Results of the largest and most diverse screening study of hemochromatosis and iron overload ever conducted ( HEIRS Study ), show that Asians and Pacific Islanders have the highest mean levels of iron in their blood of all other ethnic groups involved in the study – African Americans, Caucasians, Hispanics, and Native Americans. Elevated iron levels in the blood are sometimes associated with accumulations of iron in vital body 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 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 Asians and Pacific Islanders had the highest blood iron levels but the lowest prevalence of HFE genetic mutations.

The study has been published in the New England Journal of Medicine.

“ Hemochromatosis is one of the most common inherited disorders,” says John Eckfeldt, at the University of Minnesota, HEIRS central laboratory director, and the HEIRS Study steering committee chair. “ 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 findings about hemochromatosis and iron overload in Caucasians confirm findings from previous studies. The high levels of iron in the blood of Asians and Pacific Islanders is surprising because they had the lowest prevalence of the HFE C282Y/C282Y genotype.

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 ).

- HFE C282Y/C282Y prevalence rates in other ethnic groups were: Native Americans ( 1.1 per 1,000 ), Hispanics ( 2.7 per 10,000 ), African Americans ( 1.4 per 10,000 ), Pacific Islanders ( 1.2 per 10,000 ), and Asians ( 3.9 per 10 million ).

- 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.

Source: University of Minnesota, 2005


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