RHEUMATIC DISEASES IN CHINA - ILAR-CHINA STUDY COMPARING THE PREVALENCE OF RHEUMATIC SYMPTOMS IN NORTHERN AND SOUTHERN RURAL POPULATIONS

Objective. To determine the prevalence of rheumatic diseases in Han Ch inese in north and south China. Methods. Samples of 4192 adults in the Beijing (north) and 5057 in the Shantou (south) areas, based on villa ge administration registers, were studied. The same questionnaire was administered by doctors who then examined those with rheumatic symptom s. One observer (QYZ) took part in both studies. Results. The prevalen ce of definite rheumatoid arthritis (RA) was 0.3 4% (95 % CI; 0.20-0.5 1) in the north and 0.32 % (0.16-0.47) in the south. Ankylosing spondy litis (AS) was noted in 0.26 %; of both samples (95 % CI; 0.11-0.32 no rth and 0.14-0.40 south). Only 3 cases of systemic lupus erythematosus (SLE) in the north and one in the south were identified, General rheu matic pain was reported more frequently in the north. Lumbar problems were recorded on examination 5 times more frequently in the north than in the south [men, 25 %:5.3 %; women 38 %:6.5 %] and knee problems 10 times more frequently [men, 24 %:1.8 %; women, 36 %:3.4 %] in the nor th. The difference was greatest in the 55 to 64 year age group. Conclu sion. The prevalence of RA was similar to that in other rural populati ons and Japan, but only half that reported from other industrialized c ommunities. The prevalence of AS was similar to that in most Caucasian populations. SLE was too infrequent to establish a prevalence with co nfidence, but did not differ from that in other populations. A study i s planned in the south to assess the contribution of interobserver err or and/or differences in cultural response to the north/south differen ces observed in the prevalence of general rheumatic symptoms and back pain.