The Impact of Obesity on the Reliability of Serum Ferritin in Evaluating Iron Stores among Young Women: A Cross‑Sectional Study

Abstract

Ferritin is considered the primary indicator for iron stores; in addition, ferritin is an acute-phase reactant upregulated by obesity-related persistent inflammation. Thus, high ferritin levels in individuals with higher Body Mass Index (BMI) could lead to an overestimation of iron status and delayed iron deficiency (ID) diagnosis. This study aimed to compare iron status markers across BMI categories in young females and to assess the impact of ferritin variation in the study subjects on the most common ID-related symptoms (fatigue and hair loss), as well as to investigate whether this variation was associated with the key determinants of ID in young females (menstruation and diet).  This study was designed as a cross-sectional study utilizing data collected from 103 young, supplement-free female medical students (aged 18–27 years) in Misurata, Libya. Demographic data, dietary habits, and menstrual severity scores were collected via structured questionnaires. Fatigue was evaluated using the Fatigue Assessment Scale (FAS), and hair loss was assessed using a modified hair shedding visual scale. Serum ferritin, hemoglobin, and C-reactive protein (CRP) were assessed; individuals with elevated CRP were excluded. Nearly half of the study subjects (48%) were overweight or obese. Serum ferritin differed significantly across BMI groups (p < 0.05), with the obese group exhibiting the highest ferritin median (21.6 μg/L) compared to the underweight group (5 μg/L). Conversely, hemoglobin levels did not differ significantly between BMI groups (p > 0.05). Unexpectedly, when participants were stratified according to ferritin status, no statistically significant differences were observed in fatigue scores, hair loss, menstrual bleeding severity, or dietary iron scores (all p > 0.05). Fluctuations in ferritin concentrations in this cohort are likely driven by adiposity-related inflammation rather than true iron sufficiency, as evidenced by the absence of corresponding increases in hemoglobin, ID-related symptoms, or established risk factors for iron depletion. Accordingly, reliance on ferritin alone for iron status assessment in patients with elevated BMI should be avoided, as this may lead to missed diagnoses of ID.