Background and objectives: Evidence suggests that cardiovascular disease (CVD) is accelerated by the oxidation of low-density lipoprotein (LDL) in the presence of iron. This study examined whether adults with elevated iron, as measured by transferrin saturation (TS), and elevated LDL are at an increased risk for mortality.
Methods: This is a cohort study of the adult US population using the National Health and Nutrition Examination Survey 1976-1980 (NHANES II) merged with the NHANES II Mortality Study in 1992. Multivariate Cox regression was performed to determine hazard ratios (HR) for CVD and all-cause mortality for high (>55%) or low (<55%) levels of TS and high (>160 mg/dl) or low (<160 mg/dl) levels of LDL.
Results: An elevated LDL alone did not significantly increase CVD mortality or all-cause mortality in the adjusted model. Individuals with elevated LDL and elevated TS had a statistically significant increase in both CVD mortality and all-cause mortality (HR=5.74 and 3.53, respectively) compared to the low LDL and low TS group.
Conclusions: The results of this study indicate an increased risk associated with the combination of elevated LDL and elevated TS, which suggests that iron-mediated oxidation of LDL may be a significant factor in the progression of CVD.