Soluble transferrin receptor, Ferritin index in Pakistani population
Inflammation affects the reliability of ferritin. The serum level of transferrin receptor protein (sTfR) represents true demand of iron in the body. This study attempts to identify levels of sTfR and correlate the trends of sTfR/ferritin index with BMI in the population of Karachi. 132 gender matched volunteers between the ages of 20-60 years were recruited for this cross-sectional study. BMI was calculated using the formula: (weight in kg / height in m2). Following groups were made according to South Asian criteria of BMI; Group A: normal weight (18.0-22.9 kg/m2), Group B: overweight (23.0-24.9 kg/m2), Group C: obese (>25.0 kg/m2). Serum ferritin, sTfR and CRP levels were determined using ELISA kits. Statistical comparisons were performed using Mann Whitney U and Spearman's rank correlation, where p<0.05 was considered significant. The results identified increased in TIBC, sTfR, ferritin and CRP in obese as compared to normal weight individuals (p<0.001). sTfR/ferritin ratio was 0.822 which signifies increased risk of acute myocardial infarction in group C. Serum iron (r=-0.359,p=0.004) showed negative correlation with BMI while serum ferritin (r=0.237,p< 0.001) and sTfR (r=0.263,p= 0.036) levels were positively associated to BMI. This study highlights a novel finding that sTfR is most likely a better clinical measure of iron status in inflammatory conditions as its expression is effected by erythropoiesis and not by inflammation. Risk of Acute myocardial infarction can also be predicted by increased sTfR/ferritin ratio.