Background: Recently cardiometabolic risk reduction has been observed in patients with slightly elevated
bilirubin concentration, as well as increased risk in subjects with excessive iron reserves. The aim of this
study was to evaluate the relationship between overweight and/or abdominal obesity, serum bilirubin and
selected iron status indicators levels in non-obese subjects.

Methods: The study group consisted of 80 healthy, non-obese subjects aged 25–40 years. In all subjects
total and direct bilirubin (T-BIL, D-BIL), iron (Fe), transferrin (TRSF), ferritin (FERR) and hepcidin (HEPC)
measurements were performed. Anthropometric parameters (BMI, waist circumference, WHR) were
measured and body composition (% of body fat, muscles and level of visceral fat) was evaluated using
body segment analyzer.

Results: Men showed significantly higher values of waist circumference, WHR, muscle mass, visceral fat
level and FERR and HEPC concentrations, compared to women. Lower concentrations of T-BIL, D-BIL and
higher concentration of FERR, HEPC occurred in the overweight group. In all subjects and in the overweight
group T-BIL, D-BIL showed negative correlations with BMI, waist circumference, fat mass and visceral fat
level, while for FERR, HEPC those correlations were positive. Overweight subjects had an approximately
4-fold higher incidence of low T-BIL, D-BIL levels (p < 0,001), as well as nearly 2-fold higher incidence of
high transferrin level (p = 0,02).

Conclusions: Overweight subjects have lower bilirubin levels and higher levels of factors potentially contributing
to increased oxidative stress, for example ferritin and hepcidin. Serum bilirubin, ferritin and hepcidin
concentration are related to body composition indicators, particullary fat mass and visceral fat level.