MMP1 and chronic obstructive pulmonary disease: In the ethnicity-specific subgroup analysis, MMP-1 -1607G/GG polymorphism had a higher risk for COPD in Caucasians in a recessive model (OR: 1.20, 95% CI: 1.01–1.44; p = 0.04), however, the same pattern of result was found for MMP-9 -1562C/T polymorphism in Asians using a dominant model (OR: 1.66, 95% CI: 1.01–2.71; p = 0.04).