Book Reviews / Comptes rendus

This volume documents the objectives, rationale, design, methods, and results of the Baltimore Longitudinal Study on Aging (BSLA) in its first23 years of operation from 1958 to 1981. The book is divided into two sections. The first consists of 7 chapters which describe experimental designs for the study of aging, the results of other longitudinal studies, the design and operation of the BSLA, methods employed, an outline of cross sectional studies which involved volunteers from the BSLA, a summary of results of BSLA longitudinal studies, and future directions planned for the BSLA. The second section is an appendix in which 35 reports of longitudinal studies involving BSLA subjects are reprinted. The BSLA is one of the most significant enterprises ever undertaken to investigate the nature of aging. Since 1958, male volunteers have undergone physiological and psychological investigations for 2 to 3 days every 2 years or so. Advantages of this type of study are greater reductions in the confounding influences of birth-cohort effects and selective mortality, better information from which to develop predictive indices, and better resolution of aging from disease effects than is possible in cross-sectional studies. Disadvantages of the longitudinal study approach include changes in measurement techniques and investigators during the course of the study, subject attrition, difficulty in resolving secular effects which affect the entire population, and expense. These issues are considered carefully in the first part of the volume. The BSLA has contributed greatly to our understanding of some of the physiological and psychological aspects of aging, and has met many of its initial objectives. One feature of the study is that the subjects are highly selected, very well educated, and socially advantaged. The generalizability of findings to other populations remains to be determined. Recruitment of women subjects began in 1981, and, as the authors point out, this will help to address the issue of generalizability of the findings of the study. One of the objectives of the study is to determine risk factors for such end points as loss of mobility, loss of independence, and institutionalization. Little has been published in this area yet, nor has information about other such clinically important matters as changes in physical signs with age or the natural history of incontinence or falling; however, investigations in some of these areas are underway currently and their outcome is eagerly awaited.