class. The mean and ranges of age are similar in each weight class. Obesity was determined by body mass index (BMI), which was calculated by body weight (in kilograms) divided by squared height (in meters). Based on the magnitude of BMI (=kg/m2), the individuals were classified into four categories: 18.5–24.9 (normal weight as controls), 25–29.9 (overweight), 30–34.9 (Class I obesity), and ≥ 35 (Class II and III obesity). Twelve individuals with BMI <18.5 were excluded in this study. Social factors used in this study were age and gender. Genotyping was performed by the Center for Inherited Disease Research using the Illumina Human1M-Duo BeadChip system. A total of 12 single nucleotide polymorphisms (SNPs) within the CYP2A6 and CYP2A7 genes were available in this sample (Table 1). All 12 SNPs were in Hardy-Weinberg equilibrium in the controls (p>0.01). This study was approved by Internal Review Board (IRB) at East Tennessee State University (ETSU).
