HFE-Related Hemochromatosis: The Haptoglobin 2-2 Type Has a Significant but Limited Influence on Phenotypic Expression of the Predominant p.C282Y Homozygous Genotype

Table 2

Regression coefficients (β) and 95% confidence intervals (CIs) for variables influencing serum ferritin (𝝁g/L; log₁₀ transformed) and iron removed by phlebotomy (g; log₁₀ transformed) in p.C282Y homozygous patients.

Variable	Serum ferritin^1		Iron removed^2
	10^β (95% CI)	P value	10^β (95% CI)	P value
Gender^3	0.33 (0.27, 0.39)	< 0.0001	0.38 (0.33, 0.45)	< 0.0001
Age at diagnosis^4
Quartile 2	1.33 (1.05, 1.69)	0.0204	1.27 (1.02, 1.58)	0.0304
Quartile 3	1.77 (1.39, 2.26)	< 0.0001	1.48 (1.19, 1.84)	0.0005
Quartile 4	1.88 (1.47, 2.39)	< 0.0001	1.63 (1.30, 2.03)	< 0.0001
Alcohol consumption^5	1.57 (1.13, 2.18)	0.0073	1.53 (1.11, 2.12)	0.0096
Hp group^6	1.31 (1.09, 1.57)	0.0033	1.29 (1.09, 1.52)	0.0024

¹N = 351 (195 males and 156 females). Adjusted r ² = 38.3%.
²N = 325 (178 males and 147 females). Adjusted r ² = 36.1%.
³Male sex was used as the reference category.
⁴Quartile 1 was used as the reference category.
⁵Daily alcohol intake < 60 g was used as the reference category.
⁶Hp1-1 and Hp2-1 genotypes were grouped and used as the reference category.