Effects of dietary macronutrients on liver fat content in adults: a systematic review and meta-analysis of randomized controlled trials

Dietary macronutrient composition may affect hepatic liver content and its associated diseases, but the results from human intervention trials have been equivocal or underpowered. We aimed to assess the effects of dietary macronutrient composition on liver fat content by conducting a systematic review and meta-analysis of randomized controlled trials in adults. Four databases (PubMed, Embase, Web of Science, and COCHRANE Library) were systematically searched for trials with isocaloric diets evaluating the effect of dietary macronutrient composition (energy percentages of fat, carbohydrates, and protein, and their specific types) on liver fat content as assessed by magnetic resonance techniques, computed tomography or liver biopsy. Data on change in liver fat content were pooled by random or fixed-effects meta-analyses and expressed as standardized mean difference (SMD). We included 26 randomized controlled trials providing data for 32 comparisons on dietary macronutrient composition. Replacing dietary fat with carbohydrates did not result in changes in liver fat (12 comparisons, SMD 0.01 (95% CI -0.36; 0.37)). Unsaturated fat as compared with saturated fat reduced liver fat content (4 comparisons, SMD -0.80 (95% CI -1.09; -0.51)). Replacing carbohydrates with protein reduced liver fat content (5 comparisons, SMD -0.33 (95% CI -0.54; -0.12)). Our meta-analyses showed that replacing carbohydrates with total fat on liver fat content was not effective, while replacing carbohydrates with proteins and saturated fat with unsaturated fat was. More well-performed and well-described studies on the effect of types of carbohydrates and proteins on liver fat content are needed, especially studies comparing proteins with fats.

The contribution of tissue-grouped BMI-associated gene sets to cardiometabolic-disease risk: a Mendelian randomization study

Background

Body mass index (BMI)-associated loci are used to explore the effects of obesity using Mendelian randomization (MR), but the contribution of individual tissues to risks remains unknown. We aimed to identify tissue-grouped pathways of BMI-associated loci and relate these to cardiometabolic disease using MR analyses.

Methods

Using Genotype-Tissue Expression (GTEx) data, we performed overrepresentation tests to identify tissue-grouped gene sets based on mRNA-expression profiles from 634 previously published BMI-associated loci. We conducted two-sample MR with inverse-variance-weighted methods, to examine associations between tissue-grouped BMI-associated genetic instruments and type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD), with use of summary-level data from published genome-wide association studies (T2DM: 74 124 cases, 824 006 controls; CAD: 60 801 cases, 123 504 controls). Additionally, we performed MR analyses on T2DM and CAD using randomly sampled sets of 100 or 200 BMI-associated genetic variants.

Results

We identified 17 partly overlapping tissue-grouped gene sets, of which 12 were brain areas, where BMI-associated genes were differentially expressed. In tissue-grouped MR analyses, all gene sets were similarly associated with increased risks of T2DM and CAD. MR analyses with randomly sampled genetic variants on T2DM and CAD resulted in a distribution of effect estimates similar to tissue-grouped gene sets.

Conclusions

Overrepresentation tests revealed differential expression of BMI-associated genes in 17 different tissues. However, with our biology-based approach using tissue-grouped MR analyses, we did not identify different risks of T2DM or CAD for the BMI-associated gene sets, which was reflected by similar effect estimates obtained by randomly sampled gene sets.

The role of C-reactive protein, adiponectin and leptin in the association between abdominal adiposity and insulin resistance in middle-aged individuals

BACKGROUND AND AIMS

In the present study, we assessed the extent of mediation by low-grade systemic inflammation and adipokines in the association between abdominal adiposity and insulin resistance.

METHODS AND RESULTS

In this cross-sectional analysis of baseline measurements of the Netherlands Epidemiology of Obesity study, total body fat (TBF) was measured in all (n = 5772) participants who did not have missing data and neither used glucose-lowering medication, and abdominal subcutaneous adipose tissue (aSAT) and visceral adipose tissue (VAT) were assessed by MRI in a random subgroup (n = 2448). C-reactive protein (CRP), adiponectin, and leptin were considered as potential mediators, and insulin resistance was assessed by Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Mediation by CRP, adiponectin, and leptin was studied by including the mediators to the fully adjusted linear regression model. Participants had a mean (SD) age of 56 (6) years, TBF of 36 (9) %, VAT of 119 (61) cm² and aSAT of 300 (111) cm². Per SD of TBF, VAT and aSAT, HOMA-IR was 64% (95% confidence interval [CI]: 59-70), 33% (95%CI: 28-42) and 20% (95%CI: 14-26) higher, respectively. The association between aSAT and HOMA-IR fully disappeared after adjustment for leptin; the association between VAT and HOMA-IR attenuated after adjustment for leptin (22%) and adiponectin (15%). No mediation was observed by CRP, and mediation estimates were similar in men and women.

CONCLUSION

Where leptin fully explained the aSAT-HOMA-IR association, the VAT-HOMA-IR association was only partly explained by leptin and adiponectin similarly in men and women.

Genome-Wide Association Study of the Postprandial Triglyceride Response Yields Common Genetic Variation in LIPC (Hepatic Lipase)

BACKGROUND

The increase in serum triglyceride (TG) concentrations in response to a meal is considered a risk factor for cardiovascular disease. We aimed to elucidate the genetics of the postprandial TG response through genome-wide association studies (GWAS).

METHODS

Participants of the NEO (Netherlands Epidemiology of Obesity) study (n=5630) consumed a liquid mixed meal after an overnight fast. GWAS of fasting and postprandial serum TG at 150 minutes were performed. To identify genetic variation of postprandial TG independent of fasting TG, we calculated the TG response at 150 minutes by the residuals of a nonlinear regression that predicted TG at 150 minutes as a function of fasting TG. Association analyses were adjusted for age, sex, and principal components in a linear regression model. Next, using the identified variants as determinants, we performed linear regression analyses on the residuals of the postprandial response of 149 nuclear magnetic resonance-based metabolite measures.

RESULTS

GWAS of fasting TG and postprandial serum TG at 150 minutes resulted in completely overlapping loci, replicating previous GWAS. From GWAS of the TG response, we identified rs7350789-A (allele frequency=0.36), mapping to hepatic lipase (LIPC), to be associated with a smaller increase in TG concentrations at 150 minutes (β=-0.11; P-value=5.1×10^-8). Rs7350789-A was associated with responses of 33 metabolite measures (P-value <1.34×10^-3), mainly smaller increases of the TG-component in almost all HDL (high-density lipoprotein) subparticles (HDL-TG), a smaller decrease of HDL diameter and smaller increases of most components of VLDL (very low density lipoprotein) subparticles.

CONCLUSIONS

GWAS of the TG response identified a variant near LIPC as a main contributor to postprandial TG metabolism independent of fasting TG concentrations, resulting in smaller increases of HDL-TG and VLDL subparticles.

Multi-ancestry GWAS of the electrocardiographic PR interval identifies 202 loci underlying cardiac conduction

The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality. Here we report a multi-ancestry (N = 293,051) genome-wide association meta-analysis for the PR interval, discovering 202 loci of which 141 have not previously been reported. Variants at identified loci increase the percentage of heritability explained, from 33.5% to 62.6%. We observe enrichment for cardiac muscle developmental/contractile and cytoskeletal genes, highlighting key regulation processes for atrioventricular conduction. Additionally, 8 loci not previously reported harbor genes underlying inherited arrhythmic syndromes and/or cardiomyopathies suggesting a role for these genes in cardiovascular pathology in the general population. We show that polygenic predisposition to PR interval duration is an endophenotype for cardiovascular disease, including distal conduction disease, AF, and atrioventricular pre-excitation. These findings advance our understanding of the polygenic basis of cardiac conduction, and the genetic relationship between PR interval duration and cardiovascular disease.

Mendelian randomization analysis does not support causal associations of birth weight with hypertension risk and blood pressure in adulthood

Epidemiology studies suggested that low birthweight was associated with a higher risk of hypertension in later life. However, little is known about the causality of such associations. In our study, we evaluated the causal association of low birthweight with adulthood hypertension following a standard analytic protocol using the study-level data of 183,433 participants from 60 studies (CHARGE-BIG consortium), as well as that with blood pressure using publicly available summary-level genome-wide association data from EGG consortium of 153,781 participants, ICBP consortium and UK Biobank cohort together of 757,601 participants. We used seven SNPs as the instrumental variable in the study-level analysis and 47 SNPs in the summary-level analysis. In the study-level analyses, decreased birthweight was associated with a higher risk of hypertension in adults (the odds ratio per 1 standard deviation (SD) lower birthweight, 1.22; 95% CI 1.16 to 1.28), while no association was found between genetically instrumented birthweight and hypertension risk (instrumental odds ratio for causal effect per 1 SD lower birthweight, 0.97; 95% CI 0.68 to 1.41). Such results were consistent with that from the summary-level analyses, where the genetically determined low birthweight was not associated with blood pressure measurements either. One SD lower genetically determined birthweight was not associated with systolic blood pressure (β = - 0.76, 95% CI - 2.45 to 1.08 mmHg), 0.06 mmHg lower diastolic blood pressure (β = - 0.06, 95% CI - 0.93 to 0.87 mmHg), or pulse pressure (β = - 0.65, 95% CI - 1.38 to 0.69 mmHg, all p > 0.05). Our findings suggest that the inverse association of birthweight with hypertension risk from observational studies was not supported by large Mendelian randomization analyses.

Smoking-by-genotype interaction in type 2 diabetes risk and fasting glucose

Smoking is a potentially causal behavioral risk factor for type 2 diabetes (T2D), but not all smokers develop T2D. It is unknown whether genetic factors partially explain this variation. We performed genome-environment-wide interaction studies to identify loci exhibiting potential interaction with baseline smoking status (ever vs. never) on incident T2D and fasting glucose (FG). Analyses were performed in participants of European (EA) and African ancestry (AA) separately. Discovery analyses were conducted using genotype data from the 50,000-single-nucleotide polymorphism (SNP) ITMAT-Broad-CARe (IBC) array in 5 cohorts from from the Candidate Gene Association Resource Consortium (n = 23,189). Replication was performed in up to 16 studies from the Cohorts for Heart Aging Research in Genomic Epidemiology Consortium (n = 74,584). In meta-analysis of discovery and replication estimates, 5 SNPs met at least one criterion for potential interaction with smoking on incident T2D at p<1x10-7 (adjusted for multiple hypothesis-testing with the IBC array). Two SNPs had significant joint effects in the overall model and significant main effects only in one smoking stratum: rs140637 (FBN1) in AA individuals had a significant main effect only among smokers, and rs1444261 (closest gene C2orf63) in EA individuals had a significant main effect only among nonsmokers. Three additional SNPs were identified as having potential interaction by exhibiting a significant main effects only in smokers: rs1801232 (CUBN) in AA individuals, rs12243326 (TCF7L2) in EA individuals, and rs4132670 (TCF7L2) in EA individuals. No SNP met significance for potential interaction with smoking on baseline FG. The identification of these loci provides evidence for genetic interactions with smoking exposure that may explain some of the heterogeneity in the association between smoking and T2D.

Adiposity is a confounding factor which largely explains the association of serum vitamin D concentrations with C-reactive protein, leptin and adiponectin

OBJECTIVE

The role of adiposity in the relationship between vitamin D and inflammation is unknown. Our aim was therefore to assess the association of serum 25-hydroxyvitamin D (25(OH)D) with C-reactive protein (CRP), leptin and adiponectin and the role of adiposity in this relationship.

METHODS

This is a cross-sectional analysis of The Netherlands Epidemiology of Obesity Study (NEO), a population-based cohort study in men and women aged 45 to 65 years. Main outcome measures were CRP, leptin and adiponectin. In the linear regression analyses we adjusted for age, sex, ethnicity, creatinine, education, alcohol use, smoking status, physical activity, number of chronic diseases, season, total body fat and waist circumference.

RESULTS

Of the 6287 participants, 21% were vitamin D deficient (serum 25(OH)D < 50 nmol/L). Mean (SD) age and BMI were 56 (6) years and 26.3 (4.4) kg/m², respectively. Although after adjustment for most examined potential confounders, each 10 nmol/L increase in serum 25(OH)D was associated with 2.3% (95%CI: -4.0 to -0.5) lower CRP, 3.5% (-4.7 to -2.2) lower leptin, and 0.13 ng/mL (0.04-0.21) higher adiponectin, most of these associations seemed to largely stem from an additional potential confounder - adiposity - as they either disappeared (leptin and CRP) or were largely diminished (adiponectin) upon further adjustment for adiposity indices (total body fat and waist circumference).

CONCLUSION

We found that measures of adiposity largely explained the negative association of serum 25(OH)D with the pro-inflammatory CRP and leptin, and the positive association with the anti-inflammatory adiponectin. These results suggest that future studies should take the effect of adiposity into account.

Hepatic saturated fatty acid fraction is associated with de novo lipogenesis and hepatic insulin resistance

Hepatic steatosis is associated with poor cardiometabolic health, with de novo lipogenesis (DNL) contributing to hepatic steatosis and subsequent insulin resistance. Hepatic saturated fatty acids (SFA) may be a marker of DNL and are suggested to be most detrimental in contributing to insulin resistance. Here, we show in a cross-sectional study design (ClinicalTrials.gov ID: NCT03211299) that we are able to distinguish the fractions of hepatic SFA, mono- and polyunsaturated fatty acids in healthy and metabolically compromised volunteers using proton magnetic resonance spectroscopy (¹H-MRS). DNL is positively associated with SFA fraction and is elevated in patients with non-alcoholic fatty liver and type 2 diabetes. Intriguingly, SFA fraction shows a strong, negative correlation with hepatic insulin sensitivity. Our results show that the hepatic lipid composition, as determined by our ¹H-MRS methodology, is a measure of DNL and suggest that specifically the SFA fraction may hamper hepatic insulin sensitivity.

Hepatic steatosis is associated with poor cardiometabolic health, with de novo lipogenesis (DNL) contributing to hepatic steatosis and subsequent insulin resistance. Here, the authors use ¹H-MRS methodology to show hepatic SFA fraction is a measure of DNL and specifically may hamper hepatic insulin sensitivity.

Metabolomics Profile in Depression: A Pooled Analysis of 230 Metabolic Markers in 5283 Cases With Depression and 10,145 Controls

BACKGROUND

Depression has been associated with metabolic alterations, which adversely impact cardiometabolic health. Here, a comprehensive set of metabolic markers, predominantly lipids, was compared between depressed and nondepressed persons.

METHODS

Nine Dutch cohorts were included, comprising 10,145 control subjects and 5283 persons with depression, established with diagnostic interviews or questionnaires. A proton nuclear magnetic resonance metabolomics platform provided 230 metabolite measures: 51 lipids, fatty acids, and low-molecular-weight metabolites; 98 lipid composition and particle concentration measures of lipoprotein subclasses; and 81 lipid and fatty acids ratios. For each metabolite measure, logistic regression analyses adjusted for gender, age, smoking, fasting status, and lipid-modifying medication were performed within cohort, followed by random-effects meta-analyses.

RESULTS

Of the 51 lipids, fatty acids, and low-molecular-weight metabolites, 21 were significantly related to depression (false discovery rate q < .05). Higher levels of apolipoprotein B, very-low-density lipoprotein cholesterol, triglycerides, diglycerides, total and monounsaturated fatty acids, fatty acid chain length, glycoprotein acetyls, tyrosine, and isoleucine and lower levels of high-density lipoprotein cholesterol, acetate, and apolipoprotein A1 were associated with increased odds of depression. Analyses of lipid composition indicators confirmed a shift toward less high-density lipoprotein and more very-low-density lipoprotein and triglyceride particles in depression. Associations appeared generally consistent across gender, age, and body mass index strata and across cohorts with depressive diagnoses versus symptoms.

CONCLUSIONS

This large-scale meta-analysis indicates a clear distinctive profile of circulating lipid metabolites associated with depression, potentially opening new prevention or treatment avenues for depression and its associated cardiometabolic comorbidity.

Hormonal Treatment and Cardiovascular Risk Profile in Transgender Adolescents

BACKGROUND AND OBJECTIVES

The effects of endocrinological treatment on cardiovascular risk profile in transgender adolescents are unknown. In this retrospective cohort study, we aim to investigate these effects and assess obesity and dyslipidemia prevalence in transgender adolescents at 22 years compared with peers.

METHODS

Changes in BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP), glucose, homeostatic model assessment for insulin resistance (HOMA-IR), and lipid values during treatment, along with the prevalence of obesity and dyslipidemia at 22 years, were recorded in 71 transwomen and 121 transmen who started gonadotropin-releasing hormone agonists in their adolescence (15 years), with a subsequent addition of sex hormones (17 years).

RESULTS

In transwomen, changes in BMI (+3.0; 95% confidence interval [CI] 1.6 to 4.4), SBP (-2 mm Hg; 95% CI -7 to 3), DBP (+10 mm Hg; 95% CI 7 to 14), glucose (0.0 mmol/L; 95% CI -0.2 to 0.2), HOMA-IR (+0.6; 95% CI -0.6 to 1.9), and lipid values were similar or more favorable compared with peers. The same was true for transmen regarding changes in BMI (+2.3; 95% CI 1.7 to 2.9), SBP (+7 mm Hg; 95% CI 3 to 10), DBP (+7 mm Hg; 95% CI 5 to 10), glucose (+0.1 mmol/L; 95% CI -0.1 to 0.3), HOMA-IR (-0.2; 95% CI -0.8 to 0.3), and lipid values. At age 22, obesity prevalence was 9.9% in transwomen, 6.6% in transmen, 2.2% in ciswomen, and 3.0% in cismen.

CONCLUSIONS

Generally, endocrinological treatment in transgender adolescents is safe regarding cardiovascular risk. Because obesity is more prevalent in transgender adolescents compared with peers, body weight management should be important during the medical trajectory.

Prevalence of Carriers of Intermediate and Pathological Polyglutamine Disease-Associated Alleles Among Large Population-Based Cohorts

Importance

Nine hereditary neurodegenerative diseases are known as polyglutamine diseases, including Huntington disease, 6 spinocerebellar ataxias (SCAs) (SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17), dentatorubral-pallidoluysion atrophy, and spinal bulbar muscular atrophy.

Objective

To determine the prevalence of carriers of intermediate and pathological polyglutamine disease-associated alleles among the general population.

Design, Setting, and Participants

This observational cross-sectional study included data from 5 large European population-based cohorts that were compiled between 1997 and 2012, and the analyses were conducted in 2018. In total, 16 547 DNA samples were obtained from participants of the 5 cohorts. Individuals with a lifetime diagnosis of major depression were excluded (n = 2351). In the remaining 14 196 participants without an established polyglutamine disease diagnosis, the CAG repeat size in both alleles of all 9 polyglutamine disease-associated genes (PDAGs) (ie, ATXN1, ATXN2, ATXN3, CACNA1A, ATXN7, TBP, HTT, ATN1, and AR) was determined.

Exposure

The number of CAG repeats in the alleles of the 9 PDAGs.

Main Outcomes and Measures

The number of individuals with alleles within the intermediate or pathological range per PDAG, as well as differences in sex, age, and body mass index between individuals carrying alleles within the normal or intermediate range and individuals carrying alleles within the pathological range of PDAGs.

Results

In the 14 196 analyzed participants (age range, 18-99 years; 56.3% female), 10.7% had a CAG repeat number within the intermediate range of at least 1 PDAG. Moreover, up to 1.3% of the participants had a CAG repeat number within the disease-causing range, predominantly in the lower pathological range associated with elderly onset. No differences in sex, age, or body mass index were found between individuals with CAG repeat numbers within the pathological range and individuals with CAG repeat numbers within the normal or intermediate range.

Conclusions and Relevance

These results indicate a high prevalence of individuals carrying intermediate and pathological ranges of polyglutamine disease-associated alleles among the general population. Therefore, a substantially larger proportion of individuals than previously estimated may be at risk of developing a polyglutamine disease later in life or bearing children with a de novo mutation.

The prevalence of metabolic syndrome and its association with body fat distribution in middle-aged individuals from Indonesia and the Netherlands: a cross-sectional analysis of two population-based studies

BACKGROUND

The prevalence of metabolic syndrome varies among populations with different ethnicities. Asian populations develop metabolic complications at lower amounts of adiposity than western populations. The role of abdominal obesity in the metabolic differences between the two populations is poorly understood.

OBJECTIVES

Our objectives were to estimate the prevalence of metabolic syndrome and the relative contribution of its components in the Indonesian and the Dutch population, as well as to examine the associations of overall and abdominal obesity with metabolic syndrome.

METHODS

In this cross-sectional study of middle-aged adults in the Netherlands Epidemiology of Obesity Study (n = 6602) and the Indonesian National Health Surveillance (n = 10,575), metabolic syndrome was defined by the unified IDF and AHA/NHLBI criteria. We performed logistic and linear regressions to examine associations of BMI and waist circumference with the metabolic syndrome, mutually adjusted for waist circumference and BMI.

RESULTS

The prevalence of metabolic syndrome was 28% and 46% in Indonesian men and women, and 36% and 24% in Dutch men and women. The most prominent components were hypertension (61%) and hyperglycemia (51%) in the Indonesian, and hypertension (62%) and abdominal obesity (40%) in the Dutch population. Per SD in BMI and waist circumference, odds ratios (ORs, 95% CI) of metabolic syndrome were 1.5 (1.3-1.8) and 2.3 (1.9-2.7) in Indonesian men and 1.7 (1.2-2.5) and 2.9 (2.1-4.1) in Dutch men. The ORs of metabolic syndrome were 1.4 (1.2-1.6) and 2.3 (2.0-2.7) in Indonesian women and 1.0 (0.8-1.3) and 4.2 (3.2-5.4) in Dutch women.

CONCLUSION

More Indonesian women than men have metabolic syndrome, whereas the opposite is true for the Dutch population. In both the Indonesian and the Dutch populations, hypertension is the primary contributor to the prevalence of metabolic syndrome. In both populations, abdominal adiposity was more strongly associated with metabolic syndrome than overall adiposity.

The association between overall and abdominal adiposity and depressive mood: A cross-sectional analysis in 6459 participants

OBJECTIVE

We aimed to evaluate the association between measures of adiposity with depressive mood and specific depressive symptoms.

METHODS

This study was performed in the Netherlands Epidemiology of Obesity (NEO) study, a population-based study that consists of 6671 middle-aged individuals. We examined the association between measures of overall adiposity (BMI and total body fat), and abdominal adiposity (waist circumference and visceral adipose tissue), with depressive mood severity subgroups and 30 depressive symptoms. Multinomial logistic regression was performed adjusting for potential confounding.

RESULTS

Measures of adiposity were associated with depressive mood in a graded fashion. Total body fat showed the strongest association with mild (Odds Ratio (OR): 1.59 per standard deviation, 95% Confidence Interval (95% CI): 1.41-1.80) and moderate to very severe (OR: 1.97, 95% CI: 1.59-2.44) depressive mood. Regarding individual symptoms of depressive mood, total body fat was associated with most depressive symptoms (strongest associations for hyperphagia and fatigability).

CONCLUSIONS

In the general population, overall and abdominal adiposity measures were associated with depressive mood. This association encompasses most of the depressive symptoms and appeared to be the strongest with specific ''atypical'' neurovegetative symptoms, which may be an indication of an alteration in the energy homeostasis.

Genome-Wide Association Study on the Early-Phase Insulin Response to a Liquid Mixed Meal: Results From the NEO Study

Early-phase insulin secretion is a determinant of postprandial glucose homeostasis. In this study, we aimed to identify novel genetic variants associated with the early-phase insulin response to a liquid mixed meal by a genome-wide association study using a discovery and replication design embedded in the Netherlands Epidemiology of Obesity (NEO) study. The early-phase insulin response was defined as the difference between the natural logarithm-transformed insulin concentrations of the postprandial state at 30 min after a meal challenge and the fasting state (Δinsulin). After Bonferroni correction, rs505922 (β: -6.5% [minor allele frequency (MAF) 0.32, P = 3.3 × 10^-8]) located in the ABO gene reached genome-wide significant level (P < 5 × 10^-8) and was also replicated successfully (β: -7.8% [MAF 0.32, P = 7.2 × 10^-5]). The function of the ABO gene was assessed using in vitro shRNA-mediated knockdown of gene expression in the murine pancreatic β-cell line MIN6. Knocking down the ABO gene led to decreased insulin secretion in the murine pancreatic β-cell line. These data indicate that the previously identified elevated risk of type 2 diabetes for carriers of the ABO rs505922:C allele may be caused by decreased early-phase insulin secretion.

Health-related Quality of Life in Patients with Hand Osteoarthritis from the General Population and the Outpatient Clinic

Objective.

To investigate the association of hand osteoarthritis (OA) and concurrent hand and knee OA with health-related quality of life (HRQOL) in the general population, and in patients consulting a rheumatology outpatient clinic.

Methods.

In the population-based Netherlands Epidemiology of Obesity (NEO) study, participants were recruited from the greater area of Leiden, the Netherlands. In the Hand OSTeoArthritis in Secondary care (HOSTAS) study, patients with a rheumatologist’s diagnosis of hand OA were recruited from a Leiden-based hospital. In both cohorts, hand and knee OA were defined by the American College of Rheumatology clinical criteria. In NEO, self-reported hospital-based specialist consultation for OA was recorded. Physical and mental HRQOL was assessed with normalized Medical Outcomes Study Short Form-36 scores. Associations were analyzed using linear regression, adjusted for age, sex, education, ethnicity, and body mass index.

Results.

Hand OA alone and concurrent hand and knee OA was present in 8% and 4% of 6334 NEO participants, and in 57% and 32% of 538 HOSTAS patients. In NEO, hand OA alone, and concurrent hand and knee OA, were associated with lower physical component summary (PCS) scores [mean difference −2.4 (95% CI −3.6, −1.3) and −7.7 (95% CI −9.3, −6.2), respectively] compared with no OA. Consulting a specialist was associated with worse PCS scores. In the HOSTAS cohort, mean PCS scores were lower than norm values (−3.5 and −7.9 for hand OA and combined OA, respectively). Mental HRQOL was not clinically relevantly associated in either cohort.

Conclusion.

Hand OA was associated with reduced physical, but not mental, HRQOL in the general population and hospital patients. Physical HRQOL was further reduced in hospital care, and with concurrent knee OA.

The Separate Contributions of Visceral Fat and Liver Fat to Chronic Kidney Disease-Related Renal Outcomes

OBJECTIVES

This study aims to investigate the separate contributions of liver fat and visceral fat on microalbuminuria and impaired renal function, and second, to examine whether non-alcoholic fatty liver disease is causally related to microalbuminuria and/or impaired renal function.

METHODS

Associations between visceral adipose tissue (VAT), hepatic triglyceride content (HTGC), and risk of microalbuminuria and renal function were studied cross-sectionally in the Netherlands Epidemiology of Obesity study. Mendelian randomization using GWAS meta-analysis data was performed to estimate the causal effect of non-alcoholic fatty liver disease (PNPLA3, LYPLAL1, NCAN, GCKR) on eGFR (N_max 118,460), microalbuminuria (N_max 54,116), and impaired renal function (N_max 118,147).

RESULTS

In total, 2,023 participants (mean age 55.5 ± 6.0 years, 53% women) were included of which 29% had fatty liver and 2.0% chronic kidney disease stage ≥3. In joint models, VAT was associated with a 2-fold increased risk of microalbuminuria which was mainly driven by the association in women (total population: per standard deviation [SD] = 55.4 cm², odds ratio [OR] 2.02, 95% confidence interval [CI] 1.18-3.47; women: OR 2.83, 95% CI 1.44, 5.56), but HTGC was not (total population: per SD = 7.9%, OR 1.20, 95% CI 0.85, 1.70). No associations were found for VAT and HTGC with eGFR (VAT: per SD = 55.4 cm², OR 1.25, 95% CI 0.83, 1.87; HTGC: per SD = 7.9%, OR 0.65, 95% CI 0.42, 0.99). No causal effect of NAFLD on microalbuminuria or impaired renal function was found.

CONCLUSIONS

In observational analyses, visceral fat was associated with microalbuminuria in women. Liver fat was not associated with microalbuminuria or renal function, which was supported by Mendelian randomization. Visceral fat might be more important than liver fat in the etiology of microalbuminuria.

Glucose metabolism affects coagulation factors: The NEO study

BACKGROUND

It is insufficiently understood if there is an association between diabetes and VT, and what the underlying mechanism would be.

OBJECTIVES

We aimed to study the association between glucose concentrations with several coagulation factors in the general population.

METHODS

This is a cross-sectional analysis of baseline measurements within 5778 participants of the Netherlands Epidemiology of Obesity (NEO) study, a population-based cohort study of individuals 45 to 65 years. Associations between fasting glucose and HbA1c concentrations, and postprandial glucose response and factor (F) VIII, FIX, FXI, and fibrinogen levels were examined using linear regression analyses and by calculating mean levels per category of glucose concentrations while adjusting for confounding factors.

RESULTS

Per each mmol/L higher fasting glucose concentration we observed higher levels of fasting FVIII (5.33%, 95% CI: 4.00-6.65), FIX (6.19%, 95% CI: 5.15-7.23), and FXI (2.11%, 95% CI: 1.20-3.02). Results for fasting HbA1c and postprandial glucose response were similar. Participants with an impaired fasting glucose, high fasting glucose, and diabetes mellitus had higher mean levels of FVIII, FIX, and FXI than those with a normal glucose metabolism, with the highest differences in the levels of FVIII, FIX, and FXI between a high fasting glucose and a normal glucose metabolism. All associations attenuated after adjustment for total body fat, yet all of the above associations remained after adjustment for the confounding factors, except for fibrinogen when contrasted to glucose.

CONCLUSION

Concentrations of fasting glucose and HbA1c and postprandial glucose response were positively associated with FVIII, FIX, and FXI, and to some extent also with fibrinogen.

Potential Interplay between Dietary Saturated Fats and Genetic Variants of the NLRP3 Inflammasome to Modulate Insulin Resistance and Diabetes Risk: Insights from a Meta-Analysis of 19 005 Individuals

SCOPE

Insulin resistance (IR) and inflammation are hallmarks of type 2 diabetes (T2D). The nod-like receptor pyrin domain containing-3 (NLRP3) inflammasome is a metabolic sensor activated by saturated fatty acids (SFA) initiating IL-1β inflammation and IR. Interactions between SFA intake and NLRP3-related genetic variants may alter T2D risk factors.

METHODS

Meta-analyses of six Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium (n = 19 005) tested interactions between SFA and NLRP3-related single-nucleotide polymorphisms (SNPs) and modulation of fasting insulin, fasting glucose, and homeostasis model assessment of insulin resistance.

RESULTS

SFA interacted with rs12143966, wherein each 1% increase in SFA intake increased insulin by 0.0063 IU mL-1 (SE ± 0.002, p = 0.001) per each major (G) allele copy. rs4925663, interacted with SFA (β ± SE = -0.0058 ± 0.002, p = 0.004) to increase insulin by 0.0058 IU mL-1 , per additional copy of the major (C) allele. Both associations are close to the significance threshold (p < 0.0001). rs4925663 causes a missense mutation affecting NLRP3 expression.

CONCLUSION

Two NLRP3-related SNPs showed potential interaction with SFA to modulate fasting insulin. Greater dietary SFA intake accentuates T2D risk, which, subject to functional validation, may be further elaborated depending on NLRP3-related genetic variants.

Associations of autozygosity with a broad range of human phenotypes

In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44-66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding.

Electrocardiographic Detection of Left Ventricular Hypertrophy; Adding Body Mass Index and Spatial QRS-T Angle: A Cross-Sectional Study

Introduction

We investigated improvement of electrocardiographic LVH detection by adding measures of adiposity and/or novel electrocardiographic measures. Left ventricular hypertrophy (LVH) is an important risk factor for adverse cardiovascular outcomes. Improvement of electrocardiographic criteria for LVH is desirable, since electrocardiography is widely used.

Methods

We included 1091 participants of the Netherlands Epidemiology of Obesity Study (NEO) who underwent cardiac magnetic resonance imaging (MRI). Performance of Sokolow–Lyon and Cornell voltage and product criteria was assessed. Stepwise regression analysis was performed with each conventional electrocardiographic criterion and age, sex, body mass index (BMI), waist circumference, and waist:hip ratio (p-entry < 0.05, p-removal > 0.10). T-wave abnormalities or the spatial QRS-T angle (SA) were added to the improved models.

Results

The study population had a mean (SD) age of 56 (6) years, BMI of 26.1 (4.0) kg/m² and 46% were men. MRI-LVH was present in 10% of participants. The c-statistic for Sokolow–Lyon voltage was 0.58, R² was 0.02 and sensitivity at 90% specificity was 16%, for Sokolow–Lyon product this was 0.62, 0.02, and 21%, for Cornell voltage 0.65, 0.04, and 28% and for Cornell product 0.67, 0.04, and 25%. Best performing models were obtained by addition of both BMI and SA (Sokolow-Lyon voltage: c-statistic 0.74, R² 0.11, sensitivity of 41% at 90% specificity; Sokolow-Lyon product: 0.75, 0.12, 42%; Cornell voltage: c-statistic 0.70, R² 0.08, sensitivity of 38% at 90% specificity; Cornell product: c-statistic 0.72, R² 0.08, sensitivity of 44% at 90% specificity).

Conclusions

Electrocardiographic detection of LVH improved by adding BMI and SA to a model with conventional electrocardiographic criteria. This approach would require little extra effort and application in clinical practice is feasible. However, results should first be replicated in high-risk populations.

Electronic supplementary material

The online version of this article (10.1007/s40119-019-00151-9) contains supplementary material, which is available to authorized users.

Metabolomics: a search for biomarkers of visceral fat and liver fat content

INTODUCTION

Excess visceral and liver fat are known risk factors for cardiometabolic disorders. Metabolomics might allow for easier quantification of these ectopic fat depots, instead of using invasive and costly tools such as MRI or approximations such as waist circumference.

OBJECTIVE

We explored the potential use of plasma metabolites as biomarkers of visceral adipose tissue (VAT) and hepatic triglyceride content (HTGC).

METHODS

We performed a cross-sectional analysis of a subset of the Netherlands Epidemiology of Obesity study. Plasma metabolite profiles were determined using the Biocrates AbsoluteIDQ p150 kit in 176 individuals with normal fasting plasma glucose. VAT was assessed with magnetic resonance imaging and HTGC with proton-MR spectroscopy. We used linear regression to investigate the associations of 190 metabolite variables with VAT and HTGC.

RESULTS

After adjustment for age, sex, total body fat, currently used approximations of visceral and liver fat, and multiple testing, three metabolite ratios were associated with VAT. The strongest association was the lysophosphatidylcholines to total phosphatidylcholines (PCs) ratio [- 14.1 (95% CI - 21.7; - 6.6) cm² VAT per SD of metabolite concentration]. Four individual metabolites were associated with HTGC, especially the diacyl PCs of which C32:1 was the strongest at a 1.31 (95% CI 1.14; 1.51) fold increased HTGC per SD of metabolite concentration.

CONCLUSION

Metabolomics may be a useful tool to identify biomarkers of visceral fat and liver fat content that have added diagnostic value over current approximations. Replication studies are required to validate the diagnostic value of these metabolites.

Target genes, variants, tissues and transcriptional pathways influencing human serum urate levels

Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A. Experimental validation showed that HNF4A transactivated the promoter of ABCG2, encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits.

The Association between Adult Weight Gain and Insulin Resistance at Middle Age: Mediation by Visceral Fat and Liver Fat

We aimed to investigate the role of the amount of visceral fat and liver fat in the association between adult weight change and insulin resistance at middle age. In the Netherlands Epidemiology of Obesity study, adult weight change was calculated with recalled body weight at age 20 years and measured body weight at middle age. Measures of insulin resistance were calculated using both fasting and postprandial glucose and insulin concentrations. Visceral fat was assessed by magnetic resonance (MR) imaging and liver fat by proton-MR spectroscopy (N = 1758). We examined the association between adult weight change and insulin resistance with linear regression, adjusted for confounding factors. To investigate mediation, we additionally adjusted for total body fat, visceral fat, and liver fat. In participants who gained ≥50% of body weight during adulthood, homeostatic model assessment for insulin resistance (HOMA-IR) was 3.22 (95% CI 2.76; 3.77) times higher than in weight maintainers. In a joint model, total body fat mediated this association for 8.1% (95% CI −9.2; 25.4), visceral fat for 32.0% (18.6; 45.4%) and liver fat for 22.5% (15.0; 30.1). The association between adult weight gain and insulin resistance at middle age is largely mediated by both visceral fat and liver fat.

Early Hormonal Treatment Affects Body Composition and Body Shape in Young Transgender Adolescents

BACKGROUND

Transgender adolescents aspiring to have the body characteristics of the affirmed sex can receive hormonal treatment. However, it is unknown how body shape and composition develop during treatment and whether transgender persons obtain the desired body phenotype.

AIM

To examine the change in body shape and composition from the start of treatment with gonadotropin-releasing hormone agonists (GnRHa) until 22 years of age and to compare these measurements at 22 years with those of age-matched peers.

METHODS

71 transwomen (birth-assigned boys) and 121 transmen (birth-assigned girls) who started treatment from 1998 through 2014 were included in this retrospective study. GnRHa treatment was started and cross-sex hormonal treatment was added at 16 years of age. Anthropometric and whole-body dual-energy x-ray absorptiometry data were retrieved from medical records. Linear mixed model regression was performed to examine changes over time. SD scores (SDS) were calculated to compare body shape and composition with those of age-matched peers.

OUTCOMES

Change in waist-hip ratio (WHR), total body fat (TBF), and total lean body mass (LBM) during hormonal treatment. SDS of measures of body shape and composition compared with age-matched peers at 22 years of age.

RESULTS

In transwomen, TBF increased (+10%, 95% CI = 7-11) while total LBM (-10%, 95% CI = -11 to -7) and WHR (-0.04, 95% CI = -0.05 to -0.02) decreased. Compared with ciswomen, SDS at 22 years of age were +0.3 (95% CI = 0.0-0.5) for WHR, and 0.0 (95% CI = -0.2 to 0.3) for TBF. Compared with cismen, SDS were -1.0 (95% CI = -1.3 to -0.7) for WHR, and +2.2 (95% CI = 2.2-2.4) for TBF. In transmen, TBF decreased (-3%, 95% CI = -4 to -1), while LBM (+3%, 95% CI = 1-4) and WHR (+0.03, 95% CI = 0.01-0.04) increased. Compared with ciswomen, SDS at 22 years of age were +0.6 (95% CI = 0.4-0.8) for WHR, and -1.1 (95% CI = -1.4 to -0.9) for TBF. Compared with cismen, SDS were -0.5 (95% CI = -0.8 to -0.3) for WHR, and +1.8 (95% CI = 1.6-1.9) for TBF.

CLINICAL IMPLICATIONS

Knowing body shape and composition outcomes at 22 years of age will help care providers in counseling transgender youth on expectations of attaining the desired body phenotype.

STRENGTHS AND LIMITATIONS

This study presents the largest group of transgender adults to date who started treatment in their teens. Despite missing data, selection bias was not found.

CONCLUSIONS

During treatment, WHR and body composition changed toward the affirmed sex. At 22 years of age, transwomen compared better to age-matched ciswomen than to cismen, whereas transmen were between reference values for ciswomen and cismen. Klaver M, de Mutsert R, Wiepjes CM, et al. Early Hormonal Treatment Affects Body Composition and Body Shape in Young Transgender Adolescents. J Sex Med 2018;15:251-260.