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Ethnic differences in hepatic and systemic insulin sensitivity and their associated determinants in obese black and white South African women.

ABSTRACT: There is evidence to suggest that ectopic fat deposition in liver and skeletal muscle may differ between black and white women resulting in organ-specific differences in insulin sensitivity. Accordingly, the aim of the study was to examine ethnic differences in hepatic and peripheral insulin sensitivity, and the association with hepatic and skeletal muscle lipid content, and skeletal muscle gene expression.In a cross-sectional study including 30 obese premenopausal black and white women, body composition (dual energy x-ray absorptiometry), liver fat and skeletal muscle (soleus and tibialis anterior) fat accumulation (proton-magnetic resonance spectroscopy), skeletal muscle gene expression, insulin sensitivity (two-step isotope labelled, hyperinsulinaemic-euglycaemic clamp with 10 mU m(-2) min(-1) and 40 mU m(-2) min(-1) insulin infusions), and serum adipokines were measured.We found that, although whole-body insulin sensitivity was not different, obese white women presented with lower hepatic insulin sensitivity than black women (% suppression of endogenous glucose production [% supp EGP], median [interquartile range (IQR)]: 17 [5-51] vs 56 [29-100] %, p?=?0.002). While liver fat tended to be lower (p?=?0.065) and skeletal muscle fat deposition tended to be higher (p?=?0.074) in black compared with white women, associations with insulin sensitivity were only observed in black women (% supp EGP vs liver fat: r?=?-0.57, p?

SUBMITTER: Goedecke JH

PROVIDER: S-EPMC4668114 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Ethnic differences in hepatic and systemic insulin sensitivity and their associated determinants in obese black and white South African women.

Goedecke Julia H JH Keswell Dheshnie D Weinreich Carsten C Fan Jia J Hauksson Jon J Victor Hendriena H Utzschneider Kristina K Levitt Naomi S NS Lambert Estelle V EV Kahn Steven E SE Olsson Tommy T

Diabetologia 20150801 11

<h4>Aims/hypothesis</h4>There is evidence to suggest that ectopic fat deposition in liver and skeletal muscle may differ between black and white women resulting in organ-specific differences in insulin sensitivity. Accordingly, the aim of the study was to examine ethnic differences in hepatic and peripheral insulin sensitivity, and the association with hepatic and skeletal muscle lipid content, and skeletal muscle gene expression.<h4>Methods</h4>In a cross-sectional study including 30 obese prem ...[more]

PMID: 26232099

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Project description:Background:High-sensitivity C-reactive protein (hsCRP) is associated with metabolic risk, however it is unclear whether the relationship is confounded by racial/ethnic differences in socioeconomic status (SES), lifestyle factors or central adiposity. The aims of the study was, (1) to investigate whether hsCRP levels differ by race/ethnicity; (2) to examine the race/ethnic-specific associations between hsCRP, HOMA-IR and serum lipids [total cholesterol (TC), triglycerides (TG), high-density lipoproteins (HDL-C) and low-density lipoproteins (LDL-C)]; and (3) to determine whether race/ethnic-specific associations are explained by SES, lifestyle factors or waist circumference (WC). Methods:The convenience sample comprised 195 black and 153 white apparently health women, aged 18-45 years. SES (education, assets and housing density) and lifestyle factors (alcohol use, physical activity and contraceptive use) were collected by questionnaire. Weight, height and WC were measured, and fasting blood samples collected for hsCRP, glucose, insulin, and lipids. Results:Black women had higher age- and BMI-adjusted hsCRP levels than white women (p?=?0.047). hsCRP was associated with HOMA-IR (p?<?0.001), TG (p?<?0.001), TC (p?<?0.05), HDL-C (p?<?0.05), and LDL-C (p?<?0.05), independent of age and race/ethnicity. The association between hsCRP and lipids differed by race/ethnicity, such that hsCRP was positively associated with TG and LDL-C in white women, and inversely associated with HDL-C in black women. Higher hsCRP was also associated with higher TC in white women and lower TC in black women. Furthermore, when adjusting for SES and lifestyle factors, the associations between hsCRP, and TC and TG, remained, however the associations between hsCRP, and HDL-C and LDL-C, were no longer significant. Conclusion:Although circulating hsCRP may identify individuals at increased metabolic risk, the heterogeneity in these associations between racial/ethnic groups highlights the need for prospective studies investigating the role of hsCRP for risk prediction in different populations.

Project description:BackgroundIschemic heart disease (IHD) rates are lower in UK black Africans and black Caribbeans and higher in South Asians when compared with white Europeans. Ethnic differences in lipid concentrations may play a part in these differences.ObjectiveThe objective was to investigate blood lipid and dietary patterns in UK children from different ethnic groups.DesignThis was a cross-sectional study in 2026 UK children (including 285 black Africans, 188 black Caribbeans, 534 South Asians, and 512 white Europeans) attending primary schools in London, Birmingham, and Leicester. We measured fasting blood lipid concentrations and collected 24-h dietary recalls.ResultsIn comparison with white Europeans, black African children had lower total cholesterol (-0.14 mmol/L; 95% CI: -0.25, -0.04 mmol/L), LDL-cholesterol (-0.10 mmol/L; 95% CI: -0.20, -0.01 mmol/L), and triglyceride concentrations (proportional difference: -0.11 mmol/L; 95% CI: -0.16, -0.06 mmol/L); HDL-cholesterol concentrations were similar. Lower saturated fat intakes (-1.4%; 95% CI: -1.9%, -0.9%) explained the differences between total and LDL cholesterol. Black Caribbean children had total, LDL-cholesterol, HDL-cholesterol, and triglyceride concentrations similar to those for white Europeans, with slightly lower saturated fat intakes. South Asian children had total and LDL-cholesterol concentrations similar to those for white Europeans, lower HDL-cholesterol concentrations (-0.7 mmol/L; 95% CI: -0.11, -0.03 mmol/L), and elevated triglyceride concentrations (proportional difference: 0.14 mmol/L; 95% CI: 0.09, 0.20 mmol/L); higher polyunsaturated and monounsaturated fat intakes did not explain these lipid differences.ConclusionsOnly black African children had a blood lipid profile and associated dietary pattern likely to protect against future IHD. The loss of historically lower LDL-cholesterol concentrations among UK black Caribbeans and South Asians may have important adverse consequences for future IHD risk in these groups.

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Project description:BACKGROUND:Adults with chronic conditions are at much greater risk of influenza-related morbidity and mortality, yet flu vaccine uptake remains suboptimal. Research focused on the high-risk population has been limited, particularly related to racial disparities in vaccination. We explore a broad range of demographic, racial, and psychosocial factors to identify predictors of vaccination among high-risk adults, with a focus on identify differences between Black and White adults. METHODS:We conducted an online survey in March 2015, utilizing international research firm GfK's KnowledgePanel, for a nationally representative sample of Black and White adults (?18, USA) and limited analysis adults with high-risk of influenza-related complications. Using two-way ANOVA, we assessed demographic, racial, and psychosocial predictors across vaccine uptake in the past five years and across racial group. RESULTS:424 (52.2%) Black and 388 (47.8%) White respondents with high-risk complications completed the survey. 383 (47.3%) reported vaccination annually, 99 (12.2%) most years, 104 (12.9%) once/twice, and 223 (27.6%) never.ANOVA confirmed significant differences in vaccine behavior for most demographic predictors (except education), all racial factors (including racial fairness, experiences of discrimination, etc.), and most psychosocial factors (including vaccine attitudes, trust in the vaccine, etc.). ANOVA confirmed significant differences for most factors by race. We observed significant interaction effects between race and vaccine behavior for subjective social status, access to medical care, knowledge of vaccine recommendations, vaccine attitudes, perceived side effect risks, descriptive norms, subjective norms, flu vaccine hesitancy, and flu vaccine confidence, thus implying racial differences in the connection between vaccine uptake and key demographic, racial, and psychosocial factors. CONCLUSIONS:This study provides a novel examination of flu vaccine behavior among high-risk Blacks and Whites that identified factors influencing vaccine uptake.We found significant differences by race. Health care professionals can use this information to more effectively target high-risk adults during flu season.

Project description:BackgroundAlthough breast cancer incidence is higher in black women than in white women among women younger than 40 years, the reverse is true among those aged 40 years or older. This crossover in incidence rates between black and white ethnic groups has been well described, has not been completely understood, and has been viewed as an artifact.MethodsTo quantify this incidence rate crossover, we examined data for 440 653 women with invasive breast cancer from the National Cancer Institute's Surveillance, Epidemiology, and End Results database from January 1, 1975, through December 31, 2004. Data on invasive female breast cancers were stratified by race, age at diagnosis, year of diagnosis, and tumor characteristics. Standard descriptive analyses were supplemented with Poisson regression models, age-period-cohort models, and two-component mixture models. All statistical tests were two-sided.ResultsWe observed qualitative (ie, crossing or reversing) interactions between age and race. That is, age-specific incidence rates overall (expressed as number of breast cancers per 100 000 woman-years) were higher among black women (15.5) than among white women (13.1) younger than 40 years (difference = 2.4, 95% confidence interval [CI] = 2.4 to 2.4), and then, age-specific rates crossed with rates higher among white women (281.3) than among black women (239.5) aged 40 years or older (difference = 41.8, 95% CI = 41.7 to 41.9). The black-to-white incidence rate crossover was observed for all tumor characteristics assessed, although the crossover occurred at earlier ages of diagnosis for low-risk tumor characteristics than for high-risk tumor characteristics. The incidence rate crossover between ethnic groups was robust (ie, reliable and reproducible) to adjustment for calendar period and birth cohort effects in age-period-cohort models (P < .001 for difference by race).ConclusionAlthough this ecologic study cannot determine the individual-level factors responsible for the racial crossover in vital rates, it confirms that the age-related crossover in breast cancer incidence rates between black and white ethnic groups is a robust age-specific effect that is independent of period and cohort effects.

Dataset Information

Ethnic differences in hepatic and systemic insulin sensitivity and their associated determinants in obese black and white South African women.

Publications

Ethnic differences in hepatic and systemic insulin sensitivity and their associated determinants in obese black and white South African women.

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