Commonalities in Risk Factors for Age-Related Disease
A great deal of medical research into aging is built upon a foundation of correlation studies: what can we identify as more often occurring for patients who suffer from a particular age-related condition? Are there environmental factors, lifestyle choices, or genetic differences that are statistically linked to the occurrence of this condition? The next step that follows from the identification of such correlations is to pick them apart looking for commonalities. Why do these many correlations exist, and do they exist because of one underlying mechanism?
For example, see this open access paper that proposes chronic inflammation as the causative process for a range of correlations:
Tobacco smoking, physical inactivity and resulting obesity are established risk factors for many chronic diseases. Yet, the aetiology of age-related diseases is complex and varies between individuals. This often makes it difficult to identify causal risk factors, especially if their relative effects are weak. For example, the associations of both obesity and air pollution with several age-related diseases remain poorly understood with regard to causality and biological mechanisms. Exposure to both, excess body fat and particulate matter, is accompanied by systemic low-grade inflammation as well as alterations in insulin/insulin-like growth factor signalling and cell cycle control.These mechanisms have also been associated in animal and some human studies with longevity and ageing in more general terms. In this paper, it is therefore hypothesised that they may, at least in part, be responsible for the adverse health effects of obesity and air pollution.
Inflammation is very much a bugbear, and in recent years a great deal of research has focused on just how chronic inflammation and the failing immune system contributes to degenerative aging. Researchers are also making good progress on understanding exactly how excess fat tissue produces chronic inflammation and damages the immune system in the process.
Nicole M. Probst-Hensch (2010). Chronic age-related diseases share risk factors:
do they share pathophysiological mechanisms and why does that matter? Swiss Medical Weekly DOI: 10.4414/smw.2010.13072