Interaction between GPR120 p.R270H loss-of-function variant and dietary fat intake on incident type 2 diabetes risk in the D.E.S.I.R. study.

BACKGROUND AND AIMS: GPR120 (encoded by FFAR4) is a lipid sensor that plays an important role in the control of energy balance. GPR120 is activated by long chain fatty acids (FAs) including omega-3 FAs. In humans, the loss of function p.R270H variant of the gene FFAR4 has been associated with a lower protein activity, an increased risk of obesity and higher fasting plasma glucose levels. The aim of this study was to investigate whether p.R270H interacts with dietary fat intake to modulate the risk of type 2 diabetes (T2D, 198 incident; 368 prevalent cases) and overweight (787 incident and 2891 prevalent cases) in the prospective D.E.S.I.R. study (n = 5,212, 9 years follow-up). METHODS AND RESULTS: The association of p.R270H with dietary fat and total calories was assessed by linear mixed models. The interaction between p.R270H and dietary fat on T2D and overweight was assessed by logistic regression analysis. The p.R270H variant had a minor allele frequency of 1.45% and was not significantly associated with total calories intake, fat intake or the total calories derived from fat (%). However, there was a significant interaction between p.R270H and dietary fat modulating the incidence of T2D (Pinteraction = 0.02) where the H-carriers had a higher risk of T2D than RR homozygotes in the low fat intake category only. The interaction between p.R270H and fat intake modulating the incidence and prevalence of overweight was not significant. CONCLUSION: The p.R270H variant of GPR120 modulates the risk of T2D in interaction with dietary fat intake in the D.E.S.I.R.

Dietary fat intake and polymorphisms at the PPARG locus modulate BMI and type 2 diabetes risk in the D.E.S.I.R. prospective study.

CONTEXT: Fat-rich diets are involved in many disorders such as obesity and type 2 diabetes (T2D). The Pro12Ala variant of peroxisome proliferator-activated receptor-γ (PPARγ) is known to modulate body mass index (BMI) and T2D risk. OBJECTIVE: Our aim was to study the interaction effect between PPARγ gene (PPARG) polymorphisms Pro12Ala and 1431C>T and fat intake on incident T2D and BMI in a 9-year prospective cohort drawn from the French general population, the D.E.S.I.R. (Data from an Epidemiological Study on the Insulin Resistance Syndrome) study (n=4676). METHODS: Nutritional intake was assessed by a food frequency self-questionnaire completed by each participant. Statistical analyses included logistic regression, analysis of covariance and haplotype analysis, with adjustment for confounding variables. RESULTS: A high fat consumption (the third sex-specific tertile of fat intake, as a percentage of energy intake) was associated with an increased T2D risk among ProPro and CC homozygotes (P(interaction)=0.05, odds ratio (OR) (95% confidence interval (95% CI))=1.73 (1.19-2.52) P=0.004 and OR=1.85 (1.27-2.71) P=0.001, respectively) but not in Ala and T carriers. There was a significant interaction effect between Pro12Ala and 1431C>T on BMI (P(interaction)=0.004); Ala was associated with lower BMI in CC homozygotes and with higher BMI in T carriers while the opposite was found for ProPro. There was also an interaction effect between Pro12Ala and dietary fat intake on BMI (P(interaction)=0.02); AlaAla individuals had a higher BMI than Pro carriers among high fat consumers (27.1 ± 1.0 versus 24.9 ± 0.1 for AlaAla and Pro+, respectively). There was no interaction effect between the 1431C>T single-nucleotide polymorphism and fat intake on BMI. CONCLUSION: Our results indicate strong genetic and nutritional interaction effects on BMI and T2D risk at the PPARG locus in a general population.

[Value of systematic screening for depressive symptoms and Charles-Bonnet syndrome in AMD patients]. / Intérêt du dépistage systématique des affects dépressifs et du syndrome de Charles­Bonnet chez les patients atteints de DMLA.

INTRODUCTION: Age-related macular degeneration (ARMD) is the leading cause of blindness in western countries. Along with decrease in vision, ARMD patients, who are often elderly, carry an increased risk of developing depression and Charles-Bonnet syndrome (CBS). However, these disorders remain under-diagnosed. Detection and treatment could considerably improve their quality of life. The aim of our study is to evaluate the relevance and feasibility of systematic screening for depression and CBS in AMD patients. MATERIALS AND METHOD: Patients with ARMD, who showed up to the ophthalmology department of CHU Brugmann (Brussels, Belgium, Université Libre de Bruxelles) over a 4-week period, were asked to measure their depression score using the Geriatric Depression Scale (GDS-15) and to complete a questionnaire on CBS. RESULTS: In total, 112 patients were recruited. One hundred and six responded to the GDS-15 score; among them 70 patients (66.04%) suffered from depressive symptoms. A multivariate analysis highlighted three risk factors: decreased vision in the better eye (P=0.023), unilateral impairment (P=0.024) and social isolation (P<0.001). One hundred and twelve patients completed the CBS questionnaire, no new diagnoses were made. Six of the 112 patients (5.7%) knew about CBS. CONCLUSION: Screening through the GDS-15 depression score should be performed systematically in all ARMD patients. It is important not to overlook psychosocial factors in those patients. In our study, more than two thirds of patients suffer from unrecognised depressive affects. Early detection and adequate treatment could significantly improve their quality of life and compliance. As far as CBS is concerned, given its low prevalence, objective criteria should be established in order to select the patients who need screening.

Empirical evaluation of the Q-Genie tool: a protocol for assessment of effectiveness.

INTRODUCTION: Meta-analyses of genetic association studies are affected by biases and quality shortcomings of the individual studies. We previously developed and validated a risk of bias tool for use in systematic reviews of genetic association studies. The present study describes a larger empirical evaluation of the Q-Genie tool. METHODS AND ANALYSIS: MEDLINE, Embase, Global Health and the Human Genome Epidemiology Network will be searched for published meta-analyses of genetic association studies. Twelve reviewers in pairs will apply the Q-Genie tool to all studies in included meta-analyses. The Q-Genie will then be evaluated on its ability to (i) increase precision after exclusion of low quality studies, (ii) decrease heterogeneity after exclusion of low quality studies and (iii) good agreement with experts on quality rating by Q-Genie. A qualitative assessment of the tool will also be conducted using structured questionnaires. DISCUSSION: This systematic review will quantitatively and qualitatively assess the Q-Genie's ability to identify poor quality genetic association studies. This information will inform the selection of studies for inclusion in meta-analyses, conduct sensitivity analyses and perform metaregression. Results of this study will strengthen our confidence in estimates of the effect of a gene on an outcome from meta-analyses, ultimately bringing us closer to deliver on the promise of personalised medicine. ETHICS AND DISSEMINATION: An updated Q-Genie tool will be made available from the Population Genomics Program website and the results will be submitted for a peer-reviewed publication.

Allelic variations of the vitamin D receptor (VDR) gene are associated with increased risk of coronary artery disease in type 2 diabetics: the DIABHYCAR prospective study.

AIM: Vitamin D deficiency is associated with coronary artery disease (CAD), and the actions of vitamin D are mediated by binding to a specific nuclear vitamin D receptor (VDR). This study investigated the associations of VDR gene variants with CAD in two cohorts of type 2 diabetes patients. METHODS: A cohort of 3137 subjects from the prospective DIABHYCAR study (CAD incidence: 14.8%; follow-up: 4.4 ± 1.3 years) and an independent, hospital-based population of 713 subjects, 32.3% of whom had CAD, were assessed. Three SNPs in the VDR gene were genotyped: rs1544410 (BsmI); rs7975232 (ApaI); and rs731236 (TaqI). RESULTS: In the DIABHYCAR cohort, an association was observed between the A allele of BsmI and incident cases of CAD (HR: 1.16, 95% CI: 1.05-1.29; P = 0.002). Associations were also observed between BsmI (P = 0.01) and TaqI (P = 0.04) alleles and baseline cases of CAD. The AAC haplotype (BsmI/ApaI/TaqI) was significantly associated with an increased CAD prevalence at the end of the study compared with the GCT haplotype (OR: 1.12, 95% CI: 1.02-1.28; P = 0.04). In a cross-sectional study of the independent hospital-based cohort, associations of ApaI (P = 0.009) and TaqI (P = 0.03) alleles with CAD were observed, with similar haplotype results (OR: 1.33, 95% CI: 1.03-1.73; P = 0.03). CONCLUSION: The haplotype comprising the minor allele of BsmI, major allele of ApaI and minor allele of TaqI of VDR (AAC) was associated with an increased risk of CAD in type 2 diabetes patients. This effect was independent of the effects of other known cardiovascular risk factors.