COHORT PROFILE Cohort Profile: the Jerusalem longitudinal cohort study

Whilst it has been suggested that about 25% of the variability in human longevity is attributed to genetic influences, the remaining 75% is consequent upon a complex interplay of biological, environmental, social and culturally determined factors. In rising to the challenge of understanding the complexities of human ageing, a valuable tool to emerge in ageing research has been the longitudinal study, and early pioneering works in North America and Europe were instrumental in defining the emergence of modern geriatrics and gerontology. Undertaking such studies among diverse populations in different cultures is of value in furthering the understanding of universal ageing processes. Furthermore in many societies the oldest old are among the fastest growing sector of the population, and the need for basic definitions and descriptions of their patterns of need is a matter of pressing urgency for health care planners, ageing researchers and policy makers alike. After fruitful collaboration in the late 1980s with Alvar Svanborg, the leader of the Gottenberg Longitudinal Study of 70 year olds, we decided to initiate a long-term longitudinal study of ageing among Jerusalem residents, who are a uniquely heterogeneous elderly population, including immigrants from the America, Europe, Africa and Asia. The study, which was designed to follow a birth cohort from age 70 at baseline as they advanced with age, still remains the only such study of its kind both in scope and magnitude in the geographical region. Funding was provided in part by the Ministry of Health, the Ministry of Labor and Social Affairs, the National Insurance Institute (the Israeli Social Security administration), Eshel—the Association for the Planning and Development of Services for the Aged in Israel, as well as several private and charitable funds. Following a pilot feasibility study in 1989, with subsequent refinement of the study protocols and questionnaires, the Jerusalem Longitudinal Cohort study was established in 1990, with follow-up continuing up until the present time.