Cardiovascular disease is the leading cause of death in the U.S. It caused 696,962 deaths in 2020.
According to the Department of Health and Human Services’ Office of Minority Health, Black Americans are 30% more likely to die from heart disease and 40% more likely to have high blood pressure than non-Hispanic white Americans.
Research has shown, however, that health outcomes vary between those who were born in the U.S. and elsewhere.
Immigrants in a country often have a health advantage over native populations, despite having a lower socioeconomic status and limited access to healthcare. Some researchers refer to this phenomenon as the “healthy immigrant effect.”
Whether the healthy immigrant effect relates to the cardiovascular health of Black people in the U.S. has been largely unclear. Research into the area may provide valuable information for preventive healthcare strategies.
In a recent study led by a team at Penn State University, researchers analyzed health and demographic data to assess health outcomes of Black people in the U.S. who had been born in or outside of the country.
They found that Black African-born individuals had lower rates of mortality from cardiovascular diseases and from all causes than Black individuals born in the U.S.
“Our finding that Black individuals who immigrated to the U.S. earlier (less than 5 years ago) and later (15 years ago or more) died at a lower rate than U.S.-born Black individuals was surprising, and our analysis could not explain this difference,“ says Dr. Alain Lekoubou Looti, an assistant professor at the Penn State Neuroscience Institute and lead author of the study.
“One potential explanation is the persistent ‘carryover’ effects from their country of birth, although this benefit fades with time,” he added.
The study will be presented at the American Heart Association’s International Stroke Conference 2022.
The researchers looked at health information from 2000–2014, taken from the National Health Interview Survey. This survey recorded self-reported health events, including stroke, as well as mortality data.
Altogether, they analyzed data from 64,717 individuals aged 25–74 years who self-identified as Black. They then identified as being born in the U.S., the Caribbean, Central or South America, or Africa.
According to Pew Research Center, as of 2019, 10% of Black people in the U.S. were immigrants and 58% of Black foreign-born people living in the U.S. had immigrated in 2000 or later.
Over the study period, 2,549 people reported a stroke. Meanwhile, 4,329 deaths were recorded. Of these, 205 were attributed to stroke and 932 to cardiovascular disease.
After analyzing the data, the researchers found that at a 10-year follow-up, people born outside of the U.S. had lower overall rates of all-cause mortality and mortality caused by cardiovascular disease or stroke.
All-cause, cardiovascular disease, and stroke mortality occurred among:
After controlling for demographic factors, the researchers found that people born in the Caribbean and Central or South America had lower rates of all-cause mortality and cardiovascular mortality than those born in the U.S., but similar stroke mortality rates.
And, after adjustments, the researchers still found that people born in Africa had lower all-cause mortality rates and tended to have lower cardiovascular mortality rates than people born in the U.S.
The team also noted that adjusting for smoking, body mass index, and time since migration did not significantly affect their findings.
As this study was observational, it does not explain the reasons behind the differences in health outcomes among Black people born inside or outside of the U.S.
When asked about the reasons for the results, Dr. Lekoubou Looti explained to Medical News Today that factors related to the so-called healthy immigrant effect may play a role:
“These factors include purported healthier lifestyle of foreign-born persons in their home country, better health than non-immigrants, and greater ability to endure stressors. Of course, we are just getting started, and more research is needed to test this hypothesis (healthy immigrant effect) and unveil other explanations to these differences.”
“Those who migrate to the U.S. quite frequently have better health than those who stay behind in their home countries,“ Dr. Mercedes Carnethon told MNT. Dr. Carnethon is a professor of preventive medicine at Northwestern University Feinberg School of Medicine and was not involved in the study.
“Moving to another country requires financial resources and connections and good baseline health to withstand the challenges associated with travel and relocation. The findings from this study are consistent with prior studies that include immigrants from other countries,” she noted.
Dr. Stephen Juraschek, a clinician investigator at Beth Israel Deaconess Medical Center, who was also not involved in the study, told MNT:
“It should be noted that some migrants to other countries often do not reflect that countries’ population. In fact, from the perspective of education, African migrants to the U.S. are among the most well-educated. These types of factors, which are difficult to measure, may also influence health outcomes, particularly when compared to the population of American-born adults.”
“Another hypothesis is that individuals born within the U.S. into racial and ethnic groups that have been historically marginalized and discriminated against have a lifetime of experiences that take a toll on their health,” explained Dr. Carnethon.
“For example,” she continued, “limited economic opportunity within families can translate into restricted access to health-promoting resources, including communities to live and work [in] and constrained access to healthcare. Over time, these limitations can build up — to lead to worse health behaviors and worse health outcomes. Immigrants coming from other cultures may face fewer of these insults to health.”
Dr. Juraschek agreed with these points and added that shift work, inconsistent healthcare access, and lifestyle factors, such as high sodium in processed foods and insufficient physical activity, may also contribute to the worse health outcomes that the researchers observed.
“The differences between Caribbean [or] South American and African migrants is also noteworthy and may require some more work to understand the factors behind these differences,” he added.
The researchers conclude that foreign-born Black Americans generally have lower all-cause mortality and cardiovascular-related mortality rates than Black people born in the U.S.
The study has certain limitations, due to its observational nature.
Dr. Lekoubou Looti explained: “A potential limitation of the study is that stroke was self-reported. Additionally, the relatively small number of outcomes of interest (all-cause mortality, [cardiovascular] mortality, and stroke mortality) could explain why we did not observe a difference in a specific mortality cause type, such as stroke mortality.”
Dr. Carnethon added that the study did not gather information about individual, interpersonal, and community-based factors that may have contributed to the results.
“For example, we don’t know whether individuals who come to the U.S. retain their diets from their home country and whether those diets are protective against the development of disease — in contrast to a U.S.-based diet, which is often high in processed foods with low nutritional value.”
“We don’t know whether cultural practices, including prayer or meditation, that are retained from one’s country of birth prove [to be] a stress reliever that allow immigrants to better manage the stressors of coming to a new country that has a different social structure,” she continued.
“Finally, even if we had information about whether immigrants engaged in these cultural practices and beliefs, we don’t know whether, if U.S.-born individuals adopted these behaviors, it would protect their health. This isn’t a clinical trial that would allow [us] to prove causality. However, what we observe is a pattern that suggests that something about immigration may be protective, whereas something about being born in the U.S. may threaten health,” she concluded.
When asked how these findings could inform public health, Dr. Lekoubou Looti, Dr. Carnethon, and Dr. Juraschek agreed that educating local and foreign-born populations about healthy lifestyles is key.
“Ensuring access to health-promoting resources — including healthy foods, safe spaces for physical activity, and opportunities to engage with the healthcare system for preventive care and not just emergency care — is important,” said Dr. Carnethon. “Making sure that all individuals are aware of what is available to them through existing community programs and policies can help.”
“Also, we should support those who immigrate to the country, because while we do show that their health outcomes are better, the longer they live in the U.S., the more they start to look like those who were born here. It is important to ensure that everyone, regardless of where they were born, is aware of what is available to them to promote health,” she added.
“In particular, it is important to caution migrants about fast and processed foods, emphasize the importance of home-cooked meals [and] the danger of latent high sodium levels, and explain how nutrition facts might be interpreted (or even obtained at restaurants) to make more informed food choices,” said Dr. Juraschek.
“It is also important to focus on healthcare access — to address the role [that] disparities in healthcare delivery play in contributing to worse health outcomes and delayed detection of disease.”
“These findings should provide a big spotlight, as well, on the poor outcomes among Black Americans living in the U.S. and highlight the urgency to address the racism, health disparities, and the social determinants contributing to the abysmal outcomes observed among this segment of the U.S. population.”
– Dr. Stephen Juraschek