IPR Research Notes

Environments Embodied: A New Look at Racial Disparities

Fall 2009 , Volume 31, Number 1

Christopher Kuzawa

When doctors could not pinpoint the source of African Americans’ elevated rates of heart disease, hypertension, and diabetes, most assumed genetics was the cause. But these and other health disparities could be the result of racism across generations, according to IPR anthropologist Christopher Kuzawa.

“Genes are important, the environment is important, but we are now learning that this is not the whole story,” Kuzawa said.

One missing piece is the malleability of the “epigenetic code,” or the process by which early environments can alter the chemical structure of chromosomes.  Whereas fetal under-nutrition and low birth weight were previously seen only as poor outcomes in and of themselves, they are increasingly being studied as markers of health risks much later in life.

In previous work, Kuzawa has examined the influence of fetal/infant nutrition and growth on adult health and function in the Philippines. The Cebu Longitudinal Health and Nutrition Survey follows more than 3,000 Filipino mothers, who were all pregnant in 1983, and their children—who are now young adults and having children of their own. Using this longitudinal data, Kuzawa and his collaborators measured blood pressure and other cardiovascular risk factors in young adulthood and linked it back to prenatal and early life conditions. They found that low birth weight actually augmented disease risk, especially when combined with other known predictors, such as adult weight gain. These results suggest that prenatal environments can lead to persistent changes in biology and health, with effects that linger far beyond childhood.

Now Kuzawa is bringing this intergenerational model of biology and health to the problem of U.S. health disparities. Evidence has already shown that maternal stress, whether nutritional or psychosocial, has harmful effects on the fetus, slowing the growth rate and altering epigenetic pathways. Kuzawa and former IPR graduate research assistant Elizabeth Sweet reviewed evidence linking problems faced by many in the African American community, such as discrimination and socioeconomic disadvantage, with maternal stress during pregnancy. Finding a strong correlation between maternal stress, low birth weight, and risk for cardiovascular disease in adulthood, their model emphasizes the important role of environmental factors in shaping “race-based” health disparities—and perpetuating those disparities across generations.

For more information about these and other IPR research projects, please visit www.northwestern.edu/ipr/.