Exposure to 5 measures of organochlorine exposure and NHL risk, stratified by genotype. Exposure and NHL risk was stratified by genotype for 2 single nucleotide polymorphisms: IFNG C−1615T (A) and IL4 5′-UTR, Ex1−168T (B). One asterisk (*) denotes significant association (P < .05) between exposure and NHL risk for that genotype. Two asterisks (**) denote highly significant association (P < .01) between exposure and NHL risk for that genotype. P value accompanies x-axis label if there was a significant interaction (P for interaction < .05) between genotype and exposure; y-axis is β coefficient from logistic regression.