In the United States there are disparities in life expectancy based on the racial, geographic, and socioeconomic make-ups of the counties in which people live. A study published this week in PLoS Medicine finds that four preventable risk factors — smoking, high blood pressure, high blood sugar and obesity—explain a good part of those differences.

 

Smoking, high blood pressure, high blood sugar, and obesity are preventable risk factors responsible for hundreds of thousands of deaths in the United States each year through chronic diseases such as cardiovascular diseases, cancers and diabetes. Together, these four risk factors are estimated to reduce life expectancy in the United States by 4.9 years in men and 4.1 years in women. The researchers calculate that disparities in life expectancy would decline by 20 percent if the four risk factors were reduced to optimal levels.

 

Goodarz Danaei of the Harvard School of Public Health and collaborators used information from national surveys to estimate the number of deaths that would have been prevented in 2005 if exposure to these four risk factors had been reduced. They estimated the effect of the risk factors on life expectancy in the United States as a whole, and also on the disparities in life expectancy and deaths from specific diseases among eight subgroups of the American population.

 

The researchers found that a person's ethnicity and where they live is a predictor of life expectancy and health. The Asian American subgroup had the lowest body mass index, smoking rates and blood sugar, while the white subgroups had the lowest blood pressure.

 

Blood pressure was highest in the U.S. black population, especially in the rural south; body mass index was highest in western Native American men and southern low-income rural black women; and smoking highest in western Native Americans and low-income whites in Appalachia and the Mississippi Valley. The effect on life expectancy of these factors was smallest in the Asian group and largest in low-income southern rural blacks.

 

The researchers said other factors, such as alcohol use and dietary salt, are also major contributors to disease, but they emphasize that public health interventions to reduce smoking, high blood pressure, blood sugar and obesity must be implemented and evaluated to improve the nation's health and reduce health disparities in the United States.