Trends in the incidence of hip fracture in Japan, 1987-1997: the third nationwide survey.

The third nationwide survey for hip fracture incidence was conducted in 1997 following the first such survey in 1987 and the second in 1992. The purpose of this study was to investigate the trends in the incidence and regional distribution of this disease during 10 years. Of 10271 orthopedic institutions in Japan, 4503 were selected as subjects for the study using the optimum allocation method. Questionnaires concerning new patients with hip fracture were mailed. The replies were obtained from 2930 institutions by the end of December 1998; the response rate was 65.1%. The number of new patients was estimated to be 89900-94900 [mean, 92400; 20100-21400 (20800) men and 69600-73600 (71600) women]. The number of cases in 1997 was about 1.7 times higher than that in the first survey and 1.2 times higher than that in the second survey. The age-specific incidence (per 10000 per year) in men and women in 1997 was 0.30 and 0.13, respectively, for age under 40 years; 0.91 and 0.60, 40-49 years; 2.00 and 2.39, 50-59 years; 5.12 and 9.07, 60-69 years; 17.3 and 40.8, 70-79 years; 57.4 and 147.8, 80-89 years; and 128.9 and 281.0, for age over 90 years. The incidence was increased compared with that of the first survey, and similar to the second survey, excepting that of women aged 80 years or older. Concerning regional differences, hip fracture incidence was relatively low in the eastern area compared to the western area in Japan, which was a trend identical to that in the previous nationwide surveys.