An explanation for the disparity in findings presented in some of these studies and our study is our use of the NMR rather than genotype. Using this method, we captured a more complete picture of the nicotine metabolic rate by encompassing more polymorphic alleles and other environmental factors that may contribute to nicotine metabolism, but that are not measured by genotyping alone. By using the NMR rather than focusing on specific genotypes, we were able to account for these differences and thus may have a wider range of faster and slower metabolizers.
