Millions of African Americans moved from the South in the early 20th century to seek better job opportunities and higher wages, but a new study on the historic Great Migration shows that with improved economic conditions came a greater risk of mortality

A study found that, on average, African Americans who migrated died 1.5 years sooner than their peers who stayed in the South. UChicago scholars were part of a study that found if an African American man lived to age 65, his chances of reaching age 70 were 82.5%, if he remained in the South. But if he migrated, those chances shrank to 75%. For an African American woman who lived to age 65, the likelihood that she would live to 70 in the South were 90% but dropped to 85% if she migrated. Medical records indicate that migrants died at much higher rates from cirrhosis and pulmonary illnesses, which are closely linked to smoking and drinking. Black said that there were other factors as well: chemicals and pollution from factories, higher population density (and, therefore, more contagious diseases), the shock of cold weather, and the stress from uneven employment prospects. "Migrants were a self-selected group: Many of them had been preparing all their lives to make the move, and everything suggested they'd be healthier than their counterparts in the South," said Dan Black, deputy dean and professor at the University of Chicago's Harris School of Public Policy Studies, who co-authored the study. "But it was shocking to learn that, in terms of longevity, the migrants weren't better off at all." Joining Black as co-authors were Seth G. Sanders of Duke University, Evan Taylor of the University of Michigan, and Lowell Taylor of Carnegie Mellon University and NORC at the University of Chicago. The authors believe that the study is the first attempt to establish a link between the Great Migration and mortality. Researchers constructed and examined the records of one million migrants extracted from the Duke SSA/Medicare Dataset — records containing information about each migrant's race, sex, age and, crucially, place of birth and death. Since most migrants came from towns near railroad lines, researchers studied old railroad maps and located links between "sending communities" and "receiving communities." Then they devised a formula to compare the longevity of people who had stayed in the South or migrated, limiting their focus to people born between 1916 and 1932 in eight states in the Deep South. "Our assessment of the long-term consequences of the Great Migration suggests that dislocation due to migration might have substantial costs in terms of individual health," Black said. He hopes that his research may be relevant for evaluating current trends in developing countries, many of which are experiencing extraordinary levels of migration from rural areas to urban centers.