The association of birth weight and infant growth with childhood autonomic nervous system activity and its mediating effects on energy-balance-related behaviours-the ABCD study

A systematic review to investigate whether birth weight affects the autonomic nervous system in adulthood

OBJECTIVE

To evaluate the relationship between birth weight and the autonomic nervous system in adulthood through a systematic review.

DATA SOURCE

This is a systematic review of publications without limitation of year and language. We included studies involving the autonomic nervous system and birth weight in adults. Manuscripts were selected based on electronic searches of Medical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science Cochrane Library and Scopus databases, using "Autonomic Nervous System" OR "Heart Rate" OR "Heart Rate Variability" AND "Birth Weight" as a search strategy. This review is registered on the International Prospective Register of Systematic Reviews - PROSPERO (ID: CRD42020165622).

DATA SYNTHESIS

We found 894 articles; 215 were excluded for duplicity. Of the remaining 679 studies, 11 remained. Two were excluded because they did not specifically treat the autonomic nervous system or birth weight. There were nine publications, two cohort and seven cross-sectional studies. The main findings were that extreme, very low, low or high birth weight may have some impact on the autonomic nervous system in adult life.

CONCLUSIONS

Birth weight outside the normality rate may have a negative influence on the autonomic nervous system, causing autonomic dysfunction and increasing the risk of cardiovascular diseases in adult life. Thus, the importance of the follow-up of health professionals from pregnancy to gestation and throughout life, with preventive care being emphasized.

The Influence of Obesity in the Autonomic Nervous System Activity in School-Aged Children in Northern Portugal: A Cross-Sectional Study

INTRODUCTION

Obesity is one of the most prevalent chronic diseases in childhood, being an important public health issue. Excessive weight has been associated with autonomic dysfunction but the evidence in children is scarce. Therefore, the aim of this study was to assess the effect of overweight and obesity on the autonomic nervous system activity, in children.

MATERIAL AND METHODS

Data from a cross-sectional study of 1602 children, aged 7 to 12 years, was used and 858 children were included in the analysis. Body mass index was calculated and classified according to criteria of the World Health Organization (WHO), Centers for Disease Control and Prevention (CDC) and the International Obesity Task Force (IOTF). Body composition was characterized by bioelectrical impedance. Linear regression models were used to determine the association between body mass index, body composition and the autonomic nervous system activity, assessed by pupillometry.

RESULTS

Average dilation velocity was higher among children with obesity, according to the CDC and percentage of body fat criteria (β = 0.053, 95% CI = 0.005 to 0.101 and β = 0.063, 95% CI = 0.016 to 0.109, respectively). The same trend was observed for WHO and IOTF criteria (β = 0.045, 95% CI = -0.001 to 0.091, and β = 0.055, 95% CI = -0.001 to 0.111, respectively). CDC and WHO body mass index z-scores were also positively associated with the values of average dilation velocity (rs = 0.030, p = 0.048; and rs = 0.027, p = 0.042, respectively).

CONCLUSION

Our findings suggest an association between body mass and changes in the autonomic activity, Moreover, this study provides proof of concept for interventions targeting the prevention/treatment of obesity in children that may offer some benefit in re-establishing the balance of the autonomic nervous system, and subsequently preventing the consequences associated with the autonomic nervous system dysfunction.

Associations between maternal awakening salivary cortisol levels in mid-pregnancy and adverse birth outcomes

PURPOSE

Elevated levels of maternal cortisol have been hypothesized as the intermediate process between symptoms of depression and psychosocial stress during pregnancy and adverse birth outcomes. Therefore, we examined associations between cortisol levels in the second trimester of pregnancy and risks of three common birth outcomes in a nested case-control study.

METHODS

This study was embedded in the PRIDE Study (n = 3,019), from which we selected all cases with preterm birth (n = 64), low birth weight (n = 49), and small-for-gestational age (SGA; n = 65), and 260 randomly selected controls, among the participants who provided a single awakening saliva sample in approximately gestational week 19 in 2012-2016. Multivariable linear and logistic regression was performed to assess the associations between continuous and categorized cortisol levels and the selected outcomes.

RESULTS

We did not observe any associations between maternal cortisol levels and preterm birth and low birth weight. However, high cortisol levels (≥ 90th percentile) seemed to be associated with SGA (adjusted odds ratio 2.1, 95% confidence interval 0.9-4.8), in particular among girls (adjusted odds ratio 3.7, 95% confidence interval 1.1-11.9, based on eight exposed cases) in an exploratory analysis.

CONCLUSION

The results of this study showed no suggestions of associations between maternal awakening cortisol levels in mid-pregnancy and adverse birth outcomes, except for an increased risk of SGA.

Infant weight-for-length gain associated with autonomic nervous system reactivity

BACKGROUND

Research suggests that children's health and well-being are supported by core adaptive systems, including the autonomic nervous system (ANS). Despite evidence for the importance of adulthood ANS regulation in the development of disease, few studies have examined how early development may influence emerging ANS function. Therefore, we examined how infant adiposity gain during early infancy related to ANS regulation at 6 months.

METHODS

Infant weight and length were abstracted from birth records and measured during the 6-month assessment in a low-income, racially/ethnically diverse sample (N = 60). WHO-standardized weight-for-length-gain change was calculated across the first 6 months of life. ANS reactivity was measured as the combined sympathetic (i.e., pre-ejection period) and parasympathetic (i.e., respiratory sinus arrhythmia) nervous system responses during the developmentally challenging Still Face Paradigm (SFP). ANS "classic reactivity" response was characterized by paired sympathetic activation and parasympathetic withdrawal.

RESULTS

Lower weight-for-length gain in the first 6 months predicted classic reactivity during still face. However, greater weight-for-length gain predicted "classic reactivity" during the reunion, when infants were expected to recover, suggesting autonomic dysregulation.

CONCLUSIONS

These findings suggest an association between early life adiposity gain and the development of infant ANS regulation.

IMPACT

Adiposity gain during early infancy was associated with autonomic nervous system regulation at 6 months. This study identifies early adiposity gain (greater than average infant weight-for-length gain) as a risk for ANS dysregulation. This research focuses on a critical developmental period of ANS plasticity. If confirmed, findings can be used to inform early intervention programs targeting obesity prevention and to promote self-regulation.

Measurement of screen time among young children aged 0-6 years: A systematic review

The impact of screen-based devices on children's health and development cannot be properly understood without valid and reliable tools that measure screen time within the evolving digital landscape. This review aimed to summarize characteristics of measurement tools used to assess screen time in young children; evaluate reporting of psychometric properties; and examine time trends related to measurement and reporting of screen time. A systematic review of articles published in English across three databases from January 2009 to April 2020 was undertaken using PROSPERO protocol (registration: CRD42019132599) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Included articles measured screen time as outcome, exposure, or confounder in children 0-6 years. The search identified 35,868 records, 1035 full-text articles were screened for eligibility, and 622 met inclusion criteria. Most measures (60%) consisted of one to three items and assessed duration of screen time on a usual day. Few measures assessed content (11%) or coviewing (7%). Only 40% of articles provided a citation for the measure, and only 69 (11%) reported psychometric properties-reliability n = 58, validity n = 19, reliability and validity n = 8. Between 2009 and 2019, the number of published articles increased from 28 to 71. From 2015, there was a notable increase in the proportion of articles published each year that assessed exposure to mobile devices in addition to television. The increasing number of published articles reflects increasing interest in screen time exposure among young children. Measures of screen time have generally evolved to reflect children's contemporary digital landscape; however, the psychometric properties of measurement tools are rarely reported. There is a need for improved measures and reporting to capture the complexity of children's screen time exposures.

Excess of ovarian nerve growth factor impairs embryonic development and causes reproductive and metabolic dysfunction in adult female mice

Nerve growth factor (NGF) is critical for the development and maintenance of the peripheral sympathetic neurons. NGF is also involved in the ovarian sympathetic innervation and in the development and maintenance of folliculogenesis. Women with the endocrine disorder, polycystic ovary syndrome (PCOS), have an increased sympathetic nerve activity and increased ovarian NGF levels. The role of ovarian NGF excess in the PCOS pathophysiology and in the PCOS-related features is unclear. Here, using transgenic mice overexpressesing NGF in the ovarian theca cells (17NF mice), we assessed the female embryonic development, and the reproductive and metabolic profile in adult females. Ovarian NGF excess caused growth restriction in the female fetuses, and a delayed gonocyte and primary oocyte maturation. In adulthood, the 17NF mice displayed irregular estrous cycles and altered ovarian expression of steroidogenic and epigenetic markers. They also exhibited an increased sympathetic output with increased circulating dopamine, and metabolic dysfunction reflected by aberrant adipose tissue morphology and function, impaired glucose metabolism, decreased energy expenditure, and hepatic steatosis. These findings indicate that ovarian NGF excess leads to adverse fetal development and to reproductive and metabolic complications in adulthood, mirroring common features of PCOS. This work provides evidence that NGF excess may be implicated in the PCOS pathophysiology.

Autonomic dysfunction in programmed hypertension

Hypertension is an important modifiable risk factor for cardiovascular diseases. Its high prevalence, combined with the significant morbidity and mortality associated with secondary complications, make it a major public health concern. Despite decades of research, over 95% of all cases of hypertension remain of unknown etiology, necessitating that treatments target the established symptoms and not the cause. One of the important recent advances in hypertension research is an understanding that hypertension often may have a developmental origin. A substantial body of evidence indicates that exposure to an adverse intrauterine environment during critical periods of development may predispose an individual to develop hypertension later in life. A causative mechanism has yet to be identified, but may include epigenetic modifications, and/or alterations in renal, vascular or autonomic cardiovascular functions. This review will present evidence regarding changes in autonomic activity as a possible causative pathophysiological mechanism underlying the development of programmed hypertension. In man, low birth weight is the best-known risk factor for hypertension of developmental origins, although this is a broad surrogate measure for intrauterine adversity. This review will include clinical studies across the lifespan that have investigated autonomic function in individuals with fetal growth restriction and those born preterm. A determination of whether altered autonomic function is seen in these individuals in early life is imperative, as hypertensive disorders that have their origins in utero, and that can be identified early, will open the door to risk stratification, and the development of new strategies that prevent or specifically target these mechanisms.

Assessment of Fetal Development Using Cardiac Valve Intervals

An automated method to assess the fetal physiological development is introduced which uses the component intervals between fetal cardiac valve timings and the Q-wave of fetal electrocardiogram (fECG). These intervals were estimated automatically from one-dimensional Doppler Ultrasound and noninvasive fECG. We hypothesize that the fetal growth can be estimated by the cardiac valve intervals. This hypothesis was evaluated by modeling the fetal development using the cardiac intervals and validating against the gold standard gestational age identified by Crown-Rump Length (CRL). Among the intervals, electromechanical delay time, isovolumic contraction time, ventricular filling time and their interactions were selected in a stepwise regression process that used gestational age as the target in a cohort of 57 fetuses. Compared with the gold standard age, the newly proposed regression model resulted in a mean absolute error of 3.8 weeks for all recordings and 2.7 weeks after excluding the low quality recordings. Since Fetal Heart Rate Variability (FHRV) has been proposed in the literature for assessing the fetal development, we compared the performance of gestational age estimation by our new valve-interval based method, vs. FHRV, while assuming the CRL as the gold standard. The valve interval-based method outperformed both the model based on FHRV. Results of evaluation for 30 abnormal cases showed that the new method is less affected by arrhythmias such as tachycardia and bradycardia compared to FHRV, however certain types of heart anomalies cause large errors (more than 10 weeks) with respect to the CRL-based gold standard age. Therefore, discrepancies between the regression based estimation and CRL age estimation could indicate the abnormalities. The cardiac valve intervals have been known to reflect the autonomic function. Therefore the new method potentially provides a novel approach for assessing the development of fetal autonomic nervous system, which may be growth curve independent.

The Association of Birth Weight and Infant Growth with Energy Balance-Related Behavior - A Systematic Review and Best-Evidence Synthesis of Human Studies

BACKGROUND

Suboptimal prenatal and early postnatal growths are associated with obesity in later life, but the underlying mechanisms are unknown. The aim of this study was to systematically review the literature that reports on the longitudinal association of (i) birth size or (ii) infant growth with later (i) energy intake, (ii) eating behaviors, (iii) physical activity or (iv) sedentary behavior in humans.

METHODS

A comprehensive search of MEDLINE, EMBASE, PsycINFO and The Cochrane Library was conducted to identify relevant publications. We appraised the methodological quality of the studies and synthesized the extracted data through a best-evidence synthesis.

RESULTS

Data from 41 publications were included. The quality of the studies was high in three papers, moderate in 11 and low in the large majority (n = 27) of papers appraised. Our best-evidence synthesis indicates that there is no evidence for an association of birth weight with later energy intake, eating behavior, physical activity or sedentary behavior. We found moderate evidence for an association of extreme birth weights (at both ends of the spectrum) with lower physical activity levels at a later age. Evidence for the association of infant growth with energy balance-related behavior was generally insufficient.

CONCLUSIONS

We conclude that current evidence does not support an association of early-life growth with energy balance-related behaviors in later life, except for an association of extreme birth weights with later physical activity.