Initial Screening Transferrin Saturations, Serum Ferritin Concentrations, and HFE Genotypes in Whites and Blacks in the Hemochromatosis and Iron Overload Screening (HEIRS) Study.

We compared initial screening data of 44,149 whites (17,043 men; 27,106 women) and 26,947 blacks (9,788 men; 17,159 women) who reported no previous diagnosis of hemochromatosis or iron overload from a primary care-based sample of ~100,000 adults ≥25 years recruited from 5 Field Centers. Each underwent transferrin saturation (TfSat) and serum ferritin (SF) measurements without regard to fasting, and HFE C282Y and H63D genotyping. We observed these mean TfSat and SF values and percentages of participants with elevated biochemical measurements (TfSat >50% and SF >300 ng/mL, men; TfSat >45% and SF >200 ng/mL, women):

In participants grouped by decade, mean TfSat was greater in white men than in black men, and in white women than in black women (all p<0.0001). Mean SF was greater in black men than in white men in all decades except 25–34 years, and in black women than in white women in decades ≥45 years. SF increased with age to ~45 years in white men and ~50 years in black men, and then decreased. In white women, SF rose with age until ~62 years and less rapidly to age ≥80. In black women, SF rose with age until ~62 years and then decreased. C282Y allele frequency was 0.0700 (95% CI: 0.0683, 0.0717) in whites and 0.0119 (0.0110, 0.0129) in blacks. H63D allele frequency was 0.1532 (0.1509, 0.1556) in whites and 0.0299 (0.0284, 0.0313) in blacks. Frequencies of genotypes with C282Y or H63D were greater in whites than in blacks (all p<0.0001). The prevalence of elevated TfSat and SF plus genotype C282Y/C282Y was 0.003 in whites and 0.00004 in blacks (p<0.0001). The prevalence of elevated TfSat and SF plus genotype C282Y/C282Y, C282Y/H63D, or H63D/H63D was 0.006 in whites and 0.0003 in blacks (p<0.0001). We conclude that: 1) the prevalence of elevated TfSat is higher in whites and the prevalence of elevated SF is higher in blacks; 2) SF levels increase with age; 3) HFE C282Y and H63D alleles occur more frequently in whites than in blacks; and 4) the prevalence of elevated TfSat and SF plus genotypes with two common HFE mutations is greater in whites than in blacks.