RESUMO
Background: Adipose tissue (AT) around and within non-AT organs (i.e., ectopic adiposity) is emerging as a strong risk factor for type 2 diabetes (T2D). Not known is whether major ectopic adiposity depots, such as hepatic, skeletal muscle, and pericardial adiposity (PAT), are associated with T2D independent of visceral adiposity (VAT). More data are particularly needed among high-risk nonobese minority populations, as the race/ethnic gap in T2D risk is greatest among nonobese. Methods: Thus, we measured several ectopic adiposity depots by computed tomography in 718 (mean age = 64 years) African-Caribbean men on the Island of Tobago overall, and stratified by obesity (obese N = 187 and nonobese N = 532). Results: In age, lifestyle risk factors, health status, lipid-lowering medication intake, body mass index and all other adiposity-adjusted regression analyses, and hepatic and skeletal muscle adiposity were associated with T2D among nonobese men only (all P < 0.05), despite no association between VAT and PAT and T2D. Conclusions: Our results support the "ectopic fat syndrome" theory in the pathogenesis of T2D among nonobese African-Caribbean men. Longitudinal studies are needed to clarify the independent role of ectopic adiposity in T2D, and to identify possible biological mechanisms underlying this relationship, particularly in high-risk African ancestry and other nonwhite populations.
Assuntos
Adiposidade , Diabetes Mellitus Tipo 2/fisiopatologia , Gordura Intra-Abdominal/fisiopatologia , Fígado/fisiopatologia , Músculo Esquelético/fisiopatologia , Obesidade/fisiopatologia , Adiposidade/etnologia , Idoso , População Negra , Estudos de Casos e Controles , Estudos Transversais , Diabetes Mellitus Tipo 2/diagnóstico por imagem , Diabetes Mellitus Tipo 2/etnologia , Humanos , Gordura Intra-Abdominal/diagnóstico por imagem , Fígado/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/diagnóstico por imagem , Obesidade/diagnóstico por imagem , Obesidade/etnologia , Prevalência , Medição de Risco , Fatores de Risco , Tomografia Computadorizada por Raios X , Trinidad e Tobago/epidemiologiaRESUMO
OBJECTIVE: Decreased radiodensity of adipose tissue (AT) located in the visceral AT (VAT), subcutaneous AT (SAT), and intermuscular AT (IMAT) abdominal depots is associated with hyperglycemia, hyperinsulinemia, and insulin resistance independent of AT volumes. These associations were sought in African-ancestry men, who have higher risk for type 2 diabetes and have been underrepresented in previous studies. METHODS: This cross-sectional analysis included 505 nondiabetic men of African-Caribbean ancestry (median age: 61 years; median BMI: 26.8 kg/m2 ) from the Tobago Health Study. AT volumes and radiodensities were assessed using computed tomography, including abdominal (VAT and SAT) and thigh (IMAT) depots. Associations between AT radiodensities were assessed with fasting serum glucose and insulin and with insulin resistance (updated homeostatic model assessment of insulin resistance, HOMA2-IR). RESULTS: Higher radiodensity in any AT depot was associated with lower log-insulin and log-HOMA2-IR (ß range: -0.16 to -0.18 for each; all P < 0.0001). No AT radiodensity was associated with glucose. Thigh IMAT radiodensity associations were independent of, and similar in magnitude to, VAT radiodensities. Model fit statistics suggested that AT radiodensities were a better predictor for insulin and insulin resistance compared with AT volumes in individuals with overweight and obesity. CONCLUSIONS: AT radiodensities at multiple depots are significantly associated with insulin and insulin resistance in African-ancestry men.
Assuntos
Adiposidade/fisiologia , População Negra/etnologia , Gordura Intra-Abdominal/metabolismo , Obesidade/etnologia , Sobrepeso/etnologia , Gordura Subcutânea/metabolismo , Tecido Adiposo/fisiopatologia , Adulto , Idoso , Glicemia/metabolismo , Composição Corporal/fisiologia , Estudos Transversais , Glucose/metabolismo , Humanos , Insulina/sangue , Gordura Intra-Abdominal/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Obesidade/diagnóstico , Obesidade/metabolismo , Sobrepeso/diagnóstico , Sobrepeso/metabolismo , Gordura Subcutânea/diagnóstico por imagem , Coxa da Perna/diagnóstico por imagem , Índias Ocidentais/etnologiaRESUMO
BACKGROUND: Among women aged 50 to 59 years at baseline in the Women's Health Initiative (WHI) Estrogen-Alone (E-Alone) trial, randomization to conjugated equine estrogen-alone versus placebo was associated with lower risk of myocardial infarction and mortality, and, in an ancillary study, the WHI-CACS (WHI Coronary Artery Calcification Study) with lower CAC, measured by cardiac computed tomography ≈8.7 years after baseline randomization. We hypothesized that higher CAC would be related to post-trial coronary heart disease (CHD), cardiovascular disease (CVD), and total mortality, independent of baseline randomization or risk factors. METHODS AND RESULTS: WHI-CACS participants (n=1020) were followed ≈8 years from computed tomography scan in 2005 (mean age=64.4) through 2013 for incident CHD (myocardial infarction and fatal CHD, n=17), CVD (n=69), and total mortality (n=55). Incident CHD and CVD analyses excluded women with CVD before scan (n=89). Women with CAC=0 (n=54%) had very low age-adjusted rates/1000 person-years of CHD (0.91), CVD (5.56), and mortality (3.45). In comparison, rates were ≈2-fold higher for women with any CAC (>0). Associations were not modified by baseline randomization to conjugated equine estrogen-alone versus placebo. Adjusted for baseline randomization and risk factors, the hazard ratio (95% confidence interval) for CAC >100 (19%) was 4.06 (2.11, 7.80) for CVD and 2.70 (1.26, 5.79) for mortality. CONCLUSIONS: Among a subset of postmenopausal women aged 50 to 59 years at baseline in the WHI E-Alone Trial, CAC at mean age of 64 years was strongly related to incident CHD, CVD, and to total mortality over ≈8 years, independent of baseline randomization to conjugated equine estrogen-alone versus placebo or CVD risk factors. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00000611.
Assuntos
Doença da Artéria Coronariana/epidemiologia , Terapia de Reposição de Estrogênios/métodos , Estrogênios Conjugados (USP)/administração & dosagem , Calcificação Vascular/epidemiologia , Saúde da Mulher , Distribuição de Qui-Quadrado , Angiografia por Tomografia Computadorizada , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/mortalidade , Terapia de Reposição de Estrogênios/efeitos adversos , Terapia de Reposição de Estrogênios/mortalidade , Estrogênios Conjugados (USP)/efeitos adversos , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Análise Multivariada , Pós-Menopausa , Modelos de Riscos Proporcionais , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Estados Unidos/epidemiologia , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/mortalidadeRESUMO
BACKGROUND AND AIMS: There is strong evidence that fat accumulating in non-adipose sites, "ectopic fat", is associated with cardiovascular disease (CVD), including vascular calcification. Most previous studies of this association have assessed only a single ectopic fat depot. Therefore, our aim was to assess the association of total, regional, and ectopic fat with abdominal aorto-illiac calcification (AAC) and coronary artery calcification (CAC) in 798 African ancestry men. METHODS: Participants (mean age 62) were from the Tobago Bone Health Study cohort. Adiposity was assessed via clinical examination, dual x-ray absorptiometry, and computed tomography (CT). Ectopic fat depots included: abdominal visceral adipose tissue (VAT), liver attenuation, and calf intermuscular adipose tissue (IMAT). Vascular calcification was assessed by CT and quantified as present versus absent. Associations were tested using multiple logistic regression adjusted for traditional cardiovascular risk factors. Models of ectopic fat were additionally adjusted for total body fat and standing height. RESULTS: All adiposity measures, except VAT, were associated with AAC. Lower liver attenuation or greater calf IMAT was associated with 1.2-1.3-fold increased odds of AAC (p < 0.03 for both), though calf IMAT was a stronger predictor than liver attenuation (p < 0.001) when entered in a single model. No ectopic fat measure was associated with CAC. CONCLUSIONS: Greater adiposity in the skeletal muscle and liver, but not in the visceral compartment, was associated with increased odds of AAC in African ancestry men. These results highlight the potential importance of both quantity and location of adiposity accumulation throughout the body.