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

New Forecasting Methodology Indicates More Disease And Earlier Mortality Ahead For Today's Younger Americans

Traditional methods of projecting population health statistics, such as calculating future death rates, can give inaccurate results and lead to inferior or even poor policy decisions. A new “three-dimensional” method of forecasting vital health statistics is more accurate because it takes into account the delayed effects of the health risks being accumulated by today’s younger generations. Applying this forecasting technique to the US obesity epidemic suggests that future death rates and health care expenditures could be far worse than currently anticipated. We suggest that public policy makers adopt this more robust forecasting tool and redouble efforts to develop and implement effective obesity-related prevention programs and interventions

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

Population assessment of future trajectories in coronary heart disease mortality.

Background: Coronary heart disease (CHD) mortality rates have been decreasing in Iceland since the 1980s, largely reflecting improvements in cardiovascular risk factors. The purpose of this study was to predict future CHD mortality in Iceland based on potential risk factor trends. Methods and findings: The previously validated IMPACT model was used to predict changes in CHD mortality between 2010 and 2040 among the projected population of Iceland aged 25–74. Calculations were based on combining: i) data on population numbers and projections (Statistics Iceland), ii) population risk factor levels and projections (Refine Reykjavik study), and iii) effectiveness of specific risk factor reductions (published meta-analyses). Projections for three contrasting scenarios were compared: 1) If the historical risk factor trends of past 30 years were to continue, the declining death rates of past decades would level off, reflecting population ageing. 2) If recent trends in risk factors (past 5 years) continue, this would result in a death rate increasing from 49 to 70 per 100,000. This would reflect a recent plateau in previously falling cholesterol levels and recent rapid increases in obesity and diabetes prevalence. 3) Assuming that in 2040 the entire population enjoys optimal risk factor levels observed in low risk cohorts, this would prevent almost all premature CHD deaths before 2040. Conclusions: The potential increase in CHD deaths with recent trends in risk factor levels is alarming both for Iceland and probably for comparable Western populations. However, our results show considerable room for reducing CHD mortality. Achieving the best case scenario could eradicate premature CHD deaths by 2040. Public health policy interventions based on these predictions may provide a cost effective means of reducing CHD mortality in the future

THE CHOICE OF A SURVIVING SIBLING AS “SCAPEGOAT” IN SOME CASES OF MATERNAL BEREAVEMENT—A CASE REPORT

— This paper presents a description of a pathological variation of the mourning process in mothers who have suffered a narcissistically damaging psychological or actual loss of a child. A surviving sibling chosen as a displacement object for the mother's sense of guilt and self-hatred. The parent-child estrangement continues for years after the trauma with an extremity and severity that often necessitates court intervention. A case illustration is presented and a concluding suggestion that counseling by available professionals at the time of the bereavement would be both economical and effective in forestalling this variety of pathological family scapegoating.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73748/1/j.1469-7610.1975.tb00367.x.pd

Can a Topical Microbicide Prevent Rectal HIV Transmission?

Florian Hladik and Charlene Dezzutti discuss a macaque study of whether rectal simian immunodeficiency virus transmission can be prevented by topical pre-exposure application of tenofovir gel

Cognitive function and metabolic features in male Sprague-Dawley rats receiving high-fat and low-calorie diets

Background: Obesity is a risk factor for cognitive disorders. However, it is still unknown whether low-calorie diet will improve cognitive function in obese patients. Aim: To evaluate cognitive function and metabolic features in male Sprague-Dawley rats receiving high-fat and low-calorie diets. Materials and methods: The work was carried out on Sprague Dawley male rats (n = 32), which were divided into 2 groups with 16 animals in each group: Control (normal / low-calorie diet) and Obesity (high-fat diet). In 90 days the rats of the Control group were transferred to a low-calorie diet, the rats of the Obesity group continued to receive high-fat diet. To assess motor activity and cognitive functions at the end of the study (180 days), following behavioral tests were conducted: "open field", "tapering beam", "elevated plus-maze" (EPM) and "passive avoidance reaction". During the study glucose tolerance test were performed: at baseline (GTT 1) and in 30 days (GTT 2). Results: Obesity group rats gained weight significantly faster than the control animals (547.69 ± 11.32 g against 442.8 ± 19.8 g at study end, p = 0.0001). GTT 2 showed normal carbohydrate metabolism in control group, postprandial hyperglycemia in obesity group. Testing in the open field showed that the rats of the obesity group moved more actively across the installation area than the control ones: the total distance covered was 9.352 ± 0.932 m against 6.781 ± 0.951 m, p = 0.046. The results of a tapering beam test showed that the number of hind limb extrusions in obese rats significantly exceeded this parameter in control group (33.7 ± 3 vs. 15.7 ± 2.7, p = 0.0001), test time in both groups did not differ. When testing in EPM, there was no significant difference in any of the key test parameters between the groups. However, the number of looking out from the closed arms in animals of the obesity group was significantly higher than in the control group (4.19 ± 0.6 vs. 2.30 ± 0.58, p = 0.044). When testing the reproduction of conditional reactions of passive avoidance it was shown that after day 1 of the pain stimulation application the latent period of transition to the dark compartment in the obesity group was significantly higher than that of the control group (180.0 ± 0.0 vs. 128 86 ± 21.45, p = 0.008). This indicates a better preservation of the memorial trail compared to the "control" rats. By the end of the study 30% of animals in the control group died. Conclusions: Rats on high-fat diet were more active, less anxious and showed better results in training tests comparing to animals on low-calorie diet. Adherence to low-calorie diet may be harmful for cognitive functions