Table 4—

Interaction of type IV collagenα3 H451R genotypes and tobacco smoking on the risk of chronic obstructive pulmonary disease

Smoking statusGenotype HHGenotype HR+RR
Cases nControls nAdjusted OR (95% CI)#Cases nControls nAdjusted OR (95% CI)#
Never-smoker8401.003131.23 (0.27–5.47)
Smoker pack-yrs
 ≤33691512.40 (1.05–5.49)24472.79 (1.11–7.05)
 >331361035.36 (2.37–12.13)***71329.51 (3.93–23.01)***
  • OR: odds ratio; CI: confidence interval. #: calculated by logistic regression, adjusted for age, with HH genotype in never-smokers as reference group. : p = 0.04; : p = 0.03. ***: p<0.001. In the multivariate model, p = 0.32 for the interaction term between the genotype and continuous cumulative smoking dose (pack-yrs of smoking).