Determinants of ferritin and soluble transferrin receptors as iron status parameters in young adult women.

OBJECTIVE: To investigate associations between nutritional and non-nutritional variables and Fe status parameters, i.e. serum ferritin and soluble transferrin receptors (sTfR).
DESIGN: Cross-sectional design. Fe status parameters were determined on a fasting venous blood sample. Nutritional variables were assessed using a 2 d food record and non-nutritional variables by a general questionnaire. A general linear model was used to investigate associations between the variables and Fe status parameters.
SETTING: Region of Ghent, Dutch-speaking part of Belgium.
SUBJECTS: Random sample of 788 women (aged 18-39 years).
RESULTS: Median (interquartile range) ferritin and sTfR were 26.3 (15.9, 48.9) ng/ml and 1.11 (0.95, 1.30) mg/l, respectively. BMI and alcohol intake were positively associated and tea intake was negatively associated with serum ferritin. Women who used a non-hormonal intra-uterine device, who gave blood within the past year or who had been pregnant within the past year had lower serum ferritin values than their counterparts. Significant determinants of sTfR were smoking habit and pregnancy, with higher values for non-smokers and women who had been pregnant within the past year.
CONCLUSIONS: The present study indicates that contraceptive use, time since last blood donation, time since last pregnancy, BMI, alcohol and tea intake are determinants of Fe stores, whereas smoking habit and time since last pregnancy are determinants of tissue Fe needs. When developing strategies to improve Fe status, special attention should be given to women who use a non-hormonal intra-uterine device, gave blood within the past year and had been pregnant within the past year.