RESUMO
BACKGROUND: Central aortic arterial stiffness (CAAS) is an independent cardiovascular risk factor. Insulin resistance (IR) contributes to CAAS-associated risk. OBJECTIVE: To evaluate the association between IR and CAAS in a Mexican population without diabetes. METHODS: IR was estimated with Homeostatic Model Assessment 2-Insulin Resistance (HOMA2-IR) and other surrogate markers (Metabolic score for IR [METS-IR], Quantitative Insulin Sensitivity Check Index [QUICKI], triglycerides/glucose index [TyG], TyG*body mass index [TyG*BMI] and triglycerides/high-density lipoprotein cholesterol ratio [TG/HDL-C]). CAAS was evaluated using carotid-femoral pulse wave velocity analysis (PWVcf) and the standardized augmentation index (AI-75). Bivariate correlations were made between surrogate markers and PWVcf. Increased CAAS was defined as PWVcf above the 90th percentile. Thresholds and area under the curve (AUC) were obtained for each surrogate marker in order to evaluate their performance in estimating increased CAAS. RESULTS: Three hundred and fifty-eight patients were included. A correlation was found between HOMA2-IR and PWVcf; this correlation was replicated with other surrogate markers. METS-IR and TyG*BMI had the highest degree of correlation with PWVcf. When adjustments were made for covariates, the correlations with TyG*BMI, METS-IR, HOMA2-IR and QUICKI maintained significance. HOMA2-IR showed the strongest correlation with AI-75. METS-IR and TyG showed the best AUC. Patients with prediabetes had the highest PWVcf. CONCLUSIONS: The relationship between IR and CAAS is present before the onset of diabetes; this association may entail higher cardiovascular risk.
ANTECEDENTES: La rigidez arterial central aórtica (RACA) es un factor de riesgo cardiovascular independiente. La resistencia a la insulina (RI) contribuye al riesgo asociado a RACA. OBJETIVO: Evaluar la asociación entre RI y RACA en una población mexicana sin diabetes. MÉTODOS: La RI se estimó con HOMA2-IR y (Homeostatic Model Assessment 2-Insulin Resistance) otros subrogados (METS-IR [Metabolic score for IR], QUICKI [Quantitative Insulin Sensitivity Check Index], TyG [ratio triglicéridos/glucosa], TyG*IMC [TyG*índice de masa corporal] y TG/HDL [ratio TG/lipoproteínas de alta densidad]). Se evaluó la RACA mediante el análisis de velocidad de onda del pulso carotídeo-femoral (VOPcf) y el índice de aumentación estandarizado (AI-75). Se realizaron correlaciones bivariante entre los subrogados y la VOPcf. RACA aumentada se definió como VOPcf arriba del percentil 90. Se obtuvieron puntos de corte y área bajo la curva (ABC) para cada subrogado para estimar RACA aumentada. RESULTADOS: Se incluyó 358 pacientes. Se encontró una correlación entre HOMA2-IR y VOPcf; esta correlación se replicó con los subrogados. METS-IR y TyG*IMC tuvieron el mayor grado de correlación con VOPcf. Al ajustar, las correlaciones con TyG*IMC, METS-IR, HOMA2-IR y QUICKI mantuvieron significancia. La correlación con AI-75 fue mayor para HOMA2-IR. METS-IR y TyG mostraron la mejor ABC. Los pacientes con prediabetes tuvieron mayor VOPcf. CONCLUSIONES: La relación entre la RI y la RACA está presente desde etapas no diabéticas; esta asociación puede conllevar mayor riesgo cardiovascular.
Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Rigidez Vascular , Glicemia , Diabetes Mellitus Tipo 2/epidemiologia , Humanos , Análise de Onda de PulsoRESUMO
No processo celular de obtenção de energia, são gerados compostos chamados espécies reativas de oxigênio (ERO) que, em excesso, podem causar danos celulares. Estresse oxidativo resulta do desequilíbrio no estado de óxido-redução a favor da oxidação. Dos mecanismos de defesa antioxidante, participam enzimas endógenas e algumas vitaminas e minerais. A vitamina E encontra-se no plasma e na partícula de LDL, protegendo lipídeos da oxidação. Estudos observacionais relataram associação inversa entre ingestão de vitamina E e risco cardiometabólico (RCM). Entretanto, ensaios clínicos não comprovaram a eficácia de sua suplementação nos desfechos cardiometabólicos. A vitamina C participa do sistema de regeneração da vitamina E, mantendo o potencial antioxidante plasmático. Dados sobre os benefícios de sua suplementação na redução do risco cardiometabólico são inconclusivos. A atividade antioxidante dos carotenoides é responsável, em parte, por seu papel protetor contra doenças cardiovasculares e cânceres. A suplementação desse nutriente também não trouxe resultados consistentes no que se refere à redução do RCM. A participação do zinco e do selênio na defesa antioxidante vem sendo estudada mais recentemente, mas a sua suplementação em indivíduos com níveis séricos normais e ingestão adequada na dieta desses minerais não parece ser necessária. De um modo geral, há muita controvérsia sobre o papel desses micronutrientes no RCM. Estudos epidemiológicos sugerem que o consumo de substâncias antioxidantes provenientes da dieta ou dietas ricas em frutas e hortaliças diminui o RCM. Mais estudos são necessários antes de se recomendar o uso de antioxidantes isolados na forma de suplementos para tal finalidade.
Oxygen reactive species (ROS) are generated during cellular processes. In excess, they may cause damages to the cell. Oxidative stress is an imbalance in the redox state that favors oxidation. Endogenous enzymes and some vitamins and minerals participate in the plasma antioxidant defense. Vitamin E is found in the plasma and in the LDL particle, avoiding lipid peroxidation. Observational studies reported an inverse association between vitamin E consumption and cardiometabolic (CM) risk. However, clinical trials were not able to prove the efficacy of its supplementation on CM endpoints. Vitamin C participates in the vitamin E regeneration system, keeping the plasma's antioxidant potential. Data about beneficial effects of its supplementation in CM risk reduction are inconclusive. The antioxidant activity of carotenoids is partially responsible for its protective role against cardiovascular diseases and cancer. Supplementation of this nutrient did not provide consistent findings in terms of CM risk reduction. Recently, zinc and selenium's participation in the antioxidant defense has been studied, yet its supplementation in individuals with normal levels and adequate ingestion of these nutrients does not seem necessary. In summary, the role of these micronutrients for CM risk is still very controversial. Epidemiological studies suggest that diets rich in antioxidants, or simply in fruit and vegetables intake, can reduce CM risk. Further studies are needed before recommending antioxidant supplements for this purpose.