Biodemographic perspectives for epidemiologists

A new scientific discipline arose in the late 20(th )century known as biodemography. When applied to aging, biodemography is the scientific study of common age patterns and causes of death observed among humans and other sexually reproducing species and the biological forces that contribute to them. Biodemography is interdisciplinary, involving a combination of the population sciences and such fields as molecular and evolutionary biology. Researchers in this emerging field have discovered attributes of aging and death in humans that may very well change the way epidemiologists view and study the causes and expression of disease. In this paper, the biodemography of aging is introduced in light of traditional epidemiologic models of disease causation and death

Pursuing the Longevity Dividend

The aging of humanity is about to experience a radical change as the demographic transformation to an older world is approaching its final stage. In recent decades, scientists have learned enough about the biological aging processes that many believe it will become possible to slow aging in humans. We contend that the social, economic, and health benefits that would result from such advances may be thought of as “longevity dividends,” and that they should be aggressively pursued as the new approach to health promotion and disease prevention in the 21st century. The time has arrived for governments and national and international healthcare organizations to make research into healthy aging a major research priority.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75679/1/annals.1396.050.pd

A biological approach to the interspecies prediction of radiation-induced mortality risk

Evolutionary explanations for why sexually reproducing organisms grow old suggest that the forces of natural selection affect the ages when diseases occur that are subject to a genetic influence (referred to here as intrinsic diseases). When extended to the population level for a species, this logic leads to the general prediction that age-specific death rates from intrinsic causes should begin to rise as the force of selection wanes once the characteristic age of sexual maturity is attained. Results consistent with these predictions have been found for laboratory mice, beagles, and humans where, after adjusting for differences in life span, it was demonstrated that these species share a common age pattern of mortality for intrinsic causes of death. In quantitative models used to predict radiation-induced mortality, risks are often expressed as multiples of those observed in a control population. A control population, however, is an aging population. As such, mortality risks related to exposure must be interpreted relative to the age-specific risk of death associated with aging. Given the previous success in making interspecies predictions of age-related mortality, the purpose of this study was to determine whether radiation-induced mortality observed in one species could also be predicted quantitatively from a model used to describe the mortality consequences of exposure to radiation in a different species. Mortality data for B6CF{sub 1} mice and beagles exposed to {sup 60}Co {gamma}-rays for the duration of life were used for analysis

Continuing the search for a fundamental law of mortality

for 170 years, scientists have attempted to explain why consistent temporal patterns of death are observed among individuals within populations. Historical efforts to identify a `law of mortality` from these patterns ended in 1935 when it was declared that such a law did not exist. These empirical tests for a law of mortality were constructed using mortality curves based on all causes of death. We predicted patterns of mortality consistent with the historical concept of a law would be revealed if mortality curves for species were constructed using only senescent causes of death. Using data on senescent mortality for laboratory animals and humans, we demonstrate patterns of mortality overlap when compared on a biologically comparable time scale. The results are consistent with the existence of a law of mortality following sexual maturity. The societal, medical, and research implications of such a law are discussed

Continuing the search for a fundamental law of mortality

for 170 years, scientists have attempted to explain why consistent temporal patterns of death are observed among individuals within populations. Historical efforts to identify a `law of mortality` from these patterns ended in 1935 when it was declared that such a law did not exist. These empirical tests for a law of mortality were constructed using mortality curves based on all causes of death. We predicted patterns of mortality consistent with the historical concept of a law would be revealed if mortality curves for species were constructed using only senescent causes of death. Using data on senescent mortality for laboratory animals and humans, we demonstrate patterns of mortality overlap when compared on a biologically comparable time scale. The results are consistent with the existence of a law of mortality following sexual maturity. The societal, medical, and research implications of such a law are discussed

The demographic components of population aging in China

Past trends in fertility and mortality in China have led to an age composition that will age rapidly in the coming decades. In this paper we examine measures of population aging in China from 1953 to 1982, and then project population aging to the year 2050 using a cohort-components methodology. The projected measures of population aging that result from these forecasts are then decomposed into the relative contributions that are made to these changes by past, present, and future trends in fertility and mortality. Results indicate that China's population will age at an unprecedented rate over the next 70 years, both in terms of the absolute size of the elderly population and their proportion of the total population. At least 50 percent of the projected increase in population aging in China between 1980 and 2050 will be a product of the momentum for aging that is already built into the present age structure and vital rates. However, prospective trends in the measures of population aging become increasingly more sensitive to varying assumptions about fertility and mortality with time, and as older age groups are considered. This analysis provides the demographic basis for evaluating the possible effects of population aging on health care, social security, and other social and economic issues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42989/1/10823_2004_Article_BF00120576.pd