Impact of race/ethnicity on the relationship between visceral fat and inflammatory biomarkers

Interleukin-6, Diabetes, and Metabolic Syndrome in a Biracial Cohort: The Reasons for Geographic and Racial Differences in Stroke Cohort

OBJECTIVE

Black Americans have a greater risk of type 2 diabetes than White Americans. The proinflammatory cytokine interleukin-6 (IL-6) is implicated in diabetes pathogenesis, and IL-6 levels are higher in Black individuals. This study investigated associations of IL-6 with incident diabetes and metabolic syndrome in a biracial cohort.

RESEARCH DESIGN AND METHODS

The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study enrolled 30,239 Black and White adults age ≥45 years in 2003-2007, with a follow-up ∼9.5 years later. Baseline plasma IL-6 was measured in 3,399 participants at risk of incident diabetes and 1,871 at risk of metabolic syndrome. Relative risk (RR) by IL-6 was estimated with modified Poisson regression for both groups.

RESULTS

Incident diabetes occurred in 14% and metabolic syndrome in 20%; both rates rose across IL-6 quartiles. There was a three-way interaction of IL-6, race, and central adiposity for incident diabetes (P = 8 × 10-5). In Black participants with and without central adiposity, RRs were 2.02 (95% CI 1.00-4.07) and 1.66 (1.00-2.75) for the fourth compared with first IL-6 quartile, respectively. The corresponding RRs were 1.73 (0.92-3.26) and 2.34 (1.17-4.66) in White participants. The pattern was similar for IL-6 and metabolic syndrome.

CONCLUSIONS

Although IL-6 was higher in Black than in White participants and those with central adiposity, the association of IL-6 with diabetes risk was statistically significant only among White participants without central adiposity. The association with metabolic syndrome risk was similarly stronger in low-risk groups. The results support the concept of interventions to lower inflammation in diabetes prevention, but to reduce race disparities, better biomarkers are needed.

Chronic GLP1 therapy reduces postprandial IL6 in obese humans with prediabetes

Single-dose glucagon-like peptide 1 (GLP1) therapy increases postprandial plasma IL6 levels in prediabetic, obese humans. GLP1-IL6 interactions underly multiple antidiabetic effects, but these may differ after acute versus chronic therapy. This study examines postprandial effects of GLP1 after chronic therapy. Seven humans (six Black) with prediabetes and obesity completed 6 weeks of exenatide extended release therapy. Then subjects returned for pre- and post-meal measurements of plasma IL6, GLP1, glucagon, and related inflammatory markers. Weight, which was measured before and after therapy, did not change. Plasma IL6 decreased from baseline to postmeal state ( = 0.016), with decreases in free fatty acids (P < 0.001) and increases in insulin (P = 0.002), glucose (P < 0.0001), triglycerides (P = 0.0178), and glucagon (P = 0.018). Baseline GLP1 levels matched 6 weeks of therapy. The fall in postprandial plasma IL6, which contrasts with the increase after acute therapy, highlights the need for more investigation regarding the mechanisms of acute versus chronic GLP1-IL6 signaling.

Mendelian randomization analyses suggest a causal role for circulating GIP and IL-1RA levels in homeostatic model assessment-derived measures of β-cell function and insulin sensitivity in Africans without type 2 diabetes

BACKGROUND

In vitro and in vivo studies have shown that certain cytokines and hormones may play a role in the development and progression of type 2 diabetes (T2D). However, studies on their role in T2D in humans are scarce. We evaluated associations between 11 circulating cytokines and hormones with T2D among a population of sub-Saharan Africans and tested for causal relationships using Mendelian randomization (MR) analyses.

METHODS

We used logistic regression analysis adjusted for age, sex, body mass index, and recruitment country to regress levels of 11 cytokines and hormones (adipsin, leptin, visfatin, PAI-1, GIP, GLP-1, ghrelin, resistin, IL-6, IL-10, IL-1RA) on T2D among Ghanaians, Nigerians, and Kenyans from the Africa America Diabetes Mellitus study including 2276 individuals with T2D and 2790 non-T2D individuals. Similar linear regression models were fitted with homeostatic modelling assessments of insulin sensitivity (HOMA-S) and β-cell function (HOMA-B) as dependent variables among non-T2D individuals (n = 2790). We used 35 genetic variants previously associated with at least one of these 11 cytokines and hormones among non-T2D individuals as instrumental variables in univariable and multivariable MR analyses. Statistical significance was set at 0.0045 (0.05/11 cytokines and hormones).

RESULTS

Circulating GIP and IL-1RA levels were associated with T2D. Nine of the 11 cytokines and hormones (exceptions GLP-1 and IL-6) were associated with HOMA-S, HOMA-B, or both among non-T2D individuals. Two-stage least squares MR analysis provided evidence for a causal effect of GIP and IL-RA on HOMA-S and HOMA-B in multivariable analyses (GIP ~ HOMA-S β =  - 0.67, P-value = 1.88 × 10-6 and HOMA-B β = 0.59, P-value = 1.88 × 10-5; IL-1RA ~ HOMA-S β =  - 0.51, P-value = 8.49 × 10-5 and HOMA-B β = 0.48, P-value = 5.71 × 10-4). IL-RA was partly mediated via BMI (30-34%), but GIP was not. Inverse variance weighted MR analysis provided evidence for a causal effect of adipsin on T2D (multivariable OR = 1.83, P-value = 9.79 × 10-6), though these associations were not consistent in all sensitivity analyses.

CONCLUSIONS

The findings of this comprehensive MR analysis indicate that circulating GIP and IL-1RA levels are causal for reduced insulin sensitivity and increased β-cell function. GIP's effect being independent of BMI suggests that circulating levels of GIP could be a promising early biomarker for T2D risk. Our MR analyses do not provide conclusive evidence for a causal role of other circulating cytokines in T2D among sub-Saharan Africans.

Cardiometabolic disease in Black African and Caribbean populations: an ethnic divergence in pathophysiology?

In the UK, populations of Black African and Caribbean (BAC) ethnicity suffer higher rates of cardiometabolic disease than White Europeans (WE). Obesity, leading to increased visceral adipose tissue (VAT) and intrahepatic lipid (IHL), has long been associated with cardiometabolic risk, driving insulin resistance and defective fatty acid/lipoprotein metabolism. These defects are compounded by a state of chronic low-grade inflammation, driven by dysfunctional adipose tissue. Emerging evidence has highlighted associations between central complement system components and adipose tissue, fatty acid metabolism and inflammation; it may therefore sit at the intersection of various cardiometabolic disease risk factors. However, increasing evidence suggests an ethnic divergence in pathophysiology, whereby current theories fail to explain the high rates of cardiometabolic disease in BAC populations. Lower fasting and postprandial TAG has been reported in BAC, alongside lower VAT and IHL deposition, which are paradoxical to the high rates of cardiometabolic disease exhibited by this ethnic group. Furthermore, BAC have been shown to exhibit a more anti-inflammatory profile, with lower TNF-α and greater IL-10. In contrast, recent evidence has revealed greater complement activation in BAC compared to WE, suggesting its dysregulation may play a greater role in the high rates of cardiometabolic disease experienced by this population. This review outlines the current theories of how obesity is proposed to drive cardiometabolic disease, before discussing evidence for ethnic differences in disease pathophysiology between BAC and WE populations.

Immune Profile of Exosomes in African American Breast Cancer Patients Is Mediated by Kaiso/THBS1/CD47 Signaling

African American (AA) women with breast cancer are more likely to have higher inflammation and a stronger overall immune response, which correlate with poorer outcomes. In this report, we applied the nanostring immune panel to identify differences in inflammatory and immune gene expression by race. We observed a higher expression of multiple cytokines in AA patients compared to EA patients, with high expression of CD47, TGFB1, and NFKB1 associated with the transcriptional repressor Kaiso. To investigate the mechanism associated with this expression pattern, we observed that Kaiso depletion results in decreased expression of CD47, and its ligand SIRPA. Furthermore, Kaiso appears to directly bind to the methylated sequences of the THBS1 promotor and repress gene expression. Similarly, Kaiso depletion attenuated tumor formation in athymic nude mice, and these Kaiso-depleted xenograft tissues showed significantly higher phagocytosis and increased infiltration of M1 macrophages. In vitro validation using MCF7 and THP1 macrophages treated with Kaiso-depleted exosomes showed a reduced expression of immune-related markers (CD47 and SIRPA) and macrophage polarization towards the M1 phenotype compared to MCF7 cells treated with exosomes isolated from high-Kaiso cells. Lastly, analysis of TCGA breast cancer patient data demonstrates that this gene signature is most prominent in the basal-like subtype, which is more frequently observed in AA breast cancer patients.

Racial differences in transcriptomics and reactive oxygen species burden in myometrium and leiomyoma

STUDY QUESTION

Are there differences in Mediator Complex Subunit 12 mutations (MED12) mutation, transcriptomics, and protein expression in uterine myometrium and leiomyomas of Black and White women?

SUMMARY ANSWER

RNA sequencing, tissue microarray, and immunohistochemistry data revealed that Black and White women have significant differences in their myometrium and leiomyoma profiles.

WHAT IS KNOWN ALREADY

Black women develop uterine leiomyoma earlier than White women, and are more likely to be anemic, have multiple tumors, undergo hysterectomy at an earlier age, have a higher uterine weight, and report very severe pelvic pain.

STUDY DESIGN, SIZE, DURATION

Uterine tissues were collected from premenopausal women undergoing hysterectomy or myomectomy at Northwestern University Prentice Women's Hospital (Chicago, IL) from 2010 to 2021. Tissues were collected from a total of 309 women, including from 136 Black women, 135 White women, and 38 women from other racial groups. A total of 529 uterine leiomyomas (290 from Black women, 184 from White women, and 55 from women of other racial groups) were subjected to molecular analysis. Leiomyoma and matched myometrium from a total of 118 cases including 60 Black women and 58 White women, were used for tissue microarrays, along with 34 samples of myometrium without leiomyoma from White women.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Tissues from the above patient cohorts were analyzed by tissue microarray, immunohistochemistry, RNA sequencing, and mutation analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

The results indicated that leiomyoma from Black women have a higher rate of MED12 mutations (79.0%) than those from White women (68.5%) (*P ≤ 0.05). RNA-sequencing analysis in myometrium revealed differentially expressed genes (270 upregulated, 374 downregulated) dependent on race, wherein reactive oxygen species, hypoxia, and oxidative phosphorylation pathways were positively correlated with samples derived from Black patients. The levels of proteins associated with oxidative DNA damage and repair, 8-hydroxyguanosine (8-OHdG), 8-oxoguanine glycosylase (OGG1), heme oxygenase-1 (HO-1), and kelch-like ECH-associated protein 1 (KEAP1), were higher in leiomyoma and matched myometrium, particularly those from Black patients, compared to the control myometrium (with leiomyoma) (***P ≤ 0.001).

LARGE SCALE DATA

The datasets are available in the NCBI (The BioProject number: PRJNA859428).

LIMITATIONS, REASONS FOR CAUTION

Myometrium without leiomyoma derived from White patients was used as a control in the tissue microarray analysis, as myometrium without leiomyoma from Black patients was not accessible in large numbers. The RNA sequencing was performed on myometrium tissue with leiomyoma present from 10 White and 10 Black women. However, one sample from a Black woman yielded low-quality RNA-sequencing data and was excluded from further analysis.

WIDER IMPLICATIONS OF THE FINDINGS

Women with symptomatic leiomyomas have a considerable loss in their quality of life. This study provides information on underlying genetic and molecular defects that may be necessary for future therapeutics targeted at leiomyomas.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from NCI (R01CA254367) and NICHD (P01HD057877). The authors declare no conflict of interest.

Racial/Ethnic Differences in Traumatic Brain Injury: Pathophysiology, Outcomes, and Future Directions

Traumatic brain injury (TBI) is a major cause of death and disability in the United States, exacting a debilitating physical, social, and financial strain. Therefore, it is crucial to examine the impact of TBI on medically underserved communities in the U.S. The purpose of the current study was to review the literature on TBI for evidence of racial/ethnic differences in the U.S. Results of the review showed significant racial/ethnic disparities in TBI outcome and several notable differences in other TBI variables. American Indian/Alaska Natives have the highest rate and number of TBI-related deaths compared with all other racial/ethnic groups; Blacks/African Americans are significantly more likely to incur a TBI from violence when compared with Non-Hispanic Whites; and minorities are significantly more likely to have worse functional outcome compared with Non-Hispanic Whites, particularly among measures of community integration. We were unable to identify any studies that looked directly at underlying racial/ethnic biological variations associated with different TBI outcomes. In the absence of studies on racial/ethnic differences in TBI pathobiology, taking an indirect approach, we looked for studies examining racial/ethnic differences in oxidative stress and inflammation outside the scope of TBI as they are known to heavily influence TBI pathobiology. The literature indicates that Blacks/African Americans have greater inflammation and oxidative stress compared with Non-Hispanic Whites. We propose that future studies investigate the possibility of racial/ethnic differences in inflammation and oxidative stress within the context of TBI to determine whether there is any relationship or impact on TBI outcome.

Cut points of the conicity index as an indicator of abdominal obesity in individuals undergoing hemodialysis: An analysis of latent classes

OBJECTIVES

Abdominal obesity favors the involvement of cardiometabolic complications in renal patients on hemodialysis. Thus, the aim of the study was to identify the cut-points of the conicity index in individuals undergoing hemodialysis.

METHODS

This was a cross-sectional study carried out with 953 individuals undergoing hemodialysis in clinics in a metropolitan region of southeastern Brazil. The conicity index was calculated using the following mathematical equation: waist circumference/0.109 × √weight/height. The receiver operating characteristic (ROC) curve was calculated from the analysis of latent classes by cross-validation through a latent variable of abdominal obesity. This latent variable was defined using the response pattern of the observed anthropometric variables considering the presence and absence of abdominal obesity: waist circumference, waist-to-height ratio, and body shape index. The cut-points identified were elucidated by the area under the curve (AUC), Youden index, sensitivity, and specificity.

RESULTS

The cut-points for the conicity index found for both sexes were similar, resulting in a cut-point for men of 1.275 (AUC, 0.921; Youden index, 0.666), with a sensitivity and specificity of 83% and 83.6%, and a cut-point for women of 1.285 (AUC, 0.921; Youden index, 0.679), with a sensitivity and specificity of 78.6% and 89.3%, respectively.

CONCLUSIONS

The conicity index showed high discriminatory power for the identification of abdominal obesity in hemodialysis patients, therefore it can be a simple and easily accessible tool to be incorporated into clinical practice in this population.

Oxidative Stress Underpins Clinical, Social, and Genetic Risk Factors for Atherosclerotic Cardiovascular Disease

Background

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death worldwide and is poorly predicted with current risk estimation tools. The biological mechanisms relating ASCVD risk factors to oxidative stress (OS) and how this accumulates ASCVD risk are misunderstood.

Purpose

To develop a comprehensive conceptual model explaining how expanded clinical, social, and genetic ASCVD risk factors accumulate ASCVD risk through OS.

Conclusions

OS (primarily from excess reactive oxygen species) and inflammation are present along the entire ASCVD pathophysiologic continuum. An expanded list of clinical and social ASCVD risk factors (including hypertension, obesity, diabetes, kidney disease, inflammatory diseases, substance use, poor nutrition, psychosocial stress, air pollution, race, and genetic ancestry) influence ASCVD largely through increased OS. Many risk factors exert a positive feedback mechanism to increase OS. One genetic risk factor, haptoglobin (Hp) genotype, is associated with higher ASCVD risk in diabetes and hypothesized to do the same in those with insulin resistance due to the Hp 2-2 genotype increasing OS.

Implications

Understanding the biological mechanisms of OS informs how these ASCVD risk factors relate to each other and compound ASCVD risk. Individualized ASCVD risk estimation should include a comprehensive, holistic perspective of risk factors to better address the clinical, social, and genetic influences of OS. Preventing and reducing OS is key to preventing ASCVD development or progression.

Correlations between the Changing Levels of Tissue Plasminogen Activator and Adiposity Following Exercise-Induced Weight Loss

Cardiovascular disease is a major threat to global public health. Tissue plasminogen activator (TPA) is a serine protease that dissolves blood clots, which can also lead to excessive bleeding. Fibrinogen (FIBR), a glycoprotein, is converted by thrombin to fibrin and then to a fibrin-based blood clot. Both TPA and FIBR levels in the blood are associated with an increased risk of coronary heart disease, and the levels of the two factors are also positively correlated with total adipose tissue amounts. Visceral and subcutaneous adipose tissues (VAT and SAT) can contribute differently to whole-body metabolism. In this study, we sought to assess: (1) the strength of the correlation between the changing levels of the two factors and the changing amounts of VAT/SAT during exercise-induced weight loss, (2) whether there is any difference between the two types of adipose tissues in terms of the correlation, and (3) which factor, TPA or FIBR, is more sensitive to changes in adiposity? For this study, we analyzed the data from the diabetes prevention program (DPP), in which the participants were divided into three groups, with one group undergoing a lifestyle change that involved maintaining a minimum of 7% weight loss with physical activity. We found that the basal amounts of VAT and SAT were correlated with TPA and FIBR levels. However, following weight loss, adiposity changes were strongly correlated with the changing levels of TPA, but not FIBR, for both men and women. Therefore, TPA, but not FIBR, is sensitive to changes in adiposity. Furthermore, regarding TPA, weight loss sensitized its correlation with SAT, but not VAT. This study shows how adipose tissues distinctively affect TPA and FIBR levels, two factors associated with cardiovascular disease and ischemic stroke.

Review article: obesity and colorectal cancer

BACKGROUND

Obesity is a growing global public health problem. More than half the European and North American population is overweight or obese. Colon and rectum cancers are still the second leading cause of cancer death worldwide, and epidemiological data support an association between obesity and colorectal cancers (CRCs).

AIM

To review the literature on CRC epidemiology in obese subjects, assessing the effects of obesity, including childhood or maternal obesity, on CRC, diagnosis, management, and prognosis, and discussing targeted prophylactic measures.

METHOD

We searched PubMed for obesity/overweight/metabolic syndrome and CRC. Other key words included 'staging', 'screening', 'treatment', 'weight loss', 'bariatric surgery' and 'chemotherapy'.

RESULTS

In Europe, about 11% of CRCs are attributed to overweight and obesity. Epidemiological data suggest that obesity is associated with a 30%-70% increased risk of colon cancer in men, the association being less consistent in women. Visceral fat or abdominal obesity seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m² increase in body mass index confers more risk (hazard ratio 1.03). Obesity might increase the likelihood of recurrence or mortality of the primary cancer and may affect initial management, including accurate staging. The risk maybe confounded by different factors, including lower adherence to organised CRC screening programmes. It is unclear whether bariatric surgery helps reduce rectal cancer risk.

CONCLUSIONS

Despite a growing body of evidence linking obesity to CRC, many questions remain unanswered, including whether we should screen patients with obesity earlier or propose prophylactic bariatric surgery for certain patients with obesity.

Clinical Features and Body Composition in Men with Hormone-Sensitive Metastatic Prostate Cancer: A Pilot Study Examining Differences by Race

Black men treated with frontline therapies for metastatic prostate cancer (MPC) show better clinical outcomes than non-Black men receiving similar treatments. Variations in body composition may contribute to these findings. However, preliminary data are required to support this concept. We conducted a retrospective cohort study for all men with MPC evaluated at our center over a 4-year period, collecting demographic and clinical data (N = 74). Of these, 55 men had diagnostic computed tomography images to quantify adipose tissue and skeletal muscle, specifically sarcopenia and myosteatosis. Nineteen men had repeat imaging to explore changes over time. Frequencies, medians, interquartile ranges, and time to event analyses (hazard ratios (HR); confidence interval (CI)) are presented, stratified by race. Overall, 49% (n = 27) of men had sarcopenia, 49% (n = 27) had myosteatosis, and 29% (n = 16) had sarcopenia and myosteatosis simultaneously. No significant relationship between body mass index (Log-rank $p=0.86$ ; HR: 1.05, 95% CI: 0.45–2.49) or sarcopenia (Log-rank $p=0.92$ ; HR: 1.01, 95% CI: 0.46–2.19) and overall survival was observed. However, the presence of myosteatosis at diagnosis was associated with decreased overall survival (Log-rank $p=0.09$ ; HR: 2.34, 95% CI: 1.05–5.23), with more pronounced (statistically nonsignificant) negative associations for Black (HR: 4.39, 95% CI: 0.92–21.1, $p=0.06$ ) versus non-Black men (HR: 1.89, 95% CI: 0.79–4.54, $p=0.16$ ). Over the median 12.5 months between imaging, the median decline in skeletal muscle was 4% for all men. Black men displayed a greater propensity to gain more adipose tissue than non-Black men, specifically subcutaneous ( $p=0.01$ ). Because of the potential for Type II errors in this pilot, future studies should seek to further evaluate the implications of body composition on outcomes. This will require larger, adequately powered investigations with diverse patient representation.

Epidemiology of interleukin-6: the 30-year follow-up of the 1982 Pelotas (Brazil) birth cohort study

BACKGROUND

Cardiovascular diseases are the main cause of death globally. Interleukin-6 (IL-6) is a biomarker of cardiovascular risk.

AIM

To investigate factors associated with IL-6 concentration in serum, from early life up to 30 years of age.

SUBJECTS AND METHODS

In the 2012-2013 follow-up, IL-6 was measured in 2809 participants of the 1982 Pelotas Birth Cohort (1369 males). Multivariable linear regressions, stratified by sex, were performed to evaluate the associations of African ancestry, family income and maternal education at birth, monthly income and education at 30 years, smoking status, harmful alcohol intake, physical activity, and body composition with IL-6, considering a conceptual hierarchical framework.

RESULTS

Males with low educational levels and current smokers had the highest mean IL-6. Among females, African ancestry and low monthly income were associated with the highest mean values for the outcome. Physical activity had an inverse association with IL-6 concentration among females. A direct relationship was observed between the measures of adiposity on IL-6, in both sexes.

CONCLUSION

Body composition was the main predictor for the outcome evaluated in males and females. Thus, the avoidance of overweight remains an important strategy for the prevention and control of cardiovascular risk and biomarkers associated with these diseases.

Racial Differences in Pain, Nutrition, and Oxidative Stress

Investigating the disproportionate rates of chronic pain and their related comorbidities between Black and non-Hispanic White (White) individuals is a growing area of interest, both in the healthcare community and in general society. Researchers have identified racial differences in chronic pain prevalence and severity, but still very little is known about the mechanisms underlying them. Current explanations for these differences have primarily focused on socioeconomic status and unequal healthcare between races as causal factors. Whereas these factors are informative, a racial gap still exists between Black and White individuals when these factors are controlled for. One potential cause of this racial gap in chronic pain is the differences in nutrition and dietary intake between groups. Certain foods play a key role in the inflammatory and oxidative stress pathways in the human body and could potentially influence the severity of the pain experience. Here, we review the previous literature on the surrounding topics and propose a potential mechanism to explain racial differences in the chronic pain population, based on established racial differences in diet and oxidative stress.

Ectopic fat deposition in populations of black African ancestry: A systematic review and meta-analysis

AIMS

In populations of black African ancestry (BA), a paradox exists whereby lower visceral adipose tissue is found despite their high risk for type 2 diabetes (T2D). This systematic review investigates ethnic differences in other ectopic fat depots (intrahepatic lipid: IHL; intramyocellular lipid: IMCL and intrapancreatic lipid; IPL) to help contextualise their potential contribution to T2D risk.

METHODS

A systematic literature search was performed in December 2020 to identify studies reporting at least one ectopic fat comparison between BA and one/more other ethnicity. For IHL, a meta-analysis was carried out with studies considered comparable based on the method of measurement.

RESULTS

Twenty-eight studies were included (IHL: n = 20; IMCL: n = 8; IPL: n = 4). Meta-analysis of 11 studies investigating IHL revealed that it was lower in BA populations vs pooled ethnic comparators (MD -1.35%, 95% CI -1.55 to -1.16, I² = 85%, P < 0.00001), white European ancestry (MD -0.94%, 95% CI -1.17 to -0.70, I² = 79%, P < 0.00001), Hispanic ancestry (MD -2.06%, 95% CI -2.49 to -1.63, I² = 81%, P < 0.00001) and South Asian ancestry comparators (MD -1.92%, 95% CI -3.26 to -0.57, I² = 78%, P = 0.005). However, heterogeneity was high in all analyses. Most studies found no significant differences in IMCL between BA and WE. Few studies investigated IPL, however, indicated that IPL is lower in BA compared to WE and HIS.

CONCLUSION

The discordance between ectopic fat and greater risk for T2D in BA populations raises questions around its contribution to T2D pathophysiology in BA.

Risk factors associated with post-operative uveitis after cataract surgery: a retrospective case-control study

BACKGROUND/AIM

Post-operative uveitis is the most common complication after cataract surgery in the UK. The study aims to evaluate the risk of post-operative uveitis in cataract surgery patients of different ethnicity in the presence and absence of co-morbidities as well as operative complications using multivariate analysis.

METHODS

A retrospective case-control study of patients undergoing phacoemulsification cataract surgery between January 2018 to December 2019 at two hospital sites. Differences in demographic and clinical characteristics were compared between two groups defined by the development of post-operative uveitis. Statistically significant factors in univariate analysis were further analysed using multivariate analysis to account for confounders.

RESULTS

One thousand and five hundred eighty seven eyes had undergone phacoemulsification cataract operations with 104 (6.6%) developing post-operative uveitis. Compared to eyes of White/Mixed/Other ethnicity, Asian and Afro-Caribbean eyes were associated with a twofold (OR 2.02, 95% CI 1.16-3.52, P = 0.013) and fivefold (OR 5.15, 95% CI 2.85-9.29, P < 0.001) risk of post-operative uveitis, respectively. Complicated surgery involving eyes with small pupil/iris hooks/Malyugin ring (OR 2.70, 95% CI 1.16-6.30, P = 0.022) and posterior capsular rupture (OR 6.00, 95% CI 2.55-14.12, P < 0.001) were associated with an increased risk of post-operative uveitis.

CONCLUSIONS

The factors significantly associated with a post-operative uveitis outcome were patients of Asian and Afro-Caribbean ethnicity, small intra-operative pupil size, use of iris hooks or Malyugin ring and PCR. The post-operative management plan should be tailored in these group of patients with a view of early assessment and prompt management of symptoms.

Relation of Abdominal Obesity to Risk of Atrial Fibrillation (From the Reasons for Geographic and Racial Differences in Stroke [REGARDS] Study)

Our knowledge of the association between abdominal obesity (AO) and the risk of atrial fibrillation (AF) after adjusting for body mass index (BMI) is limited. We included 11,617 Black and White participants (mean age 63.0 ± 8.4 years) from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) national cohort study who were free of AF at baseline. A multivariable logistic regression model was used to estimate the odds ratio (OR) with 95% confidence interval (CI) of incident AF associated with AO. We also evaluated the association between waist circumference (WC) and incident AF. Over a median follow-up of 9.4 years, 999 participants developed AF. AO was associated with an increased risk of AF in a multivariable model adjusted for sociodemographic, lifestyle, and cardiovascular risk factors (OR 1.43, 95% CI 1.24 to 1.65, p <0.001). The association was attenuated after adjusting for BMI (OR 1.13, 95% CI 0.95 to 1.35, p = 0.16). There was no evidence of interaction between AO and incident AF by age category (age >65 vs age ≤65), gender, race, obesity, or BMI category. Conversely, a 10cm increase in WC was associated with a higher incidence of AF after controlling for BMI (OR 1.18 95% CI 1.09 to 1.29, p <0.001), in both nonobese (OR 1.14, 95% CI 1.03 to 1.28, p = 0.02) and obese (OR 1.26, 95% CI 1.11 to 1.42, p <0.001) people. In conclusion, there was an association between AO and incident AF, but the association was weakened after adjusting for BMI. There was a significant association between WC and incident AF, after taking other AF risk factors and BMI into account. WC is a potentially modifiable risk factor for AF, and further research is warranted to explore the effect of decreasing WC on the population AF burden.

Thrombo-inflammatory biomarkers and D-dimer in a biracial cohort study

BACKGROUND

Higher D-dimer is a risk factor for cardiovascular diseases and venous thromboembolism. In the general population, D-dimer and other thrombo-inflammatory biomarkers are higher among Black individuals, who also have higher risk of these conditions compared to White people.

OBJECTIVE

To assess whether Black individuals have an exaggerated correlation between D-dimer and thrombo-inflammatory biomarkers characteristic of cardiovascular diseases.

METHODS

Linear regression was used to assess correlations of 11 thrombo-inflammatory biomarkers with D-dimer in a cross-sectional study of 1068 participants of the biracial Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort.

RESULTS

Adverse levels of most biomarkers, especially fibrinogen, factor VIII, C-reactive protein, N-terminal pro-B-type natriuretic peptide, and interleukin (IL)-6, were associated with higher D-dimer. Several associations with D-dimer differed significantly by race. For example, the association of factor VIII with D-dimer was more than twice as large in Black compared to White participants. Specifically, D-dimer was 26% higher per standard deviation (SD) higher factor VIII in Black adults and was only 11% higher per SD higher factor VIII in White adults. In Black but not White adults, higher IL-10 and soluble CD14 were associated with higher D-dimer.

CONCLUSIONS

Findings suggest that D-dimer might relate to Black/White differences in cardiovascular diseases and venous thromboembolism because it is a marker of amplified thrombo-inflammatory response in Black people. Better understanding of contributors to higher D-dimer in the general population is needed.

Genome-wide analyses of multiple obesity-related cytokines and hormones informs biology of cardiometabolic traits

BACKGROUND

A complex set of perturbations occur in cytokines and hormones in the etiopathogenesis of obesity and related cardiometabolic conditions such as type 2 diabetes (T2D). Evidence for the genetic regulation of these cytokines and hormones is limited, particularly in African-ancestry populations. In order to improve our understanding of the biology of cardiometabolic traits, we investigated the genetic architecture of a large panel of obesity- related cytokines and hormones among Africans with replication analyses in African Americans.

METHODS

We performed genome-wide association studies (GWAS) in 4432 continental Africans, enrolled from Ghana, Kenya, and Nigeria as part of the Africa America Diabetes Mellitus (AADM) study, for 13 obesity-related cytokines and hormones, including adipsin, glucose-dependent insulinotropic peptide (GIP), glucagon-like peptide-1 (GLP-1), interleukin-1 receptor antagonist (IL1-RA), interleukin-6 (IL-6), interleukin-10 (IL-10), leptin, plasminogen activator inhibitor-1 (PAI-1), resistin, visfatin, insulin, glucagon, and ghrelin. Exact and local replication analyses were conducted in African Americans (n = 7990). The effects of sex, body mass index (BMI), and T2D on results were investigated through stratified analyses.

RESULTS

GWAS identified 39 significant (P value < 5 × 10-8) loci across all 13 traits. Notably, 14 loci were African-ancestry specific. In this first GWAS for adipsin and ghrelin, we detected 13 and 4 genome-wide significant loci respectively. Stratified analyses by sex, BMI, and T2D showed a strong effect of these variables on detected loci. Eight novel loci were successfully replicated: adipsin (3), GIP (1), GLP-1 (1), and insulin (3). Annotation of these loci revealed promising links between these adipocytokines and cardiometabolic outcomes as illustrated by rs201751833 for adipsin and blood pressure and locus rs759790 for insulin level and T2D in lean individuals.

CONCLUSIONS

Our study identified genetic variants underlying variation in multiple adipocytokines, including the first loci for adipsin and ghrelin. We identified population differences in variants associated with adipocytokines and highlight the importance of stratification for discovery of loci. The high number of African-specific loci detected emphasizes the need for GWAS in African-ancestry populations, as these loci could not have been detected in other populations. Overall, our work contributes to the understanding of the biology linking adipocytokines to cardiometabolic traits.

Pre-transplant morphometry by computed tomography scan and post-transplant dialysis risk in overweight or obese kidney transplant recipients

PURPOSE

Adipose distribution and sarcopenia could better assess kidney transplantation outcomes than body mass index (BMI) and have been poorly evaluated among obese and overweight recipients. We aimed to evaluate morphometric radiologic markers to predict post-operative dialysis within this population.

METHODS

We conducted a retrospective study including patients with a BMI > 25 kg/m² undergoing kidney transplantation during 5 years. Subcutaneous adipose tissue surface (SAT), visceral adipose tissue surface (VAT), and psoas surface were measured on CT scans sections. A model predictive of post-transplantation dialysis was elaborated through a multivariable logistic regression and was compared to a model including only BMI.

RESULTS

Overall, 248 patients were included whom mean (SD) BMI and age were, respectively, 29.7 kg/m2 (3.6) and 56 years (12.7). Of them, 83 (33.5%) needed dialysis: 14 (5.7%) for primary kidney failure and 69 (27.8%) for delayed kidney function. On multivariable analysis, SAT, VAT and deceased donor were significantly associated with post-operative dialysis (respectively, OR [95%CI]:1.6 [1.1-2.6], 1.6[1.1-2.6], and 7.5 [1.6-56]). The area under the curve of this predictive model was 0.70 versus 0.64 for a BMI-based model.

CONCLUSION

High VAT and SAT were associated with post-transplantation dialysis. A predictive model based on these morphometrics could provide a better appreciation of graft recovery after transplantation among obese and overweight recipients. External validation is needed.

Contribution of Adipose Tissue Oxidative Stress to Obesity-Associated Diabetes Risk and Ethnic Differences: Focus on Women of African Ancestry

Adipose tissue (AT) storage capacity is central in the maintenance of whole-body homeostasis, especially in obesity states. However, sustained nutrients overflow may dysregulate this function resulting in adipocytes hypertrophy, AT hypoxia, inflammation and oxidative stress. Systemic inflammation may also contribute to the disruption of AT redox equilibrium. AT and systemic oxidative stress have been involved in the development of obesity-associated insulin resistance (IR) and type 2 diabetes (T2D) through several mechanisms. Interestingly, fat accumulation, body fat distribution and the degree of how adiposity translates into cardio-metabolic diseases differ between ethnicities. Populations of African ancestry have a higher prevalence of obesity and higher T2D risk than populations of European ancestry, mainly driven by higher rates among African women. Considering the reported ethnic-specific differences in AT distribution and function and higher levels of systemic oxidative stress markers, oxidative stress is a potential contributor to the higher susceptibility for metabolic diseases in African women. This review summarizes existing evidence supporting this hypothesis while acknowledging a lack of data on AT oxidative stress in relation to IR in Africans, and the potential influence of other ethnicity-related modulators (e.g., genetic-environment interplay, socioeconomic factors) for consideration in future studies with different ethnicities.

Racial Difference in the Association of Long-Term Exposure to Fine Particulate Matter (PM2.5) and Cardiovascular Disease Mortality among Renal Transplant Recipients

Ambient air pollutants are known risk factors for cardiovascular disease (CVD) morbidity and mortality with significant racial disparities. However, few studies have explored racial differences among highly susceptible subpopulations, such as renal transplant recipients (RTRs). Despite improvements in quality of life after transplantation, CVD remains the major cause of mortality, especially among Black recipients. This study aimed to evaluate potential racial differences in the association between long-term levels of PM2.5 and the risk of all-cause, total CVD, and coronary heart disease (CHD) mortality among RTRs. This retrospective study consists of 93,857 non-smoking adults who received a renal transplant between 2001 and 2015. Time-dependent Cox regression was used to assess the association between annual concentrations of PM2.5 and mortality risk. In the multivariable-adjusted models, a 10 μg/m3 increase in ambient PM2.5 levels found increased risk of all-cause (HR = 3.45, 95% CI: 3.08-3.78), CVD (HR = 2.38, 95% CI: 1.94-2.92), and CHD mortality (HR = 3.10, 95% CI: 1.96-4.90). Black recipients had higher risks of all-cause (HR = 4.09, 95% CI: 3.43-4.88) and CHD mortality (HR = 6.73, 95% CI: 2.96-15.32). High levels of ambient PM2.5 were associated with all-cause, CVD, and CHD mortality. The association tended to be higher among Black recipients than non-Blacks.

The Link between Obesity and Inflammatory Markers in the Development of Type 2 Diabetes in Men of Black African and White European Ethnicity

In this study, we aimed to assess ethnic differences in visceral (VAT), deep subcutaneous (dSAT), and superficial subcutaneous (sSAT) adipose tissue and their relationships with inflammatory markers between white European (WE) and black West African (BWA) men with normal glucose tolerance (NGT) and type 2 diabetes (T2D). Forty-two WE (23 NGT/19 T2D) and 43 BWA (23 NGT/20 T2D) men underwent assessment of plasma inflammatory markers using immunoassays alongside Dixon magnetic resonance imaging to quantify L4-5 VAT, dSAT and sSAT. Despite no ethnic differences in sSAT and dSAT, BWA men exhibited lower VAT (p = 0.002) and dSAT:sSAT (p = 0.047) than WE men. Adiponectin was inversely associated with sSAT in WE (p = 0.041) but positively associated in BWA (p = 0.031) men with T2D. Interleukin-6 (IL-6) was associated with VAT in WE but not in BWA men with NGT (WE: p = 0.009, BWA: p = 0.137) and T2D (WE: p = 0.070, BWA: p = 0.175). IL-6 was associated with dSAT in only WE men with NGT (WE: p = 0.030, BWA: p = 0.833). The only significant ethnicity interaction present was for the relationship between adiponectin and sSAT (P_interaction = 0.003). The favourable adipose tissue distribution and the weaker relationships between adiposity and inflammation in BWA men suggest that adipose tissue inflammation may play a lesser role in T2D in BWA than WE men.

Covid-19: Fat, Obesity, Inflammation, Ethnicity, and Sex Differences

Although obesity is known to be a risk factor for COVID-19 severity, there is an urgent need to distinguish between different kinds of fat—visceral and subcutaneous fat—and their inflammation status in COVID-19. These different fat types have partially diverging biochemical roles in the human body, and they are differentially associated with SARS-CoV-2, which targets the angiotensin-converting enzyme 2 (ACE2) for cell entry. ACE2 is highly expressed in adipose tissue, especially in visceral fat, suggesting an important role for this tissue in determining COVID-19 disease severity. In this perspective article, we discuss group differences in the amount of visceral fat levels and the extent of inflammation in adipocytes of visceral fat tissue, which may, in part, drive population, cross-national, ethnic, and sex differences in COVID-19 disease. It is vital to steer the scientific community’s attention to the effects of visceral fat in creating individual and population differences in COVID-19 severity. This can help researchers unravel the reasons for the reported population, ethnic, and sex differences in COVID-19 severity and mortality.

Surgical complications risk in obese and overweight recipients for kidney transplantation: a predictive morphometric model based on sarcopenia and vessel-to-skin distance

PURPOSE

Sarcopenia or adipose tissue distribution within obese and overweight renal transplanted have been poorly evaluated. Our objective was to evaluate morphometric markers to predict surgical complications in kidney transplantation.

METHODS

We retrospectively included patients with a BMI > 25 kg/m² undergoing kidney transplantation from 2012 to 2017. Following measurements were performed on CT-scan sections: Sub-cutaneous Adipose Tissue surface (SAT), Visceral Adipose Tissue surface (VAT), Vessel-to-Skin distance (VSK), Abdominal Perimeter (AP), and Psoas surface. A multivariable logistic regression model with BMI was compared to a model containing morphometric variables to determine the best predictive model for surgical complications.

RESULTS

248 patients were included, 15 (6%) experienced transplant nephrectomy, 18 (7.3%) urinary leakage, and 29 (11.7%) subcapsular renal hematoma. Multivariable logistic regression evidenced that sarcopenia and VSK were risk factors of surgical complication within a year post-transplantation (respectively, OR = 0.9, 95%CI (0.8-0.9), p = 0.04 and OR = 1.2, 95%CI (1.1-1.3), p = 0.002). Area under the curve for a predictive model including VSK, age and psoas surface was 0.69, whereas BMI model was 0.65.

CONCLUSION

Combined morphometric parameters of obesity were associated with surgical complications in kidney transplantation. Morphometric threshold may provide a more accurate and objective criteria than BMI to evaluate kidney transplantation outcomes. External validation is needed.

[Abdominal obesity in ELSA-Brasil (Brazil's Longitudinal Study of Adult Health): construction of a latent gold standard and evaluation of the accuracy of diagnostic indicators]

This study evaluated the accuracy of abdominal obesity (AO) indicators, defining a latent variable as the gold standard. The study included 12,232 participants of the ELSA-Brasil (Brazil's Longitudinal Study of Adult Health), between 35 and 74 years of age. Three AO indicators were evaluated: waist circumference (WC), waist hip ratio (WHR) and conicity index (C index). Analyses were stratified by sex and race/skin color. All groups had a high prevalence of AO, being greater among white men (~70%) and black women (~60%). A high incidence of WC was observed for men, WHR and C index between men and women for discriminating latent AO. The following cutoff points for AO indicators were identified among white, brown and black men, respectively: WC: 89.9cm; 90.2cm and 91.7cm; WHR: 0.92; 0.92 and 0.90; C index: 1.24; 1.24 and 1.24. The cutoff points identified among white, brown and black women were, respectively: WC: 80.4cm, 82.7cm and 85.4cm; WHR: 0.82; 0.83 and 0.84; C index: 1.20; 1.22 and 1.19 The WC among men and the WHR and C index among men and women presented high power to discriminate latent AO, the C index being the best indicator.

Racial differences in CD8+ T cell infiltration in breast tumors from Black and White women

Background

African American/Black women with breast cancer have poorer survival than White women, and this disparity persists even after adjusting for non-biological factors. Differences in tumor immune biology have been reported between Black and White women, and the tumor immune milieu could potentially drive racial differences in breast cancer etiology and outcome.

Methods

We examined the association of CD8⁺ cytotoxic T cells with clinical-pathological variables in the Women’s Circle of Health Study (WCHS) population of predominantly Black breast cancer patients. We evaluated 688 invasive breast tumor samples (550 Black, 138 White) using immunohistochemical staining of tissue microarray slides. CD8⁺ T cells were scored for each patient tumor sample with digital image analysis.

Results

Black women had a significantly higher percentage of high-grade, estrogen receptor (ER)-negative, and triple-negative tumors than White women and significantly higher CD8⁺ T cell density (median 87.6/mm² vs. 53.1/mm²; p < 0.001). Within the overall population and in the population of Black women only, CD8⁺ T cell density was significantly higher in younger patients and patients with high-grade and ER/PR-negative tumors. No significant associations were observed between CD8⁺ T cell density and overall survival or breast cancer-specific survival in the overall population, or when Black patients were analyzed as a separate group. However, when stratified by subtype, Black women with triple-negative breast cancer and high CD8⁺ T cell density showed a trend towards better overall survival in comparison with patients with low CD8⁺ T cell density (HR = 0.51; 95% CI 0.25–1.04).

Conclusions

Our data raise the possibility that distinct mechanisms of immune cell action may occur in different racial groups.

Temporary contraindication of obese recipients in kidney transplantation: A new morphometric tool for decision support

BACKGROUND

Morbid obesity, based on body mass index (BMI) and/or clinical examination, can be a temporary contraindication (TCI) of kidney transplantation. However, BMI alone does not evaluate the intra- or extra-peritoneal distribution of fatty tissue, and clinical examination alone is subjective. The objective was to evaluate the interest of morphometric criteria to ensure reproducible and consensual decision of TCI.

METHODS

We retrospectively included patients with a BMI >30 transplanted or temporarily contraindicated because of their weight from 2012 to 2017. The following measurements were performed on CT scan sections using a semiautomatic Hounsfield density detection software: subcutaneous adipose tissue surface (SAT), visceral adipose tissue surface (VAT), vessel-to-skin distance (VSK), abdominal perimeter (AP), and psoas index. Performance of morphometric measures to predict TCI was assessed through ROC analysis.

RESULTS

Ninety-seven patients were included: 76 kidney transplant recipients and 21 on the TCI list. The area under the curve (AUC, 95%CI) for the BMI model to predict TCI was 0.81 (0.72-0.90). A 5-variable model including BMI, VAT, VSK, AP, and age gave an AUC of 0.88 (0.78-0.98).

CONCLUSIONS

Morphometric obesity parameters are associated with TCI decision-making for kidney transplantation: When combined with BMI in a "morphometric tool," they were predictive of a TCI decision.

Longitudinal Associations between Obesity, Inflammation, and the Incidence of Type 2 Diabetes Mellitus among US Black and White Adults in the CARDIA Study

AIM

Assess prospective relationships between obesity and inflammation on the incidence of type 2 diabetes mellitus (T2DM).

METHODS

A cohort of nondiabetic respondents from the Coronary Artery Risk Development in Young Adults (CARDIA) study was followed from 2005-2006 (wave 7) to 2010-2011 (wave 8). Diabetes status was determined in wave 8 based on self-report, blood glucose level, and anti-hyperglycemic medication use in conjunction with a homeostatic model assessment-based classification for distinguishing diabetes subtype. We performed a series of multivariable logistic regression analyses to assess the relative influence of obesity (waist circumference) and individual inflammatory biomarkers (i.e., C-reactive protein, fibrinogen, and sex-specific serum uric acid and gamma-glutamyltransferase) on the odds of developing incident T2DM between waves 7 and 8.

RESULTS

Among 2784 nondiabetic CARDIA respondents, 146 (5.2%) new cases of T2DM were identified between waves. Having a high waist circumference (AOR = 6.15; 95%CI = 4.14, 9.14) and being Black (vs. White) (AOR = 1.60; 95%CI = 1.05, 2.44) were associated with T2DM. Adjusting for inflammation biomarkers attenuated the effects of waist circumference and race with T2DM. Clinically elevated CRP (AOR = 1.83; 95%CI = 1.18, 2.82) and uric acid (AOR = 2.57; 95%CI = 1.70, 3.89) predicted T2DM among all respondents. However, stratification by race showed greater attenuation of the effects of waist circumference on T2DM in Whites than in Blacks when inflammation biomarkers were accounted for in the model.

CONCLUSION

Targeted control of systemic inflammation may reduce the risk of developing T2DM, especially among Blacks, and could help address Black-White disparities in diabetes care and outcomes.

Racial Differences in Immunological Landscape Modifiers Contributing to Disparity in Prostate Cancer

Prostate cancer affects African Americans disproportionately by exhibiting greater incidence, rapid disease progression, and higher mortality when compared to their Caucasian counterparts. Additionally, standard treatment interventions do not achieve similar outcome in African Americans compared to Caucasian Americans, indicating differences in host factors contributing to racial disparity. African Americans have allelic variants and hyper-expression of genes that often lead to an immunosuppressive tumor microenvironment, possibly contributing to more aggressive tumors and poorer disease and therapeutic outcomes than Caucasians. In this review, we have discussed race-specific differences in external factors impacting internal milieu, which modify immunological topography as well as contribute to disparity in prostate cancer.

Ethnic differences in hepatic, pancreatic, muscular and visceral fat deposition in healthy men of white European and black west African ethnicity

AIMS

We aimed to assess ethnic differences in visceral adipose tissue (VAT), intrahepatic (IHL), intrapancreatic (IPL) and intramyocellular lipids (IMCL) between healthy white European (WE) and black west African (BWA) men.

METHODS

23 WE and 20 BWA men underwent Dixon-magnetic resonance imaging to quantify VAT, IHL and IPL; and proton-magnetic resonance spectroscopy to quantify IMCL. Insulin sensitivity and beta-cell function were determined using homeostasis model assessment (HOMA-2).

RESULTS

BWA men exhibited significantly lower VAT (P = 0.021) and IHL (P = 0.044) than WE men, but comparable IPL (P = 0.92) and IMCL (P = 0.87). VAT was associated with IPL in both ethnicities (WE: P < 0.001; BWA: P = 0.001) but the relationship with IHL differed by ethnicity (P_interaction = 0.018) and was only significant in WE men (WE: P < 0.001; BWA: P = 0.36). All ectopic fat depots inversely associated with insulin sensitivity and positively associated with beta-cell function in WE but not BWA men.

CONCLUSIONS

Lower VAT and IHL, and their lack of interrelation, in BWA men suggests ethnic differences exist in the mechanisms of ectopic fat deposition. The lack of association between ectopic fat with insulin sensitivity and beta-cell function in BWA men may indicate a lesser role for ectopic fat in the development of type 2 diabetes mellitus in black populations.

Higher baseline fat oxidation promotes gynoid fat mobilization in response to a 12-week exercise intervention in sedentary, obese black South African women

This 12-week exercise intervention study assessed changes in cardiorespiratory fitness (CRF), energy expenditure (EE), and substrate utilisation at rest and during exercise in obese, black South African (SA) women and explored associations with changes in body composition. Black SA women (body mass index: 30-40 kg·m^-2, age: 20-35 years) were randomised into control (CTL; n = 15, maintaining usual activity) or exercise (EXE; n = 20; 12 weeks, 4 days·week^-1, 40-60 min·day^-1 at >70% peak heart rate) groups. Pre- and post-intervention testing included peak oxygen consumption, resting and steady state (50% peak oxygen consumption) EE, respiratory exchange, and body composition (dual-energy X-ray absorptiometry). Dietary intake (4-day) and daily step-count (ActivPAL, activPAL3c; PAL Technologies Ltd, Glasgow, UK) was collected at pre-testing and at 4, 8, and 12 weeks. EXE increased peak oxygen consumption (24.9 ± 2.4 to 27.6 ± 3.4 mL·min^-1·kg^-1; p < 0.001) and steady state fat oxidation rates (7.5 ± 2.5 to 9.0 ± 2.7 mg·min^-1·kg^-1 fat-free soft tissue mass; p = 0.003) (same relative exercise intensity). CTL remained unchanged (p > 0.05). EXE reduced proportional gynoid fat mass (percentage total fat mass, p = 0.002). Baseline resting carbohydrate oxidation rates (p = 0.036) and steady state fat oxidation rates (p = 0.021) explained 60.6% of the variability in Δgynoid fat mass (p < 0.001) in EXE. This 12-week exercise intervention improved CRF and steady state fat oxidation rates. Greater reliance on fat oxidation at baseline promoted proportional reductions in gynoid, not visceral, fat mass in response to exercise training. Novelty Combined exercise training in obese black South African women increased cardiorespiratory fitness and rates of fat oxidation during steady state exercise. Exercise training reduced proportional gynoid, not visceral, fat, potentially representing an ethnic/sex-specific response. Baseline substrate utilisation (resting and steady state exercise (50% peak oxygen uptake)) predicted changes in gynoid fat mass.

Pubertal Status and Age are Differentially Associated with Inflammatory Biomarkers in Female and Male Adolescents

A better understanding of the maturational correlates of inflammatory activity during adolescence is needed to more appropriately study both normal and abnormal development. Inflammation is the immune system's first response to infection, injury, or psychological stress, and it has been shown to be elevated in individuals with both physical and psychological conditions. This study examined unique associations between (1) pubertal status and inflammatory biomarkers, and (2) age and inflammatory biomarkers, and whether these relationships differed by sex in a diverse sample of 155 adolescents (54.2% female, 45.8% male; M_age = 16.22) from a northeastern city in the US. A more advanced pubertal status was uniquely associated with lower levels of tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8). Chronological age was uniquely associated with lower IL-8 levels. The association between pubertal status and C-reactive protein (CRP) levels differed by sex: more mature females had higher CRP, whereas pubertal status and CRP were not significantly associated in males. These findings highlight an important relation between pubertal development and inflammatory activity during adolescence.

Association of baseline inflammatory biomarkers with cancer mortality in the REGARDS cohort

This study examines the association between inflammatory biomarkers and risk of cancer mortality by race. Data were obtained from 1,856 participants in the prospective REGARDS cohort who were cancer-free at baseline, and analyzed in relation to cancer mortality prospectively. Biomarkers were log-transformed and categorized into tertiles due to non-normal distributions, and Cox proportional hazard regression models were utilized to compute hazard ratios with 95% confidence intervals using robust sandwich methods. Individuals in the highest tertile of IL-6 had over a 12-fold increased risk of cancer mortality (HR: 12.97, 95% CI: 3.46–48.63); those in the highest tertile of IL-8 had over a 2-fold increased risk of cancer mortality (HR: 2.21, 95% CI: 0.86–5.71), while those in the highest tertile of IL-10 had over a 3-fold increased risk of cancer mortality (HR: 3.06, 95% CI: 1.35–6.89). In race-stratified analysis, each unit increase in IL-6 was associated with increased risk of cancer mortality among African-Americans (HR: 3.88, 95% CI: 1.17–12.88) and Whites (5.25, 95% CI: 1.24–22.31). If replicated in larger, racially diverse prospective cohorts, these results suggest that cancer patients may benefit from clinical or lifestyle approaches to regulate systemic inflammation as a cancer prevention strategy.

Obesity-induced MBD2_v2 expression promotes tumor-initiating triple-negative breast cancer stem cells

Obesity is a risk factor for triple-negative breast cancer (TNBC) incidence and poor outcomes, but the underlying molecular biology remains unknown. We previously identified in TNBC cell cultures that expression of epigenetic reader methyl-CpG-binding domain protein 2 (MBD2), specifically the alternative mRNA splicing variant MBD variant 2 (MBD2_v2), is dependent on reactive oxygen species (ROS) and is crucial for maintenance and expansion of cancer stem cell-like cells (CSCs). Because obesity is coupled with inflammation and ROS, we hypothesized that obesity can fuel an increase in MBD2_v2 expression to promote the tumor-initiating CSC phenotype in TNBC cells in vivo. Analysis of TNBC patient datasets revealed associations between high tumor MBD2_v2 expression and high relapse rates and high body mass index (BMI). Stable gene knockdown/overexpression methods were applied to TNBC cell lines to elucidate that MBD2_v2 expression is governed by ROS-dependent expression of serine- and arginine-rich splicing factor 2 (SRSF2). We employed a diet-induced obesity (DIO) mouse model that mimics human obesity to investigate whether obesity causes increased MBD2_v2 expression and increased tumor initiation capacity in inoculated TNBC cell lines. MBD2_v2 and SRSF2 levels were increased in TNBC cell line-derived tumors that formed more frequently in DIO mice relative to tumors in lean control mice. Stable MBD2_v2 overexpression increased the CSC fraction in culture and increased TNBC cell line tumor initiation capacity in vivo. SRSF2 knockdown resulted in decreased MBD2_v2 expression, decreased CSCs in TNBC cell cultures, and hindered tumor formation in vivo. This report describes evidence to support the conclusion that MBD2_v2 expression is induced by obesity and drives TNBC cell tumorigenicity, and thus provides molecular insights into support of the epidemiological evidence that obesity is a risk factor for TNBC. The majority of TNBC patients are obese and rising obesity rates threaten to further increase the burden of obesity-linked cancers, which reinforces the relevance of this report.

Incremental Elevations in TNFα and IL6 in the Human Colon and Procancerous Changes in the Mucosal Transcriptome Accompany Adiposity

BACKGROUND

Obesity, a risk factor for colorectal cancer, raises systemic levels of proinflammatory mediators. Whether increased levels also reside in the colons of obese individuals and are accompanied by procancerous alterations in the mucosal transcriptome is unknown.

METHODS

Concentrations of TNFα, IL1β, and IL6 in blood and colonic mucosa of 16 lean and 26 obese individuals were examined. Differences in the mucosal transcriptome between the two groups were defined.

RESULTS

Plasma IL6 and TNFα were 1.4- to 3-fold elevated in obese subjects [body mass index (BMI) ≥ 34 kg/m²] compared with the lean controls (P < 0.01). Among individuals with BMI ≥ 34 kg/m² colonic concentrations of IL6 and TNFα were 2- to 3-fold greater than in lean subjects (P < 0.03). In a general linear model, adjusted for NSAID use, colonic IL6 (partial r = 0.41; P < 0.01) and TNFα (partial r = 0.41; P = 0.01) increased incrementally over the entire range of BMIs (18.1-45.7). Regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) was associated with a reduction in colonic IL6 (β = -0.65, P < 0.02). RNA sequencing (NSAID users excluded) identified 182 genes expressed differentially between lean and obese subjects. The two gene networks most strongly linked to changes in expression included several differentially expressed genes known to regulate the procarcinogenic signaling pathways, NFκB and ERK 1/2, in a pattern consistent with upregulation of each in the obese subjects.

CONCLUSIONS

Incremental increases in two major proinflammatory colonic cytokines are associated with increasing BMI, and in the obese state are accompanied by procancerous changes in the transcriptome.

IMPACT

These observations delineate means by which an inflammatory milieu may contribute to obesity-promoted colon cancer.

An Empirical Dietary Inflammatory Pattern Score Is Associated with Circulating Inflammatory Biomarkers in a Multi-Ethnic Population of Postmenopausal Women in the United States

BACKGROUND

The empirical dietary inflammatory pattern (EDIP) score has been associated with concentrations of circulating inflammatory biomarkers in European Americans.

OBJECTIVE

We used the EDIP score, a weighted sum of 18 food groups that characterizes dietary inflammatory potential based on circulating concentrations of inflammatory biomarkers, to test the hypothesis that a pro-inflammatory dietary pattern is associated with inflammatory biomarker concentrations in a US multi-ethnic population.

METHODS

In this cross-sectional study, we calculated EDIP scores using baseline food frequency questionnaire data from 31,472 women, aged 50-79 y, in the Women's Health Initiative observational study and clinical trials. Circulating biomarkers outcomes at baseline were: C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor (TNF)-α, TNF receptor (TNFR) 1 and 2, and adiponectin. We used multivariable-adjusted linear regression analyses to estimate absolute concentrations and relative differences in biomarker concentrations, overall and in subgroups of race/ethnicity and BMI (body mass index) categories.

RESULTS

Independent of energy intake, BMI, physical activity, and other potential confounding variables, higher EDIP scores were significantly associated with higher (lower for adiponectin) absolute concentrations of all 6 biomarkers. On the relative scale, the percentage of difference in the concentration of biomarkers, among women in the highest compared to the lowest EDIP quintile, was: CRP, +13% (P-trend < 0.0001); IL-6, +15% (P-trend < 0.0001); TNF-α, +7% (P-trend = 0.0007); TNFR1, +4% (P-trend = 0.0009); TNFR2, +5% (P-trend < 0.0001); and adiponectin, -13% (P-trend <0.0001). These associations differed by racial/ethnic groups and by BMI categories. Whereas the absolute biomarker concentrations were lower among European-American women and among normal-weight women, the associations with diet were stronger than among women of African-American or Hispanic/Latino origin and among overweight and obese women.

CONCLUSIONS

Findings demonstrate the successful replication of an empirical hypothesis-oriented a posteriori dietary pattern score in a multi-ethnic population of postmenopausal women, with subgroup differences by race/ethnicity and body weight. Future research needs to apply the score in non-US populations.

Black-white disparity in physical performance among older women with newly diagnosed non-metastatic breast cancer: Exploring the role of inflammation and physical activity

OBJECTIVE

To examine racial differences in physical performance among older women with newly diagnosed non-metastatic breast cancer and identify clinical, behavioral and biological factors that might contribute to such disparities.

METHODS

This is a cross-sectional study of women aged ≥65 years with newly diagnosed stage I-III breast cancer recruited from ambulatory oncology clinics at an academic center, between September 2010 and August 2015. Participants completed a Comprehensive Geriatric Assessment and laboratory testing for biomarkers of inflammation [interleukin-6 (IL6)] prior to receiving systemic treatment for cancer. The primary outcome was poor physical performance, defined as scoring ≤7 on the Short Physical Performance Battery, Yes or No. Logistic regression analyses were undertaken.

RESULTS

Among 135 women with mean age of 74.8 years (SD = 6.9), 31% were African-American (AA), and 33% had poor physical performance. Controlling for age, education, comorbidities and geriatric syndromes, participants with poor physical performance were more likely to be AA [versus (vs.) Non-Hispanic Whites (NHW)], odds ratio (OR) = 3.10, 95% confidence interval (CI) = 1.18-8.15. Controlling further for physical activity (PA) attenuated the racial disparity in physical performance (OR = 2.50, CI = 0.91-6.84). Lastly, controlling for IL6 further diminished the racial disparity in physical performance (OR = 1.93, CI = 0.67-5.56). In adjusted models, PA and IL6 explained 29% and 38%, respectively, of the racial disparity in poor physical performance.

CONCLUSION

Among older women with newly diagnosed non-metastatic breast cancer, poor physical performance was prevalent and AA were disproportionately affected. Less engagement in physical activity and subclinical inflammation partly contributed to this disparity.

L-Cysteine in vitro can restore cellular glutathione and inhibits the expression of cell adhesion molecules in G6PD-deficient monocytes

L-Cysteine is a precursor of glutathione (GSH), a potent physiological antioxidant. Excess glucose-6-phosphate dehydrogenase (G6PD) deficiency in African Americans and low levels of L-cysteine diet in Hispanics can contributes to GSH deficiency and oxidative stress. Oxidative stress and monocyte adhesion was considered to be an initial event in the progression of vascular dysfunction and atherosclerosis. However, no previous study has investigated the contribution of GSH/G6PD deficiency to the expression of monocyte adhesion molecules. Using human U937 monocytes, this study examined the effect of GSH/G6PD deficiency and L-cysteine supplementation on monocyte adhesion molecules. G6PD/GSH deficiency induced by either siRNA or inhibitors (6AN/BSO, respectively) significantly (p < 0.005) increased the levels of cell adhesion molecules (ICAM-1, VCAM-1, SELL, ITGB1 and 2); NADPH oxidase (NOX), reactive oxygen species (ROS) and MCP-1 were upregulated, and decreases in levels of GSH, and nitric oxide were observed. The expression of ICAM-1 and VCAM-1 mRNA levels increased in high glucose, MCP-1 or TNF-α-treated G6PD-deficient compared to G6PD-normal cells. L-Cysteine treatment significantly (p < 0.005) increased G6PD activity and levels of GSH, and decreased NOX, ROS, and adhesion molecules. Thus, GSH/G6PD deficiency increases susceptibility to monocyte adhesion processes, whereas L-cysteine supplementation can restore cellular GSH/G6PD and attenuates NOX activity and expression of cell adhesion molecules.

Differential effect of subcutaneous abdominal and visceral adipose tissue on cardiometabolic risk

Metabolic and cardiovascular diseases are increasing worldwide due to the rise in the obesity epidemic. The metabolic consequences of obesity vary by distribution of adipose tissue. Visceral and ectopic adipose accumulation are associated with adverse cardiometabolic consequences, while gluteal-femoral adipose accumulation are negatively associated with these adverse complications and subcutaneous abdominal adipose accumulation is more neutral in its associations. Gender, race and ethnic differences in adipose tissue distribution have been described and could account for the observed differences in risk for cardiometabolic disease. The mechanisms behind the differential impact of adipose tissue on cardiometabolic risk have started to be unraveled and include differences in adipocyte biology, inflammatory profile, connection to systemic circulation and most importantly the inability of the subcutaneous adipose tissue to expand in response to positive energy balance.

Clinical and Economic Burden of Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease with an increasing global prevalence associated with tremendous clinical, economic, and health-related quality-of-life burden. Clinically, NAFLD is considered the liver manifestation of metabolic syndrome. However, diagnosing NAFLD presents significant challenges due to the limited noninvasive and accurate diagnostic tools available to not only accurately diagnose nonalcoholic steatohepatitis but also to stage hepatic fibrosis, the major predictor of long-term outcomes, including mortality.

The Metabolic Syndrome and Its Components in African-American Women: Emerging Trends and Implications

The Metabolic Syndrome (MetS) is recognized as a predictor of cardiovascular outcomes and type 2 diabetes (T2DM). The MetS is a constellation of clinical and metabolic risk factors that include abdominal obesity, dyslipidemia, glucose intolerance, and hypertension. There are ethnic and racial differences in the prevalence of MetS and its components. In general, African-Americans have lower prevalence of MetS when compared to whites, but suffer disproportionately from higher cardiovascular mortality and T2DM. Specifically, African-American women (AAW) have higher rates of T2DM and cardiovascular mortality despite a more favorable lipid and lipoprotein profile. This is paradoxical. However, there is a general upward trend in the prevalence of MetS in the US. The reasons are debatable, but could be multifactorial, including genetics and environmental factors. Thus, there is a need to understand the increasing trend in the MetS, its components, and the associated outcomes for AAW. Therefore, the purpose of this mini review is to (1) understand the increasing prevalence of MetS and its components in AAW and (2) provide suggestions for future prevention of cardiovascular disease and T2DM in AAW.

Global burden of NAFLD and NASH: trends, predictions, risk factors and prevention

NAFLD is one of the most important causes of liver disease worldwide and will probably emerge as the leading cause of end-stage liver disease in the coming decades, with the disease affecting both adults and children. The epidemiology and demographic characteristics of NAFLD vary worldwide, usually parallel to the prevalence of obesity, but a substantial proportion of patients are lean. The large number of patients with NAFLD with potential for progressive liver disease creates challenges for screening, as the diagnosis of NASH necessitates invasive liver biopsy. Furthermore, individuals with NAFLD have a high frequency of metabolic comorbidities and could place a growing strain on health-care systems from their need for management. While awaiting the development effective therapies, this disease warrants the attention of primary care physicians, specialists and health policy makers.

Novel Protein Glycan-Derived Markers of Systemic Inflammation and C-Reactive Protein in Relation to Glycemia, Insulin Resistance, and Insulin Secretion

OBJECTIVE

N-acetylglucosamine/galactosamine (GlycA) and sialic acid (GlycB) moieties of glycosylated serum proteins are nonspecific measures of inflammation, but conclusive data on their relationship with insulin resistance or insulin secretion are missing. Therefore, we aimed to examine the relation of GlycA, GlycB, and C-reactive protein (CRP) to direct measures of insulin sensitivity (insulin sensitivity index [S_I]) and insulin secretion (acute insulin response [AIR]).

RESEARCH DESIGN AND METHODS

This study used cross-sectional analyses and included 1,225 participants with and without type 2 diabetes in the Insulin Resistance Atherosclerosis Study (IRAS). S_I and AIR were measured using the frequently sampled intravenous glucose tolerance test, and GlycA and GlycB were measured using nuclear magnetic resonance spectroscopy.

RESULTS

GlycA and GlycB had a strong correlation with CRP (r = 0.60 [P < 0.001] and r = 0.46 [P < 0.001], respectively). In a linear regression model with both GlycA and CRP as independent variables, GlycA (β × 1 SD, -0.04 ± 0.02; P < 0.01) and CRP (-0.06 ± 0.02; P < 0.001) were independently associated with S_I even after adjusting for demographics, smoking, physical activity, plasma glucose, and BMI. However, neither CRP nor GlycA had an independent relationship with AIR.

CONCLUSIONS

GlycA may complement CRP in evaluating the relationship between inflammation, glucose tolerance, and insulin resistance.

Endometrial cancer associated biomarkers in bariatric surgery candidates: exploration of racial differences

BACKGROUND

Obesity is the main risk factor for endometrial cancer (EC), the most common gynecologic malignancy in the United States. A number of potential risk biomarkers have been associated with EC development, including altered proinflammatory cytokines, chemokines, and adipokines.

OBJECTIVES

The overarching aim of this research is to investigate racial differences in the expression of EC-associated biomarkers among bariatric surgery candidates.

SETTING

Tertiary academic medical center METHODS: Blood samples were collected from 175 women aged 18 to 72 (mean age: 42.93; standard deviation 11.66), before bariatric surgery. Levels of biomarkers associated with obesity and EC risk were measured using xMAP immunoassays. Wilcoxon rank sum and Fisher's exact tests were utilized to compare biomarker and demographic variables between African American and European American women. Linear regression models, adjusted for menopause status and diabetes, were utilized to identify factors associated with biomarker levels.

RESULTS

When the biomarker levels were compared by race, insulin-like growth factor-binding protein 1 and adiponectin were significantly lower in African American women (P<.05), whereas estradiol was significantly higher in African American women (P<.05). Linear regression models found that race significantly predicted insulin-like growth factor binding protein 1, adiponectin, resistin, and interleukin-1 receptor alpha expression levels, menopause status and diabetes status were significantly associated with adiponectin and leptin levels, whereas body mass index was significantly associated with leptin, adiponectin, interleukin-1 receptor alpha, and interleukin-6 levels.

CONCLUSION

As one of the first efforts to explore racial differences in EC-associated biomarkers in a cohort of women with severe obesity, this study found several significant differences that should be further explored in large-scale studies.

Body Mass Index as a Measure of Obesity: Racial Differences in Predictive Value for Health Parameters During Pregnancy

BACKGROUND

As a measure of obesity, body mass index (BMI; kg/m²) is an imperfect predictor of health outcomes, particularly among African Americans. However, BMI is used to guide prenatal care. We examined racial differences in the predictive value of maternal BMI for physiologic correlates of obesity, serum interleukin (IL)-6 and C-reactive protein (CRP), as well as cesarean section and infant birth weight.

METHODS

One hundred five pregnant women (40 European American, 65 African American) were assessed during the second trimester. BMI was defined as per prepregnancy weight. Electrochemiluminescence and enzyme-linked immunosorbent assays were used to quantify IL-6 and CRP, respectively. Birth outcomes were determined by medical record review.

RESULTS

Women of both races classified as obese had higher serum IL-6 and CRP than their normal-weight counterparts (ps ≤ 0.01). However, among women with overweight, elevations in IL-6 (p < 0.01) and CRP (p = 0.06) were observed among European Americans, but not African Americans (ps ≥ 0.61). Maternal obesity was a significantly better predictor of cesarean section among European Americans versus African Americans (p = 0.03) and BMI was associated with infant birth weight among European Americans (p < 0.01), but not African Americans (p = 0.94). Effects remained after controlling for gestational age at delivery, gestational diabetes, and gestational weight gain as appropriate.

CONCLUSIONS

BMI may be a less valid predictor of correlates of overweight/obesity among African Americans versus European Americans during pregnancy. This should be considered in epidemiological studies of maternal-child health. In addition, studies examining the comparative validity of alternative/complementary measures to define obesity in pregnancy are warranted to inform clinical care.

Dietary fibre linked to decreased inflammation in overweight minority youth

OBJECTIVE

The objective of this study was to examine the relationship between diet and inflammation, and adiposity in minority youth.

DESIGN AND METHODS

The study was designed as a cross-sectional analysis of 142 overweight (≥85th body mass index percentile) Hispanic and African-American adolescents (14-18 years) with the following measures: anthropometrics, adiposity via magnetic resonance imaging, dietary intake via 24-h dietary recalls, and inflammation markers from fasting blood draws utilizing a multiplex panel. Partial correlations were estimated and analysis of covariance (ancova) models fit to examine the relationship among dietary variables, inflammation markers and adiposity measures with the following a priori covariates: Tanner stage, ethnicity, sex, total energy intake, total body fat and total lean mass.

RESULTS

Inference based on ancova models showed that the highest tertile of fibre intake (mean intake of 21.3 ± 6.1 g d(-1) ) vs. the lowest tertile of fibre intake (mean intake of 7.4 ± 1.8 g d(-1) ) was associated with 36% lower plasminogen activator inhibitor-1 (P = 0.02) and 43% lower resistin (P = 0.02), independent of covariates. Similar results were seen for insoluble fibre. No other dietary variables included in this study were associated with inflammation markers.

CONCLUSIONS

These results suggest that increases in dietary fibre could play an important role in lowering inflammation and therefore metabolic disease risk in high-risk minority youth.

Nonalcoholic Fatty Liver Disease in Latinos

Nonalcoholic fatty liver disease (NAFLD) is a serious public health concern that affects almost one third of the US population. The prevalence of NAFLD varies among ethnic/racial groups, with the Latin American population being affected disproportionately. The severity of NAFLD also may be greater in the Latino population. The increased prevalence and severity of NAFLD in Latino Americans likely is related to the interplay between issues such as genetic factors, access to health care, or the prevalence of chronic diseases such as metabolic syndrome or diabetes. In this review, we summarize the current literature on the prevalence and risk factors of NAFLD that are seen to be more common in the Latino population in the United States. Finally, we discuss available treatment options, medical and surgical, that are available for NAFLD and how they affect the Latino population. Health care providers need to address modifiable risk factors that impact the natural history as well as treatment outcomes for NAFLD among Latinos. Additional efforts are needed to improve awareness and health care utilization for Latinos.

Associations between Obstructive Sleep Apnea, Sleep Duration, and Abnormal Fasting Glucose. The Multi-Ethnic Study of Atherosclerosis

RATIONALE

No data exist as to the role of ethnicity in the associations between obstructive sleep apnea (OSA), sleep duration, and metabolic dysfunction.

OBJECTIVES

To examine links between OSA, objectively measured habitual sleep duration, and fasting glucose in U.S. ethnic groups.

METHODS

The Multi-Ethnic Study of Atherosclerosis is a multisite community-based study that conducted polysomnography and wrist actigraphy. In 2,151 subjects (1,839 in fully adjusted models), the apnea-hypopnea index was used to classify OSA as none (0-4.9/h), mild (5-14.9/h), or moderate to severe (≥15/h). Actigraphic sleep duration was classified as short (≤5 h/night), intermediate (>5 and <8 h/night), or long (≥8 h/night). Subjects were classified as having normal fasting glucose (<100 mg/dl and no hypoglycemic medication use) or abnormal fasting glucose (≥100 mg/dl and/or hypoglycemic medication use).

MEASUREMENTS AND MAIN RESULTS

The sample was 45.8% male, age 68.5 ± 9.2 (mean ± SD) years, and 27.3% African American, 37.2% white, 11.8% Chinese, and 23.8% Hispanic. The prevalence of abnormal fasting glucose was 40.2%. Relative to subjects without apnea, moderate-to-severe OSA was significantly associated with abnormal fasting glucose in African Americans (odds ratio, 2.14; 95% confidence interval, 1.12-4.08) and white participants (odds ratio, 2.85; 95% confidence interval, 1.20-6.75), but not among Chinese or Hispanic subjects, after adjusting for site, age, sex, waist circumference, and sleep duration (P = 0.06 for ethnicity-by-OSA severity interaction). In contrast, sleep duration was not significantly associated with abnormal fasting glucose after considering the influence of OSA.

CONCLUSIONS

This large multiethnic study confirmed previous reports of an independent association between OSA and metabolic dysfunction, and suggested that this association may vary by ethnicity.