Imanaka T, Shichikawa K, Inoue K, Shimaoka Y, Takenaka Y, Wakitani S
Department of Rheumatology, Shichikawa Arthritis, Research Centre, Mie, Japan.
Ann Rheum Dis. 1997 May;56(5):313-6. doi: 10.1136/ard.56.5.313.
To determine changes in demographic variables and severity of rheumatoid arthritis (RA) that may have occurred during the 30 year period from 1960 to 1990 in Japan.
Using records of patients diagnosed with RA from two hospitals, demographic and clinical features at initial visit were compared between two groups, one from 1960 to 1965 (group I) and the other from 1985 to 1990 (group II).
Mean age at the time of onset of the disease increased significantly from 37.5 years in group I to 46.9 in group II. The peak age at onset of RA shifted from the third to the fifth decade between group I and group II. There was no obvious change in morbidity as determined by seropositivity, rheumatoid nodules, and assessments of hip involvement.
The age at onset of RA was delayed during a recent 30 year period in Japan. This increase in age at onset might result from environmental changes that occurred in Japan or may reflect a birth cohort phenomenon. Improvement of severity of disease was not found in this study.
确定1960年至1990年这30年间日本类风湿关节炎（RA）患者的人口统计学变量及疾病严重程度的变化情况。
利用两家医院确诊为RA患者的记录，比较两组患者初诊时的人口统计学和临床特征，一组为1960年至1965年（第一组），另一组为1985年至1990年（第二组）。
疾病发病时的平均年龄从第一组的37.5岁显著增加至第二组的46.9岁。RA发病的高峰年龄在第一组和第二组之间从第三年龄段转移至第五年龄段。通过血清阳性、类风湿结节及髋关节受累评估确定的发病率无明显变化。
在日本，近30年间RA的发病年龄有所推迟。发病年龄的增加可能是日本发生的环境变化所致，也可能反映了出生队列现象。本研究未发现疾病严重程度有所改善。
