Meta-analysis of type 2 Diabetes in African Americans Consortium

Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

Product usage and firm-generated word of mouth: some results from FMCG product trials

Theory and past research suggests that greater levels of consumer involvement and product usage lead to higher levels of word of mouth (WOM). This paper presents some tests of hypotheses related to product usage and WOM, based on secondary consumer panel data from five fmcg product trials. The main findings are that brand usage range within a product category has a pervasive effect on pre-trial intentions to recommend the trialled product, as well as the actual number of WOM conversations generated by the trial and their effectiveness (the rate of attitudinal conversion based on interest generated). Frequency of product use only significantly affects the number of WOM conversations. Second, compared to non-users, being a loyal user of the trialled product (having used the brand more frequently than other brands) has a negative effect on WOM effectiveness, while non-loyal users' WOM is more effective compared to that of loyal users. The study thereby provides more evidence that loyal users are not necessarily the best targets of WOM marketing campaigns, and suggests that research on the interaction between involvement or product usage and loyalty in relation to firm-generated WOM may be an interesting area of further research