Disrupted coupling between ferritin and iron absorption in enteropathy-related anemia: Evidence for a dual-pathway model

Table 2 Summary of stepwise regression analyses for pathways linking enteropathy to erythrocyte status

Pathway tested	F-statistic	P value	R2	Outcome
Dual-pathway model
Enteropathy → iron absorption	F(4, 48) = 4.23	0.005	0.26	Supported
Enteropathy → ferritin stores	F(4, 48) = 5.09	0.002	0.30	Supported
Iron absorption → ferritin stores	F(1, 50) = 0.25	0.619	0.01	Not supported
Ferritin stores → RBC quality	F(1, 51) = 14.70	< 0.001	0.22	Supported
Ferritin stores → RBC quantity	F(1, 51) = 0.62	0.434	0.01	Not supported
Serial via serum iron model
Iron absorption → serum iron	F(1, 50) = 1.79	0.186	0.04	Not supported
Serial via ferritin model
Serum iron → RBC quality	F(1, 51) = 32.3	< 0.001	0.39	Supported
Serum iron → RBC quantity	F(1, 51) = 2.52	0.118	0.05	Not supported

The results indicate that simple serial mediation models (serial via serum iron model and serial via ferritin model) were not supported, owing to disruptions in key links of the proposed causal pathways. In contrast, the data most strongly support a dual-pathway model (dual-pathway model) in which enteropathy independently influences both intestinal iron absorption and serum ferritin levels. RBC: Red blood cell.