Some dietary factors can modulate the effect of the zinc transporters 8 polymorphism on the risk of metabolic syndrome

Abstract

There are conflicting data on the impact of zinc transporter 8 (ZNT8) gene variations on the metabolic syndrome (MetS). Hence, the effects of the interaction between rs13266634 and dietary factors on the risk of MetS were investigated in this study. Subjects of this nested case-control study were selected from the participants in Tehran Lipid and Glucose Study. Each of the cases (n = 817) was individually matched with a control. Dietary patterns were determined using factor analysis. The ZNT8 rs13266634 were genotyped by the Tetra-refractory mutation system-polymerase chain reaction analysis. Two dietary patterns were extracted. There were no significant interactions between the ZNT8 SNP and the dietary patterns on the risk of MetS or its components. An interaction was observed between rs13266634 and the omega-3 fatty acid intakes on the risk of MetS in subjects with the CC genotype (P interaction < 0.01). Zinc modified the association of the ZNT8 variant with high fasting blood sugar (P interaction = 0.05) in CC genotype carriers. An interaction was also observed between rs13266634 and salty snacks at the risk of abdominal obesity (P interaction < 0.05). Our findings suggest an interaction between omega-3 fatty acids, zinc, salty snacks and rs13266634, which may affect the risk of MetS or its components.

Figure 1

Adjusted ORs (95% CI) for high FPG (Fasting Plasma Glucose) across tertiles of polyunsaturated fatty acids (PUFA) by the ZNT8 genotypes (P interaction = 0.03); CIs are shown after the bootstrap analysis (T1 < 4.93, T2:4.93–6.58., T3 > 6.58% of energy), in the CC genotype carriers, the risk of high FPG decreased across tertiles of PUFA intake (P trend = 0.008) (a), an association, however, not significant in the CT + TT genotype groups (b).

Figure 2

Adjusted ORs for high FPG (Fasting Plasma Glucose) across tertiles of zinc intake by the ZNT8 genotypes (P interaction = 0.05); CIs are shown after the bootstrap analysis (T1 < 10.52 mg, T2:10.52–14.24 mg, T3 > 14.24 mg), in the CC genotype carriers, the risk of high FPG decreased across tertiles of zinc intake (P trend = 0.007) (a), an association, however, not significant in the CT + TT genotype groups (b).

Figure 3

Adjusted ORs for high triglycerides (TG) across tertiles of omega-3 fatty acid intakes by the ZNT8 genotypes (P interaction = 0.05); CIs are shown after the bootstrap analysis (T1 < 0.38, T2:0.38–0.54., T3 > 0.54% of energy). The risk of high TG decreased across tertiles of omega-3 fatty acid intakes in CC genotype carriers (a), a trend not observed in the CT + TT genotype groups (b).

Figure 4

Adjusted ORs for low HDL-C to tertiles of omega-3 fatty acid intake by the ZNT8 genotypes (P interaction = 0.02); CIs are shown after the bootstrap analysis, (T1 < 0.38, T2:0.38–0.54., T3 > 0.54%of energy). The risk of low HDL-C decreased across tertiles of omega-3 fatty acid intakes in CC genotype carriers (a), a trend not observed in CT + TT genotype groups (b).

Figure 5

Adjusted ORs for abdominal obesity across tertiles of fish intake (variety of fish and tuna) by the ZNT8 genotypes (P interaction = 0.04); CIs are shown after the bootstrap analysis, (T1 < 4.23, T2:4.23–10.86, T3 > 10.86 gr/day). The ORs for abdominal obesity decreased significantly with increased consumption of fish by CC genotype carriers (P trend = 0.005) (a), although consumption of this food group had no significant effect on the ORs for abdominal obesity in the CT + TT genotype groups (P trend = 0.11) (b).

Figure 6

Adjusted ORs for abdominal obesity across tertiles of salty snack intakes (Crackers, pretzels chips, pickles and salted vegetables) by ZNT8 genotypes (P interaction = 0.02); CIs are shown after the bootstrap analysis, (T1 < 2.83, T2:2.83–10.70, T3 > 10.70 gr/day). In the CT + TT genotype groups, the risk of abdominal obesity increased across tertiles of salty snack intakes (P trend = 0.02) (a), an association not significant in the CC homozygote carriers (P trend = 0.31) (b).