Higher levels of iron have been linked to increased diabetes risk among European and European American (EA) populations; whether this is true for other populations where anemia is more common is unknown. Ferritin is an iron storage protein linked to diabetes risk; transferrin transports catalytic iron, reducing its oxidative damage. We tested whether proteomic measurements of ferritin and transferrin were associated with diabetes risk in a biracial cohort of current and former smokers. EA and African American (AA) participants from the COPDGene Cohort who were free of diabetes (n=4,671) at study baseline were followed for the incidence of diabetes. The Somascan was used on plasma measured at followup to determine relative amounts of proteins among participants. Logistic regression was used to calculate OR (95% CIs) of the cross-sectional relationship of natural log transformed ferritin and transferrin with diabetes risk. During an average of 5.6 years of follow-up, the incidence of diabetes was 7.9%. Ferritin was associated with increased diabetes risk (OR=1.29, 1.04-1.61), while higher transferrin linked with decreased risk (OR=0.19, 0.06-0.56) controlling for age, sex, BMI, hepcidin and smoking. When stratified by race, increased risk was associated with higher ferritin only among AA (OR=1.46, 1.07-2.01) and not for EA (OR=1.11, 0.81-1.52). Stratification by sex revealed that the relationship of ferritin was similar among AA men and women and EA women, with non-significant ORs ranging from 1.49-1.55; but null association among EA men (OR = 1.00, 0.65-1.52). Similarly, ORs for transferrin non-significantly ranged from 0.24-0.29 for AA men and women and EA women, but for EA men there was a significant 93% decreased risk for each natural long increase in transferrin (OR=0.07, 0.001-0.60). Our data suggest that higher body iron stores, as measured by ferritin, increases diabetes risk among both AA and EA. Ferritin may be a better marker for AA men and women and EA women while transferrin is a better marker for EU men.


R. B. Conway: None. K. Young: None. K. A. Pratte: None. G. L. Kinney: None. E. Austin: None. Y. Li: None. R. Bowler: None. D. A. Mcclain: None. J. Crappo: None.


National Heart, Lung, and Blood Institute (U01HL089897, U01HL089856); AstraZeneca; Bayer Pharmaceuticals; Boehringer Ingelheim; Genentech; GlaxoSmithKline; Novartis; Pfizer Inc.; Sunovion

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals.org/content/license.