Genetic drivers of heterogeneity in type 2 diabetes pathophysiology

Type 2 diabetes (T2D) is a heterogeneous disease that develops through diverse pathophysiological processes1,2 and molecular mechanisms that are often specific to cell type3,4. Here, to characterize the genetic contribution to these processes across ancestry groups, we aggregate genome-wide association study data from 2,535,601 individuals (39.7% not of European ancestry), including 428,452 cases of T2D. We identify 1,289 independent association signals at genome-wide significance (P < 5 × 10-8) that map to 611 loci, of which 145 loci are, to our knowledge, previously unreported. We define eight non-overlapping clusters of T2D signals that are characterized by distinct profiles of cardiometabolic trait associations. These clusters are differentially enriched for cell-type-specific regions of open chromatin, including pancreatic islets, adipocytes, endothelial cells and enteroendocrine cells. We build cluster-specific partitioned polygenic scores5 in a further 279,552 individuals of diverse ancestry, including 30,288 cases of T2D, and test their association with T2D-related vascular outcomes. Cluster-specific partitioned polygenic scores are associated with coronary artery disease, peripheral artery disease and end-stage diabetic nephropathy across ancestry groups, highlighting the importance of obesity-related processes in the development of vascular outcomes. Our findings show the value of integrating multi-ancestry genome-wide association study data with single-cell epigenomics to disentangle the aetiological heterogeneity that drives the development and progression of T2D. This might offer a route to optimize global access to genetically informed diabetes care.

Genome-wide association study and functional characterization identifies candidate genes for insulin-stimulated glucose uptake

Distinct tissue-specific mechanisms mediate insulin action in fasting and postprandial states. Previous genetic studies have largely focused on insulin resistance in the fasting state, where hepatic insulin action dominates. Here we studied genetic variants influencing insulin levels measured 2 h after a glucose challenge in >55,000 participants from three ancestry groups. We identified ten new loci (P < 5 × 10-8) not previously associated with postchallenge insulin resistance, eight of which were shown to share their genetic architecture with type 2 diabetes in colocalization analyses. We investigated candidate genes at a subset of associated loci in cultured cells and identified nine candidate genes newly implicated in the expression or trafficking of GLUT4, the key glucose transporter in postprandial glucose uptake in muscle and fat. By focusing on postprandial insulin resistance, we highlighted the mechanisms of action at type 2 diabetes loci that are not adequately captured by studies of fasting glycemic traits.

Multi-ancestry genome-wide study in >2.5 million individuals reveals heterogeneity in mechanistic pathways of type 2 diabetes and complications

Type 2 diabetes (T2D) is a heterogeneous disease that develops through diverse pathophysiological processes. To characterise the genetic contribution to these processes across ancestry groups, we aggregate genome-wide association study (GWAS) data from 2,535,601 individuals (39.7% non-European ancestry), including 428,452 T2D cases. We identify 1,289 independent association signals at genome-wide significance (P<5×10-8) that map to 611 loci, of which 145 loci are previously unreported. We define eight non-overlapping clusters of T2D signals characterised by distinct profiles of cardiometabolic trait associations. These clusters are differentially enriched for cell-type specific regions of open chromatin, including pancreatic islets, adipocytes, endothelial, and enteroendocrine cells. We build cluster-specific partitioned genetic risk scores (GRS) in an additional 137,559 individuals of diverse ancestry, including 10,159 T2D cases, and test their association with T2D-related vascular outcomes. Cluster-specific partitioned GRS are more strongly associated with coronary artery disease and end-stage diabetic nephropathy than an overall T2D GRS across ancestry groups, highlighting the importance of obesity-related processes in the development of vascular outcomes. Our findings demonstrate the value of integrating multi-ancestry GWAS with single-cell epigenomics to disentangle the aetiological heterogeneity driving the development and progression of T2D, which may offer a route to optimise global access to genetically-informed diabetes care.

Erratum: Ancestral diversity improves discovery and fine-mapping of genetic loci for anthropometric traits-The Hispanic/Latino Anthropometry Consortium

[This corrects the article DOI: 10.1016/j.xhgg.2022.100099.].

Weight loss and β-cell responses following gastric banding or pharmacotherapy in adults with impaired glucose tolerance or type 2 diabetes: a randomized trial

OBJECTIVE

The extent to which weight loss contributes to increases in insulin sensitivity (IS) and β-cell function after surgical or medical intervention has not been directly compared in individuals with impaired glucose tolerance or newly diagnosed type 2 diabetes.

METHODS

The Restoring Insulin Secretion (RISE) Study included adults in the Beta-Cell Restoration Through Fat Mitigation Study (n = 88 randomized to laparoscopic gastric banding or metformin [MET]) and the Adult Medication Study (n = 267 randomized to placebo, MET, insulin glargine/MET, or liraglutide + MET [L + M]). IS and β-cell responses were measured at baseline and after 12 months by modeling of oral glucose tolerance tests and during arginine-stimulated hyperglycemic clamps. Linear regression models assessed differences between and within treatments over time.

RESULTS

BMI decreased in all treatment groups, except placebo, at 12 months. IS increased in all arms except placebo and was inversely correlated with changes in BMI. L + M was the only treatment arm that enhanced multiple measures of β-cell function independent of weight loss. Insulin secretion decreased in the laparoscopic gastric banding arm proportional to increases in IS, with no net benefit on β-cell function.

CONCLUSIONS

Reducing demand on the β-cell by improving IS through weight loss does not reverse β-cell dysfunction. L + M was the only treatment that enhanced β-cell function.

Multi-ancestry genetic study of type 2 diabetes highlights the power of diverse populations for discovery and translation

We assembled an ancestrally diverse collection of genome-wide association studies (GWAS) of type 2 diabetes (T2D) in 180,834 affected individuals and 1,159,055 controls (48.9% non-European descent) through the Diabetes Meta-Analysis of Trans-Ethnic association studies (DIAMANTE) Consortium. Multi-ancestry GWAS meta-analysis identified 237 loci attaining stringent genome-wide significance (P < 5 × 10-9), which were delineated to 338 distinct association signals. Fine-mapping of these signals was enhanced by the increased sample size and expanded population diversity of the multi-ancestry meta-analysis, which localized 54.4% of T2D associations to a single variant with >50% posterior probability. This improved fine-mapping enabled systematic assessment of candidate causal genes and molecular mechanisms through which T2D associations are mediated, laying the foundations for functional investigations. Multi-ancestry genetic risk scores enhanced transferability of T2D prediction across diverse populations. Our study provides a step toward more effective clinical translation of T2D GWAS to improve global health for all, irrespective of genetic background.

Ancestral diversity improves discovery and fine-mapping of genetic loci for anthropometric traits-The Hispanic/Latino Anthropometry Consortium

Hispanic/Latinos have been underrepresented in genome-wide association studies (GWAS) for anthropometric traits despite their notable anthropometric variability, ancestry proportions, and high burden of growth stunting and overweight/obesity. To address this knowledge gap, we analyzed densely imputed genetic data in a sample of Hispanic/Latino adults to identify and fine-map genetic variants associated with body mass index (BMI), height, and BMI-adjusted waist-to-hip ratio (WHRadjBMI). We conducted a GWAS of 18 studies/consortia as part of the Hispanic/Latino Anthropometry (HISLA) Consortium (stage 1, n = 59,771) and generalized our findings in 9 additional studies (stage 2, n = 10,538). We conducted a trans-ancestral GWAS with summary statistics from HISLA stage 1 and existing consortia of European and African ancestries. In our HISLA stage 1 + 2 analyses, we discovered one BMI locus, as well as two BMI signals and another height signal each within established anthropometric loci. In our trans-ancestral meta-analysis, we discovered three BMI loci, one height locus, and one WHRadjBMI locus. We also identified 3 secondary signals for BMI, 28 for height, and 2 for WHRadjBMI in established loci. We show that 336 known BMI, 1,177 known height, and 143 known WHRadjBMI (combined) SNPs demonstrated suggestive transferability (nominal significance and effect estimate directional consistency) in Hispanic/Latino adults. Of these, 36 BMI, 124 height, and 11 WHRadjBMI SNPs were significant after trait-specific Bonferroni correction. Trans-ancestral meta-analysis of the three ancestries showed a small-to-moderate impact of uncorrected population stratification on the resulting effect size estimates. Our findings demonstrate that future studies may also benefit from leveraging diverse ancestries and differences in linkage disequilibrium patterns to discover novel loci and additional signals with less residual population stratification.

Using Patient-Generated Health Data From Twitter to Identify, Engage, and Recruit Cancer Survivors in Clinical Trials in Los Angeles County: Evaluation of a Feasibility Study

BACKGROUND

Failure to find and attract clinical trial participants remains a persistent barrier to clinical research. Researchers increasingly complement recruitment methods with social media-based methods. We hypothesized that user-generated data from cancer survivors and their family members and friends on the social network Twitter could be used to identify, engage, and recruit cancer survivors for cancer trials.

OBJECTIVE

This pilot study aims to examine the feasibility of using user-reported health data from cancer survivors and family members and friends on Twitter in Los Angeles (LA) County to enhance clinical trial recruitment. We focus on 6 cancer conditions (breast cancer, colon cancer, kidney cancer, lymphoma, lung cancer, and prostate cancer).

METHODS

The social media intervention involved monitoring cancer-specific posts about the 6 cancer conditions by Twitter users in LA County to identify cancer survivors and their family members and friends and contacting eligible Twitter users with information about open cancer trials at the University of Southern California (USC) Norris Comprehensive Cancer Center. We reviewed both retrospective and prospective data published by Twitter users in LA County between July 28, 2017, and November 29, 2018. The study enrolled 124 open clinical trials at USC Norris. We used descriptive statistics to report the proportion of Twitter users who were identified, engaged, and enrolled.

RESULTS

We analyzed 107,424 Twitter posts in English by 25,032 unique Twitter users in LA County for the 6 cancer conditions. We identified and contacted 1.73% (434/25,032) of eligible Twitter users (127/434, 29.3% cancer survivors; 305/434, 70.3% family members and friends; and 2/434, 0.5% Twitter users were excluded). Of them, 51.4% (223/434) were female and approximately one-third were male. About one-fifth were people of color, whereas most of them were White. Approximately one-fifth (85/434, 19.6%) engaged with the outreach messages (cancer survivors: 33/85, 38% and family members and friends: 52/85, 61%). Of those who engaged with the messages, one-fourth were male, the majority were female, and approximately one-fifth were people of color, whereas the majority were White. Approximately 12% (10/85) of the contacted users requested more information and 40% (4/10) set up a prescreening. Two eligible candidates were transferred to USC Norris for further screening, but neither was enrolled.

CONCLUSIONS

Our findings demonstrate the potential of identifying and engaging cancer survivors and their family members and friends on Twitter. Optimization of downstream recruitment efforts such as screening for digital populations on social media may be required. Future research could test the feasibility of the approach for other diseases, locations, languages, social media platforms, and types of research involvement (eg, survey research). Computer science methods could help to scale up the analysis of larger data sets to support more rigorous testing of the intervention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03408561; https://clinicaltrials.gov/ct2/show/NCT03408561.

Hyperglucagonemia Does Not Explain the β-Cell Hyperresponsiveness and Insulin Resistance in Dysglycemic Youth Compared With Adults: Lessons From the RISE Study

OBJECTIVE

To determine whether β-cell hyperresponsiveness and insulin resistance in youth versus adults in the Restoring Insulin Secretion (RISE) Study are related to increased glucagon release.

RESEARCH DESIGN AND METHODS

In 66 youth and 350 adults with impaired glucose tolerance (IGT) or recently diagnosed type 2 diabetes (drug naive), we performed hyperglycemic clamps and oral glucose tolerance tests (OGTTs). From clamps we quantified insulin sensitivity (M/I), plasma fasting glucagon and C-peptide, steady-state glucagon and C-peptide at glucose of 11.1 mmol/L, and arginine-stimulated glucagon (acute glucagon response [AGR]) and C-peptide (ACPRmax) responses at glucose >25 mmol/L.

RESULTS

Mean ± SD fasting glucagon (7.63 ± 3.47 vs. 8.55 ± 4.47 pmol/L; P = 0.063) and steady-state glucagon (2.24 ± 1.46 vs. 2.49 ± 1.96 pmol/L, P = 0.234) were not different in youth and adults, respectively, while AGR was lower in youth (14.1 ± 5.2 vs. 16.8 ± 8.8 pmol/L, P = 0.001). Significant age-group differences in insulin sensitivity, fasting C-peptide, steady-state C-peptide, and ACPRmax were not related to glucagon. Fasting glucose and glucagon were positively correlated in adults (r = 0.133, P = 0.012) and negatively correlated in youth (r = -0.143, P = 0.251). In both age-groups, higher fasting glucagon was associated with higher fasting C-peptide (youth r = 0.209, P = 0.091; adults r = 0.335, P < 0.001) and lower insulin sensitivity (youth r = -0.228, P = 0.066; adults r = -0.324, P < 0.001). With comparable fasting glucagon, youth had greater C-peptide and lower insulin sensitivity. OGTT suppression of glucagon was greater in youth.

CONCLUSIONS

Youth with IGT or recently diagnosed type 2 diabetes (drug naive) have hyperresponsive β-cells and lower insulin sensitivity, but their glucagon concentrations are not increased compared with those in adults. Thus, α-cell dysfunction does not appear to explain the difference in β-cell function and insulin sensitivity in youth versus adults.

Baseline Predictors of Glycemic Worsening in Youth and Adults With Impaired Glucose Tolerance or Recently Diagnosed Type 2 Diabetes in the Restoring Insulin Secretion (RISE) Study

OBJECTIVE

To identify predictors of glycemic worsening among youth and adults with impaired glucose tolerance (IGT) or recently diagnosed type 2 diabetes in the Restoring Insulin Secretion (RISE) Study.

RESEARCH DESIGN AND METHODS

A total of 91 youth (10-19 years) were randomized 1:1 to 12 months of metformin (MET) or 3 months of glargine, followed by 9 months of metformin (G-MET), and 267 adults were randomized to MET, G-MET, liraglutide plus MET (LIRA+MET), or placebo for 12 months. All participants underwent a baseline hyperglycemic clamp and a 3-h oral glucose tolerance test (OGTT) at baseline, month 6, month 12, and off treatment at month 15 and month 21. Cox models identified baseline predictors of glycemic worsening (HbA_1c increase ≥0.5% from baseline).

RESULTS

Glycemic worsening occurred in 17.8% of youth versus 7.5% of adults at month 12 (P = 0.008) and in 36% of youth versus 20% of adults at month 21 (P = 0.002). In youth, glycemic worsening did not differ by treatment. In adults, month 12 glycemic worsening was less on LIRA+MET versus placebo (hazard ratio 0.21, 95% CI 0.05-0.96, P = 0.044). In both age-groups, lower baseline clamp-derived β-cell responses predicted month 12 and month 21 glycemic worsening (P < 0.01). Lower baseline OGTT-derived β-cell responses predicted month 21 worsening (P < 0.05). In youth, higher baseline HbA_1c and 2-h glucose predicted month 12 and month 21 glycemic worsening, and higher fasting glucose predicted month 21 worsening (P < 0.05). In adults, lower clamp- and OGTT-derived insulin sensitivity predicted month 12 and month 21 worsening (P < 0.05).

CONCLUSIONS

Glycemic worsening was more common among youth than adults with IGT or recently diagnosed type 2 diabetes, predicted by lower baseline β-cell responses in both groups, hyperglycemia in youth, and insulin resistance in adults.

Effect of Medical and Surgical Interventions on α-Cell Function in Dysglycemic Youth and Adults in the RISE Study

OBJECTIVE

To compare effects of medications and laparoscopic gastric band surgery (LB) on α-cell function in dysglycemic youth and adults in the Restoring Insulin Secretion (RISE) Study protocols.

RESEARCH DESIGN AND METHODS

Glucagon was measured in three randomized, parallel, clinical studies: 1) 91 youth studied at baseline, after 12 months on metformin alone (MET) or glargine followed by metformin (G/M), and 3 months after treatment withdrawal; 2) 267 adults studied at the same time points and treated with MET, G/M, or liraglutide plus metformin (L+M) or given placebo (PLAC); and 3) 88 adults studied at baseline and after 12 and 24 months of LB or MET. Fasting glucagon, glucagon suppression by glucose, and acute glucagon response (AGR) to arginine were assessed during hyperglycemic clamps. Glucagon suppression was also measured during oral glucose tolerance tests (OGTTs).

RESULTS

No change in fasting glucagon, steady-state glucagon, or AGR was seen at 12 months following treatment with MET or G/M (in youth and adults) or PLAC (in adults). In contrast, L+M reduced these measures at 12 months (all P ≤ 0.005), which was maintained 3 months after treatment withdrawal (all P < 0.01). LB in adults also reduced fasting glucagon, steady-state glucagon, and AGR at 12 and 24 months (P < 0.05 for all, except AGR at 12 months [P = 0.098]). Similarly, glucagon suppression during OGTTs was greater with L+M and LB. Linear models demonstrated that treatment effects on glucagon with L+M and LB were largely associated with weight loss.

CONCLUSIONS

Glucagon concentrations were reduced by L+M and LB in adults with dysglycemia, an effect principally attributable to weight loss in both interventions.

Liver Fat Reduction After Gastric Banding and Associations with Changes in Insulin Sensitivity and β-Cell Function

OBJECTIVE

The aim of this study was to examine the relationship between changes in liver fat and changes in insulin sensitivity and β-cell function 2 years after gastric banding surgery.

METHODS

Data included 23 adults with the surgery who had prediabetes or type 2 diabetes for less than 1 year and BMI 30 to 40 kg/m² at baseline. Body adiposity measures including liver fat content (LFC), insulin sensitivity (M/I), and β-cell responses (acute, steady-state, and arginine-stimulated maximum C-peptide) were assessed at baseline and 2 years after surgery. Regression models were used to assess associations adjusted for age and sex.

RESULTS

Two years after surgery, all measures of body adiposity, LFC, fasting and 2-hour glucose, and hemoglobin A1c significantly decreased; M/I significantly increased; and β-cell responses adjusted for M/I did not change significantly. Among adiposity measures, reduction in LFC had the strongest association with M/I increase (r = -0.61, P = 0.003). Among β-cell measures, change in LFC was associated with change in acute C-peptide response to arginine at maximal glycemic potentiation adjusted for M/I (r = 0.66, P = 0.007). Significant reductions in glycemic measures and increase in M/I were observed in individuals with LFC loss >2.5%.

CONCLUSIONS

Reduction in LFC after gastric banding surgery appears to be an important factor associated with long-term improvements in insulin sensitivity and glycemic profiles in adults with obesity and prediabetes or early type 2 diabetes.

Genome-wide association study of body fat distribution traits in Hispanics/Latinos from the HCHS/SOL

Central obesity is a leading health concern with a great burden carried by ethnic minority populations, especially Hispanics/Latinos. Genetic factors contribute to the obesity burden overall and to inter-population differences. We aimed to identify the loci associated with central adiposity measured as waist-to-hip ratio (WHR), waist circumference (WC) and hip circumference (HIP) adjusted for body mass index (adjBMI) by using the Hispanic Community Health Study/Study of Latinos (HCHS/SOL); determine if differences in associations differ by background group within HCHS/SOL and determine whether previously reported associations generalize to HCHS/SOL. Our analyses included 7472 women and 5200 men of mainland (Mexican, Central and South American) and Caribbean (Puerto Rican, Cuban and Dominican) background residing in the USA. We performed genome-wide association analyses stratified and combined across sexes using linear mixed-model regression. We identified 16 variants for waist-to-hip ratio adjusted for body mass index (WHRadjBMI), 22 for waist circumference adjusted for body mass index (WCadjBMI) and 28 for hip circumference adjusted for body mass index (HIPadjBMI), which reached suggestive significance (P < 1 × 10-6). Many loci exhibited differences in strength of associations by ethnic background and sex. We brought a total of 66 variants forward for validation in cohorts (N = 34 161) with participants of Hispanic/Latino, African and European descent. We confirmed four novel loci (P < 0.05 and consistent direction of effect, and P < 5 × 10-8 after meta-analysis), including two for WHRadjBMI (rs13301996, rs79478137); one for WCadjBMI (rs3168072) and one for HIPadjBMI (rs28692724). Also, we generalized previously reported associations to HCHS/SOL, (8 for WHRadjBMI, 10 for WCadjBMI and 12 for HIPadjBMI). Our study highlights the importance of large-scale genomic studies in ancestrally diverse Hispanic/Latino populations for identifying and characterizing central obesity susceptibility that may be ancestry-specific.

The trans-ancestral genomic architecture of glycemic traits

Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 × 10-8), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.

Aerobic and resistance exercise improve patient-reported sleep quality and is associated with cardiometabolic biomarkers in Hispanic and non-Hispanic breast cancer survivors who are overweight or obese: results from a secondary analysis

STUDY OBJECTIVES

Poor sleep quality affects nearly one-third of breast cancer survivors and is associated with insulin resistance. The purpose of this secondary analysis was to examine the effects of a 16-week exercise intervention on patient-reported sleep quality among breast cancer survivors and assess whether changes in patient-reported sleep quality were associated with cardiometabolic biomarkers. We explored Hispanic ethnicity as a moderator of the effects of exercise on patient-reported sleep quality.

METHODS

Breast cancer survivors who were overweight or obese were randomized to exercise (n = 50) or usual care (n = 50). The 16-week intervention included aerobic and resistance exercise. Patient-reported sleep quality (Pittsburgh Sleep Quality Index [PSQI]) and biomarkers of cardiometabolic health were assessed at baseline and post-intervention. Within- and between-group differences were assessed using general linear models repeated-measures analyses of variance and mixed-model repeated-measure analysis, respectively. Associations between changes in PSQI and cardiometabolic biomarkers were computed using Pearson correlations. Linear mixed-models were used to evaluate effect modification by ethnicity.

RESULTS

Participants were 52 ± 10.4 years old, and over half were of Hispanic ethnicity. As compared to usual care, PSQI global scores improved significantly in the exercise group (mean between-group difference -2.2; 95% CI -3.2 to -0.6). Change in PSQI was inversely associated with changes in all cardiometabolic biomarkers (p < 0.01) among the exercise group. Ethnicity was found to moderate the effects of exercise training on global sleep quality (p < 0.001).

CONCLUSIONS

An aerobic and resistance exercise intervention effectively improved patient-reported sleep quality in breast cancer survivors. Hispanic ethnicity as a moderator showed greater improvement in patient-reported sleep indicating Hispanic versus non-Hispanic breast cancer survivors may derive larger sleep benefits.

CLINICAL TRAIL INFORMATION

NCT01140282.

Islet Autoimmunity in Adults With Impaired Glucose Tolerance and Recently Diagnosed, Treatment Naïve Type 2 Diabetes in the Restoring Insulin SEcretion (RISE) Study

The presence of islet autoantibodies and islet reactive T cells (T+) in adults with established type 2 diabetes (T2D) have been shown to identify those patients with more severe β-cell dysfunction. However, at what stage in the progression toward clinical T2D does islet autoimmunity emerge as an important component influencing β-cell dysfunction? In this ancillary study to the Restoring Insulin SEcretion (RISE) Study, we investigated the prevalence of and association with β-cell dysfunction of T+ and autoantibodies to the 65 kDa glutamic acid decarboxylase antigen (GADA) in obese pre-diabetes adults with impaired glucose tolerance (IGT) and recently diagnosed treatment naïve (Ndx) T2D. We further investigated the effect of 12 months of RISE interventions (metformin or liraglutide plus metformin, or with 3 months of insulin glargine followed by 9 months of metformin or placebo) on islet autoimmune reactivity. We observed GADA(+) in 1.6% of NdxT2D and 4.6% of IGT at baseline, and in 1.6% of NdxT2D and 5.3% of IGT at 12 months, but no significant associations between GADA(+) and β-cell function. T(+) was observed in 50% of NdxT2D and 60.4% of IGT at baseline, and in 68.4% of NdxT2D and 83.9% of IGT at 12 months. T(+) NdxT2D were observed to have significantly higher fasting glucose (p = 0.004), and 2 h glucose (p = 0.0032), but significantly lower steady state C-peptide (sscpep, p = 0.007) compared to T(-) NdxT2D. T(+) IGT participants demonstrated lower but not significant (p = 0.025) acute (first phase) C-peptide response to glucose (ACPRg) compared to T(-) IGT. With metformin treatment, T(+) participants were observed to have a significantly lower Hemoglobin A1c (HbA1c, p = 0.002) and fasting C-peptide (p = 0.002) compared to T(-), whereas T(+) treated with liraglutide + metformin had significantly lower sscpep (p = 0.010) compared to T(-) participants. In the placebo group, T(+) participants demonstrated significantly lower ACPRg (p = 0.001) compared to T(-) participants. In summary, T(+) were found in a large percentage of obese pre-diabetes adults with IGT and in recently diagnosed T2D. Moreover, T(+) were significantly correlated with treatment effects and β-cell dysfunction. Our results demonstrate that T(+) are an important component in T2D.

Precision and accuracy of hyperglycemic clamps in a multicenter study

Application of glucose clamp methodologies in multicenter studies brings challenges for standardization. The Restoring Insulin Secretion (RISE) Consortium implemented a hyperglycemic clamp protocol across seven centers using a combination of technical and management approaches to achieve standardization. Two-stage hyperglycemic clamps with glucose targets of 200 mg/dL and >450 mg/dL were performed utilizing a centralized spreadsheet-based algorithm that guided dextrose infusion rates using bedside plasma glucose measurements. Clamp operators received initial and repeated training with ongoing feedback based on surveillance of clamp performance. The precision and accuracy of the achieved stage-specific glucose targets were evaluated, including differences by study center. We also evaluated robustness of the method to baseline physiologic differences and on-study treatment effects. The RISE approach produced high overall precision (3%-9% variance in achieved plasma glucose from target at various times across the procedure) and accuracy (SD < 10% overall). Statistically significant but numerically small differences in achieved target glucose concentrations were observed across study centers, within the magnitude of the observed technical variability. Variation of the achieved target glucose over time in placebo-treated individuals was low (<3% variation), and the method was robust to differences in baseline physiology (youth vs. adult, IGT vs. diabetes status) and differences in physiology induced by study treatments. The RISE approach to standardization of the hyperglycemic clamp methodology across multiple study centers produced technically excellent standardization of achieved glucose concentrations. This approach provides a reliable method for implementing glucose clamp methodology across multiple study centers.NEW & NOTEWORTHY The Restoring Insulin Secretion (RISE) study centers undertook hyperglycemic clamps using a simplified methodology and a decision guidance algorithm implemented in an easy-to-use spreadsheet. This approach, combined with active management including ongoing central data surveillance and routine feedback to study centers, produced technically excellent standardization of achieved glucose concentrations on repeat studies within and across study centers.

β-cells in youth with impaired glucose tolerance or early type 2 diabetes secrete more insulin and are more responsive than in adults

OBJECTIVE

Glycemic control deteriorates more rapidly in youth vs adults. We compared model-derived measures of β-cell function between youth and adults with either impaired glucose tolerance (IGT) or type 2 diabetes to determine if a β-cell defect differentiates these age groups.

METHODS

This is a cross-sectional analysis of baseline data from the Restoring Insulin Secretion (RISE) Study. Youth (54 Y-IGT, 33 Y-D) and adults (250 A-IGT, 104 A-D) underwent 3-hour oral glucose tolerance tests for modeling of insulin secretion rates (ISRs), glucose sensitivity, and rate sensitivity. Insulin sensitivity was quantified as the glucose infusion rate/insulin (M/I) from a hyperglycemic clamp.

RESULTS

Youth had lower insulin sensitivity despite similar body mass index. Analyses were adjusted for insulin sensitivity. Youth had higher basal ISRs (Y-IGT 200 ± 161 vs A-IGT 152 ± 74, P < .001; Y-D 245 ± 2.5 vs A-D 168 ± 115 pmol/min/m² , P = .007) and total ISRs (Y-IGT 124 ± 86 vs A-IGT 98 ± 39, P < .001; Y-D 116 ± 110 vs A-D 97 ± 62 nmol/m² , P = .002). Within IGT, glucose sensitivity (Y-IGT 140 ± 153 vs A-IGT 112 ± 70 pmol/min/m² /mM, P = .004) and rate sensitivity (median[interquartile range]:Y-IGT 2271[1611, 3222] vs A-IGT 1164[685, 1565] pmol/m² /mM, P < .001) were higher in youth, but not different by age group within diabetes.

CONCLUSIONS

Model-derived measures of β-cell function provide additional insight into the pathophysiology of type 2 diabetes in youth with higher ISRs and β-cell secretion more responsive to glucose in youth relative to adults even after adjusting for differences in insulin sensitivity. It is unknown whether these findings in youth reflect β-cells that are healthier or whether this is a defect that contributes to more rapid loss of function.

Withdrawal of medications leads to worsening of OGTT parameters in youth with impaired glucose tolerance or recently-diagnosed type 2 diabetes

BACKGROUND

The RISE Pediatric Medication Study compared strategies for preserving β-cell function, including a 9-month follow-up after treatment withdrawal to test treatment effect durability.

OBJECTIVE

Evaluate OGTT measures of glucose and β-cell response through 12 months of intervention and 9 months of medication washout.

PARTICIPANTS

Youth (n = 91) aged 10 to 19 years with BMI ≥85th percentile and impaired glucose tolerance (IGT) or recently diagnosed type 2 diabetes (T2D).

METHODS

A multicenter randomized clinical trial comparing insulin glargine for 3 months followed by metformin for 9 months (G→Met) or metformin alone (Met) for 12 months. We report within-group changes from baseline to end of medication intervention (M12), baseline to 9 months post-medication withdrawal (M21), and end of medication (M12) to M21. OGTT C-peptide index [CPI] paired with 1/fasting insulin evaluated β-cell response.

RESULTS

At M12, both treatments were associated with stable fasting glucose (G→Met baseline 6.0 ± 0.1 vs M12 5.9 ± 0.2 mmol/L, P = .62; Met baseline 6.1 ± 0.2 vs M12 6.0 ± 0.2 mmol/L, P = .73) and 2-hour glucose (G→Met baseline 10.2 ± 0.4 vs M12 9.3 ± 0.5 mmol/L, P = .03; Met baseline 10.2 ± 0.4 vs M12 10.6 ± 0.6 mmol/L, P = .88). Following medication withdrawal, fasting glucose worsened (G→Met M21 8.6 ± 1.8, P = .004; Met M21 7.8 ± 0.7 mmol/L, P = .003), as did 2-hour glucose (G→Met M21 13.2 ± 1.4, P = .002; Met M21 13.1 ± 1.2 mmol/L, P = .006), associated with declines in β-cell response.

CONCLUSIONS

G→Met and Met were associated with stable glucose measures during 12 months of treatment in youth with IGT or recently diagnosed T2D. Glucose and β-cell response worsened post-medication withdrawal, suggesting treatment must be long-term or alternative treatments pursued.

Hispanic ethnicity as a moderator of the effects of aerobic and resistance exercise on physical fitness and quality-of-life in breast cancer survivors

BACKGROUND

Exercise can profoundly affect physical fitness and quality of life in breast cancer survivors; however, few studies have focused on minorities. This secondary analysis examines Hispanic ethnicity as a moderator of the effects of a 16-week aerobic and resistance exercise intervention on physical fitness and quality of life in breast cancer survivors.

METHODS

Eligible breast cancer survivors (n = 100) were randomized to exercise (n = 50) or usual care (n = 50). The exercise intervention consisted of supervised moderate-vigorous aerobic and resistance exercise thrice weekly for 16 weeks. Physical fitness and quality of life were measured at baseline, post-intervention, and 28-week follow-up (exercise only). Linear mixed-models adjusted for baseline value of the outcome, age, disease stage, adjuvant treatment, and recent physical activity were used to evaluate effect modification by ethnicity.

RESULTS

The study sample included 57% Hispanic and 43% non-Hispanic breast cancer survivors. Hispanic breast cancer survivors were younger, less fit, and diagnosed with more advanced cancers compared with non-Hispanic breast cancer survivors (p < 0.001). Ethnicity was found to moderate the effects of exercise training on all physical fitness and quality-of-life measures including VO_2max (8.4 mL/kg/min; 95% confidence interval (95% CI) 3.2 to 13.4), physical well-being (12.3; 95% CI 4.2 to 18.4), and emotional well-being (11.4; 95% CI 5.9 to 15.5). In all cases, Hispanics experienced larger benefits than non-Hispanics.

CONCLUSIONS

Hispanic breast cancer survivors have poorer cardiorespiratory fitness, muscle strength, and quality-of-life and therefore may derive larger benefits from exercise than non-Hispanic breast cancer survivors. Clinical exercise interventions may attenuate existing health disparities among minority breast cancer survivors.

IMPLICATION OF CANCER SURVIVORS

Here we report psychosocial and fitness-related disparities among Hispanic breast cancer survivors when compared with their non-Hispanic counterparts. Our exercise intervention highlights the importance of exercise for minority cancer survivors and the need for distinct, culturally tailored exercise intervention approaches to reduce psychosocial and fitness-related disparities among this understudied population of cancer survivors.

Abstract C123: Ethnocentric differences in sarcopenic obesity and body composition in response to an aerobic and resistance exercise intervention for breast cancer survivors

Background and Purpose: Hispanic breast cancer survivors (HBCS) have a 1.1-1.5 greater risk of breast cancer mortality when compared to non-Hispanic breast cancer survivors (NHBCS). This disparity may result from modifiable lifestyle factors, as Hispanic women are more apt to be obese and sedentary than matched non-Hispanic counterparts, placing them at risk for obesity-related comorbidities. Also, gains in fat mass with declines in lean mass, known as sarcopenic obesity (SOb), often occur as a side effect of cancer treatment. Thus, participation in physical activity is paramount, as exercise is strongly associated with lowering the risk of cancer recurrence and premature mortality. The purpose of this analysis was to examine ethnicity as a moderator of the effects of a 16-week supervised aerobic and resistance exercise intervention on SOb and body composition (BCM) in overweight/obese breast cancer survivors.

Experimental Design: Sedentary, overweight or obese (BMI&gt;25.0 kg/m2) breast cancer survivors (Stage I-III; n=100) were randomized to exercise (n=50) or usual care (n=50). The exercise intervention promoted supervised, progressive moderate-vigorous (65-85% maximum heart rate [MHR]) aerobic and resistance exercise thrice weekly for 16 weeks. Markers of SOB and BCM, including appendicular skeletal muscle index (ASMI), BMI, % body fat and truncal fat were measured at baseline and post-intervention (4 months). Differences in mean changes for outcomes by ethnicity were evaluated using linear mixed-models to assess effect modification.

Summary of Results: The study enrolled 57 HBCS and 43 NHBCS with an average age of 53.5±10.4 years and BMI of 33.5±5.5 kg/m2. HBCS were diagnosed with more advanced cancers, were significantly more obese and less physically active compared to NHBCS (p&lt;0.001); 96% of the HBCS and 92% of the NHBCS presented with SOb. Post-intervention, SOb and BCM indices were significantly improved in the exercise arm (both HBCS and NHBCS) as compared to baseline (p 0.01) and usual care (p&lt;0.001). However, HBCS exhibited more favorable improvements compared to NHBCS, including an increase in ASMI (mean difference, -2.1; 95% confidence interval (95% CI), 0.4 to 5.1; p&lt;0.001) and truncal fat (-4.4; 95% CI, -9.1 to -0.8; p&lt;0.001). Ethnicity was found to moderate the effect of the exercise intervention on fat mass (P for interaction=0.09) and % body fat (P for interaction=0.09).

Conclusions: HBCS may achieve better outcomes with exercise in attenuating disparities related to SOb and BCM. To our knowledge, this is the first study to investigate ethnocentric differences between HBCS and NHBCS as they pertain to participation in physical activity and high-risk comorbidities related to poorer cancer prognosis and mortality. Exercise presents as a useful lifestyle modifiable intervention to attenuate ethnic health disparities in breast cancer survivors; future studies should aim to enroll diverse populations.

Citation Format: Frank C. Sweeney, Wendy Demark-Wahnefried, Kerry S. Courneya, Debu Tripathy, Nathalie Sami, Kyuwan Lee, Thomas A. Buchanan, Darcy Spicer, Leslie Bernstein, Joanne E. Mortimer, Christina M. Dieli-Conwright. Ethnocentric differences in sarcopenic obesity and body composition in response to an aerobic and resistance exercise intervention for breast cancer survivors [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C123.

Abstract C122: Ethnicity as a moderator of the effects of aerobic and resistance exercise on metabolic syndrome in breast cancer survivors

Background and Purpose: Metabolic syndrome (MSY) is associated with increased risk of cardiovascular disease, type 2 diabetes, and recurrence in breast cancer survivors (BCS). MSY is 1.5 times more common in Hispanic compared to non-Hispanic women. Hispanic women in the United States are more likely to be obese and physically inactive than matched non-Hispanic counterparts, raising risk for developing MSY. Exercise mitigates MSY in BCS; however, few studies have focused on minorities. The purpose of this secondary analysis was to examine ethnicity as a moderator of the effects of a 16-week combined aerobic and resistance clinical exercise intervention on MSY and related biomarkers in BCS.

Experimental Design: Sedentary, overweight or obese (BMI&gt;25.0 kg/m2) BCS (Stage I-III; n=100) were randomized to exercise (n=50) or usual care (n=50). The exercise intervention promoted supervised, progressive moderate-vigorous (65-85% heart rate maximum) aerobic and resistance exercise thrice weekly for 16 weeks. Aerobic exercise included cycling, walking, or jogging at 65-85% maximum heart rate. Resistance exercise was performed in circuit-fashion with 3 sets of 10-15 repetitions including upper and lower body exercises at 65-70% 1-repetition maximum. MSY variables (blood pressure, waist circumference, triglycerides, glucose, and high-density lipoprotein-cholesterol) and related biomarkers (insulin, insulin resistance HOMA-IR, C-reactive protein [CRP]) were measured at baseline and post-intervention (4 months). Differences in mean changes for outcomes by ethnicity were evaluated using linear mixed-models to assess effect modification.

Summary of Results: Fifty-seven Hispanic BCS and 43 non-Hispanic BCS with an average age of 53.5±10.4 years and BMI of 33.5±5.5 kg/m2 were included. Hispanic BCS were younger, of greater adiposity, had higher-stage cancers, and had worse metabolic profiles at baseline compared to non-Hispanic BCS (p&lt;0.001). Ethnicity was found to moderate the effects of exercise training on triglycerides (mean difference, -36.4; 95% confidence interval (95% CI), -62.1-18.3; p=0.04) and glucose (mean difference, -8.6; 95% CI, -18.7-3.1; p=0.05) with Hispanic BCS exhibiting larger improvements than non-Hispanic BCS. Ethnicity moderated the effect of exercise on insulin (P for interaction=0.09), HOMA-IR (P for interaction=0.06), and CRP (P for interaction=0.05).

Conclusions: Hispanic, as compared to non-Hispanic, BCS have poorer metabolic profiles, but may achieve better outcomes from exercise. To our knowledge, this is the first study to explore racial/ethnic disparities in MSY between Hispanic and non-Hispanic BCS and document differential response to exercise. Clinical exercise interventions may attenuate ethnic health disparities in BCS. Future trials should aim for diversity.

Citation Format: Christina M. Dieli-Conwright, Frank C. Sweeney, Kerry S. Courneya, Debu Tripathy, Nathalie Sami, Kyuwan Lee, Thomas A. Buchanan, Darcy Spicer, Leslie Bernstein, Joanne E. Mortimer, Wendy Demark-Wahnefried. Ethnicity as a moderator of the effects of aerobic and resistance exercise on metabolic syndrome in breast cancer survivors [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C122.

Classification of Type 2 Diabetes Genetic Variants and a Novel Genetic Risk Score Association With Insulin Clearance

CONTEXT

Genome-wide association studies have identified more than 450 single nucleotide polymorphisms (SNPs) for type 2 diabetes (T2D).

OBJECTIVE

To facilitate use of these SNPs in future genetic risk score (GRS)-based analyses, we aimed to classify the SNPs based on physiology. We also sought to validate GRS associations with insulin-related traits in deeply phenotyped Mexican Americans.

DESIGN, SETTING, AND PARTICIPANTS

A total of 457 T2D SNPs from the literature were assigned physiologic function based on association studies and cluster analyses. All SNPs (All-GRS), beta-cell (BC-GRS), insulin resistance (IR-GRS), lipodystrophy (Lipo-GRS), and body mass index plus lipids (B + L-GRS) were evaluated for association with diabetes and indices of insulin secretion (from oral glucose tolerance test), insulin sensitivity and insulin clearance (from euglycemic clamp), and adiposity and lipid markers in 1587 Mexican Americans.

RESULTS

Of the 457 SNPs, 52 were classified as BC, 30 as IR, 12 as Lipo, 12 as B + L, whereas physiologic function of 351 was undefined. All-GRS was strongly associated with T2D. Among nondiabetic Mexican Americans, BC-GRS was associated with reduced insulinogenic index, IR-GRS was associated with reduced insulin sensitivity, and Lipo-GRS was associated with reduced adiposity. B + L-GRS was associated with increased insulin clearance. The latter did not replicate in an independent cohort wherein insulin clearance was assessed by a different method.

CONCLUSIONS

Supporting their utility, BC-GRS, IR-GRS, and Lipo-GRS, based on SNPs discovered largely in Europeans, exhibited expected associations in Mexican Americans. The novel association of B + L-GRS with insulin clearance suggests that impaired ability to reduce insulin clearance in compensation for IR may play a role in the pathogenesis of T2D. Whether this applies to other ethnic groups remains to be determined.

Effect of Aerobic and Resistance Exercise Intervention on Cardiovascular Disease Risk in Women With Early-Stage Breast Cancer: A Randomized Clinical Trial

Importance

The Framingham Risk Score (FRS) is a valid method for predicting the 10-year risk of developing cardiovascular disease. Higher FRS is reported in patients with early-stage breast cancer who are overweight than in healthy, age-matched women, but whether exercise reduces FRS in this patient population is unclear.

Objective

To examine the effects of a 16-week aerobic and resistance exercise intervention on the FRS in women with early-stage breast cancer and with overweight condition or obesity.

Design, Setting, and Participants

This single-center, prospective randomized clinical trial included 100 women with stage I to III breast cancer who were sedentary, with overweight condition or obesity (body mass index of ≥25.0 or body fat of ≥30%), and completed cancer treatment within 6 months prior to enrollment. Participants were randomized to either the usual care or exercise group. Differences in mean changes for outcomes were evaluated using mixed-model repeated-measures analyses. Data were collected from August 1, 2012, through July 1, 2017. Data analysis, which followed the intention-to-treat approach, was performed from May 24 to October 2, 2018.

Interventions

The exercise group underwent supervised aerobic and resistance exercise sessions thrice weekly for 16 weeks.

Main Outcomes and Measures

The FRS was calculated for each participant using preset points for each of the 6 FRS categories: age, systolic blood pressure, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, diabetes presence, and smoking status.

Results

In total, 100 women were randomized to either the exercise group (n = 50) or usual care group (n = 50). Of these women, 55 (55%) were of Hispanic white race/ethnicity and the mean (SD) age was 53.5 (10.4) years. The mean (SD) total FRS scores postintervention were 2.0 (1.5) in the exercise group and 13.0 (3.0) in the usual care group. The postintervention FRS was significantly reduced in the exercise group compared with the usual care group (mean, -9.5; 95% CI, -13.0 to -6.0), which corresponds to an 11% (95% CI, -15.0 to -5.0) decrease on the FRS-predicted 10-year risk of developing cardiovascular disease.

Conclusions and Relevance

A 16-week supervised aerobic and resistance exercise intervention appeared to reduce the FRS-predicted 10-year risk of cardiovascular disease in women with early-stage breast cancer with overweight condition or obesity.

Clinical Trial Registration

ClinicalTrials.gov identifier: NCT01140282.

Aerobic and Resistance Exercise Improves Shoulder Function in Women Who Are Overweight or Obese and Have Breast Cancer: A Randomized Controlled Trial

BACKGROUND

Adverse upper limb musculoskeletal effects occur after surgical procedures and radiotherapy for breast cancer and can interfere with activities of daily living.

OBJECTIVE

The objective of this study was to examine the effects of a 16-week exercise intervention on shoulder function in women who are overweight or obese and have breast cancer.

DESIGN

This study was a randomized controlled trial.

SETTING

The study was performed at the Division of Biokinesiology and Physical Therapy at the University of Southern California.

PARTICIPANTS

One hundred women with breast cancer were randomly allocated to exercise or usual-care groups. The mean (SD) age of the women was 53.5 (10.4) years, 55% were Hispanic white, and their mean (SD) body mass index was 33.5 (5.5) kg/m2.

INTERVENTION

The 16-week exercise intervention consisted of supervised, progressive, moderate to vigorous aerobic and resistance exercise 3 times per week.

MEASUREMENTS

Shoulder active range of motion, isometric muscular strength, and patient-reported outcome measures (including Disabilities of the Arm, Shoulder, and Hand and the Penn Shoulder Scale) were assessed at baseline, after the intervention, and at the 3-month follow-up (exercise group only). Differences in mean changes for outcomes were evaluated using mixed-model repeated-measures analysis.

RESULTS

Compared with the usual-care group, the exercise group experienced significant increases in shoulder active range of motion (the mean between-group differences and 95% confidence intervals (CIs) were as follows: shoulder flexion = 36.6° [95% CI = 55.2-20.7°], external rotation at 0° = 23.4° [95% CI = 31.1-12.5°], and external rotation at 90° = 34.3° [95% CI = 45.9-26.2°]), improved upper extremity isometric strength, and improved Disabilities of the Arm, Shoulder, and Hand and Penn Shoulder Scale scores.

LIMITATIONS

Limitations include a lack of masking of assessors after the intervention, an attention control group, and statistical robustness (shoulder function was a secondary end point).

CONCLUSIONS

A 16-week exercise intervention effectively improved shoulder function following breast cancer treatment in women who were overweight or obese, who were ethnically diverse, and who had breast cancer.

Hemoglobin A1c Levels During Pregnancy and Risk of Autism Spectrum Disorders in Offspring

This cohort study uses electronic medical record (EMR) data to examine the association between maternal hemoglobin A_1c levels during pregnancy and risk of autism spectrum disorder in offspring.

Children Exposed to Maternal Obesity or Gestational Diabetes Mellitus During Early Fetal Development Have Hypothalamic Alterations That Predict Future Weight Gain

OBJECTIVE

Exposure in utero to maternal obesity or gestational diabetes mellitus (GDM) is linked to a high risk for obesity in offspring. Animal studies suggest that these exposures disrupt the development of the hypothalamus, a brain region that regulates body weight, predisposing offspring to develop obesity. This study tested the hypothesis in humans that in utero exposure to maternal obesity and/or GDM is associated with alterations in the hypothalamic response to glucose and the altered hypothalamic response would predict greater increases in child adiposity 1 year later.

RESEARCH DESIGN AND METHODS

Participants were 91 children aged 7-11 years with and without in utero exposure to GDM. Maternal prepregnancy BMI and GDM exposures were determined from electronic medical records. Arterial spin labeling MRI was used to determine the child's hypothalamic blood flow response to oral glucose. Anthropometric measures were acquired in all children at their initial visit and again 1 year later in a subset of 44 children.

RESULTS

Children exposed to GDM diagnosed at ≤26 weeks' gestation had increased hypothalamic blood flow (a marker of hypothalamic activation) in response to glucose when compared with unexposed children, and results remained after adjustments for child age, sex, BMI, and maternal prepregnancy BMI. Maternal prepregnancy BMI was positively associated with the child's hypothalamic response to glucose. Greater hypothalamic response to glucose predicted greater increases in child's BMI 1 year later.

CONCLUSIONS

Increased glucose-linked hypothalamic activation during childhood represents a possible mechanism by which exposure to maternal metabolic disorders during fetal development increases future risk for obesity.

Adiposity-Independent Effects of Aging on Insulin Sensitivity and Clearance in Mice and Humans

OBJECTIVE

Aging is associated with impaired insulin sensitivity and increased prevalence of type 2 diabetes. However, it remains unclear whether aging-associated insulin resistance is due to increased adiposity or other age-related factors. To address this question, the impact of aging on insulin sensitivity was investigated independently of changes in body composition.

METHODS

Cohorts of mice aged 4 to 8 months ("young") and 18 to 27 months ("aged") exhibiting similar body composition were characterized for glucose metabolism on chow and high-fat diets. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp analyses. The relationship between aging and insulin resistance in humans was investigated in 1,250 nondiabetic Mexican Americans who underwent hyperinsulinemic-euglycemic clamps.

RESULTS

In mice with similar body composition, age had no detrimental effect on plasma glucose and insulin levels. While aging did not diminish glucose tolerance, hyperinsulinemic-euglycemic clamps demonstrated impaired insulin sensitivity and reduced insulin clearance in aged mice on chow and high-fat diets. Consistent with results in the mouse, age remained an independent determinant of insulin resistance after adjustment for body composition in Mexican American males.

CONCLUSIONS

This study demonstrates that in addition to altered body composition, adiposity-independent mechanisms also contribute to aging-associated insulin resistance in mice and humans.

Trans-ethnic kidney function association study reveals putative causal genes and effects on kidney-specific disease aetiologies

Chronic kidney disease (CKD) affects ~10% of the global population, with considerable ethnic differences in prevalence and aetiology. We assemble genome-wide association studies of estimated glomerular filtration rate (eGFR), a measure of kidney function that defines CKD, in 312,468 individuals of diverse ancestry. We identify 127 distinct association signals with homogeneous effects on eGFR across ancestries and enrichment in genomic annotations including kidney-specific histone modifications. Fine-mapping reveals 40 high-confidence variants driving eGFR associations and highlights putative causal genes with cell-type specific expression in glomerulus, and in proximal and distal nephron. Mendelian randomisation supports causal effects of eGFR on overall and cause-specific CKD, kidney stone formation, diastolic blood pressure and hypertension. These results define novel molecular mechanisms and putative causal genes for eGFR, offering insight into clinical outcomes and routes to CKD treatment development.

Estimated glomerular filtration rate (eGFR) is a measure of kidney function used to define chronic kidney disease. Here, Morris et al. perform trans-ethnic genome-wide meta-analyses for eGFR in 312,468 individuals and identify novel loci and downstream putative causal genes.

Maternal Gestational Diabetes Mellitus, Type 1 Diabetes, and Type 2 Diabetes During Pregnancy and Risk of ADHD in Offspring

OBJECTIVE

To examine the relative importance of maternal preexisting type 1 diabetes (T1D), preexisting type 2 diabetes (T2D), and gestational diabetes mellitus (GDM) on risk of attention deficit/hyperactivity disorder (ADHD) in offspring.

RESEARCH DESIGN AND METHODS

This retrospective birth cohort study included 333,182 singletons born in 1995-2012 within Kaiser Permanente Southern California hospitals. Children were prospectively followed through electronic medical records from age 4 years. Relative risks of ADHD associated with diabetes exposures in utero were estimated by hazard ratios (HRs) using Cox regression with adjustment for potential confounders. For GDM, timing of exposure was evaluated by gestational age at diagnosis and severity was assessed by the need for antidiabetes medication treatment during pregnancy.

RESULTS

A total of 37,878 (11.4%) children were exposed to diabetes (522 exposed to T1D, 7,822 T2D, and 29,534 GDM). During a median of 4.9 years (interquartile range 2.2, 9.6) of follow-up after age 4 years, 17,415 (5.2%) children were diagnosed with ADHD. ADHD risk was not associated with GDM taken as a whole (P = 0.50) or with gestational age at GDM diagnosis (P = 0.16). However, the risk was significantly greater for the GDM requiring versus not requiring antidiabetes medications (P < 0.001). Compared with children unexposed to diabetes, the adjusted HRs for ADHD in children were 1.57 (95% CI 1.09-2.25) for exposure to T1D, 1.43 (1.29-1.60) for T2D, 1.26 (1.14-1.41) for GDM requiring antidiabetes medications, and 0.93 (0.86-1.01) for GDM not requiring medications.

CONCLUSIONS

The hierarchy of risks suggests that severity of maternal diabetes (T1D vs. T2D vs. GDM requiring antidiabetes medications) influences the risk of ADHD in offspring of mothers with diabetes.

Impact of Gastric Banding Versus Metformin on β-Cell Function in Adults With Impaired Glucose Tolerance or Mild Type 2 Diabetes

OBJECTIVE

Type 2 diabetes (T2D) results from progressive loss of β-cell function. The BetaFat study compared gastric banding and metformin for their impact on β-cell function in adults with moderate obesity and impaired glucose tolerance (IGT) or recently diagnosed, mild T2D.

RESEARCH DESIGN AND METHODS

Eighty-eight people aged 21-65 years, BMI 30-40 kg/m², with IGT or diabetes known for <1 year, were randomized to gastric banding or metformin for 2 years. Hyperglycemic clamps (11.1 mmol/L) followed by arginine injection at maximally potentiating glycemia (>25 mmol/L) were performed at baseline, 12 months, and 24 months to measure steady-state C-peptide (SSCP) and acute C-peptide response to arginine at maximum glycemic potentiation (ACPRmax) and insulin sensitivity (M/I).

RESULTS

At 24 months, the band group lost 10.7 kg; the metformin group lost 1.7 kg (P < 0.01). Insulin sensitivity increased 45% in the band group and 25% in the metformin group (P = 0.30 between groups). SSCP adjusted for insulin sensitivity fell slightly but not significantly in each group (P = 0.34 between groups). ACPRmax adjusted for insulin sensitivity fell significantly in the metformin group (P = 0.002) but not in the band group (P = 0.25 between groups). HbA_1c fell at 12 and 24 months in the band group (P < 0.004) but only at 12 months (P < 0.01) in the metformin group (P > 0.14 between groups). Normoglycemia was present in 22% and 15% of band and metformin groups, respectively, at 24 months (P = 0.66 between groups).

CONCLUSIONS

Gastric banding and metformin had similar effects to preserve β-cell function and stabilize or improve glycemia over a 2-year period in moderately obese adults with IGT or recently diagnosed, mild T2D.

Hispanic ethnicity as a moderator of the effects of aerobic and resistance exercise in survivors of breast cancer

BACKGROUND

Metabolic syndrome (MSY) is associated with an increased risk of cardiovascular disease, type 2 diabetes, and recurrence in breast cancer survivors (BCS). MSY is 1.5 times more common in Hispanic women compared with non-Hispanic women. Although exercise mitigates MSY in BCS, to the best of the authors' knowledge, few studies to date have focused on minorities. This secondary analysis examined ethnicity as a moderator of the effects of a 16-week aerobic and resistance exercise intervention on MSY, sarcopenic obesity, and serum biomarkers in BCS.

METHODS

A total of 100 eligible BCS were randomized to exercise (50 BCS) or usual care (50 BCS). The exercise intervention promoted moderate to vigorous aerobic and resistance exercise 3 times a week for 16 weeks. MSY z scores, sarcopenic obesity, and serum biomarkers were measured at baseline, after the intervention, and at the 28-week follow-up (exercise group only). Linear mixed models adjusted for baseline values of the outcome, age, disease stage, adjuvant treatment, and recent physical activity were used to evaluate effect modification by ethnicity.

RESULTS

The study sample was 57% Hispanic BCS (HBCS) and 43% non-Hispanic BCS (NHBCS). HBCS were younger, of greater adiposity, and had been diagnosed with more advanced cancers compared with NHBCS (P<.001). Ethnicity was found to moderate the mean differences in exercise training on triglycerides (-36.4 mg/dL; 95% confidence interval [95% CI],-64.1 to -18.8 mg/dL), glucose (-8.6 mg/dL; 95% CI, -19.1 to -3.0 mg/dL), and C-reactive protein (-3.3 mg/L; 95% CI, -7.3 to -0.9 mg/L).

CONCLUSIONS

HBCS appear to have poorer metabolic profiles and therefore may derive relatively larger metabolic changes from exercise compared with NHBCS. Clinical exercise interventions may attenuate existing health disparities across diverse groups of BCS.

Aerobic and resistance exercise improves physical fitness, bone health, and quality of life in overweight and obese breast cancer survivors: a randomized controlled trial

Background

Exercise is an effective strategy to improve quality of life and physical fitness in breast cancer survivors; however, few studies have focused on the early survivorship period, minorities, physically inactive and obese women, or tested a combined exercise program and measured bone health. Here, we report the effects of a 16-week aerobic and resistance exercise intervention on patient-reported outcomes, physical fitness, and bone health in ethnically diverse, physically inactive, overweight or obese breast cancer survivors.

Methods

One hundred breast cancer survivors within 6 months of completing adjuvant treatment were assessed at baseline, post-intervention, and 3-month follow-up (exercise group only) for physical fitness, bone mineral density, serum concentrations of bone biomarkers, and quality of life. The exercise intervention consisted of moderate-vigorous (65–85% heart rate maximum) aerobic and resistance exercise thrice weekly for 16 weeks. Differences in mean changes for outcomes were evaluated using mixed-model repeated measure analysis.

Results

At post-intervention, the exercise group was superior to usual care for quality of life (between group difference: 14.7, 95% CI: 18.2, 9.7; p < 0.001), fatigue (p < 0.001), depression (p < 0.001), estimated VO_2max (p < 0.001), muscular strength (p < 0.001), osteocalcin (p = 0.01), and BSAP (p = 0.001). At 3-month follow-up, all patient-reported outcomes and physical fitness variables remained significantly improved compared to baseline in the exercise group (p < 0.01).

Conclusions

A 16-week combined aerobic and resistance exercise program designed to address metabolic syndrome in ethnically-diverse overweight or obese breast cancer survivors also significantly improved quality of life and physical fitness. Our findings further support the inclusion of supervised clinical exercise programs into breast cancer treatment and care.

Trial registration

This trial is registered on ClinicalTrials.gov: NCT01140282 as of June 9, 2010.

A cautionary response to SMFM statement: pharmacological treatment of gestational diabetes

Use of oral agents to treat gestational diabetes mellitus remains controversial. Recent recommendations from the Society for Maternal-Fetal Medicine assert that metformin may be a safe first-line alternative to insulin for gestational diabetes mellitus treatment and preferable to glyburide. However, several issues should give pause to the widespread adoption of metformin use during pregnancy. Fetal concentrations of metformin are equal to maternal, and metformin can inhibit growth, suppress mitochondrial respiration, have epigenetic modifications on gene expression, mimic fetal nutrient restriction, and alter postnatal gluconeogenic responses. Because both the placenta and fetus express metformin transporters and exhibit high mitochondrial activity, these properties raise important questions about developmental programming of metabolic disease in offspring. Animal studies have demonstrated that prenatal metformin exposure results in adverse long-term outcomes on body weight and metabolism. Two recent clinical randomized controlled trials in women with gestational diabetes mellitus or polycystic ovary syndrome provide evidence that metformin exposure in utero may produce a metabolic phenotype that increases childhood weight or obesity. These developmental programming effects challenge the conclusion that metformin is equivalent to insulin. Although the Society for Maternal-Fetal Medicine statement endorsed metformin over glyburide if oral agents are used, there are few studies directly comparing the 2 agents and it is not clear that metformin alone is superior to glyburide. Moreover, it should be noted that prior clinical studies have dosed glyburide in a manner inconsistent with its pharmacokinetic properties, resulting in poor glycemic control and high rates of maternal hypoglycemia. We concur with the American Diabetes Association and American Congress of Obstetricians and Gynecologists, which recommend insulin as the preferred agent, but we believe that it is premature to embrace metformin as equivalent to insulin or superior to glyburide. Due to the uncertainty of the long-term metabolic risks of either metformin or glyburide, we call for carefully controlled studies that optimize oral medication dosing according to their pharmacodynamic and pharmacokinetic properties in pregnancy, appropriately target medications based on individual patterns of hyperglycemia, and follow the offspring long-term for metabolic risk.

Monitoring Twitter Conversations for Targeted Recruitment in Cancer Trials in Los Angeles County: Protocol for a Mixed-Methods Pilot Study

BACKGROUND

Insufficient recruitment of participants remains a critical roadblock to successful clinical research, particularly clinical trials. Social media provide new ways for connecting potential participants with research opportunities. Researchers suggest that the social network Twitter may serve as a rich avenue for exploring how patients communicate about their health issues and increasing enrollment in cancer clinical trials. However, there is a lack of evidence that Twitter offers practical utility and impact.

OBJECTIVE

This pilot study aimed to examine the feasibility and impact of using Twitter monitoring data (ie, user activity and their conversations about cancer-related conditions and concerns expressed by Twitter users in Los Angeles County) as a tool for enhancing clinical trial recruitment at a comprehensive cancer center.

METHODS

We will conduct a mixed-methods interrupted time series study design with a before-and-after social media recruitment intervention. On the basis of a preliminary analysis of eligible trials, we plan to onboard at least 84 clinical trials across 6 disease categories: breast cancer, colon cancer, kidney cancer, lymphoma, non-small cell lung cancer, and prostate cancer that are open to accrual at the University of Southern California (USC) Norris Comprehensive Cancer Center. We will monitor messages about these 6 cancer conditions posted by Twitter users in Los Angeles County. Recruitment for the trials will occur through the Twitter account (@USCTrials). Primary study outcomes-feasibility and acceptance of the social media intervention among targeted Twitter users and the study teams of the onboarded trials-will be assessed using qualitative interviews and the 4-point Likert scale and by calculating the proportion of targeted Twitter users who engaged with outreach messages. Second, impact of the social media intervention will be measured by calculating the proportion of enrollees in trials. The enrollment rate will be compared between the active intervention period and the prior 10 months as historical control for each disease trial group. This study has been funded by the National Center for Advancing Translational Science through a Clinical and Translational Science Award. Study approval was obtained from the clinical investigations committee at USC Norris and the institutional review board at USC.

RESULTS

Recruitment on Twitter started in February 2018. Data collection will be completed in November 2018.

CONCLUSIONS

This pilot project will provide preliminary data and practical insight into the application of publicly available Twitter data to identify and recruit clinical trial participants across 6 cancer disease types. We will shed light on the acceptance of the social media intervention among Twitter users and study team members of the onboarded trials. If successful, the findings will inform a multisite randomized controlled trial to determine the efficacy of the social media intervention across different locations and populations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03408561; https://clinicaltrials.gov/ct2/show/NCT03408561 (Archived by WebCite at http://www.webcitation.org/72LihauzW).

REGISTERED REPORT IDENTIFIER

RR1-10.2196/9762.

Association of weight gain and fifteen adipokines with declining beta-cell function in Mexican Americans

Obesity and adipokines are associated with development of type 2 diabetes. However, limited longitudinal studies have examined their roles on declining β-cell function over time. This report assessed three adiposity measures (BMI, percent body fat, trunk fat), insulin resistance, and fifteen adipokines in relationship to longitudinal change in β-cell function measured by disposition index (DI) from frequently-sampled-intravenous-glucose-tolerance testing. The results showed that three factors were significantly and independently associated with rate of change in DI over time: rate of change in BMI (negative), rate of change in IL-6 (negative), and baseline adiponectin (positive). The association was the strongest for changing BMI and was largely explained by changing insulin resistance; the association with changing IL-6 was also largely explained by changing insulin resistance. Baseline adiponectin remained positively associated after adjustment for changing insulin resistance, suggesting an independent effect of adiponectin to preserve or improve β-cell function. These findings provide evidence and potential mechanisms for the role of obesity in promoting β-cell dysfunction, highlighting the potential importance of mitigating obesity and its metabolic effects in preventing and treating type 2 diabetes.

Metabolic Contrasts Between Youth and Adults With Impaired Glucose Tolerance or Recently Diagnosed Type 2 Diabetes: I. Observations Using the Hyperglycemic Clamp

OBJECTIVE

To compare insulin sensitivity (M/I) and β-cell responses in youth versus adults with impaired glucose tolerance (IGT) or drug-naïve, recently diagnosed type 2 diabetes.

RESEARCH DESIGN AND METHODS

In 66 youth (80.3% with IGT) and 355 adults (70.7% IGT), hyperglycemic clamps were used to measure 1) M/I, 2) acute (0-10 min [first phase]) C-peptide (ACPR_g) and insulin (AIR_g) responses to glucose, 3) steady-state C-peptide and insulin concentrations at plasma glucose of 11.1 mmol/L, and 4) arginine-stimulated maximum C-peptide (ACPR_max) and insulin (AIR_max) responses at plasma glucose >25 mmol/L. The fasting C-peptide-to-insulin ratio was used as an estimate of insulin clearance.

RESULTS

Insulin sensitivity was 46% lower in youth compared with adults (P < 0.001), and youth had greater acute and steady-state C-peptide (2.3- and 1.3-fold, respectively; each P < 0.001) and insulin responses to glucose (AIR_g 3.0-fold and steady state 2.2-fold; each P < 0.001). Arginine-stimulated C-peptide and insulin responses were also greater in youth (1.6- and 1.7-fold, respectively; each P < 0.001). After adjustment for insulin sensitivity, all β-cell responses remained significantly greater in youth. Insulin clearance was reduced in youth (P < 0.001). Participants with diabetes had greater insulin sensitivity (P = 0.026), with lesser C-peptide and insulin responses than those with IGT (all P < 0.001) but similar insulin clearance (P = 0.109).

CONCLUSIONS

In people with IGT or recently diagnosed diabetes, youth have lower insulin sensitivity, hyperresponsive β-cells, and reduced insulin clearance compared with adults. Whether these age-related differences contribute to declining β-cell function and/or impact responses to glucose-lowering interventions remains to be determined.

Impact of Insulin and Metformin Versus Metformin Alone on β-Cell Function in Youth With Impaired Glucose Tolerance or Recently Diagnosed Type 2 Diabetes

OBJECTIVE

Pediatric type 2 diabetes prevalence is increasing, with β-cell dysfunction key in its pathogenesis. The RISE Pediatric Medication Study compared two approaches-glargine followed by metformin and metformin alone-in preserving or improving β-cell function in youth with impaired glucose tolerance (IGT) or recently diagnosed type 2 diabetes during and after therapy withdrawal.

RESEARCH DESIGN AND METHODS

Ninety-one pubertal, overweight/obese 10-19-year-old youth with IGT (60%) or type 2 diabetes of <6 months duration (40%) were randomized to either 3 months of insulin glargine with a target glucose of 4.4-5.0 mmol/L followed by 9 months of metformin or to 12 months of metformin alone. β-Cell function (insulin sensitivity paired with β-cell responses) was assessed by hyperglycemic clamp at baseline, 12 months (on treatment), and 15 months (3 months off treatment).

RESULTS

No significant differences were observed between treatment groups at baseline, 12 months, or 15 months in β-cell function, BMI percentile, HbA_1c, fasting glucose, or oral glucose tolerance test 2-h glucose results. In both treatment groups, clamp-measured β-cell function was significantly lower at 12 and 15 months versus baseline. HbA_1c fell transiently at 6 months within both groups. BMI was higher in the glargine followed by metformin versus metformin alone group between 3 and 9 months. Only 5% of participants discontinued the interventions, and both treatments were well tolerated.

CONCLUSIONS

In youth with IGT or recently diagnosed type 2 diabetes, neither 3 months of glargine followed by 9 months of metformin nor 12 months of metformin alone halted the progressive deterioration of β-cell function. Alternate approaches to preserve β-cell function in youth are needed.

Maternal Type 1 Diabetes and Risk of Autism in Offspring

This cohort study uses electronic health record data to examine associations between maternal diabetes (preexisting type 1, type 2, and gestational) and autism spectrum disorder in children.

Longitudinal Increases in Adiposity Contribute to Worsening Adipokine Profile over Time in Mexican Americans

OBJECTIVE

Limited studies have assessed the relationship between longitudinal changes in adiposity and changes in multiple adipokines over time. This study examined changes in BMI, total body fat, and trunk fat associated with changes in 16 circulating adipokines in Mexican Americans at risk for type 2 diabetes.

METHODS

Participants included 1,213 individuals with cross-sectional data and a subset of 368 individuals with follow-up measures (mean 4.6 ± 1.5 years from baseline). Joint multivariate associations between 3 adiposity measures and 16 adipokines were assessed by canonical correlation analysis.

RESULTS

Longitudinal increases in adiposity were most strongly associated with increasing leptin, C-reactive protein (CRP), and interleukin 1 receptor antagonist (IL-1Ra) and decreasing adiponectin and secreted frizzled protein 5 (SFRP5) over time. Participants with BMI ≥ 30 kg/m² at baseline had greater increases in leptin, CRP, IL-1Ra, and interleukin 6 (IL-6) and greater decreases in adiponectin and SFRP5, associated with increasing adiposity over follow-up, than those with BMI < 30 kg/m² . Associations between adiposity and adipokines were most accounted for by leptin; adjustment for leptin greatly reduced the magnitude of all associations between adiposity and remaining adipokines.

CONCLUSIONS

Increasing adiposity contributes to a worsening imbalance of pro- and anti-inflammatory adipokines over time, in which leptin may have an important role as a key mediator of metabolic disease risk in Mexican Americans.

Abstract P5-13-01: Effects of a 16-week combined aerobic and resistance exercise intervention on metabolic syndrome in overweight/Obese Hispanic breast cancer survivors

Purpose. Metabolic syndrome (MetS) is associated with increased risk of cardiovascular disease, type 2 diabetes, and possibly cancer recurrence, and is higher in breast cancer survivors than age-matched postmenopausal women. Further, MetS is 1.5 times more prevalent in Hispanic women (&gt;40 years of age) than in non-Hispanic Whites and African Americans, thereby increasing the need to attenuate MetS in Hispanic breast cancer survivors (HBCS). This study examined the effects of a 16-week combined aerobic and resistance exercise intervention on MetS in overweight and obese HBCS.

Methods. This pre-planned sub-analysis included 60 sedentary HBCS (BMI325 kg/m2) from our larger MetS trial. HBCS were randomized to the exercise intervention (EXE; n=30) or usual care (UC; n=30). The EXE group participated in 3 supervised exercise sessions per week for 16 weeks. Aerobic exercise was performed at 65-85% heart rate maximum for ˜30 minutes. Resistance exercise was performed in circuit-fashion with 3 sets of 10-15 repetitions including upper and lower body exercises at 65-85% 1-repetition maximum. The UC group was asked not to increase their current exercise levels during the study period. Participants were tested for MetS (blood pressure, waist circumference, fasting blood glucose, HDL-C, and triglycerides) at baseline, within one week following the 16-week study period, and at 12-week follow-up for the EXE group only. Fasting blood samples were used to measure glucose, HDL-C, and triglycerides. Waist circumference was measured at the midpoint between the lower margin of the last palpable rib and the top of the iliac crest using a fabric tape measure. Blood pressure was measured with an automated sphygmomanometer. Body composition was assessed via dual energy X-ray absorptiometry.

Results. At baseline, 82% (overall and by group) of the HBCS met the criteria for MetS. There were no significant group differences in the MetS variables between the EXE and UC groups at baseline (p&gt;0.01). Post-intervention, all MetS components were significantly lower in the EXE group than the UC group (p&lt;0.01) and only 15% of participants in the EXE group met the criteria for MetS, representing a 67% absolute decrease. This is in comparison to 84% of participants in the UC group. Body fat mass decreased by 10% during the 16-week EXE period, compared to a 2% increase in the UC group (p&lt;0.01). MetS changes remained significantly improved in the EXE group when fat mass was included as a covariate in the statistical model. At the follow-up assessment in the EXE group, all MetS variables remained significantly improved compared to baseline (p&lt;0.01) and were not significantly different post-intervention (p&gt;0.25) despite slight increases (&lt;2%) in waist circumference and triglyceride levels.

Conclusion. This is one of few exercise trials in minority BCS and the first study to target MetS with exercise in HBCS. This 16-week supervised combined aerobic and resistance exercise intervention reduced MetS in sedentary, overweight and obese HBCS. Reductions in MetS components were maintained after completion of the intervention, suggesting the benefits of the intervention on MetS were sustainable in the absence of a supervised intervention.

Citation Format: Dieli-Conwright CM, Sami N, Lee K, Spicer D, Buchanan TA, Demark-Wahnefried W, Courneya K, Tripathy D, Mortimer J. Effects of a 16-week combined aerobic and resistance exercise intervention on metabolic syndrome in overweight/Obese Hispanic breast cancer survivors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-13-01.

Effects of Aerobic and Resistance Exercise on Metabolic Syndrome, Sarcopenic Obesity, and Circulating Biomarkers in Overweight or Obese Survivors of Breast Cancer: A Randomized Controlled Trial

Purpose Metabolic syndrome is associated with an increased risk of cardiovascular disease, type 2 diabetes, and breast cancer recurrence in survivors of breast cancer. This randomized controlled trial assessed the effects of a 16-week combined aerobic and resistance exercise intervention on metabolic syndrome, sarcopenic obesity, and serum biomarkers among ethnically diverse, sedentary, overweight, or obese survivors of breast cancer. Methods Eligible survivors of breast cancer (N = 100) were randomly assigned to exercise (n = 50) or usual care (n = 50). The exercise group participated in supervised moderate-to-vigorous-65% to 85% of heart rate maximum-aerobic and resistance exercise three times per week for 16 weeks. Metabolic syndrome z-score (primary outcome), sarcopenic obesity, and serum biomarkers were measured at baseline, postintervention (4 months), and 3-month follow-up (exercise only). Results Participants were age 53 ± 10.4 years, 46% were obese, and 74% were ethnic minorities. Adherence to the intervention was 95%, and postintervention assessments were available in 91% of participants. Postintervention metabolic syndrome z-score was significantly improved in exercise versus usual care (between-group difference, -4.4; 95% CI, -5.9 to -2.7; P < .001). Sarcopenic obesity (appendicular skeletal mass index, P = .001; body mass index, P = .001) and circulating biomarkers, including insulin ( P = .002), IGF-1 ( P = .001), leptin ( P = .001), and adiponectin ( P = .001), were significantly improved postintervention compared with usual care. At 3-month follow-up, all metabolic syndrome variables remained significantly improved compared with baseline in the exercise group ( P < .01). Conclusion Combined resistance and aerobic exercise effectively attenuated metabolic syndrome, sarcopenic obesity, and relevant biomarkers in an ethnically diverse sample of sedentary, overweight, or obese survivors of breast cancer. Our findings suggest a targeted exercise prescription for improving metabolic syndrome in survivors of breast cancer and support the incorporation of supervised clinical exercise programs into breast cancer treatment and survivorship care plans.

Duplication of the Optic Disc: True or Pseudo? A Coloboma or not a Coloboma?

Purpose

To present an unusual case of optic disc pseudoduplication with colobomata.

METHODS

Clinical evaluation, fundus photography and literature review.

Results

Optic disc duplication is a rare clinical entity.

CONCLUSIONS

We report what we believe to be the first case of pseudoduplication of the optic disc with coexistent bilateral optic disc colobomata.

Review of methods for measuring β-cell function: Design considerations from the Restoring Insulin Secretion (RISE) Consortium

The Restoring Insulin Secretion (RISE) study was initiated to evaluate interventions to slow or reverse the progression of β-cell failure in type 2 diabetes (T2D). To design the RISE study, we undertook an evaluation of methods for measurement of β-cell function and changes in β-cell function in response to interventions. In the present paper, we review approaches for measurement of β-cell function, focusing on methodologic and feasibility considerations. Methodologic considerations included: (1) the utility of each technique for evaluating key aspects of β-cell function (first- and second-phase insulin secretion, maximum insulin secretion, glucose sensitivity, incretin effects) and (2) tactics for incorporating a measurement of insulin sensitivity in order to adjust insulin secretion measures for insulin sensitivity appropriately. Of particular concern were the capacity to measure β-cell function accurately in those with poor function, as is seen in established T2D, and the capacity of each method for demonstrating treatment-induced changes in β-cell function. Feasibility considerations included: staff burden, including time and required methodological expertise; participant burden, including time and number of study visits; and ease of standardizing methods across a multicentre consortium. After this evaluation, we selected a 2-day measurement procedure, combining a 3-hour 75-g oral glucose tolerance test and a 2-stage hyperglycaemic clamp procedure, augmented with arginine.

The Association of Estrogen Receptor-β Gene Variation With Salt-Sensitive Blood Pressure

CONTEXT

Hypertension in young women is uncommon compared with young men and older women. Estrogen appears to protect most women against hypertension, with incidence increasing after menopause. Because some premenopausal women develop hypertension, estrogen may play a different role in these women. Genetic variations in the estrogen receptor (ER) are associated with cardiovascular disease. ER-β, encoded by ESR2, is the ER predominantly expressed in vascular smooth muscle.

OBJECTIVE

To determine an association of single nucleotide polymorphisms in ESR2 with salt sensitivity of blood pressure (SSBP) and estrogen status in women.

METHODS

Candidate gene association study with ESR2 and SSBP conducted in normotensive and hypertensive women and men in two cohorts: International Hypertensive Pathotype (HyperPATH) (n = 584) (discovery) and Mexican American Hypertension-Insulin Resistance Study (n = 662) (validation). Single nucleotide polymorphisms in ESR1 (ER-α) were also analyzed. Analysis conducted in younger (<51 years, premenopausal, "estrogen-replete") and older women (≥51 years, postmenopausal, "estrogen-deplete"). Men were analyzed to control for aging.

RESULTS

Multivariate analyses of HyperPATH data between variants of ESR2 and SSBP documented that ESR2 rs10144225 minor (risk) allele carriers had a significantly positive association with SSBP driven by estrogen-replete women (β = +4.4 mm Hg per risk allele, P = 0.004). Findings were confirmed in Hypertension Insulin-Resistance Study premenopausal women. HyperPATH cohort analyses revealed risk allele carriers vs noncarriers had increased aldosterone/renin ratios. No associations were detected with ESR1.

CONCLUSIONS

The variation at rs10144225 in ESR2 was associated with SSBP in premenopausal women (estrogen-replete) and not in men or postmenopausal women (estrogen-deplete). Inappropriate aldosterone levels on a liberal salt diet may mediate the SSBP.

A Genome-Wide Association Study of IVGTT-Based Measures of First-Phase Insulin Secretion Refines the Underlying Physiology of Type 2 Diabetes Variants

Understanding the physiological mechanisms by which common variants predispose to type 2 diabetes requires large studies with detailed measures of insulin secretion and sensitivity. Here we performed the largest genome-wide association study of first-phase insulin secretion, as measured by intravenous glucose tolerance tests, using up to 5,567 individuals without diabetes from 10 studies. We aimed to refine the mechanisms of 178 known associations between common variants and glycemic traits and identify new loci. Thirty type 2 diabetes or fasting glucose-raising alleles were associated with a measure of first-phase insulin secretion at P < 0.05 and provided new evidence, or the strongest evidence yet, that insulin secretion, intrinsic to the islet cells, is a key mechanism underlying the associations at the HNF1A, IGF2BP2, KCNQ1, HNF1B, VPS13C/C2CD4A, FAF1, PTPRD, AP3S2, KCNK16, MAEA, LPP, WFS1, and TMPRSS6 loci. The fasting glucose-raising allele near PDX1, a known key insulin transcription factor, was strongly associated with lower first-phase insulin secretion but has no evidence for an effect on type 2 diabetes risk. The diabetes risk allele at TCF7L2 was associated with a stronger effect on peak insulin response than on C-peptide-based insulin secretion rate, suggesting a possible additional role in hepatic insulin clearance or insulin processing. In summary, our study provides further insight into the mechanisms by which common genetic variation influences type 2 diabetes risk and glycemic traits.

Maternal obesity, gestational diabetes, breastfeeding and childhood overweight at age 2 years

BACKGROUND

Maternal obesity, excessive gestational weight gain (EGWG), gestational diabetes mellitus (GDM) and breastfeeding are four important factors associated with childhood obesity.

OBJECTIVES

The objective of the study was to assess the interplay among these four factors and their independent contributions to childhood overweight in a cohort with standard clinical care.

METHODS

The cohort included 15 710 mother-offspring pairs delivered in 2011. Logistic regression was used to assess associations between maternal exposures and childhood overweight (body mass index >85th percentile) at age 2 years.

RESULTS

Mothers with pre-pregnancy obesity or overweight were more likely to have EGWG, GDM and less likely to breastfeed ≥6 months. Mothers with GDM had 40-49% lower EGWG rates and similar breastfeeding rates compared with mothers without GDM. Analysis adjusted for exposures and covariates revealed an adjusted odds ratio (95% confidence interval) associated with childhood overweight at age 2 years of 2.34 (2.09-2.62), 1.50 (1.34-1.68), 1.23 (1.12-1.35), 0.95 (0.83-1.10) and 0.76 (0.69-0.83) for maternal obesity, overweight, EGWG, GDM and breastfeeding ≥6 months vs. <6 months, respectively.

CONCLUSIONS

In this large clinical cohort, GDM was not associated with, but maternal pre-pregnancy obesity or overweight and EGWG were independently associated with an increased risk, and breastfeeding ≥6 months was associated with a decreased risk of childhood overweight at age 2 years.

Pioglitazone is equally effective for diabetes prevention in older versus younger adults with impaired glucose tolerance

To determine the efficacy of pioglitazone to prevent type 2 diabetes in older compared to younger adults with pre-diabetes. Six hundred two participants with impaired glucose tolerance (IGT) were randomized in double blind fashion to placebo or pioglitazone for diabetes prevention in the ACT NOW study (NEJM 364:1104-1115, 2011). Cox proportional hazard regression was used to compare time to development of diabetes over a mean of 2 years between older (≥61 years) and younger participants. We compared effects of pioglitazone versus placebo on metabolic profiles, inflammatory markers, adipokines, β cell function (disposition index), insulin sensitivity (Matsuda index), and body composition by ANOVA. Diabetes incidence was reduced by 85 % in older and 69 % in younger subjects (p = 0.41). β cell function (disposition index) increased by 35.0 % in the older and 26.7 % in younger subjects (p = 0.83). Insulin sensitivity (Matsuda index) increased by 3.07 (5.2-fold) in older and by 2.54 (3.8-fold) in younger participants (p = 0.58). Pioglitazone more effectively increased adiponectin in older versus younger subjects (22.9 ± 3.2 μg/mL [2.7-fold] vs. 12.7 ± 1.4 μg/mL [2.2-fold], respectively; p = 0.04). Younger subjects tended to have a greater increase in whole body fat mass compared to older subjects (3.6 vs. 3.1 kg; p = 0.061). Younger and older subjects had similar decreases in bone mineral density (0.018 ± 0.0071 vs. 0.0138 ± 0.021 g/cm²). Younger and older pre-diabetic adults taking pioglitazone had similar reductions in conversion to diabetes and older adults had similar or greater improvements in metabolic risk factors, demonstrating that pioglitazone is useful in preventing diabetes in older adults.