The association of biomarkers of iron status with peripheral arterial disease in US adults

BACKGROUND Several studies have examined the association of biomarkers of iron metabolism with measures of carotid artery atherosclerosis, with inconsistent results. Few studies, however, have evaluated the association between biomarkers of iron metabolism and peripheral arterial disease (PAD). The purpose of this study is to examine the association of ferritin and transferrin saturation with PAD. METHODS Serum ferritin, transferrin saturation, and PAD, defined as having an ankle-brachial blood pressure index <0.9, were measured in 1,631 men and 1,031 postmenopausal women participating in the 19992002 National Health and Nutrition Examination Survey (NHANES). RESULTS The multivariable adjusted odds ratios (95% confidence interval) for PAD associated with a two-fold increase in serum ferritin and transferrin saturation were 1.18 (1.001.41) and 1.45 (0.832.51), respectively, for men and 1.04 (0.871.25) and 1.55 (0.982.45), respectively, for women. After stratifying by cholesterol levels, the multivariable adjusted odds ratios (95% confidence intervals) for PAD associated with a two-fold increase in ferritin and transferrin saturation was 1.04 (0.781.39) and 0.73 (0.351.50), respectively, for men with total cholesterol <200 mg/dL and 1.30 (0.991.72) and 2.59 (0.996.78), respectively, for men with total cholesterol >or= 200 mg/dL (p-value for interaction was 0.58 for ferritin and 0.08 for transferrin saturation). After stratifying by cholesterol levels, the multivariable adjusted odds ratios (95% confidence intervals) for PAD associated with a two-fold increase in ferritin and transferrin saturation was 0.66 (0.411.05) and 0.75 (0.441.28), respectively, for women with total cholesterol <200 mg/dL, and 1.20 (0.951.51) and 2.07 (1.014.22), respectively, for women with total cholesterol >or= 200 mg/dL (p-value for interaction was 0.05 for ferritin and 0.02 for transferrin saturation). CONCLUSION In this large nationally representative sample of men and postmenopausal women, we found a modest association of ferritin and transferrin saturation with PAD, particularly among those with high cholesterol levels.