n 370 267 103 144 226 294 76 178 192 Genotype Null Present Null Present Ile/Ile Ile/Val Val/Val n 121 249 213 157 212 139 19 Journal of Toxicology 3 Table 1: The geometric mean of blood cadmium concentrations in a nonoccupational exposed population. Blood cadmium concentration (μg/L) 95% CI a Signiﬁcantly diﬀerent from smoker, P < 0.05 Student’s t-test. GM = Geometric mean. 95% CI = 95% Conﬁdence interval. Table 2: Geometric means of blood cadmium concentrations in a nonoccupational exposed population categorized by diﬀerent genotype. Frequency Blood cadmium (μg/L) GM ± SE 0.46 ± 0.02 0.46 ± 0.02 0.45 ± 0.03 0.45 ± 0.03 0.46 ± 0.02 0.41 ± 0.02a 0.72 ± 0.04 0.44 ± 0.02 0.47 ± 0.02 % 32.7 67.3 57.6 42.4 57.3 37.6 5.1 0.43–0.49 0.42–0.50 0.40–0.50 0.40–0.51 0.42–0.50 0.38–0.42 0.62–0.85 0.40–0.48 0.43–0.53 GM ± SE 0.49 ± 0.03 0.44 ± 0.02 0.47 ± 0.02 0.44 ± 0.02 0.45 ± 0.02 0.45 ± 0.03 0.71 ± 0.08a,b Characteristics Total Gender male female Age (yrs) 45–55 yrs >55 yrs Smoking habit nonsmoker Smoker Alcohol consumption Nondrinker Drinker Gene GSTT1 GSTM1 GSTP1-105 rs1695 a,b Signiﬁcantly diﬀerent GSTP1 from Ile/Ile and Ile/Val genotypes, respectively, P < 0.05. concentrations was 0.46 ± 0.02 μg/L (with 95% CI; 0.43– 0.49 μg/L) (Table 1). The level of blood cadmium in smokers was signiﬁcantly higher than those in nonsmokers (0.72 versus 0.42 μg/L, P < 0.05). There were no signiﬁcantly diﬀerence in blood cadmium concentration between gender and alcohol consumption. The distribution of genetic polymorphisms and mean of blood cadmium concentration for each genotype are shown in Table 2. All genes were in Hardy-Weinberg equilibrium (P-value >0.05). The GSTT1 present was the most prevalent genotype found in study population (67.3%). Homozygous variant of GSTP1 Val/Val was the lowest genotype in study population (5.1%). Subjects with GSTP1 Val/Val had signiﬁcantly higher blood cadmium concentration (0.71 μg/L) than did the GSTP1 wild-type (Ile/Ile) (0.45 μg/L) and heterozygous variant of GSTP1 Ile/Val (0.45 μg/L, P < 0.05). There were no signiﬁcant diﬀerences on blood cadmium concentration among subjects with GSTT1 and GSTM1 deletions. Three of the putative genes with risk genotypes were examined (Table 3). The linear regression analysis indicated a function of genetic polymorphisms on blood Cd level. In this model, the results of regression coeﬃcient of GSTT1 Val105Ile (β = 0.59, P = 0.034) exhibited strong potential predictors on blood Cd concentration. Considering the signiﬁcant impact of GSTP1 variant allele and the very small number of GSTP1 Val/Val genotype (n = 19), we combined these variant-allele subjects with heterozygous genotype (n = 158). Moreover, signiﬁcant eﬀect of gene combination was observed for GSTP1 variant allele with GSTM1 and GSTT1. Combined GSTP1-105 Ile/Val and Val/Val with GSTM1 and GSTT1 genotypes were shown as statistical predictors of blood Cd concentrations (β = 0.67, P = 0.044 and β = 0.72, P = 0.038, resp.). However, no other eﬀects of gene combinations were observed on blood Cd levels. 4. Discussion A nonoccupationally exposed population may be exposed to cadmium through ingestion of food and drinking water and inhalation of particulates from ambient air or tobacco smoke. In the present study, we found that the geometric