Table 3.

Genotype frequencies of TNF-α +489 G/A gene polymorphism in subgroups of COPD patients versus population control group*

	GG	GA	AA	P-value † Patients versus controls
Patients without radiological emphysema	18 (62)	11 (38)	0	0.004
Patients with radiological emphysema	92 (77)	26 (22)	1 (1)	0.131
Population controls	264 (84)	45 (14)	6 (2)

* Values are expressed as absolute numbers; percentages are given in parentheses. For technical reasons, not all the samples were successfully genotyped. † χ²-test of the genotype frequencies of TNF-α +489G/A gene polymorphism. Statistical significance was defined as p < 0.025 using Bonferroni correction.