Press Releases: Northwest
April 27, 2005
International study of iron overload that included people in Oregon and Washington yields surprising results
Asians and Pacific Islanders have highest iron levels of all ethnic groups
PORTLAND, Ore. – The largest screening study of hemochromatosis and iron overload ever conducted shows that Asians and Pacific Islanders have the highest mean levels of iron in their blood, higher than all other ethnic groups involved in the study – African Americans, Caucasians, Hispanics, and Native Americans. The results were unexpected, since iron overload was thought to be more of a problem among Caucasians.
Elevated iron levels in the blood are sometimes associated with accumulations of iron in vital organs, which can lead to an increased risk of diabetes, arthritis, sexual dysfunction, liver disease and liver cancer and heart disease. At the start of the Hemochromatosis and Iron Overload Screening Study (HEIRS Study) in 1999, it was known that most cases of hemochromatosis in Caucasians resulted from mutations in the HFE gene (known as C282Y), which was first discovered in 1996. Little was known about iron overload in other racial and ethnic groups. Surprisingly, results of the HEIRS Study show that although Asians and Pacific Islanders have the lowest prevalence of HFE genetic mutations they had the highest blood iron levels. The full results of the screening study will appear in the April 28 issue of the New England Journal of Medicine.
The HEIRS Study recruited more than 100,000 participants in primary care settings and blood drawing laboratories at five field centers in the United States and Canada. The five-year study is funded by the National Heart, Lung and Blood Institute and the National Human Genome Research Institute. Other major findings of the study include the following:
· Caucasians had the highest prevalence of the HFE C282Y/C282Y genotype (4.4 per 1,000 people). The genotype was found in other ethnic groups at the following rates:Asians (3.9 per 10 million)
Hispanics (2.7 per 10,000)
African Americans (1.4 per 10,000)
Pacific Islanders (1.2 per 10,000)
Native Americans (1.1 per 1,000)
Most participants with the HFE C282Y/C282Y genotype had elevated levels of iron in the blood (measured by serum ferritin and transferrin saturation).
Men with the HFE C282Y/C282Y genotype were more likely to report a history of liver disease than participants without HFE mutations.
"Our findings about hemochromatosis and iron overload in Caucasians confirm findings from previous studies," says Emily Harris, PhD, co-author and principal investigator for the study’s field center at Kaiser Permanente Center for Health Research in Portland, "and our other findings help everyone better understand the prevalence of these conditions in other ethnic groups. The result that really surprised us was the finding that Asians and Pacific Islanders had the highest levels of iron in the blood, even though they had the lowest prevalence of the HFE C282Y/C282Y genotype. Does this mean that Asians and Pacific Islanders who have high levels of iron in the blood do not have hemochromatosis or iron overload, Ore. does it mean they have a different genetic mutation that has not yet been discovered? We’re hopeful that the later phases of this study, which involve a more detailed study visit and follow-up data on these participants from their physicians, will answer these important questions."
"Hemochromatosis is one of the most common inherited disorders," says Paul Adams, MD, lead author and principal investigator for the field center at London Health Sciences Centre in Ontario, Canada. "It can lead to iron overload, which if detected early, can be treated easily through regular blood draws. The problem is that it is difficult to diagnose early before severe complications have occurred. When the HEIRS Study is completed, we hope to have answers to the key questions that will help policymakers decide who should be screened for hemochromatosis and iron overload, when should they be screened, and what screening methods should be used."
The HEIRS Study is being conducted at five field centers in the United States and Canada:
- Howard University (Washington, D.C.)
- Kaiser Permanente Center for Health Research, Northwest and Hawaii (Portland and Honolulu)
- London Health Sciences Centre (London, Ontario)
- University of Alabama at Birmingham
- University of California, Irvine
The coordinating center for the study is located at Wake Forest University (Winston-Salem, NC). A central laboratory that tests blood samples from study participants is located at the University of Minnesota (Minneapolis). Funding for the study at Kaiser Permanente Center for Health Research, Northwest and Hawaii, totaled just under $5 million and was provided by the National Heart, Lung and Blood Institute and the National Human Genome Research Institute.
Kaiser Permanente’s Center for Health Research, founded in 1964, is a not-for-profit research institution whose mission is advancing knowledge to improve health.
Kaiser Permanente Northwest is a group practice health care organization providing health care services to about 465,000 people in Oregon and Southwest Washington.
