of patients who had been diagnose d as having RA or related diseases during the period of January 1, 198 7 through December 31, 1990. Results. Annual age-standardized incidenc e of classic or definite RA (according to the American College of Rheu matology [formerly, the American Rheumatism Association] 1958 criteria ) in patients aged 18 or older was 22 per 100,000 in men and 60 per 10 0,000 in women. The incidence of RA increased with age, with a marked increase in women older than 50. Conclusion. We found no secular chang e in RA incidence compared with the similarly ascertained historical d ata.