Immunogenetics, gender, and longevity

Abstract

In this article we discuss relevant data on aging, longevity, and gender with particular focus on inflammation gene polymorphisms which could affect an individual's chance to reach the extreme limit of human life. The present review is not an extensive revision of the literature, but rather an expert opinion based on selected data from the authors' laboratories. In 2000-2005 in the more developed regions, the life expectancy at birth is 71.9 years for men (78.3 in Japan) and 79.3 years for women (86.3 in Japan). Indeed, gender accounts for important differences in the prevalence of a variety of age-related diseases. Considering people of far-advanced age, demographic data document a clear-cut prevalence of females compared to males, suggesting that sex-specific mortality rates follow different trajectories during aging. In Italy this female/male ratio is relatively lower (about 5/1; F/M ratios are usually 5-6:1 in other developed countries), but significant differences have been observed between Italian regions in the distribution of centenarians by gender--from two women per man in the South to more than eight in certain regions in the North. Thus, a complex interaction of environmental, historical, and genetic factors, differently characterizing the various parts of Italy, likely plays an important role in determining the gender-specific probability of achieving longevity. This can be due to gender-specific cultural and anthropological characteristics of Italian society in the last 100 years. Age-related immunoinflammatory factors increase during proinflammatory status, and the frequency of pro/anti-inflammatory gene variants also show gender differences. There is some suggestion that people genetically predisposed to weak inflammatory activity may be at reduced chance of developing coronary heart disease (CHD) and, therefore, may achieve longer lifespan if they avoid serious life-threatening infectious disease thoroughout life. Thus, the pathogen burden, by interacting with host genotype, could determine the type and intensity of the immune-inflammatory response responsible for both proinflammatory status and CHD. These findings point to a strong relationship between the genetics of inflammation, successful aging, and the control of cardiovascular disease, but seem to suggest that the evidence for men is much stronger. The importance of these studies lies in the fact that half of the population (males) lives approximately 10% shorter lives than the other half (females). Understanding the different strategies that men and women seem to follow to achieve longevity may help us to comprehend better the basic phenomenon of aging and allow us to search for safe ways to increase male lifespan.