The association of biomarkers of iron status with mortality in US adults

Background and Aims: Elevated iron biomarkers are associated with diabetes and other cardiometabolic abnormalities in the general population. It is unclear whether they are associated with an increased risk of all-cause or cause-specific mortality. The purpose of the current analysis was to evaluate the association of ferritin and transferrin saturation levels with all-cause, cardiovascular, and cancer mortality in the general US adult population. Methods and Results: A prospective cohort study was conducted with 12,258 adults participating in the Third National Health and Nutrition Examination Survey (NHANES III), a nationally representative sample of the US population. Study participants were recruited in 1988-1994 and followed through December 31, 2006 for all-cause, cardiovascular disease, and cancer mortality. The multivariable-adjusted hazard ratios (95% confidence interval) for all-cause mortality comparing the fourth versus the second quartiles of ferritin and transferrin saturation were 1.09 (0.82-1.44; p-trend across quartiles = 0.92) and 1.08 (0.82-1.43; p-trend across quartiles = 0.62), respectively, for men, 1.43 (0.63-3.23; p-trend across quartiles = 0.31) and 1.48 (0.70-3.11; p-trend across quartiles = 0.60), respectively, for premenopausal women, and 1.03 (0.79-1.34; p-trend across quartiles = 0.95) and 1.17 (0.92-1.49; p-trend across quartiles = 0.63), respectively, for postmenopausal women. Quartile of ferritin and transferrin saturation also showed no association between biomarkers of iron status and mortality. Conclusions: In a large nationally representative sample of US adults, within the spectrum of normal iron metabolism, ferritin and transferrin saturation were not associated with risk of