Exploration of the causal relationship between inflammatory cytokines and type 2 diabetes via mendelian randomization and polygenic score.
To investigate the potential causal relationship between inflammatory cytokines and type 2 diabetes (T2D) using two-sample Mendelian randomization (MR) and to explore the transferability of inflammatory genetic susceptibility in a Mongolian population through polygenic score (PGS) analysis.
A two-sample MR analysis was conducted using genome-wide association study (GWAS) summary statistics. Inflammatory cytokine data were obtained from protein quantitative trait locus GWAS datasets (GCST90274758-GCST90274848), and T2D summary statistics were derived from the IEU Open GWAS database (ebi-a-GCST006867). The inverse variance weighted method was used as the primary MR approach, complemented by sensitivity analyses. In an independent Mongolian cohort (N = 351), a PGS was constructed from directly genotyped cytokine-associated SNPs. We assessed PGS-T2D associations using logistic regression adjusted for age, sex, and principal components (PCs), with sensitivity analyses to determine the optimal PC number.
In the European population, genetically predicted higher FGF-21 levels were associated with an increased risk of T2D (OR = 1.141, 95% CI: 1.032-1.261, P = 0.010), and IL-5 also showed a positive association with T2D risk (OR = 1.114, 95% CI: 1.004-1.237, P = 0.042). In contrast, ARTN, CD5, CSF-1, CXCL10, CXCL9, FGF-19, and SLAMF1 were associated with lower T2D risk. In the Mongolian population, the PGS for inflammation-related cytokine levels demonstrated a significant association with T2D status across models adjusting for 0 to 6 principal components (all P< 0.05). In the full model (adjusted for age, sex, and the first 4 PCs), each 1-SD increase in the PGS corresponded to a 25.4% increase in the odds of T2D (OR = 1.254, 95% CI: 1.005-1.575, P = 0.048; AUC = 0.625). These findings are suggestive and exploratory, necessitating further validation in independent cohorts.
This study identified nine inflammatory cytokines with potential causal associations with T2D in European populations. Notably, in a Mongolian cohort, a PGS for genetically predicted cytokine levels showed a modest yet independent association with T2D risk after controlling for population stratification. These cross-population findings warrant replication in larger-scale studies.
A two-sample MR analysis was conducted using genome-wide association study (GWAS) summary statistics. Inflammatory cytokine data were obtained from protein quantitative trait locus GWAS datasets (GCST90274758-GCST90274848), and T2D summary statistics were derived from the IEU Open GWAS database (ebi-a-GCST006867). The inverse variance weighted method was used as the primary MR approach, complemented by sensitivity analyses. In an independent Mongolian cohort (N = 351), a PGS was constructed from directly genotyped cytokine-associated SNPs. We assessed PGS-T2D associations using logistic regression adjusted for age, sex, and principal components (PCs), with sensitivity analyses to determine the optimal PC number.
In the European population, genetically predicted higher FGF-21 levels were associated with an increased risk of T2D (OR = 1.141, 95% CI: 1.032-1.261, P = 0.010), and IL-5 also showed a positive association with T2D risk (OR = 1.114, 95% CI: 1.004-1.237, P = 0.042). In contrast, ARTN, CD5, CSF-1, CXCL10, CXCL9, FGF-19, and SLAMF1 were associated with lower T2D risk. In the Mongolian population, the PGS for inflammation-related cytokine levels demonstrated a significant association with T2D status across models adjusting for 0 to 6 principal components (all P< 0.05). In the full model (adjusted for age, sex, and the first 4 PCs), each 1-SD increase in the PGS corresponded to a 25.4% increase in the odds of T2D (OR = 1.254, 95% CI: 1.005-1.575, P = 0.048; AUC = 0.625). These findings are suggestive and exploratory, necessitating further validation in independent cohorts.
This study identified nine inflammatory cytokines with potential causal associations with T2D in European populations. Notably, in a Mongolian cohort, a PGS for genetically predicted cytokine levels showed a modest yet independent association with T2D risk after controlling for population stratification. These cross-population findings warrant replication in larger-scale studies.
Authors
Zhang Zhang, Zhao Zhao, Pang Pang, Li Li, Zheng Zheng, Dong Dong, Liu Liu, Li Li, Li Li, Zhang Zhang, Zhao Zhao, Zhao Zhao
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