BIOLOGICAL AND SOCIAL DETERMINANTS OF BODY-SIZE ACROSS THE LIFE-SPAN - A MODEL FOR THE INTEGRATION OF POPULATION-GENETICS AND DEMOGRAPHY

The accuracy of demographic models designed to project future trends o f population-level health and disease can be improved by incorporating biological data. One barrier to this process are quantitative charact eristics of the data themselves. Biological data are characteristicall y time-dependent phenomena that behave in a nonlinear fashion. To deve lop accurate projections of the morbidity, disability, and mortality e xperience among future cohorts in late life, research needs to focus o n development of models that create the opportunity to distinguish all -or-none, boundaries, and latency aspects of biological factors drivin g demographic phenomena, development of methods to identify time-depen dent effects, and development of genetically informative samples. This presentation focuses on the biology of adult body size, its behavior as a variable in statistical analyses, and strategies for the incorpor ation of this variable into demographic models of population aging in the United States. First, several examples of generally observed quant itative characteristics of biological variables are reviewed. To illus trate the nonlinear character of biological data, three general patter ns of change with aging are presented. Next, issues concerning the mea surement of body size are discussed. Scenarios describing body size ov er the adult life span are described. By the end of this process, reco mmendations for starting a dialogue between researchers interested in biological endpoints (individual weight change, disease risk) and thos e interested in demographic outcomes (population-level disease and dis ability issues) using body size will be presented.