Albertine Donker

Chapter 7 260 Effect of body mass index (BMI) on serum hepcidin levels, hepcidin/ferritin ratios and TSAT/hepcidin ratios Since serum hepcidin levels have been reported to be influenced by BMI in both adults 8 and children 9 , and also in mice studies 10 , we assessed and interpreted the BMI in all subjects according to international standards, which describe age-dependent cut off points for underweight, normal weight, overweight and obesity. 11 The majority of children (84%) had a normal BMI according to age-adjusted reference values. 11 Distribution of BMI was similar for the different age groups (Chi Square p 0.310) ( Supplemental Figure 2 ). Multivariate analyses including age, sampling time, BMI and other biochemical parameters showed that underweight was associated with increased hepcidin levels in males (β= 0.16; 95% CI 0.03– 1.05 ( p 0.039)), while other BMI categories did not influence hepcidin levels. In females, no significant effect of any BMI category on serum hepcidin levels was found ( Table 3, Table 4 ). The hepcidin/ferritin ratio significantly increased while the TSAT/hepcidin ratio significantly decreased in underweight males (β= 0.51; 95% CI 0.01– 1.01 ( p 0.046) and β= -0.64; 95% CI -1.16– -0.11 ( p 0.018) respectively). Again, in females no significant effect of any BMI category on the hepcidin/ferritin ratio and TSAT/hepcidin ratio was observed. ( Supplemental Table 6, Supplemental Table 7 ). Since our study population contained only a few children with underweight, overweight or adiposity ( Table 1 ), our data lack the power to draw conclusions on the effect of BMI on serum hepcidin levels (relative to iron indicators).