01/08/2013 01:48 pm ET Updated Mar 10, 2013

The Global Burden of Disease and 'Big Science'

When we think of "big science," we think of research in subatomic particle physics, the Human Genome Project, the "war on cancer," all of which received considerable public press. It might come as a shock, therefore, that in 2012 one of the most important "big science" collaborative projects, called the "Global Burden of Disease 2010 Project," was quietly published without much fanfare. This comprehensive report, overseen by the Institute for Health Metrics and Evaluation in Seattle, Wash. and funded by the Bill and Melinda Gates Foundation, resets our view of the nature of global disease. The results of this study, published in The Lancet (Dec. 15, 2012; 380(9859): 2224-60), describes quantification of global disease burden attributable to 67 risk factors from 1990-2010. This project represented an enormous undertaking that involved hundreds of investigators across 291 diseases in 21 countries and a large team of bioinformatics and statistical experts to collate and analyze the data. No complete revision of global disease burden had been done since 2000, so this data is very important in evaluating trends in global health issues. The study evaluated the disability-adjusted life years (DALYs, sum of years lived with disability and years of life lost attributable to the independent effects of the 67 risk factors).

The results of this study were very revealing. Worldwide, the contribution of different risk factors to global disease burden has changed substantially, with a shift away from risks for communicable diseases in children towards those of for non-communicable diseases in adults. The results indicate that changes are related to a global reduction in mortality among children younger than five years, and that changes in cause of death composition are related to chronic diseases and associated changes in lifestyle risk factors. Over the years 1990 to 2010, the greatest increase in disability is ischemic heart disease (now number one -- an increase of 29 percent from number four in 1990), stroke (a 19 percent increase since 1990), depressive disorders (a 37 percent increase), and metabolic disease such as diabetes. As was stated in the summary of the study, "The global disease burden has continued to shift away from communicable to non-communicable diseases and from premature death to years lived with chronic disease. The rising burden from mental and behavioral disorders, musculoskeletal disorders, and diabetes will impose new challenges on global health systems."

In some sense, the rising prevalence of chronic disease is following a pattern of global expansion not unlike an infectious disease. Dr. Garry Egger, who is considered to be a leading authority in Australia on chronic disease, recently wrote an article titled "In Search of a Germ Theory Equivalent for Chronic Disease" (Preventing Chronic Disease 2012; 9: 95-99), in which he stated "The discovery of a form low-grade and chronic inflammation linked to inducers (broadly termed 'anthropogens') associated with modern man-made environments and lifestyles, suggests an underlying basis for chronic disease that could provide a 21st-century equivalent of the germ theory."

This data is critically important for setting health priorities across both developed and developing countries. The surprising revelation is that the rising burden of disease is similar among all countries regardless of socioeconomic status, and these increases are in cardiovascular, inflammatory, and metabolic diseases, which have historically been considered "Western diseases." This family of diseases is associated with "metainflammation" (i.e. metabolic inflammation), a concept in which a low-grade chronic inflammatory state is associated with a "hostile" gene-environment interaction. The solution to these problems lies in a better understanding of how to apply personalized lifestyle medicine.

Several recent clinical trials have demonstrated the value of implementing an intensive lifestyle medical program in reducing the progression and adverse health outcomes associated with insulin resistance and Type 2 diabetes. In a recent issue of the Journal of the American Medical Association (Dec. 19, 2012; 308: 2489-96), a study titled "Association of an Intensive Lifestyle Intervention With Remission of Type 2 Diabetes" was published. This study of lifestyle intervention programs in modestly overweight patients with Type 2 diabetes indicated that those who received the personalized intensive lifestyle program had a much greater likelihood of a partial remission of Type 2 diabetes compared with normal diabetes support and education. In a recent report in Diabetes Metabolism Research and Reviews (Dec. 28, 2012; 2: 79-84) it was pointed out that an individualized approach with careful consideration of the patient's risk and genetic status is needed to implement a successful intervention program. A report in the Archives of Internal Medicine (Dec. 10, 2012: 1-9) indicated that a personalized lifestyle medicine program can be successfully implemented in a primary care setting to reduce the incidence of Type 2 diabetes. A 13-year follow-up study of the impact of an intensive lifestyle intervention program in Type 2 diabetics found that the adjusted risk to diabetes was 39 percent lower in the lifestyle intervention group versus the control group over this decade-plus length of time. The conclusion of the principal investigators in this study: "Lifestyle intervention in people at high risk of Type 2 diabetes induces sustaining lifestyle change and results in long-term prevention of progression to Type 2 diabetes." (Diabetologia 2013; 56(2): 284-293.)

Taken together, the "big science" news for 2013 is that the global burden of chronic disease is increasing as the prevalence of communicable disease is decreasing, and that the solution to this changing pattern of disease is to move forward rapidly with advocacy for the development and deployment of both public health and personalized lifestyle medical programs to stem the rising tide of diseases associated with metainflammation.

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