Body mass index trajectories in young adulthood predict nonâ alcoholic fatty liver disease in middle age: The CARDIA cohort study

Background & AimsNonâ alcoholic fatty liver disease is an epidemic. Identifying modifiable risk factors for nonâ alcoholic fatty liver disease development is essential to design effective prevention programmes. We tested whether 25â year patterns of body mass index change are associated with midlife nonâ alcoholic fatty liver disease.MethodsIn all, 4423 participants from Coronary Artery Risk Development in Young Adults, a prospective populationâ based biracial cohort (age 18â 30), underwent body mass index measurement at baseline (1985â 1986) and 3 or more times over 25 years. At Year 25, 3115 had liver fat assessed by nonâ contrast computed tomography. Nonâ alcoholic fatty liver disease was defined as liver attenuation â ¤40 Hounsfield Units after exclusions. Latent mixture modelling identified 25â year trajectories in body mass index per cent change (%Î ) from baseline.ResultsWe identified four distinct trajectories of BMI%Î : stable (26.2% of cohort, 25â year BMI %Π = 3.1%), moderate increase (46.0%, BMI%Π = 21.7%), high increase (20.9%, BMI%Π = 41.9%) and extreme increase (6.9%, BMI%Π = 65.9%). Y25 nonâ alcoholic fatty liver disease prevalence was higher in groups with greater BMI %Î : 4.1%, 9.3%, 13.0%, and 17.6%, respectively (Pâ trend <.0001). In multivariable analyses, participants with increasing BMI%Î had increasingly greater odds of nonâ alcoholic fatty liver disease compared to the stable group: OR: 3.35 (95% CI: 2.07â 5.42), 7.80 (4.60â 13.23) and 12.68 (6.68â 24.09) for moderate, high and extreme body mass index increase, respectively. Associations were only moderately attenuated when adjusted for baseline or Y25 body mass index.ConclusionsTrajectories of weight gain during young adulthood are associated with greater nonâ alcoholic fatty liver disease prevalence in midlife independent of metabolic covariates and baseline or concurrent body mass index highlighting the importance of weight maintenance throughout adulthood as a target for primary nonâ alcoholic fatty liver disease prevention.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142937/1/liv13603.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142937/2/liv13603_am.pd

Gene set of nuclear-encoded mitochondrial regulators is enriched for common inherited variation in obesity

There are hints of an altered mitochondrial function in obesity. Nuclear-encoded genes are relevant for mitochondrial function (3 gene sets of known relevant pathways: (1) 16 nuclear regulators of mitochondrial genes, (2) 91 genes for oxidative phosphorylation and (3) 966 nuclear-encoded mitochondrial genes). Gene set enrichment analysis (GSEA) showed no association with type 2 diabetes mellitus in these gene sets. Here we performed a GSEA for the same gene sets for obesity. Genome wide association study (GWAS) data from a case-control approach on 453 extremely obese children and adolescents and 435 lean adult controls were used for GSEA. For independent confirmation, we analyzed 705 obesity GWAS trios (extremely obese child and both biological parents) and a population-based GWAS sample (KORA F4, n = 1,743). A meta-analysis was performed on all three samples. In each sample, the distribution of significance levels between the respective gene set and those of all genes was compared using the leading-edge-fraction-comparison test (cut-offs between the 50(th) and 95(th) percentile of the set of all gene-wise corrected p-values) as implemented in the MAGENTA software. In the case-control sample, significant enrichment of associations with obesity was observed above the 50(th) percentile for the set of the 16 nuclear regulators of mitochondrial genes (p(GSEA,50) = 0.0103). This finding was not confirmed in the trios (p(GSEA,50) = 0.5991), but in KORA (p(GSEA,50) = 0.0398). The meta-analysis again indicated a trend for enrichment (p(MAGENTA,50) = 0.1052, p(MAGENTA,75) = 0.0251). The GSEA revealed that weak association signals for obesity might be enriched in the gene set of 16 nuclear regulators of mitochondrial genes

Twentyâ fiveâ year trajectories of insulin resistance and pancreatic βâ cell response and diabetes risk in nonalcoholic fatty liver disease

Background & AimsInsulin resistance is a risk marker for nonâ alcoholic fatty liver disease, and a risk factor for liver disease progression. We assessed temporal trajectories of insulin resistance and βâ cell response to serum glucose concentration throughout adulthood and their association with diabetes risk in nonâ alcoholic fatty liver disease.MethodsThree thousand and sixty participants from Coronary Artery Risk Development in Young Adults, a prospective biâ racial cohort of adults age 18â 30 years at baseline (1985â 1986; Y0) who completed up to 5 exams over 25 years and had fasting insulin and glucose measurement were included. At Y25 (2010â 2011), nonâ alcoholic fatty liver disease was assessed by noncontrast computed tomography after exclusion of other liver fat causes. Latent mixture modelling identified 25â year trajectories in homeostatic model assessment insulin resistance and βâ cell response homeostatic model assessmentâ β.ResultsThree distinct trajectories were identified, separately, for homeostatic model assessment insulin resistance (lowâ stable [47%]; moderateâ increasing [42%]; and highâ increasing [12%]) and homeostatic model assessmentâ β (lowâ decreasing [16%]; moderateâ decreasing [63%]; and highâ decreasing [21%]). Y25 nonâ alcoholic fatty liver disease prevalence was 24.5%. Among nonâ alcoholic fatty liver disease, highâ increasing homeostatic model assessment insulin resistance (referent: lowâ stable) was associated with greater prevalent (OR 95% CI = 8.0, 2.0â 31.9) and incident (OR = 10.5, 2.6â 32.8) diabetes after multivariable adjustment including Y0 or Y25 homeostatic model assessment insulin resistance. In contrast, nonâ alcoholic fatty liver disease participants with lowâ decreasing homeostatic model assessmentâ β (referent: highâ decreasing) had the highest odds of prevalent (OR = 14.1, 3.9â 50.9) and incident (OR = 10.3, 2.7â 39.3) diabetes.ConclusionTrajectories of insulin resistance and βâ cell response during young and middle adulthood are robustly associated with diabetes risk in nonâ alcoholic fatty liver disease. Thus, how persons with nonâ alcoholic fatty liver disease develop resistance to insulin provides important information about risk of diabetes in midlife above and beyond degree of insulin resistance at the time of nonâ alcoholic fatty liver disease assessment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146427/1/liv13747_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146427/2/liv13747.pd

Impact of FTO genotypes on BMI and weight in polycystic ovary syndrome : a systematic review and meta-analysis

Aims/hypothesis FTO gene single nucleotide polymorphisms (SNPs) have been shown to be associated with obesity-related traits and type 2 diabetes. Several small studies have suggested a greater than expected effect of the FTO rs9939609 SNP on weight in polycystic ovary syndrome (PCOS). We therefore aimed to examine the impact of FTO genotype on BMI and weight in PCOS. Methods A systematic search of medical databases (PubMed, EMBASE and Cochrane CENTRAL) was conducted up to the end of April 2011. Seven studies describing eight distinct PCOS cohorts were retrieved; seven were genotyped for SNP rs9939609 and one for SNP rs1421085. The per allele effect on BMI and body weight increase was calculated and subjected to meta-analysis. Results A total of 2,548 women with PCOS were included in the study; 762 were TT homozygotes, 1,253 had an AT/CT genotype, and 533 were AA/CC homozygotes. Each additional copy of the effect allele (A/C) increased the BMI by a mean of 0.19 z score units (95% CI 0.13, 0.24; p = 2.26 × 10−11) and body weight by a mean of 0.20 z score units (95% CI 0.14, 0.26; p = 1.02 × 10−10). This translated into an approximately 3.3 kg/m2 increase in BMI and an approximately 9.6 kg gain in body weight between TT and AA/CC homozygotes. The association between FTO genotypes and BMI was stronger in the cohorts with PCOS than in the general female populations from large genome-wide association studies. Deviation from an additive genetic model was observed in heavier populations. Conclusions/interpretation The effect of FTO SNPs on obesity-related traits in PCOS seems to be more than two times greater than the effect found in large population-based studies. This suggests an interaction between FTO and the metabolic context or polygenic background of PCOS

Genomeâ Wide Study of Subcutaneous and Visceral Adipose Tissue Reveals Novel Sexâ Specific Adiposity Loci in Mexican Americans

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141319/1/oby22074.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141319/2/oby22074_am.pd

A Systematic Mapping Approach of 16q12.2/FTO and BMI in More Than 20,000 African Americans Narrows in on the Underlying Functional Variation: Results from the Population Architecture using Genomics and Epidemiology (PAGE) Study

Genetic variants in intron 1 of the fat mass- and obesity-associated (FTO) gene have been consistently associated with body mass index (BMI) in Europeans. However, follow-up studies in African Americans (AA) have shown no support for some of the most consistently BMI-associated FTO index single nucleotide polymorphisms (SNPs). This is most likely explained by different race-specific linkage disequilibrium (LD) patterns and lower correlation overall in AA, which provides the opportunity to fine-map this region and narrow in on the functional variant. To comprehensively explore the 16q12.2/FTO locus and to search for second independent signals in the broader region, we fine-mapped a 646-kb region, encompassing the large FTO gene and the flanking gene RPGRIP1L by investigating a total of 3,756 variants (1,529 genotyped and 2,227 imputed variants) in 20,488 AAs across five studies. We observed associations between BMI and variants in the known FTO intron 1 locus: the SNP with the most significant p-value, rs56137030 (8.3×10-6) had not been highlighted in previous studies. While rs56137030was correlated at r2>0.5 with 103 SNPs in Europeans (including the GWAS index SNPs), this number was reduced to 28 SNPs in AA. Among rs56137030 and the 28 correlated SNPs, six were located within candidate intronic regulatory elements, including rs1421085, for which we predicted allele-specific binding affinity for the transcription factor CUX1, which has recently been implicated in the regulation of FTO. We did not find strong evidence for a second independent signal in the broader region. In summary, this large fine-mapping study in AA has substantially reduced the number of common alleles that are likely to be functional candidates of the known FTO locus. Importantly our study demonstrated that comprehensive fine-mapping in AA provides a powerful approach to narrow in on the functional candidate(s) underlying the initial GWAS findings in European populations

Adult obesity susceptibility variants are associated with greater childhood weight gain and a faster tempo of growth: the 1946 British Birth Cohort Study123

Background: Longitudinal growth associations with genetic variants identified for adult BMI may provide insights into the timing of obesity susceptibility

Genetic evidence for a normal-weight "metabolically obese" phenotype linking insulin resistance, hypertension, coronary artery disease, and type 2 diabetes

PublishedJournal ArticleResearch Support, Non-U.S. Gov'tThe mechanisms that predispose to hypertension, coronary artery disease (CAD), and type 2 diabetes (T2D) in individuals of normal weight are poorly understood. In contrast, in monogenic primary lipodystrophy-a reduction in subcutaneous adipose tissue-it is clear that it is adipose dysfunction that causes severe insulin resistance (IR), hypertension, CAD, and T2D. We aimed to test the hypothesis that common alleles associated with IR also influence the wider clinical and biochemical profile of monogenic IR. We selected 19 common genetic variants associated with fasting insulin-based measures of IR. We used hierarchical clustering and results from genome-wide association studies of eight nondisease outcomes of monogenic IR to group these variants. We analyzed genetic risk scores against disease outcomes, including 12,171 T2D cases, 40,365 CAD cases, and 69,828 individuals with blood pressure measurements. Hierarchical clustering identified 11 variants associated with a metabolic profile consistent with a common, subtle form of lipodystrophy. A genetic risk score consisting of these 11 IR risk alleles was associated with higher triglycerides (β = 0.018; P = 4 × 10(-29)), lower HDL cholesterol (β = -0.020; P = 7 × 10(-37)), greater hepatic steatosis (β = 0.021; P = 3 × 10(-4)), higher alanine transaminase (β = 0.002; P = 3 × 10(-5)), lower sex-hormone-binding globulin (β = -0.010; P = 9 × 10(-13)), and lower adiponectin (β = -0.015; P = 2 × 10(-26)). The same risk alleles were associated with lower BMI (per-allele β = -0.008; P = 7 × 10(-8)) and increased visceral-to-subcutaneous adipose tissue ratio (β = -0.015; P = 6 × 10(-7)). Individuals carrying ≥17 fasting insulin-raising alleles (5.5% population) were slimmer (0.30 kg/m(2)) but at increased risk of T2D (odds ratio [OR] 1.46; per-allele P = 5 × 10(-13)), CAD (OR 1.12; per-allele P = 1 × 10(-5)), and increased blood pressure (systolic and diastolic blood pressure of 1.21 mmHg [per-allele P = 2 × 10(-5)] and 0.67 mmHg [per-allele P = 2 × 10(-4)], respectively) compared with individuals carrying ≤9 risk alleles (5.5% population). Our results provide genetic evidence for a link between the three diseases of the "metabolic syndrome" and point to reduced subcutaneous adiposity as a central mechanism

17‐Beta Hydroxysteroid Dehydrogenase 13 Is a Hepatic Retinol Dehydrogenase Associated With Histological Features of Nonalcoholic Fatty Liver Disease

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148371/1/hep30350.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148371/2/hep30350_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148371/3/hep30350-sup-0001-Supinfo.pd