BACKGROUND: The goal of this study is to estimate the long-term careneeds of the Hong Kong Chinese population age 70 years and older, and toidentify risk factors for institutionalization. METHODS: A three- yearprospective follow-up study was carried out in Hong Kong SpecialAdministrative Region, China. 2,032 subjects aged 70 years and older wererecruited territory-wide by stratified random sampling of the Old Age andDisability Allowance register, covering over 90% of the elderly population.A questionnaire was administered at baseline to obtain information onsocial, functional, physical, and mental health status, and place ofresidence. A repeat interview was carried out at 36 months. The number ofsubjects moving from home to institution or vice versa, and the number whohad died, were noted. Univariate analysis was performed to determine riskfactors for institutionalization, and backward stepwise multiple logisticregression was used to identify independent factors predisposing toinstitutionalization. RESULTS: The institutionalization rate per year isestimated to be 0.7% for the 70- 79 age group, and 1.5% for the 80+ agegroup. Using population figures projected by the Hong Kong Census, thecorresponding number of places required will be 24,150 and 42,000,respectively, for the two age groups by 2005, whereas the number ofgovernment subvented places projected to be available is unlikely to bemore than 40,000 for the whole population. Age, being a woman, beingsingle, not having a formal education, cognitive impairment, physicaldependency, and the presence of depressive symptoms were factorspredisposing to institutionalization. In multivariate analysis, age,marital status, and dependency were identified as independent factors.CONCLUSION: The requirement for institutional places is unlikely to be metby government, the shortfall likely to be met by the private sector.Maintenance of functional independence, good social support network,engagement in social activities, and good informal carer support may reducedemand for institutional care.