Replication and extension of genome-wide association study results for obesity in 4,923 adults from Northern Sweden

• Published in: Human Molecular Genetics
• Main Authors: Renström, Frida, Payne, Felicity, Nordström, Anna, Brito, Ema C., GIANT Consortium, Rolandsson, Olov, Hallmans, Göran, Barroso, Ines, Nordström, Peter, Franks, Paul W.
• Format: Text
• Language: English
• Published: Oxford University Press 2009
• Subjects: Article; Northern Sweden
• Online Access: http://hmg.oxfordjournals.org/cgi/content/short/ddp041v1; https://doi.org/10.1093/hmg/ddp041

Recent genome-wide association studies (GWAS) have identified multiple risk loci for common obesity ( FTO, MC4R, TMEM18, GNPDA2, SH2B1, KCTD15, MTCH2, NEGR1 , and PCSK1 ). Here we extend those studies by examining associations with adiposity and type 2 diabetes in Swedish adults. The nine single nucleotide polymorphisms (SNPs) were genotyped in 3,885 non-diabetic and 1,038 diabetic individuals with available measures of height, weight and BMI. Adipose mass and distribution was objectively assessed using dual energy X-ray absorptiometry (DEXA) in a sub-group of non-diabetics (n=2,206). In models with adipose mass traits, BMI or obesity as outcomes, the most strongly associated SNP was FTO rs1121980 ( P <0.001). Five other SNPs ( SH2B1 rs7498665, MTCH2 rs4752856, MC4R rs17782313, NEGR1 rs2815752, and GNPDA2 rs10938397) were significantly associated with obesity. To summarize the overall genetic burden, a weighted risk score comprising a subset of SNPs was constructed; those in the top quintile of the score were heavier (+2.6kg) and had more total (+2.4kg), gynoid (+191g), and abdominal (+136g) adipose tissue than those in the lowest quintile (all P <0.001). The genetic burden score significantly increased diabetes risk, with those in the highest quintile (n=193/594 cases/controls) being at 1.55-fold (95% CI: 1.21-1.99; P <0.0001) greater risk of type 2 diabetes than those in the lowest quintile (n=130/655 cases/controls). In summary, we have statistically replicated six of the previously associated obese-risk loci and our results suggest that the weight-inducing effects of these variants are explained largely by increased adipose accumulation.