Investigation of Hematological Indices and Their Relationship with Thyroid Hormone Levels Among Adults in Tripoli, Libya: A Cross-Sectional Pilot Study and Methodological Enhancement Framework
Keywords:
Nutritional Anemia, Hypothyroidism, Thyroid-Stimulating Hormone (TSH), Free Thyroxine (FT4), Hemoglobin, Red Blood Cell Indices, Tripoli, Libya, STROBE GuidelinesAbstract
Anemia and thyroid dysfunction represent two major global health burdens that frequently intersect in clinical practice. Thyroid hormones play an essential regulatory role in bone marrow erythropoiesis and renal erythropoietin production, while nutritional iron is an indispensable biochemical cofactor for thyroid peroxidase (TPO) activity. Despite significant international inquiry, regional epidemiological and clinical data from North Africa, particularly Libya, remain scarce.
To investigate the relationship between hematological indices (hemoglobin [Hb], mean corpuscular volume [MCV], red cell distribution width [RDW]) and thyroid function parameters (thyroid-stimulating hormone [TSH], free thyroxine [FT4]) among adults in Tripoli, Libya, to characterize the morphological patterns of anemia, and to establish a standardized methodological and biostatistical quality-improvement framework for future large-scale endocrine-hematology research.
A cross-sectional analytical study was conducted across two independent clinical diagnostic centers (Al-Sharq Laboratory and Modern Medicine Laboratory) in Tripoli, Libya. Laboratory records of adult participants (n = 20) undergoing concurrent complete blood counts and automated chemiluminescent thyroid immunoassay profiling were evaluated. Participants were categorized according to World Health Organization (WHO) diagnostic thresholds for anemia (Hb < 12.0 g/dL in non-pregnant females, < 13.0 g/dL in males) and morphological subtypes based on MCV. Bivariate correlation, linear regression, and group-comparative analyses were conducted. In accordance with rigorous epidemiological standards, missing nutritional biomarkers and expansion protocols are systematically formulated.
The cohort exhibited a mean age of 40.60 ± 10.95 years with a female predominance (65.0%, n = 13). The mean Hb was 12.08 ± 1.56 g/dL, mean TSH was 4.60 ± 2.41 mIU/L, and mean FT4 was 13.54 ± 3.26 pmol/L. Anemia was identified in 50.0% (n = 10) of participants. Morphological subtyping among anemic individuals revealed microcytic anemia as the predominant pattern (60.0%, n = 6), followed by normocytic (20.0%, n = 2) and macrocytic anemia (20.0%, n = 2). Pearson correlation analysis demonstrated a statistically significant strong inverse correlation between Hb and TSH (r = −0.901, p < 0.001) and a robust positive correlation between Hb and FT4 (r = 0.948, p < 0.001). Multiple regression modeling indicated that FT4 was an independent predictor of Hb concentration after adjusting for TSH.
Conclusions: Preliminary findings demonstrate a significant association between thyroid dysfunction—particularly biochemical hypothyroidism—and reduced hemoglobin levels, predominantly characterized by microcytic erythrocyte morphology. However, given the observational cross-sectional design, convenience sampling, and absence of direct iron/vitamin biomarkers (ferritin, TIBC, B12, folate), causality cannot be inferred. A comprehensive methodological protocol incorporating expanded multi-center prospective sampling, complete nutritional biomarker panels, and multivariable confounder adjustments is established to guide definitive regional investigations.
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