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Leukemia incidence increasing among Hispanic children in California
Leukemia incidence increased in Hispanic children from 1990 to 2012, but declined in black and Asian/Pacific Islander children, according to the results of a prospective study conducted in California.
Research showed that from 1975 to 2012, the incidence of acute myeloid leukemia increased 0.8% yearly among children, and pediatric acute lymphoblastic leukemia incidence increased 1.1% yearly. Especially high leukemia rates have been reported among children in Latin America and Hispanic children in the United States.
“Given that high rates of leukemia have been reported among Hispanic children in the United States and internationally, California's large Hispanic population affords an important opportunity to examine the leukemia burden among Hispanic children,” Brenda M. Giddings, MA, research scientist for the California Cancer Reporting and Epidemiologic Surveillance Program at the Institute for Populations Health Improvement at University of California, Davis Health System, and colleagues wrote.
Giddings and colleagues used the California cancer registry to identify 11,084 children diagnosed with leukemia between birth and 19 years of age. The cohort included children who were non-Hispanic white (n = 3,699; 57% male; 77.3% ALL), Hispanic (n = 5,803; 56% male; 81.2% ALL), black (n = 497; 56.3% male; 65.2% ALL), and Asian/Pacific Islander (n = 1,085; 57.1% male; 71.95 ALL)
Non-Hispanic white children represented the reference population for age-adjusted incidence ratio comparisons.
Incidence of all leukemia disease types was higher among Hispanic children (standardized rate ratio [SRR] = 1.26; 95% CI, 1.21-1.32), but lower among black children (SRR = 0.06; 95% CI, 0.6-0.72).
ALL incidence was higher among Hispanic children (SRR = 1.32; 95% CI, 1.26-1.39), but lower among black children (SRR = 0.05; 95% CI, 0.49-0.62) and Asian/Pacific Islander children (SRR = 0.09; 95% CI, 0.84-0.98).
From 1990 to 2012, the annual percent change (APC) of childhood ALL was 1.1% (P .01).
ALL incidence also significantly increased in the following subgroups:
- girls (APC = 1%; P .01);
- boys (APC = 1.3%; P .01);
- all Hispanic children (APC = 1.1%; P .01);
- Hispanic girls (APC = 1.5%; P .01);
- all black children (APC = 1.9%; P = .03);
- black boys (APC = 2.8%; P .01); and
- Asian/Pacific islander boys (APC = 1.9%; P = .04).
Additional analyses stratified by age showed ALL incidence increased specifically among Hispanic males aged 15 to 19 years (APC = 2.5%; P .01), as well as among Hispanic females aged birth to 4 years (APC = 2.2%; P .01) and 15 to 19 years (APC = 1.9%; P = .05).
AML accounted for 17.8% of all leukemias diagnosed. Overall AML incidence did not appear to differ among racial/ethnic groups and remained stable from 1990 to 2012 (APC, 0.6%). However, the incidence of AML increased among:
- all Hispanic children (APC = 1.2%; P .01);
- girls (APC = 1%; P .01); and
- Hispanic girls (APC = 2.3%; P .01).
Additional subgroup analyses showed significant increases among Hispanic girls aged 15 to 19 years (APC = 3.4%; P = .03) and non-Hispanic white girls from birth to 4 years of age from 1998 to 2012 (APC, 6.3%; P = .03).
Leukemia types other than ALL and AML accounted for 4.2% of diagnoses and occurred more commonly among Asian/Pacific Islander children (SRR = 1.42; 95% CI, 1.07-1.86).
Researchers acknowledged that potential self-reported racial/ethnicity data and imprecise population estimates may have limited findings.
“The incidence of ALL and AML significantly increased among Hispanic children, predominantly among Hispanic females, and remained stable among non-Hispanic white children,” Giddings and colleagues wrote. “There is some evidence to suggest that racial/ethnic differences in childhood ALL incidence reflect differences in genetic susceptibility, as well as differences in patterns of carcinogenic exposure between populations.” – by Nick Andrews
Disclosure: The researchers report no relevant financial disclosures.