Human growth from the cell to the organism: Saltations and integrative physiology

Emerging Adulthood, a Pre-adult Life-History Stage

The duration of human maturation has been underestimated; an additional 4-6-year pre-adult period of "emerging adulthood," should be included in models of human maturation. It is a period of brain maturation, learning about intimacy and mutual support, intensification of pre-existing friendships, family-oriented socialization, and the attainment of those social skills that are needed for mating and reproduction. We propose that emerging adulthood is a life-history stage that is a foundation of the high reproductive success of human beings. The period of emerging adulthood has an evolutionary context and developmental markers, and we present evidence that supports the idea that emerging adults require protection because they are still learning and maturing.

High-fibre enteral feeding results in improved anthropometrics and favourable gastrointestinal tolerance in malnourished children with growth failure

Aim

The practical value of using fibre‐enriched enteral feeding regimens to rehabilitate malnourished children remains inconclusive. This study determined the usage patterns, gastrointestinal tolerance, anthropometrics and safety of high‐fibre enteral feeding in malnourished children with growth failure.

Methods

This Turkish observational study between February 2013 and June 2015 comprised 345 paediatric patients from 17 centres with malnutrition‐related growth failure, with a weight and height of <2 SD percentiles for their age. Changes in anthropometrics, gastrointestinal symptoms, defecation habits and safety data relating to adverse events were analysed during the six‐month follow‐up period.

Results

Most subjects (99.7%) were supplemented with enteral feeding. The absolute difference and 95% confidence interval values for the Z scores of height for age, weight for age, weight for height and body mass index for height increased significantly in four months to six months to 0.21 (0.09–0.32), 0.61 (0.51–0.70), 0.81 (0.56–1.06) and 0.70 (0.53–0.86), respectively (p < 0.001 for each). The percentage of patients with normal defecation frequency significantly increased from 70.3% to 92.8% at the four months to six months visit (p = 0.004). Adverse events occurred in 15 (4.3%) of patients.

Conclusion

Using a six‐month high‐fibre enteral feeding was associated with favourable outcomes in anthropometrics, appetite, gastrointestinal tolerance and safety in malnourished children.

Physical Growth, Body Scale, and Perceptual-Motor Development

In this chapter we consider from the theoretical framework of the ecological approach to perception and action, the relations between physical growth and body scale in the context of children's perceptual-motor development. Body scale and the timescale of its change through growth are shown to relate to the emergence and dissolution of the fundamental skills in infancy, the perception of what an environment affords functionally for action, together with the emergent pattern of movement coordination. A central issue in typical and atypical motor development is the mapping of the timescale of adaptive change in the acquisition of perceptual-motor skill to the accompanying timescale of change in physical growth.

A time-varying biased random walk approach to human growth

Growth and development are dominated by gene-environment interactions. Many approaches have been proposed to model growth, but most are either descriptive or describe population level phenomena. We present a random walk-based growth model capable of predicting individual height, in which the growth increments are taken from time varying distributions mimicking the bursting behaviour of observed saltatory growth. We derive analytic equations and also develop a computational model of such growth that takes into account gene-environment interactions. Using an independent prospective birth cohort study of 190 infants, we predict height at 6 years of age. In a subset of 27 subjects, we adaptively train the model to account for growth between birth and 1 year of age using a Bayesian approach. The 5-year predicted heights compare well with actual data (measured height = 0.838*predicted height + 18.3; R² = 0.51) with an average error of 3.3%. In one patient, we also exemplify how our growth prediction model can be used for the early detection of growth deficiency and the evaluation of the effectiveness of growth hormone therapy.

Longitudinal growth and health outcomes in nutritionally at-risk children who received long-term nutritional intervention

BACKGROUND

The benefits of short-term oral nutritional supplementation (ONS) in undernourished children are well-established. The benefits of long-term ONS in promoting longitudinal growth and health in children who are at risk of undernutrition have not been reported previously.

METHODS

In this 48-week prospective, single-arm, multicentre trial, 200 Filipino children aged 3-4 years with weight-for-height percentiles from 5th to 25th (WHO Child Growth Standards) were enrolled. Parents received dietary counselling at baseline, and at weeks 4 and 8. Two servings of ONS (450 mL) were consumed daily, providing 450 kcal, 13.5 g protein and micronutrients. Weight, height, dietary intake using 24-h dietary recalls, and physical activity and appetite using the visual analogue scales were assessed at baseline and weeks 4, 8, 16, 24, 32, 40 and 48. The number of sick days for acute illnesses was collected over the study period.

RESULTS

At baseline, mean age was 41.2 months with 50% being male. Weight-for-height percentiles showed the greatest increase in the first 4 weeks (12.1 and 12.8 percentiles, respectively, P < 0.0001) and remained significantly higher than baseline (P < 0.0001) but were relatively stable from week 4 onwards. Height-for-age percentiles increased steadily over time and became significantly higher than baseline from week 24 onwards (P < 0.0001). Appetite and physical activity scores at all post-baseline visits improved from baseline (P < 0.0001), and a reduction in the number of sick days from week 16 onwards was also observed (P < 0.0001). Higher parental education level, being male and higher baseline weight-for-height percentiles were significantly associated with higher ponderal and linear growth over time in repeated measures analysis of covariance.

CONCLUSIONS

Intervention consisting of initial dietary counselling and continued ONS helped sustain normal growth after a catch-up growth in nutritionally at-risk children.

Early growth velocities and weight gain plasticity improve linear growth in Peruvian infants

Growth velocity patterns have the potential to signal unhealthy responses to environmental insults with long-term consequences. We aimed to investigate velocities in Peruvian infants (n = 259) in relation to attained anthropometric outcomes at 12 months and to identify determinants of velocities during critical periods of infancy. From 1995 to 1997, a randomised controlled trial of maternal zinc supplementation was conducted in a peri-urban slum area of Lima. Infants were followed monthly through 1 year on a range of anthropometric measures. Three types of velocity variables were studied: (1) incremental velocity (1 months and 3 months); (2) proportional changes (% of total size gained/month); and (3) individual velocity variability [standard deviation (SD) of individual child incremental velocities]. Mean individual child SD of weight velocity was 417 g (±126). In multivariate ordinary least squares regression analyses, growth velocities in month 1 and individual weight velocity variability positively predicted attained length and weight by 12 months. Panel regression by generalised least-squares with random effects of length and weight velocities confirmed the exponentially decelerating pace of growth through infancy and the importance of birth size in driving this trajectory. This study contributes evidence to support the importance of early growth velocities and greater degrees of weight gain plasticity for attained length and weight.

A novel approach to the analysis of human growth

Objectives

Several formulations have been proposed in order to model human growth from birth to maturity. They are usually based on “ad hoc” heuristic assumptions. In the present contribution we adopt, as an alternative, a completely general (interdisciplinary) approach, based on the formalism of the Phenomenological Universalities (PUN).

Methods

The main PUN class investigated to date, i.e. UN, can only account for the overall growth pattern. For a realistic description it is necessary to add to it one or more “spurts”, as expected on biological grounds, due to the stimulation of growth and sex hormones.

Results

A new PUN class (UN + FM) is generated and shown to be able to provide excellent agreement with standard auxological datasets. The accuracy of the fitting and reliability of the model suggest applications both at the diagnostic and therapeutic level.

Conclusions

The developed formalism can be suitably related to the biological description of bone plate growth under selective hormonal stimulation on the bone epiphysis; i.e., the additional increase of stature is the “macroscopic” response to a well defined biological signal.