Kichizou Yamamoto

Hip fracture incidence in Japan

The purpose of this study was to determine incidence and regional distribution of hip fracture throughout Japan. The incidence rate of hip fracture in Japan was estimated by a nationwide survey for departments of orthopedics of all hospitals with 200 beds or more and supplementary survey for all medical institutions in three prefectures.The mail survey was used in main and supplementary survey. The mail questionnaire included items such as the number of new patients seen during 1 January through 31 December 1987 regardeless of cause of fracture, and also sex, age and address of each patients.According to these two surveys, the incidence of hip fracture in Japan was estimated to be approximately 41,000–48,000 (males 10,400–12,000, females 30,600–36,000) in 1987. Incidence rate of hip fracture increased approximately exponential throughout life. The incidence rate was 22–26 per 10,000 persons in females aged 70–74 and 118–139 in those aged 85–89.As regards regional differences, incidence for females showed to be higher in the western region than in the eastern, while such tendency was not observed in males.A further epidemiological survey will be necessary to elucidate regional differences of hip fracture.

Hip fracture in elderly Japanese women; a review

Some papers have reported the incidence ratio of hip fractures. According to those studies, the age-adjusted incidence in Japan is one-half or onethird of that in Europe or North America(1L This difference and related factors were not clearly explained. In order to investigate potential risk factors, we carried out a case-control study. One hundred hip-fracture cases aged 60 and over were chosen and an equal number of agematched controls, diagnosed with osteoporosis, were selected (Table 1). The average age was 75.5 for cases and controls. Information on stature, labor, food, milk, drinking or smoking and lifestyle was obtained by mailed questionnaires sent to patients directly. Relative risk was estimated and tested by the McNemar Method. Lean stature, food shortages in their youth, low milk intake, drinking or smoking and a chair lifestyle (compared with a TATAMI lifestyle) were related to hip fractures (Table 2) . Although the relative risk for habitual drinking was 0.78, heavy drinkers were found only in the case group. Heavy smokers were also more prevalent in the case group than in the control group. Hip fracture is related both to bone fragility and to force upon the bone. Therefore we investigated risk factors in respect to osteoporosis and falls. Lean stature may be associated with fractures for both reasons. Lean women, generally, are smaller boned and have less fat which may offer cushioning protection during a fall. Other studies of hip fractures ~2), as well as this study, found that the thinnest women are at somewhat higher risk for fractures. Heavy physical labor during younger ages may have some beneficial influence on bone