An article published on March 23, 2010 in the journal PLoS Medicine reveals the conclusions of researchers from the Harvard School of Public Health and the University of Washington that smoking, high blood pressure, elevated blood glucose, and being overweight or obese decrease life expectancy by an average of 4.9 years for U.S. men and by 4.1 years for women.
Harvard School of Public Health associate professor of international health Majid Ezzati and associates evaluated 2005 data from the National Center for Health Statistics, the National Health and Nutrition Examination Survey and the Behavioral Risk Factor Surveillance System, along with a review of epidemiologic studies concerning the effects of these factors. They also estimated the risk factors' effects on 8 eight U.S. subgroups including Asians, Northland low-income rural whites, middle America, Appalachia and Mississippi Valley low-income whites, Western Native Americans, black middle America, high-risk urban blacks and Southern rural blacks.
Dr Ezzati and colleagues estimated the amount of deaths that would not have occurred in 2005 if exposure to the risk factors had been reduced to optimal levels or common guidelines. Elimination of obesity was calculated to increase life expectancy by an average of 1.3 years, normalization of hypertension was estimated to result in an added 1.5 years for men and 1.6 years for women, smoking cessation was correlated with an extra 2.5 years for men and 1.8 years for women, and optimization of blood glucose was estimated to confer an extra 0.5 years on male life expectancy and 0.3 years on that of females. Among those who had all four factors, Southern rural blacks experienced the greatest reduction in life expectancy and Asians had the least reduction. The four factors were determined to account for nearly 20 percent of U.S. life expectancy disparities, 75 percent of cardiovascular mortality disparities, and 50 percent of cancer disparities.
The investigation is the first to examine the consequences of these preventable risk factors on life expectancy across the United States. "This study demonstrates the potential of disease prevention to not only improve health outcomes in the entire nation but also to reduce the enormous disparities in life expectancy that we see in the U.S.," Dr Ezzati commented.
"It's important that public health policy makers understand that these behavioral and metabolic risk factors are not just personal choices or the responsibility of doctors," added lead author and Harvard School of Public Health postdoctoral research fellow Goodarz Danaei. "To improve the nation's overall health and reduce health disparities, both population-based and personal interventions that reduce these preventable risk factors must be identified, implemented, and rigorously evaluated."