Mid-regional pro-atrial natriuretic peptide and blood pressure in adolescents: effect of gender and pubertal stage

Intensive Lifestyle Intervention Increases Plasma Midregional Proatrial Natriuretic Peptide Concentrations in Overweight Children

Background

Overweight adults have low circulating concentrations of ANP (atrial natriuretic peptide) and proANP fragments. We tested the hypothesis that an intensive lifestyle intervention with an intended weight loss would increase plasma concentrations of a proANP fragment in overweight children.

Methods and Results

We measured MR‐proANP (midregional proANP) concentrations in plasma from overweight children who participated in the OOIS (Odense Overweight Intervention Study). OOIS randomized 115 overweight children (11–13 years, 55% girls) to an intensive day‐camp intervention arm with increased physical activity and healthy diet or to a less intensive standard intervention arm for 6 weeks. We used linear mixed‐effects modeling for repeated measures to estimate the difference in the mean change with 95% CIs in fasting plasma MR‐proANP concentrations between the 2 arms, and we used partial least squares regression analysis to identify candidate mediators. Differences in weight, fitness, and metabolic factors were also analyzed. At baseline, fasting plasma MR‐proANP concentrations were (median [interquartile range]) 35.0 pmol/L (26.8–42.0) in the day‐camp intervention arm and 37.2 pmol/L (31.7–44.7) in standard intervention arm participants, respectively. After 6 weeks intervention, children in the day‐camp intervention arm had increased their MR‐proANP (5.4 pmol/L [0.8–10.0], P=0.022) and their fitness (2.33 mL O₂/min per kg [0.52–4.14], P=0.012) and they had deceased their body mass index (−2.12 kg/m² [−2.59 to −1.65], P<0.001) as compared with children in standard intervention arm. In the partial least squares analysis, decreases in fasting insulin and in estimated insulin resistance were associated with the observed increase in MR‐proANP concentrations.

Conclusions

An intensive lifestyle intervention increases plasma MR‐proANP among overweight children.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01574352.

Survival analysis under the Cox proportional hazards model with pooled covariates

For a continuous time-to-event outcome and an expensive-to-measure exposure, we develop a pooling design and propose a likelihood-based approach to estimate the hazard ratios (HRs) of a Cox proportional hazards (PH) model. Our proposed approach fits a PH model based on pooled exposures with individually observed time-to-event outcomes. The design and estimation exploits the equivalence of the conditional logistic likelihood functions arising from a matched case-control study and the partial likelihood function of a riskset-matched, nested case-control (NCC) subset of a cohort study. To create the pools, we first focus on an NCC subcohort. Pools are formed at random while keeping the matching intact. Pool-level exposure and confounders are then evaluated and used in the likelihood to estimate the HR and the standard error of the estimates. The estimators are MLEs, provide consistent estimates of the individual-level HRs, and are asymptotically normal. Our simulation results indicate that the pooled estimates are comparable to the estimates obtained from the NCC subcohort. The units of analysis for the pooled design are the pools and not the individual participants. Hence the effective sample size is reduced. Therefore, the variance of the HR estimate increases with increasing poolsize. However, this variance inflation in small samples can be offset by including more matched controls per case within the NCC subcohort. An application is demonstrated with the Second Manifestations of ARTerial disease (SMART) study.

Association between systolic blood pressure and uric acid in Chinese children and adolescents with idiopathic short stature: a cross-sectional study

The purpose of this study was to investigate the relationship between systolic blood pressure (SBP) and uric acid (UA) in patients with idiopathic short stature (ISS). The present study was a cross-sectional study. A total of 210 Chinese children and adolescents with ISS were included, and their anthropometrics and biochemical parameters were measured. Growth hormone peak levels were assessed after provocation tests with L-dopa and insulin. The univariate analysis results showed a significant positive association between UA and SBP levels (P < 0.001). Furthermore, a non-linear relationship was detected between UA and SBP. In multivariate piecewise linear regression, the inflection point of UA was 4.13 mg/dl (95% CI 3.28, 6.65; P = 0.03), the levels of SBP increased with the increase in UA when the UA level was >4.13 mg/dl (β 2.63, 95% CI: 0.94, 4.31; P = 0.002). However, we did not observe a significant relationship between UA and SBP when the UA level was <4.13 mg/dl (β −2.72, 95% CI −6.89, 1.45; P = 0.202). Our study found a nonlinear relationship between UA and SBP in Chinese children and adolescents with ISS and showed that SBP levels were associated positively with the rise of UA levels when the UA levels reached the inflection point.

Association of copeptin, a surrogate marker for arginine vasopressin secretion, with insulin resistance: Influence of adolescence and psychological stress

In middle-aged and elderly individuals, circulating copeptin concentrations, a surrogate marker for arginine vasopressin (AVP) secretion, associates with insulin resistance (IR). Whether this association is present in adolescents and young adults is unclear. Because psychological stress associates with higher circulating copeptin concentrations and IR, it has been speculated that increased AVP secretion could be a link between psychological stress and IR. We measured plasma copeptin concentrations in 351 14-16-year-old adolescents and 617 20-28-year-old young adults from the Danish site of the European Youth Heart Study, a population-based cardiovascular risk factor study in adolescents and young adults. IR was determined by the homeostatic model assessment method. Among the young adults, we used symptoms of depression, evaluated by means of the Major Depression Inventory (MDI) scale, as a measure of psychological stress. We applied linear regressions to examine associations, expressed as unstandardized regression coefficients (B) with 95% confidence intervals (CIs), between variables of interest, stratified by age group and adjusting for age, sex and Tanner stages. Copeptin and IR were log-transformed. Among the young adults, copeptin associated with IR (B (95%CI) = 0.19 (0.11 to 0.27), P < 0.001). This association was not found among the adolescents (B=-0.01 (-0.12 to 0.09), P = 0.78). MDI score associated with IR (B = 0.010 (0.004 to 0.016), P < 0.001) and copeptin (B=0.010 (0.004 to 0.015); P<0.002) in the young adults. Adjusted for copeptin, the strength of the association between MDI score and IR somewhat diminished (to B=0.008). In conclusion, adolescence and psychological stress appear to influence the association between copeptin and IR.

Metabolic trajectories across early adolescence: differences by sex, weight, pubertal status and race/ethnicity

Background: Biomarkers of cardiovascular and metabolic risk track from adolescence into adulthood, therefore characterising the direction and magnitude of these changes is an important first step to identifying health trajectories that presage future disease risk.Aim: To characterise changes in metabolic biomarkers across early adolescence in a multi-ethnic cohort.Subjects and methods: Among 891 participants in Project Viva we estimated changes in insulin resistance (HOMA-IR), adipokines, lipids, and SBP between ages 6-10 years and 11-16 years. Next, we used multivariable linear regression to examine associations of sex, baseline overweight/obesity, baseline pubertal status and race/ethnicity with change in the biomarkers during follow-up.Results: Boys exhibited a larger decrement in adiponectin (-0.66 [95% CI = -1.14, -0.18)] ng/mL) and a greater increase in SBP (3.20 [2.10, 4.30] mmHg) than girls. Overweight/obese participants experienced larger increases in HOMA-IR, leptin, and triglycerides; and a steeper decrement in HDL. Pubertal youth showed larger decrements in total and LDL cholesterol than their pre-pubertal counterparts. In comparison to White participants, Black youth experienced a larger magnitude of increase in HOMA-IR, and Hispanic youth exhibited larger decrements in adiponectin and HDL.Conclusions: Change in metabolic biomarkers across early adolescence differed by sex, weight status, pubertal status and race/ethnicity. Some of the metabolic changes may reflect normal physiological changes of puberty, while others may presage future disease risk. Future studies are warranted to link metabolic changes during adolescence to long-term health.

Natriuretic peptides in the control of lipid metabolism and insulin sensitivity

Natriuretic peptides have long been known for their cardiovascular function. However, a growing body of evidence emphasizes the role of natriuretic peptides in human substrate and energy metabolism, thereby connecting the heart with several insulin-sensitive organs like adipose tissue, skeletal muscle and liver. Obesity may be associated with an impaired regulation of the natriuretic peptide system, also indicated as a natriuretic handicap. Evidence points towards a contribution of this natriuretic handicap to the development of obesity, type 2 diabetes mellitus and cardiometabolic complications, although the causal relationship is not fully understood. Nevertheless, targeting the natriuretic peptide pathway may improve metabolic health in obesity and type 2 diabetes mellitus. This review will focus on current literature regarding the metabolic roles of natriuretic peptides with emphasis on lipid metabolism and insulin sensitivity. Furthermore, it will be discussed how exercise and lifestyle intervention may modulate the natriuretic peptide-related metabolic effects.

Associations of Proatrial Natriuretic Peptide with Components of the Metabolic Syndrome in Adolescents and Young Adults from the General Population

BACKGROUND

In middle-aged and elderly populations, circulating natriuretic peptide concentrations are negatively associated with several components of the metabolic syndrome. Whether these negative associations are also present in healthy adolescents and young adults from the general population are unknown.

METHODS

In a cross-sectional setting, we measured plasma concentrations of mid-regional proatrial natriuretic peptide (MR-proANP) in 343 adolescents (age 14-16 years) and 616 young adults (age 20-28 years) from the Danish site of the European Youth Heart Study, which is a population-based study of cardiovascular disease risk factors in children, adolescents and young adults. We used linear regression analysis to examine the associations, expressed as standardized regression coefficients, of various variables of interest with MR-proANP stratified according to age group, adjusting for age and gender.

RESULTS

Among the young adults, MR-proANP was negatively associated with body mass index (BMI) (β = -0.10, P = 0.02), waist circumference (WC) (β = -0.14, P < 0.001), systolic blood pressure (BP) (β = -0.08, P = 0.03), diastolic BP (β = -0.23, P < 0.001), insulin (β = -0.15, P < 0.001), and triglycerides (β = -0.14, P < 0.001). Among the adolescents a somehow different pattern was observed since MR-proANP was not significantly associated with BMI (β = -0.00, P = 0.98), WC (β = -0.01, P = 0.90) and insulin (β = -0.02, P = 0.69). Nevertheless, among the adolescents, MR-proANP was negatively associated with triglycerides (β = -0.13, P = 0.01), diastolic BP (β = -0.12, P = 0.01) and systolic BP (β = -0.10, P = 0.10), although the latter association was of borderline significance.

CONCLUSIONS

The young adults displayed significant negative associations between MR-proANP and several components of the metabolic syndrome, whereas such associations were not found among the adolescents besides triglycerides and diastolic BP.