International migrants who relocate to high-income countries to work, study or join family members are less likely to die prematurely than people born in their new homelands, a research review suggests.
For the analysis, researchers examined data from 96 studies with mortality estimates for more than 15.2 million international migrants in 92 countries.
Overall, migrants were about 30 percent less likely to experience premature death from all causes than other people in the general populations of the countries where they moved, the analysis found.
"Migrants to rich countries have lower rates of death due to most major disease areas compared to the general population," said lead study author Robert Aldridge of University College London in the U.K.
"We know from U.N. data that the majority of migrants to these rich countries tend to be moving for work or study," Aldridge said by email.
About 258 million people worldwide reside outside their countries of birth, accounting for more than 3 percent of the world's population, researchers note in The Lancet.
In many high-income nations, public perception that migrants place an undue burden on society in general and on health resources in particular has led to restrictions on migrants' access to care, the authors write.
But the current analysis suggests that, if anything, migrants may use fewer health resources than native-born residents, Aldridge said by email.
Diseases, external causes
The only causes of death that were more common among migrants were infectious disease and external causes like homicide, the analysis found.
Immigrants were 28 percent more likely to die of external causes and more than twice as likely to die of infectious diseases such as tuberculosis, hepatitis and HIV than people who were born in their adopted homelands.
However, immigrants were less likely to die from a variety of other causes including heart disease, digestive disorders, endocrine or circulatory problems, mental health disorders, cancers or diseases of the respiratory or nervous systems.
Both men and women appeared to have a longevity advantage after migration. Male immigrants were 28 percent less likely to die prematurely from all causes than native-born men, while female immigrants were 25 percent less likely to die prematurely.
The vast majority of the studies in the analysis focused on migration to high-income countries, not on refugees or asylum seekers. Researchers also excluded studies from their analysis that focused just on migrants with serious or chronic health problems or just on maternal and infant health outcomes.
It may be, however, that migrants in the study were healthier than people in their native countries who didn't migrate, said Anjali Borhade, director of the Disha Foundation in Gurugram, India, and co-author of an editorial accompanying the study.
"Educated migrants have better sources of income and being healthy doesn't affect their choice to migrate," Borhade said by email. "Also, educated migrants have better living or working conditions and their health status is similar to the host populations, both for risks as well as outcomes."
Infectious disease and homicide deaths may be higher among migrants than other people in the general population because of unfavorable conditions immigrants face at work and in their new communities, Borhade added. That's because many young, relatively healthy migrants may take low-paying and dangerous jobs and only be able to afford housing in subpar conditions.
"Hazardous jobs and low living conditions increase their risk of dying due to external causes and infectious diseases," Borhade said. "However, since migrants are healthier to begin with, their mortality due to other causes might be lower."
