Prediction of Insulin Resistance with Anthropometric and Clinical Laboratory Measures in Nondiabetic Teenagers

Complete autonomic blockade reveals nitric oxide contribution to blood pressure regulation in obese Black women

PURPOSE

Hypertension is one of the major causes of cardiovascular morbidity and mortality in the USA and disproportionately affects Black women. Endothelial-derived nitric oxide (eNO) substantially regulates blood pressure in humans, and impaired NO-mediated vasodilation has been reported in the Black population. Previous studies using an NO synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA) did not fully determine the NO contribution to blood pressure because of baroreflex buffering. Therefore, in the present study we used trimethaphan, a ganglionic blocker, to inhibit baroreflex buffering and study NO modulation of blood pressure in Black women during L-NMMA infusion.

METHODS

L-NMMA at doses of 250 μg/kg per minute was infused in combination with trimethaphan at doses of 4 mg/min to eliminate baroreflex mechanisms. Heart rate (HR) was obtained with continuous electrocardiogram monitoring, and continuous blood pressure was measured with the volume clamp method. The increase in systolic blood pressure (SBP) during both infusions was used to estimate the contribution of NO to blood pressure.

RESULTS

Ten Black (age range 30-50 years, body mass index [BMI] 30-45 kg/m2), and nine White women (age range 30-50 years, body mass index 30-45 kg/m2) were enrolled in this study. During autonomic blockade, there was no difference in the decrease in SBP between Black and White women (- 20 ± 16.45 vs. - 24 ± 15.49 mm Hg, respectively; P = 0.659). When autonomic blockade was combined with L-NMMA, Black women had a significant increase in SBP compared to White women (54 ± 13.62 vs. 39 ± 09.64 mm Hg, respectively; P = 0.022, respectively).

CONCLUSION

Autonomic blood pressure regulation was similar between Black and White women. However, NO contribution to blood pressure was significantly greater in Black women compared to White women.

REGISTRATION

ClinicalTrials.gov: NCT01122407.

Obesity and dyslipidemia in early life: Impact on cardiometabolic risk

Childhood obesity with its growing prevalence worldwide presents one of the most important health challenges nowadays. Multiple mechanisms are involved in the development of this condition, as well as in its associations with various cardiometabolic complications, such as insulin resistance, diabetes, metabolic dysfunction-associated steatotic liver disease and cardiovascular diseases. Recent findings suggest that childhood obesity and associated dyslipidemia at least partly originate from epigenetic modifications that take place in the earliest periods of life, namely prenatal and perinatal periods. Hence, alterations of maternal metabolism could be fundamentally responsible for fetal and neonatal metabolic programming and consequently, for metabolic health of offspring in later life. In this paper, we will review recent findings on the associations among intrauterine and early postnatal exposure to undesirable modulators of metabolism, development of childhood obesity and later cardiometabolic complications. Special attention will be given to maternal dyslipidemia as a driven force for undesirable epigenetic modulations in offspring. In addition, newly proposed lipid biomarkers of increased cardiometabolic risk in obese children and adolescents will be analyzed, with respect to their predictive potential and clinical applicability.

Disproportionate School Punishment and Significant Life Outcomes: A Prospective Analysis of Black Youths

This study tested relationships between racial inequalities in the school system-specifically, the disproportionate punishment of Black students-and life outcomes for Black youths, along with moderating psychological factors. In an 18-year longitudinal study of 261 Black youths (ages 11-29), we investigated whether adult life outcomes varied as a function of adolescent self-control and academic achievement. We tested whether relationships were moderated by the racial climates of the high schools that youths attended, using administrative data on relative punishment rates of Black and White students. Among Black youths who attended schools that disproportionately punished Black students, high self-control in early adolescence presaged higher academic orientation in late adolescence, which in turn predicted higher educational attainment, higher income, and better mental health in adulthood. However, among these same youths, higher academic orientation forecasted higher adult insulin resistance, a key process in cardiometabolic disease. These findings suggest that achieving successes in life in the face of racial inequalities may come at a physical health cost for Black youths.

Prevalence of Optimal Metabolic Health in U.S. Adolescents, NHANES 2007-2016

Background: While the overweight and obesity epidemic in the adolescent population is well described, a comprehensive evaluation of cardiometabolic health markers has not been reported. Our purpose was therefore to determine the prevalence of cardiometabolic risk factors among non-diabetic individuals 12 to19 years of age in the United States. Methods: We analyzed data from nationally representative samples of U.S. adolescents (NHANES, 2007-2016). Optimal cardiometabolic health was defined as an absence of risk factors, that is, at least normal values on each of the following 11 measures: body mass index (BMI) percentile, waist circumference percentile, blood pressure, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, non-HDL cholesterol, triglycerides, fasting plasma glucose, alanine aminotransferase, and insulin resistance. Domain analyses were conducted with Rao-Scott chi-square tests of independence. Multivariable linear/logistic regressions examined sociodemographic associations with cardiometabolic health. Results: Less than a quarter of the population (22.0%; 95% CI; 19.4%-24.8%) was found to have no cardiometabolic risk factors. Among individuals with a normal BMI, 35.7% (95% CI; 31.6%-40.1%) had no cardiometabolic risk factors. Family poverty-to-income ratio was identified as an independent predictor of cardiometabolic health (P = 0.01). A consistent trend was present between increasing BMI percentile and number of cardiometabolic risk markers. Conclusions: The overall prevalence of U.S. adolescents with no cardiometabolic risk factors is less than 25%. Even among those without increased BMI, less than half meet all metabolic health criteria. In addition, socioeconomic disparities are predictors of metabolic health.