Effect of obesity and overweight on serum concentrations of hepcidin and iron in cats

AIMS: To determine whether obesity in cats is associated with increased serum hepcidin concentrations, alterations in iron parameters, and evidence of anaemia, as described in humans. METHODS: A cross-sectional study was conducted on client-owned adult cats (n = 79) classified by body condition score (BCS) as ideal (4-5/9; n = 25), overweight (6-7/9; n = 27), or obese (8-9/9; n = 27). Haematological parameters and serum concentrations of iron, total iron-binding capacity (TIBC), and hepcidin were measured. Associations between body condition (BCS and body weight) and outcomes were evaluated using multivariable linear regression models adjusted for age, sex, and infectious disease status. RESULTS: No cats showed evidence of anaemia. There was no evidence of an association between body condition and serum hepcidin concentration in either the body weight model (β = 0.015 (95% CI = -0.159 to 0.190); p = 0.861) or the BCS model (β = -0.033 (95% CI = -0.146 to 0.080); p = 0.568). After adjustment for multiple comparisons, no associations were observed between body condition and erythrocyte parameters or serum iron concentration, but TIBC was positively associated with body condition (weight model: β = 5.59 (95% CI = 1.90-9.29), p = 0.027; BCS model: β = 4.15 (95% CI = 1.79-6.51), p = 0.009) in both models. CONCLUSIONS: This study found no evidence that obesity in cats is associated with increased serum hepcidin concentrations, changes in serum iron concentrations, or evidence of anaemia. The finding of increased TIBC with increasing body weight/condition should therefore be interpreted cautiously and not as evidence of a significant alteration in iron metabolism in obese cats. CLINICAL RELEVANCE: These findings suggest that, unlike in humans, obesity in cats is not linked to clinically relevant disturbances in iron metabolism or the development of anaemia, indicating important species-specific differences in the relationship between adiposity, inflammation, and iron homeostasis.