TY - JOUR T1 - Impact of common genetic determinants of Hemoglobin A1c on type 2 diabetes risk and diagnosis in ancestrally diverse populations: A transethnic genome-wide meta-analysis. JF - PLoS Med Y1 - 2017 A1 - Wheeler, Eleanor A1 - Leong, Aaron A1 - Liu, Ching-Ti A1 - Hivert, Marie-France A1 - Strawbridge, Rona J A1 - Podmore, Clara A1 - Li, Man A1 - Yao, Jie A1 - Sim, Xueling A1 - Hong, Jaeyoung A1 - Chu, Audrey Y A1 - Zhang, Weihua A1 - Wang, Xu A1 - Chen, Peng A1 - Maruthur, Nisa M A1 - Porneala, Bianca C A1 - Sharp, Stephen J A1 - Jia, Yucheng A1 - Kabagambe, Edmond K A1 - Chang, Li-Ching A1 - Chen, Wei-Min A1 - Elks, Cathy E A1 - Evans, Daniel S A1 - Fan, Qiao A1 - Giulianini, Franco A1 - Go, Min Jin A1 - Hottenga, Jouke-Jan A1 - Hu, Yao A1 - Jackson, Anne U A1 - Kanoni, Stavroula A1 - Kim, Young Jin A1 - Kleber, Marcus E A1 - Ladenvall, Claes A1 - Lecoeur, Cécile A1 - Lim, Sing-Hui A1 - Lu, Yingchang A1 - Mahajan, Anubha A1 - Marzi, Carola A1 - Nalls, Mike A A1 - Navarro, Pau A1 - Nolte, Ilja M A1 - Rose, Lynda M A1 - Rybin, Denis V A1 - Sanna, Serena A1 - Shi, Yuan A1 - Stram, Daniel O A1 - Takeuchi, Fumihiko A1 - Tan, Shu Pei A1 - van der Most, Peter J A1 - van Vliet-Ostaptchouk, Jana V A1 - Wong, Andrew A1 - Yengo, Loic A1 - Zhao, Wanting A1 - Goel, Anuj A1 - Martinez Larrad, Maria Teresa A1 - Radke, Dörte A1 - Salo, Perttu A1 - Tanaka, Toshiko A1 - van Iperen, Erik P A A1 - Abecasis, Goncalo A1 - Afaq, Saima A1 - Alizadeh, Behrooz Z A1 - Bertoni, Alain G A1 - Bonnefond, Amélie A1 - Böttcher, Yvonne A1 - Bottinger, Erwin P A1 - Campbell, Harry A1 - Carlson, Olga D A1 - Chen, Chien-Hsiun A1 - Cho, Yoon Shin A1 - Garvey, W Timothy A1 - Gieger, Christian A1 - Goodarzi, Mark O A1 - Grallert, Harald A1 - Hamsten, Anders A1 - Hartman, Catharina A A1 - Herder, Christian A1 - Hsiung, Chao Agnes A1 - Huang, Jie A1 - Igase, Michiya A1 - Isono, Masato A1 - Katsuya, Tomohiro A1 - Khor, Chiea-Chuen A1 - Kiess, Wieland A1 - Kohara, Katsuhiko A1 - Kovacs, Peter A1 - Lee, Juyoung A1 - Lee, Wen-Jane A1 - Lehne, Benjamin A1 - Li, Huaixing A1 - Liu, Jianjun A1 - Lobbens, Stephane A1 - Luan, Jian'an A1 - Lyssenko, Valeriya A1 - Meitinger, Thomas A1 - Miki, Tetsuro A1 - Miljkovic, Iva A1 - Moon, Sanghoon A1 - Mulas, Antonella A1 - Müller, Gabriele A1 - Müller-Nurasyid, Martina A1 - Nagaraja, Ramaiah A1 - Nauck, Matthias A1 - Pankow, James S A1 - Polasek, Ozren A1 - Prokopenko, Inga A1 - Ramos, Paula S A1 - Rasmussen-Torvik, Laura A1 - Rathmann, Wolfgang A1 - Rich, Stephen S A1 - Robertson, Neil R A1 - Roden, Michael A1 - Roussel, Ronan A1 - Rudan, Igor A1 - Scott, Robert A A1 - Scott, William R A1 - Sennblad, Bengt A1 - Siscovick, David S A1 - Strauch, Konstantin A1 - Sun, Liang A1 - Swertz, Morris A1 - Tajuddin, Salman M A1 - Taylor, Kent D A1 - Teo, Yik-Ying A1 - Tham, Yih Chung A1 - Tönjes, Anke A1 - Wareham, Nicholas J A1 - Willemsen, Gonneke A1 - Wilsgaard, Tom A1 - Hingorani, Aroon D A1 - Egan, Josephine A1 - Ferrucci, Luigi A1 - Hovingh, G Kees A1 - Jula, Antti A1 - Kivimaki, Mika A1 - Kumari, Meena A1 - Njølstad, Inger A1 - Palmer, Colin N A A1 - Serrano Ríos, Manuel A1 - Stumvoll, Michael A1 - Watkins, Hugh A1 - Aung, Tin A1 - Blüher, Matthias A1 - Boehnke, Michael A1 - Boomsma, Dorret I A1 - Bornstein, Stefan R A1 - Chambers, John C A1 - Chasman, Daniel I A1 - Chen, Yii-Der Ida A1 - Chen, Yduan-Tsong A1 - Cheng, Ching-Yu A1 - Cucca, Francesco A1 - de Geus, Eco J C A1 - Deloukas, Panos A1 - Evans, Michele K A1 - Fornage, Myriam A1 - Friedlander, Yechiel A1 - Froguel, Philippe A1 - Groop, Leif A1 - Gross, Myron D A1 - Harris, Tamara B A1 - Hayward, Caroline A1 - Heng, Chew-Kiat A1 - Ingelsson, Erik A1 - Kato, Norihiro A1 - Kim, Bong-Jo A1 - Koh, Woon-Puay A1 - Kooner, Jaspal S A1 - Körner, Antje A1 - Kuh, Diana A1 - Kuusisto, Johanna A1 - Laakso, Markku A1 - Lin, Xu A1 - Liu, Yongmei A1 - Loos, Ruth J F A1 - Magnusson, Patrik K E A1 - März, Winfried A1 - McCarthy, Mark I A1 - Oldehinkel, Albertine J A1 - Ong, Ken K A1 - Pedersen, Nancy L A1 - Pereira, Mark A A1 - Peters, Annette A1 - Ridker, Paul M A1 - Sabanayagam, Charumathi A1 - Sale, Michele A1 - Saleheen, Danish A1 - Saltevo, Juha A1 - Schwarz, Peter Eh A1 - Sheu, Wayne H H A1 - Snieder, Harold A1 - Spector, Timothy D A1 - Tabara, Yasuharu A1 - Tuomilehto, Jaakko A1 - van Dam, Rob M A1 - Wilson, James G A1 - Wilson, James F A1 - Wolffenbuttel, Bruce H R A1 - Wong, Tien Yin A1 - Wu, Jer-Yuarn A1 - Yuan, Jian-Min A1 - Zonderman, Alan B A1 - Soranzo, Nicole A1 - Guo, Xiuqing A1 - Roberts, David J A1 - Florez, Jose C A1 - Sladek, Robert A1 - Dupuis, Josée A1 - Morris, Andrew P A1 - Tai, E-Shyong A1 - Selvin, Elizabeth A1 - Rotter, Jerome I A1 - Langenberg, Claudia A1 - Barroso, Inês A1 - Meigs, James B KW - Diabetes Mellitus, Type 2 KW - Genetic Variation KW - Genome-Wide Association Study KW - Glycated Hemoglobin A KW - Humans KW - Phenotype KW - Risk AB -

BACKGROUND: Glycated hemoglobin (HbA1c) is used to diagnose type 2 diabetes (T2D) and assess glycemic control in patients with diabetes. Previous genome-wide association studies (GWAS) have identified 18 HbA1c-associated genetic variants. These variants proved to be classifiable by their likely biological action as erythrocytic (also associated with erythrocyte traits) or glycemic (associated with other glucose-related traits). In this study, we tested the hypotheses that, in a very large scale GWAS, we would identify more genetic variants associated with HbA1c and that HbA1c variants implicated in erythrocytic biology would affect the diagnostic accuracy of HbA1c. We therefore expanded the number of HbA1c-associated loci and tested the effect of genetic risk-scores comprised of erythrocytic or glycemic variants on incident diabetes prediction and on prevalent diabetes screening performance. Throughout this multiancestry study, we kept a focus on interancestry differences in HbA1c genetics performance that might influence race-ancestry differences in health outcomes.

METHODS & FINDINGS: Using genome-wide association meta-analyses in up to 159,940 individuals from 82 cohorts of European, African, East Asian, and South Asian ancestry, we identified 60 common genetic variants associated with HbA1c. We classified variants as implicated in glycemic, erythrocytic, or unclassified biology and tested whether additive genetic scores of erythrocytic variants (GS-E) or glycemic variants (GS-G) were associated with higher T2D incidence in multiethnic longitudinal cohorts (N = 33,241). Nineteen glycemic and 22 erythrocytic variants were associated with HbA1c at genome-wide significance. GS-G was associated with higher T2D risk (incidence OR = 1.05, 95% CI 1.04-1.06, per HbA1c-raising allele, p = 3 × 10-29); whereas GS-E was not (OR = 1.00, 95% CI 0.99-1.01, p = 0.60). In Europeans and Asians, erythrocytic variants in aggregate had only modest effects on the diagnostic accuracy of HbA1c. Yet, in African Americans, the X-linked G6PD G202A variant (T-allele frequency 11%) was associated with an absolute decrease in HbA1c of 0.81%-units (95% CI 0.66-0.96) per allele in hemizygous men, and 0.68%-units (95% CI 0.38-0.97) in homozygous women. The G6PD variant may cause approximately 2% (N = 0.65 million, 95% CI 0.55-0.74) of African American adults with T2D to remain undiagnosed when screened with HbA1c. Limitations include the smaller sample sizes for non-European ancestries and the inability to classify approximately one-third of the variants. Further studies in large multiethnic cohorts with HbA1c, glycemic, and erythrocytic traits are required to better determine the biological action of the unclassified variants.

CONCLUSIONS: As G6PD deficiency can be clinically silent until illness strikes, we recommend investigation of the possible benefits of screening for the G6PD genotype along with using HbA1c to diagnose T2D in populations of African ancestry or groups where G6PD deficiency is common. Screening with direct glucose measurements, or genetically-informed HbA1c diagnostic thresholds in people with G6PD deficiency, may be required to avoid missed or delayed diagnoses.

VL - 14 IS - 9 ER -