Similarly, the Institute of Medicine (IOM) concluded in 2008 that there is limited or suggestive evidence of an association between Agent Orange or dioxin exposure and ischemic heart disease. The IOM based this decision on an approach that used all the available data from epidemiological, toxicological, and mechanistic studies. There are several challenges and limitations of the toxicological and epidemiological studies. In experimental animals, dioxin increases the severity and incidence of cardiomyopathy that is already present in aging rats. Similarly in humans, dioxin is not causing a unique cardiovascular disease, but increases the risk of developing ischemic heart disease, which has a significant background incidence. Thus there are a number of other risk factors that can influence the development of this disease. The epidemiological studies that the IOM evaluated and considered in their recommendations for ischemic heart disease varied considerably in their attempts to adjust or control for all the major risk factors of ischemic heart disease, such as, age, smoking, high blood pressure, diabetes and obesity. It should be noted that few of the studies attempted to control for all of these major risk factors. Also, the epidemiological studies have not attempted to compare the attributable risks of developing ischemic heart disease from dioxins to these other risk factors and have not reported the data in a manner that would allow the quantification of these comparisons. It may be possible to obtain some of this data and reanalyze it in order to address these questions. However, at present this analysis is not available.