High serum ferritin levels are associated with insulin resistance but not with impaired glucose tolerance in a healthy people population

Aim To assess the association between elevated serum ferritin levels and the presence of insulin resistance (IR) or impaired glucose tolerance (IGT) in a population of individuals with no endocrine or metabolic disorders background. Methods Analytical cross-sectional study, carried out in adults of both sexes with no medical history of type 2 diabetes mellitus (T2DM) or other metabolic or endocrine disorder, who attended the outpatient service of a private clinic in Lima-Peru during 2012–2014 period. Impaired serum ferritin levels were defined as serum ferritin values >300 μg/L in men and >200 μg/L in women. IR was defined as a Homeostasis Model Assessment (HOMA-IR) value ≥3.8 and IGT was defined as an oral glucose tolerance test (OGTT) value between 126 mg/dL and 199 mg/dL. The reported association measure was the prevalence ratio (PR) with their respective 95% confidence intervals (95% CI). Results We analyzed 213 participants, the average age was 35.8 ± 11.1 years and 35.7% were males. The prevalence of impaired serum ferritin levels, IR and IGT in the population was 12.7%, 33.3% and 9.9% respectively. In the adjusted Poisson regression models, the prevalence of IR was higher among the group with impaired serum ferritin levels (PR = 1.74; 95%CI:1.18–2.56); however, we found no association between impaired serum ferritin levels and IGT (PR = 1.42; 95%CI:0.47–4.30). Conclusions Impaired levels of serum ferritin are associated with IR, nevertheless, not with IGT in a metabolically healthy population. Serum ferritin could be considered as an early marker of IR prior to the onset of glycaemia disorders.