Preterm birth and the endocrine regulation of growth in childhood and adolescence

Growth patterns of preterm and small for gestational age children during the first 10 years of life

Background

Preterm and small for gestational age (SGA) remain significant public health concerns worldwide. Yet limited evidence exists on their growth patterns during childhood from low-or middle-income countries.

Objectives

We investigated the postnatal growth patterns of preterm and SGA compared to term appropriate for gestational age (AGA) children from birth to 10-11y, and examined the impact of birth status on child nutritional status during the school age years.

Methods

Children born to women who participated in a double-blinded randomized controlled trial of preconception micronutrient supplementation in Vietnam were classified into three groups: preterm AGA (n = 130), full-term SGA (n = 165) and full-term AGA (n = 1,072). Anthropometric data (weight and height) were collected prospectively at birth, 3, 6, 12, 18, 24 months and at 6-7 and 10-11y. We used ANOVA and multiple regression models to examine the differences in growth patterns from birth to 10-11y as well as child undernutrition and overnutrition by birth status.

Results

Children who were born preterm exhibited rapid postnatal growth, but still had lower HAZ at 1y and 2y and showed catch up to the AGA group at 6y. Compared to those born AGA, SGA infants had higher risk of thinness (BMIZ < -2) at 2y and 6y (adjusted Odds Ratio, AOR [95% CI] 2.5 [1.0, 6.1] and 2.6 [1.4, 4.6], respectively); this risk reduced at 10-11y (1.6 [0.9, 2.8]). The risk of stunting (HAZ < -2) was also 2.4 [1.5, 3.8] and 2.3 times [1.2, 4.1] higher in SGA than AGA group at ages 2y and 6-7y, respectively, with no differences at 10y. Although preterm children had higher rates of thinness and stunting at 2y compared to AGA children, these differences were not statistically significant. No associations were found between preterm or SGA and overweight /obesity at age 10-11y.

Conclusion

Children who were born term-SGA continued to demonstrate deficits in weight and height during childhood whereas those born preterm showed catch-up growth by age 6-7y. Additional efforts to reduce the burden of these conditions are needed, particularly during school-age and early adolescents when children are exposed to challenging environments and have higher demands for nutrition.

Correction: Accelerated weight gain, prematurity, and the risk of childhood obesity: A meta-analysis and systematic review

[This corrects the article DOI: 10.1371/journal.pone.0232238.].

A. Sørensen T, Elhakeem A, Santos AC, Pinot de Moira A, Heude B, Iñiguez C, Pizzi C, Simons E, Voerman E, Corpeleijn E, Zariouh F, Santorelli G, Inskip HM, Barros H, Carson J, Harris JR, Nader JL, Ronkainen J, Strandberg-Larsen K, Santa-Marina L, Calas L, Cederkvist L, Popovic M, Charles MA, Welten M, Vrijheid M, Azad M, Subbarao P, Burton P, Mandhane PJ, Huang RC, Wilson RC, Haakma S, Fernández-Barrés S, Turvey S, Santos S, Tough SC, Sebert S, Moraes TJ, Salika T, Jaddoe VWV, Lawlor DA, Nybo Andersen AM. Gestational age at birth and body size from infancy through adolescence: An individual participant data meta-analysis on 253,810 singletons in 16 birth cohort studies

BACKGROUND

Preterm birth is the leading cause of perinatal morbidity and mortality and is associated with adverse developmental and long-term health outcomes, including several cardiometabolic risk factors and outcomes. However, evidence about the association of preterm birth with later body size derives mainly from studies using birth weight as a proxy of prematurity rather than an actual length of gestation. We investigated the association of gestational age (GA) at birth with body size from infancy through adolescence.

METHODS AND FINDINGS

We conducted a two-stage individual participant data (IPD) meta-analysis using data from 253,810 mother-child dyads from 16 general population-based cohort studies in Europe (Denmark, Finland, France, Italy, Norway, Portugal, Spain, the Netherlands, United Kingdom), North America (Canada), and Australasia (Australia) to estimate the association of GA with body mass index (BMI) and overweight (including obesity) adjusted for the following maternal characteristics as potential confounders: education, height, prepregnancy BMI, ethnic background, parity, smoking during pregnancy, age at child's birth, gestational diabetes and hypertension, and preeclampsia. Pregnancy and birth cohort studies from the LifeCycle and the EUCAN-Connect projects were invited and were eligible for inclusion if they had information on GA and minimum one measurement of BMI between infancy and adolescence. Using a federated analytical tool (DataSHIELD), we fitted linear and logistic regression models in each cohort separately with a complete-case approach and combined the regression estimates and standard errors through random-effects study-level meta-analysis providing an overall effect estimate at early infancy (>0.0 to 0.5 years), late infancy (>0.5 to 2.0 years), early childhood (>2.0 to 5.0 years), mid-childhood (>5.0 to 9.0 years), late childhood (>9.0 to 14.0 years), and adolescence (>14.0 to 19.0 years). GA was positively associated with BMI in the first decade of life, with the greatest increase in mean BMI z-score during early infancy (0.02, 95% confidence interval (CI): 0.00; 0.05, p < 0.05) per week of increase in GA, while in adolescence, preterm individuals reached similar levels of BMI (0.00, 95% CI: -0.01; 0.01, p 0.9) as term counterparts. The association between GA and overweight revealed a similar pattern of association with an increase in odds ratio (OR) of overweight from late infancy through mid-childhood (OR 1.01 to 1.02) per week increase in GA. By adolescence, however, GA was slightly negatively associated with the risk of overweight (OR 0.98 [95% CI: 0.97; 1.00], p 0.1) per week of increase in GA. Although based on only four cohorts (n = 32,089) that reached the age of adolescence, data suggest that individuals born very preterm may be at increased odds of overweight (OR 1.46 [95% CI: 1.03; 2.08], p < 0.05) compared with term counterparts. Findings were consistent across cohorts and sensitivity analyses despite considerable heterogeneity in cohort characteristics. However, residual confounding may be a limitation in this study, while findings may be less generalisable to settings in low- and middle-income countries.

CONCLUSIONS

This study based on data from infancy through adolescence from 16 cohort studies found that GA may be important for body size in infancy, but the strength of association attenuates consistently with age. By adolescence, preterm individuals have on average a similar mean BMI to peers born at term.

Growth patterns of preterm infants in Korea

With advancements in neonatal care and nutrition, the postnatal growth of preterm infants has improved; however, it remains an issue. Accurate assessments of growth using a standardized reference are needed to interpret the intrauterine and postnatal growth patterns of preterm infants. Growth in the earlier periods of life can contribute to later outcomes, and the refinement of postnatal growth failure is needed to optimize outcomes. Catchup growth occurs mainly before discharge and until 24 months of age, and very low birth weight infants in Korea achieve retarded growth later in life. Knowing an infant's perinatal history, reducing morbidity rates during admission, and performing regular monitoring after discharge are required. Preterm infants with a lower birth weight or who were small for gestational age are at increased risk of poor neurodevelopmental outcomes. Furthermore, poor postnatal growth is predictive of adverse neurodevelopmental outcomes. Careful monitoring and early intervention will contribute to better development outcomes and national public health improvements.

The Effect of the Physical Factors of Parents and Children on Stunting at Birth Among Newborns in Indonesia

Objectives

This study examined stunting at birth and its associations with physical factors of parents and children in Indonesia.

Methods

This study analyzed secondary data from the national cross-sectional Indonesian Basic Health Survey 2018, conducted across 34 provinces and 514 districts/cities. Birth length data were available for 756 newborns. Univariable, bivariable, and multivariable logistic regression analyses were performed to determine associations between the physical factors of parents and children and stunting at birth.

Results

In total, 10.2% of children aged 0 months were stunted at birth (10.7% of males and 9.5% of females). Stunting at birth was associated with the mother’s age at first pregnancy, parity, parents’ heights, parents’ ages, and gestational age. Children from mothers with short statures (height <145.0 cm) and fathers with short statures (height <161.9 cm) had an almost 6 times higher likelihood of being stunted at birth (adjusted odds ratio, 5.93; 95% confidence interval, 5.53 to 6.36). A higher maternal age at first pregnancy had a protective effect against stunting. However, other variables (firstborn child, preterm birth, and both parents’ ages being <20 or >35 years) corresponded to a 2-fold higher likelihood of stunting at birth compared to the reference.

Conclusions

These findings provide evidence that interventions to reduce stunting aimed at pregnant females should also consider the parents’ stature, age, and parity, particularly if it is the first pregnancy and if the parents are short in stature or young. Robust programs to support pregnant females and monitor children’s heights from birth will help prevent intergenerational stunting.

Incidence of and risk factors for short stature in children with chronic kidney disease: results from the KNOW-Ped CKD

BACKGROUND

Preserving optimal growth has long been a significant concern for children with chronic kidney disease (CKD). We aimed to examine the incidence of and risk factors for short stature in Asian pediatric patients with CKD.

METHODS

We analyzed growth status by height, weight, and body mass index (BMI) standard deviation scores (SDSs) for 432 participants in the KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease.

RESULTS

The median height, weight, and BMI SDSs were - 0.94 (interquartile range (IQR) - 1.95 to 0.05), - 0.58 (IQR - 1.46 to 0.48), and - 0.26 (IQR - 1.13 to 0.61), respectively. A high prevalence of short stature (101 of 432 patients, 23.4%) and underweight (61 of 432 patients, 14.1%) was observed. In multivariable logistic regression analysis, CKD stages 4 and 5 (adjusted odds ratio (aOR) 2.700, p = 0.001), onset before age 2 (aOR 2.928, p < 0.0001), underweight (aOR 2.353, p = 0.013), premature birth (aOR 3.484, p < 0.0001), LBW (aOR 3.496, p = 0.001), and low household income (aOR 1.935, p = 0.030) were independent risk factors associated with short stature in children with CKD.

CONCLUSIONS

Children with CKD in Korea were shorter and had lower body weight and BMI than the general population. Short stature in children with CKD was most independently associated with low birth weight, followed by premature birth, onset before age 2, CKD stages 4 and 5, underweight, and low household income. Among these, underweight is the only modifiable factor. Therefore, we suggest children with CKD should be carefully monitored for weight, nutritional status, and body composition to achieve optimal growth.

Effect of foetal and infant growth and body composition on respiratory outcomes in preterm-born children

Body composition and growth outcomes of preterm-born subjects have been studied by many researchers. In general, preterm-born children have lower height and weight especially in infancy. Despite showing potential for catch-up growth, they continue to lag behind their term counterparts in adolescence and adulthood. The various methods of studying body composition and the differing gestations and ages at which it is assessed may go some way to explaining the inconsistent results observed in different studies. In addition, there is a paucity of data on the effects of foetal and infant growth and of body composition on later respiratory outcomes. In largely term-born subjects, foetal growth and growth trajectories appear to have differential effects on later respiratory outcomes. Early weight gain in infancy appears to be associated with increased respiratory symptoms in childhood but catch-up growth in infancy appears to be associated with possible improved lung function status.

MANAGEMENT OF ENDOCRINE DISEASE: Growth and growth hormone therapy in short children born preterm

Approximately 15 million babies are born preterm across the world every year, with less than 37 completed weeks of gestation. Survival rates increased during the last decades with the improvement of neonatal care. With premature birth, babies are deprived of the intense intrauterine growth phase, and postnatal growth failure might occur. Some children born prematurely will remain short at later ages and adult life. The risk of short stature increases if the child is also born small for gestational age. In this review, the effects of being born preterm on childhood growth and adult height and the hormonal abnormalities possibly associated with growth restriction are discussed, followed by a review of current information on growth hormone treatment for those who remain with short stature during infancy and childhood.

Association Between Preterm Birth and Lower Adult Height in Women

We examined whether being born preterm was associated with changes in adult anthropometry in women. We assessed data on 201,382 women (born in 1973-1988) from the Swedish Birth Register. The mean age was 26.0 years. Of the women in our cohort, 663 were born very preterm (<32 weeks of gestation), 8,247 were born moderately preterm (at least 32 weeks but <37 weeks), and 192,472 were born at term (37-41 weeks). Subgroup analyses were carried out among siblings and also after adjustment for maternal anthropometric data. Statistical tests were 2-sided. Decreasing gestational age was associated with lower height (-1.1 mm per week of gestation; P < 0.0001), so that women who were born very preterm were on average 12 mm shorter than women who were born moderately preterm (P < 0.0001) and 17 mm shorter than women born at term (P < 0.0001). Compared with women who were born at term, those who were born very preterm had 2.9 times higher odds of short stature (<155.4 cm), and those born moderately preterm had 1.43 times higher odds. Subgroup analyses showed no differences between women born moderately preterm and those born at term but accentuated differences from women born very preterm. Among siblings (n = 2,388), very preterm women were 23 mm shorter than those born at term (P = 0.003), with a 20-mm difference observed in subgroup analyses (n = 27,395) that were adjusted for maternal stature (P < 0.001). A shorter final height was associated with decreasing gestational age, and this association was particularly marked in women born very preterm.

Response to IGF-1 Generation Test in Short Prepubertal Children Born Very Preterm or at Term

AIMS

To investigate whether short children born very preterm (<32 weeks of gestation) exhibit features of growth hormone (GH) resistance compared to term peers.

METHODS

We studied 26 prepubertal children (aged 7.0 ± 2.0 years) with short stature (height adjusted for parents' heights <10th percentile), who were born appropriate for gestational age and either very preterm (n = 11) or at term (n = 15). Children underwent insulin-like growth factor-1 (IGF-1) generation test via a daily recombinant human GH (rhGH) dose (0.05 mg/kg/day) over 4 consecutive days. Hormone and binding proteins were measured at baseline and day 5.

RESULTS

At baseline, preterm children had lower IGF-binding protein 1 (IGFBP-1; -22%; p = 0.049) and IGFBP-3 (-24%; p = 0.013) concentrations than term children. Preterm children also had insulin concentrations that tended to be 39% higher (p = 0.059) than term peers. After stimulation, IGF-1 and IGFBP-3 concentrations increased similarly in term and preterm groups, while GH-binding protein (GHBP) concentrations decreased in both groups. Preterm children had higher GHBP (+50%; p = 0.049), insulin (+86%; p = 0.005), and leptin (+107%; p = 0.020) but lower IGFBP-1 (-47%; p = 0.006) concentrations than term children following rhGH stimulation.

CONCLUSIONS

Preterm children who are short for genetic height potential show no evidence of GH resistance that would explain their short stature. However, there was indirect evidence of insulin resistance in the preterm children, as previously described in this group.

What a general paediatrician needs to know about early life programming

The process whereby early exposure to an adverse environment has an influence on later life outcomes has been called 'early life programming'. While epidemiological evidence for this has been available for decades, only in recent years have the mechanisms, in particular epigenetic modifications, for this process begun to be elucidated. We discuss the evidence for early life programming, the possible mechanisms, how effects may be transmitted across generations, and conclude by looking at some examples relevant to general paediatrics.

Prematurity and low birth weight lead to altered bone geometry, strength, and quality in children

PURPOSE

Prematurity and low birth weight are associated with a decrease in bone mass. Aim of the study was to investigate bone geometry, strength, and quality in children born at term small for gestational age (term SGA), premature appropriate for gestational age (prem AGA), and premature SGA (prem SGA).

METHODS

91 patients (46 f, 45 m), mean age 11.28 years, height SDS 0.03 ± 0.21, and BMI SDS -0.31 ± 0.19. 20 were term SGA, 22 prem SGA, and 49 prem AGA. Bone geometry was assessed on the 2nd metacarpal bone, by evaluating the outer and inner diameter, the cortical area, medullary area, metacarpal index, cross-sectional area, and bone strength. Bone quality was evaluated by ultrasound and expressed as amplitude-dependent speed of sound and bone transmission time (BTT).

RESULTS

Term SGA, prem SGA, and prem AGA had values of bone geometry, strength, and quality significantly lower than our reference range (p < 0.05). Findings in the three groups were similar, apart from BTT, which was significantly reduced in prem SGA (p < 0.05). Fat percentage was the main determinant of BTT.

CONCLUSIONS

Children born either prematurely or SGA seem to have smaller and weaker bones. Those born both premature and SGA were the most affected.

Decreasing birth weight is associated with adverse metabolic profile and lower stature in childhood and adolescence

Objective

We aimed to evaluate the association of birth weight SDS with insulin resistance, blood pressure, and auxology in children and adolescents born 23–42 weeks of gestation.

Methods

We studied 143 singleton children and adolescents aged 9.3 ± 3.3 years (range 2.0–17.9 years). Clinical assessments included insulin resistance measured by HOMA2-IR, auxology, and blood pressure from sphygmomanometer measurements. Continuous associations were examined, and stratified analyses carried out. For the latter, participants were divided into those of below-average birth weight (BABW, <0 SDS) and above-average birth weight (AABW, ≥0 SDS).

Results

Irrespective of gestational age, lower birth weight SDS was associated with progressively greater HOMA2-IR (p<0.0001) and higher fasting insulin concentrations (p<0.0001). Decreasing birth weight SDS was associated with higher systolic (p = 0.011) and diastolic (p = 0.006) blood pressure. Lower birth weight SDS was also associated with decreasing stature (p<0.010). The BABW group was ~40% more insulin resistant than AABW participants (p = 0.004), with the former also displaying fasting insulin concentrations 37% higher (p = 0.004). BABW participants were 0.54 SDS shorter than those of higher birth weight (p = 0.002). On average, BABW participants had not met their genetic potential, tending to be shorter than their parents (p = 0.065). As a result, when corrected for parents' heights, BABW participants were 0.62 SDS shorter than those born of higher birth weight (p = 0.001). Sub-group analyses on participants born appropriate-for-gestational-age (n = 128) showed that associations of birth weight SDS with both insulin resistance and stature remained (although attenuated).

Conclusion

Decreasing birth weight SDS (even within the normal range) is associated with adverse metabolic profile and lower stature in children and adolescents.

Boys who are born preterm show a relative lack of fat-free mass at 5 years of age compared to their peers

AIM

Prematurity is associated with features of metabolic syndrome in young adulthood. We investigated the body composition and blood pressure of children born preterm.

METHODS

A longitudinal, observational study was conducted with preterm infants who had a birth weight of <1500 g and a gestational age of <32 weeks. Growth and body composition were assessed by air displacement plethysmography at term equivalent age and at school age and were compared to those of 61 healthy, term breastfed subjects.

RESULTS

A total of 63 preterm infants were enrolled. At term equivalent age, growth and fat-free mass were lower in preterm infants than in term newborns, but fat mass was higher. At 5 years of age, children born preterm were still lighter and shorter than children born at term. When the results were analysed by gender, the fat-free mass index was lower in boys born preterm than in their peers (12.1 ± 1.1 versus 13.0 ± 1.0 kg/h(2) p < 0.005), whereas no difference was detected among girls. Diastolic blood pressure was higher in children born preterm than in children born at term (61.14 ± 7.8 vs 56.69 ± 8.2 mmHg, p = 0.009).

CONCLUSION

Boys born preterm showed a relative lack of fat-free mass at school age compared to their peers.

Optimum feeding and growth in preterm neonates

Approximately 10% of all babies worldwide are born preterm, and preterm birth is the leading cause of perinatal mortality in developed countries. Although preterm birth is associated with adverse short- and long-term health outcomes, it is not yet clear whether this relationship is causal. Rather, there is evidence that reduced foetal growth, preterm birth and the long-term health effects of both of these may all arise from a suboptimal intrauterine environment. Further, most infants born preterm also experience suboptimal postnatal growth, with potential adverse effects on long-term health and development. A number of interventions are used widely in the neonatal period to optimise postnatal growth and development. These commonly include supplementation with macronutrients and/or micronutrients, all of which have potential short-term risks and benefits for the preterm infant, whereas the long-term health consequences are largely unknown. Importantly, more rapid postnatal growth trajectory (and the interventions required to achieve this) may result in improved neurological outcomes at the expense of increased cardiovascular risk in later life.

Increased adiposity in adults born preterm and their children

Background

Preterm birth is associated with abnormalities in growth, body composition, and metabolism during childhood, but adult data are scarce and none exist for their offspring. We therefore aimed to examine body composition and cardiovascular risk factors in adults born preterm and their children.

Methods

A cohort of 52 adults (aged 35.7 years, 54% female, 31 born preterm) and their term-born children (n=61, aged 8.0 years, 54% female, 60% from a preterm parent) were studied. Auxology and body composition (whole-body dual-energy X-ray absorptiometry) were measured, and fasting blood samples taken for metabolic and hormonal assessments.

Results

Adults born preterm had greater abdominal adiposity, displaying more truncal fat (p=0.006) and higher android to gynoid fat ratio (p=0.004). Although women born preterm and at term were of similar weight and BMI, men born preterm (n=8) were on average 20 kg heavier (p=0.010) and of greater BMI (34.2 vs 28.4 kg/m²; p=0.021) than men born at term (n=16). Adults born preterm also displayed a less favourable lipid profile, including lower HDL-C concentrations (p=0.007) and greater total cholesterol to HDL-C ratio (p=0.047). Children of parents born preterm tended to have more body fat than the children of parents born at term (21.3 vs 17.6%; p=0.055). Even after adjustment for mean parental BMI, children of parents born preterm had altered fat distribution, with more truncal fat (p=0.048) and greater android to gynoid fat ratio (p=0.009).

Conclusions

Adults born preterm, particularly men, have markedly increased fat mass and altered fat distribution. A similar increase in abdominal adiposity was observed in the term born offspring of parents born preterm, indicating that adverse outcomes associated with preterm birth may extend to the next generation.

Insulin-like growth factor I: could it be a marker of prematurity in the foal?

Insulin-like growth factor (IGF)-I represents one of the most important growth regulators, playing a central role in fetal and neonatal growth. Plasma IGF-I levels increase rapidly after birth, and they are influenced by numerous factors, including sex, age, nutritional state, and premature birth. The aims of this study were: (1) to evaluate the IGF-I plasma profile in healthy newborn foals during the first 2 weeks of life; (2) to assess the possible influence of sex and birth weight on this hormone; (3) to analyze the percentage increment of IGF-I values in healthy foals; (4) to evaluate the influence of prematurity on IGF-I profile; (5) to verify the role of IGF-I as a diagnostic marker of prematurity; and (6) to analyze the percentage increment of IGF-I in premature foals. Thirty-four healthy term foals were enrolled as the control group and from each foal plasma was collected within 6 hours from birth, at 12 hours, daily from Day 1 to Day 7, and at Days 10 and 14 after birth. Eleven foals aged younger than 1 week and diagnosed as premature and hospitalized at a Equine Perinatology Unit were also enrolled; from each foal plasma was collected daily from the day of admission to discharge or death. Insulin-like growth factor I was analyzed by RIA. In the control group, an increasing trend of IGF-I concentrations was found, with higher values from Day 4 to 10 compared with data obtained at less than 6 hours of life, and from Day 5 to 10 compared with 12 and 24 hours and 3 days. No differences were found in healthy foals analyzed in relation to birth weight and sex. In premature foals an increasing trend was observed but no statistical differences were found among sampling times, and no differences were found between healthy and premature foals. The IGF value in premature foals at admission was always higher compared with the lowest recorded level in healthy age-matched foals, thus this parameter does not seem to have a diagnostic role for prematurity in foals. Finally, the evaluation of the percentage increment of IGF-I concentrations showed a significant increase in full-term foals on Day 5, 6, 7, and 10 compared with 12 and 24 hours, and no differences were observed in premature foals. In conclusion, prematurity in newborn foals seems to affect only partially IGF-I plasma concentrations and it does not seem to be a reliable marker for this pathological condition.