Beyond anemia: a comprehensive analysis of iron deficiency symptoms in women and their correlation with biomarkers.

Background: Iron deficiency, the most widespread micronutrient deficiency globally, is especially common among women and seriously impacts their health considerably. The symptom spectrum in non-anemic iron deficiency (NAID) is less well described than in anemic forms. The aim of this study was to demonstrate the diversity and frequency of symptoms in NAID and compare with anemic cases and explore the association of symptoms with biomarkers.

Methods: This retrospective and cross-sectional study was conducted on female patients at a university hospital. Patients admitted to the iron deficiency outpatient clinic between March 2021 and August 2022 were analyzed. Patients aged 18 years and older with iron deficiency (ferritin < 30 mcg/L) were included. Iron parameters, hemoglobin levels, and symptoms were included into the dataset, and these independent variables were compared between patient groups categorized as NAID and iron deficiency anemia (IDA).

Results: The study sample consisted of 239 patients. The frequencies of IDA and NAID were 70.3% (n = 168) and 29.7% (n = 71), respectively. Forty-one distinct symptoms or symptom groups were documented, ranging from neuropsychiatric to gastrointestinal manifestations. The mean number of symptoms per person was 16.5 (7.03). The top ten most common symptoms were weakness (87.03%), fatigue (82.43%), easy fatigability (78.66%), amnesia (72.38%), feeling cold (71.55%), alopecia (70.29%), cold intolerance (69.04%), sleep problems (66.53%), nervosity (63.18%), and cold foot (59.83%). The IDA group had more diverse symptoms than the NAID group (P <.05). Most of the forty-one symptoms or symptom groups were similar in frequency in the IDA and NAID groups. Only palpitations, cold intolerance, easy fatigability, and unclassifiable group differed between the groups (P <.05). The highest correlation between iron parameters and symptom diversity was transferrin saturation (TSAT) (r=-.229, P <.001). All but three of the positive symptoms showed TSAT levels below 8%.

Conclusions: This study confirms that anemia is not a prerequisite for the majority of iron deficiency symptoms, which are common in non-anemic women. TSAT demonstrates a robust correlation, underscoring its potential as an early diagnostic biomarker. Clinicians must acknowledge various non-specific symptoms irrespective of anemia. Additional research is required to corroborate findings and investigate symptom mechanisms and treatments.