TY - JOUR A1 - Zheng, Ju-Sheng A1 - Luan, Jian'an A1 - Sofianopoulou, Eleni A1 - Imamura, Fumiaki A1 - Stewart, Isobel D. A1 - Day, Felix R. A1 - Pietzner, Maik A1 - Wheeler, Eleanor A1 - Lotta, Luca A. A1 - Gundersen, Thomas E. A1 - Amiano, Pilar A1 - Ardanaz, Eva A1 - Chirlaque, Maria-Dolores A1 - Fagherazzi, Guy A1 - Franks, Paul W. A1 - Kaaks, Rudolf A1 - Laouali, Nasser A1 - Mancini, Francesca Romana A1 - Nilsson, Peter M. A1 - Onland-Moret, N. Charlotte A1 - Olsen, Anja A1 - Overvad, Kim A1 - Panico, Salvatore A1 - Palli, Domenico A1 - Ricceri, Fulvio A1 - Rolandsson, Olov A1 - Spijkerman, Annemieke M. W. A1 - Sanchez, Maria-Jose A1 - Schulze, Matthias Bernd A1 - Sala, Nuria A1 - Sieri, Sabina A1 - Tjonneland, Anne A1 - Tumino, Rosario A1 - van der Schouw, Yvonne T. A1 - Weiderpass, Elisabete A1 - Riboli, Elio A1 - Danesh, John A1 - Butterworth, Adam S. A1 - Sharp, Stephen J. A1 - Langenberg, Claudia A1 - Forouhi, Nita G. A1 - Wareham, Nicholas J. T1 - Plasma vitamin C and type 2 diabetes BT - genome-wide association study and Mendelian randomization analysis in European populations JF - Diabetes care N2 - OBJECTIVE: Higher plasma vitamin C levels are associated with lower type 2 diabetes risk, but whether this association is causal is uncertain. To investigate this, we studied the association of genetically predicted plasma vitamin C with type 2 diabetes. RESEARCH DESIGN AND METHODS: We conducted genome-wide association studies of plasma vitamin C among 52,018 individuals of European ancestry to discover novel genetic variants. We performed Mendelian randomization analyses to estimate the association of genetically predicted differences in plasma vitamin C with type 2 diabetes in up to 80,983 case participants and 842,909 noncase participants. We compared this estimate with the observational association between plasma vitamin C and incident type 2 diabetes, including 8,133 case participants and 11,073 noncase participants. RESULTS: We identified 11 genomic regions associated with plasma vitamin C (P < 5 x 10(-8)), with the strongest signal at SLC23A1, and 10 novel genetic loci including SLC23A3, CHPT1, BCAS3, SNRPF, RER1, MAF, GSTA5, RGS14, AKT1, and FADS1. Plasma vitamin C was inversely associated with type 2 diabetes (hazard ratio per SD 0.88; 95% CI 0.82, 0.94), but there was no association between genetically predicted plasma vitamin C (excluding FADS1 variant due to its apparent pleiotropic effect) and type 2 diabetes (1.03; 95% CI 0.96, 1.10). CONCLUSIONS: These findings indicate discordance between biochemically measured and genetically predicted plasma vitamin C levels in the association with type 2 diabetes among European populations. The null Mendelian randomization findings provide no strong evidence to suggest the use of vitamin C supplementation for type 2 diabetes prevention. Y1 - 2020 U6 - https://doi.org/10.2337/dc20-1328 SN - 0149-5992 SN - 1935-5548 VL - 44 IS - 1 SP - 98 EP - 106 PB - American Diabetes Association CY - Alexandria ER - TY - JOUR A1 - Kroeger, Janine A1 - Meidtner, Karina A1 - Stefan, Norbert A1 - Guevara, Marcela A1 - Kerrison, Nicola D. A1 - Ardanaz, Eva A1 - Aune, Dagfinn A1 - Boeing, Heiner A1 - Dorronsoro, Miren A1 - Dow, Courtney A1 - Fagherazzi, Guy A1 - Franks, Paul W. A1 - Freisling, Heinz A1 - Gunter, Marc J. A1 - Maria Huerta, Jose A1 - Kaaks, Rudolf A1 - Key, Timothy J. A1 - Khaw, Kay Tee A1 - Krogh, Vittorio A1 - Kuehn, Tilman A1 - Mancini, Francesca Romana A1 - Mattiello, Amalia A1 - Nilsson, Peter M. A1 - Olsen, Anja A1 - Overvad, Kim A1 - Palli, Domenico A1 - Ramon Quiros, J. A1 - Rolandsson, Olov A1 - Sacerdote, Carlotta A1 - Sala, Nuria A1 - Salamanca-Fernandez, Elena A1 - Sluijs, Ivonne A1 - Spijkerman, Annemieke M. W. A1 - Tjonneland, Anne A1 - Tsilidis, Konstantinos K. A1 - Tumino, Rosario A1 - van der Schouw, Yvonne T. A1 - Forouhi, Nita G. A1 - Sharp, Stephen J. A1 - Langenberg, Claudia A1 - Riboli, Elio A1 - Schulze, Matthias Bernd A1 - Wareham, Nicholas J. T1 - Circulating Fetuin-A and Risk of Type 2 Diabetes BT - a mendelian randomization analysis JF - Diabetes : a journal of the American Diabetes Association N2 - Fetuin-A, a hepatic-origin protein, is strongly positively associated with risk of type 2 diabetes in human observational studies, but it is unknown whether this association is causal. Weaimed to study the potential causal relation of circulating fetuin-A to risk of type 2 diabetes in a Mendelian randomization study with single nucleotide polymorphisms located in the fetuin-A-encoding AHSG gene. We used data from eight European countries of the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study including 10,020 incident cases. Plasma fetuin-A concentration was measured in a subset of 965 subcohort participants and 654 case subjects. A genetic score of the AHSG single nucleotide polymorphisms was strongly associated with fetuin-A (28% explained variation). Using the genetic score as instrumental variable of fetuin-A, we observed no significant association of a 50 mu g/mL higher fetuin-A concentration with diabetes risk (hazard ratio 1.02 [95% CI 0.97, 1.07]). Combining our results with those from the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) consortium (12,171 case subjects) also did not suggest a clear significant relation of fetuin-A with diabetes risk. In conclusion, although there is mechanistic evidence for an effect of fetuin-A on insulin sensitivity and secretion, this study does not support a strong, relevant relationship between circulating fetuin-A and diabetes risk in the general population. Y1 - 2018 U6 - https://doi.org/10.2337/db17-1268 SN - 0012-1797 SN - 1939-327X VL - 67 IS - 6 SP - 1200 EP - 1205 PB - American Diabetes Association CY - Alexandria ER -