Cancer often seems to appear without warning. This can be particularly true for leukemia, as most types of this blood cancer do not appear heritable, meaning they do not usually run in families. Leukemia is a broad term for cancers that affect blood cells. Although we know that leukemia is caused by genetic mutations, it is still unclear what causes these mutations in the first place.
Researchers are investigating potential causes of leukemia, including underlying genetic and chromosomal differences, as well as exposure to radiation and chemicals. These appear to be factors associated with a higher risk of leukemia. Race and ethnicity also appear to be factors in the incidence of leukemia: People from certain racial and ethnic groups have been found to be at a higher risk of developing the condition. However, the reasons for this remain unclear.
Multiple studies involving childhood leukemias in the U.S. have revealed that white people appear to be most at risk for developing leukemia, whereas Black Americans appear to have the lowest risk. Moreover, some research has suggested that people of Asian descent face a greater risk of developing acute myeloid leukemia (AML) and that Hispanic Americans may have a relatively higher risk for childhood leukemia.
Black Americans appear less likely to develop leukemia. However, according to research from Scientific Reports, they have the lowest survival rates across all the subtypes of leukemia compared to Americans who are non-Hispanic white, Hispanic white, or Asian and Pacific Islander.
When medical professionals and scientists talk about risk in terms of disease, they are usually referring to whether or not certain factors appear associated with higher numbers of people acquiring a disease. Compared to Black Americans, white Americans appear to be at higher risk of leukemia, because higher numbers of white Americans were diagnosed with the condition over a certain period of time. That said, the fact that Black Americans experience worse outcomes and shorter lives as a result of leukemia represents a different kind of risk, one that practitioners and families should be aware of.
Leukemia has four main subtypes:
Other, more rare types of leukemia include hairy cell leukemia, acute promyelocytic leukemia, and chronic myelomonocytic leukemia. Since these types are more rare, there is less information about risk in regard to race and ethnicity.
ALL is most commonly diagnosed in childhood, constituting about one quarter of all pediatric cancers. One study of childhood cancer, centered in California, found that Black children were the least likely to develop ALL compared to white, Asian, and Hispanic children. Hispanic children were most likely to acquire ALL. The fact that Hispanics were found to be at the higher risk of ALL aligns with the data suggesting that Hispanics bear a disproportionate burden of all childhood leukemia.
Some researchers have observed that Black people with CLL are more likely than members of other races and ethnicities to have concurrent mutations in genes and chromosomes, as well as different levels of certain blood markers. These biological differences may explain in part why Black people with CLL have worse outcomes and tend to die sooner than white people with the condition. However, more research is necessary to confirm this. White Americans appear at most risk for developing CLL compared to minority populations.
Some research suggests that Asian people are at more risk of acquiring AML. AML is most commonly diagnosed later in life, with an average age of diagnosis being 66. However, AML is also diagnosed in childhood, with Hispanic people appearing at greater risk of acquiring AML at a young age.
Studies also have found that Hispanic and African Americans are less likely to receive treatment for AML. This could explain at least in part why Black people with leukemia continue to live shorter lives than people from different backgrounds. Researcher have found that poverty is linked to worse outcomes among African American people with AML
CML is the more rare of these four subtypes, and so it is least understood at this time. However, researchers have found that African Americans — particularly African American women — have shorter survival rates than other races. One study suggests that Black women may have heightened resistance to a common treatment for CML, making it less effective. However, further research is needed to verify this finding. White people appear disproportionately affected by CML, representing the highest numbers of cases.
More research needs to be done to fully understand the link between race, ethnicity and cancer.
Some of the disparities in different risk levels among ethnic and racial groups may end up being explained in different ways. For example, some researchers suggest that African Americans have lower survival rates for AML because they receive treatment less often. This can be due to numerous factors, such as living in areas far from treatment centers, lacking insurance to pay for treatments, or avoiding health care providers for numerous reasons. If these disparities are corrected in the future, will the overall survival rates of African American people with leukemia improve?
Questions regarding the prevalence of diagnosis may also warrant further investigation. Are white Americans diagnosed with leukemia more often than African Americans because more white people have access to health care providers who are able to make that diagnosis? Medical and social scientists in the United States have come together only in the past few decades to robustly research these kinds of questions. Together, they continue to work toward a more equitable future and a more full understanding of the ways race and ethnic status influence our health.
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