Stem/progenitor cells in fetuses and newborns: overview of immunohistochemical markers

Microanatomy of the vast majority of human organs at birth is characterized by marked differences as compared to adult organs, regarding their architecture and the cell types detectable at histology. In preterm neonates, these differences are even more evident, due to the lower level of organ maturation and to ongoing cell differentiation. One of the most remarkable finding in preterm tissues is the presence of huge amounts of stem/progenitor cells in multiple organs, including kidney, brain, heart, adrenals, and lungs. In other organs, such as liver, the completely different burden of cell types in preterm infants is mainly related to the different function of the liver during gestation, mainly focused on hematopoiesis, a function that is taken by bone marrow after birth. Our preliminary studies showed that the antigens expressed by stem/progenitors differ significantly from one organ to the next. Moreover, within each developing human tissue, reactivity for different stem cell markers also changes during gestation, according with the multiple differentiation steps encountered by each progenitor during development. A better knowledge of stem/progenitor cells of preterms will allow neonatologists to boost preterm organ maturation, favoring the differentiation of the multiple cells types that characterize each organ in at term neonates.

A survey around the Italian pediatric units on current clinical practice for Sleep Disordered Breathing (SDB)

Background

During recent years, interest on Sleep Disordered Breathing (SDB) in pediatric age has increased, due to the impact on quality of life, psycho-physical attitude and other serious morbidities if undiagnosed and untreated.

Methods

Italian Pediatric Respiratory Diseases Society (SIMRI) SDB-Working Group carried out an exploratory survey in Italy, from January to December 2016, to assess the diagnostic and therapeutic pathways, perception and relevance of SDB in Italian Hospitals.

Results

A questionnaire was sent to 180 Pediatric Units (PUs) distributed throughout the Italy; 102 Pediatric Units (PUs; 56.6%) answered and among them 57% dealt with SDB, and 94% recognized SDB as a major problem. Instrumental tests performed by the PUs were saturimetry (66%), nocturnal polygraphy with complete cardio-respiratory monitoring (46%) and full polysomnography (23%). In addition, hospital pediatricians reported that 54% of parents were unaware of the SDB and 84% did not know their complications. In the Northern Italy, the diagnosis was frequently performed with instrumental tools and the treatment was often surgical. In the Southern Italy the diagnosis was clinical, and the treatment was usually with drugs.

Conclusions

The results of our study showed a heterogeneity in the diagnosis and treatment of SDB throughout Italy. Parents know little about SDB and their complications. The operator satisfaction was associated with the availability of tools for diagnosing SDB.

Electronic supplementary material

The online version of this article (10.1186/s13052-019-0658-2) contains supplementary material, which is available to authorized users.

Diagnostic Effectiveness of Simultaneous Thyroxine and Thyroid-Stimulating Hormone Screening Measurements. Thirteen Years' Experience in the Northeast Italian Screening Programme

Objectives:

To evaluate the effectiveness of thyroid-stimulating hormone (TSH) and thyroxine [T4) measurements at neonatal screening for congenital hypothyroidism, we compared our false-negative results with those we would have obtained if we had used TSH screening alone.

Subjects and methods:

Between January 1989 and December 2001 745,258 newborns were screened (98.3% of total born) for congenital hypothyroidism in northeast Italy. T4 and TSH were measured simultaneously on blood spots collected after birth. Between 1989 and 1998, semiquantitative total T4 (tT4) and TSH concentrations were measured by radiolabelled immunological assay and, from 1999 to 2001, using time-resolved fluorometer Delfia instruments (EG&G Wallac Oy, Finland) and fluoroimmunometric assay (Delfia neonatal hTSH and T4 kits).

Results:

Ten neonates were missed by our screening programme (normal tT4 and TSH) and classified as false negatives; these infants were diagnosed later in life with central hypothyroidism. If we had measured TSH alone in our screening programme, we would have missed an additional 21 patients with low tT4 and normal TSH; of these, four were affected by central hypothyroidism and 17 were diagnosed within the second month of life as affected by primary hypothyroidism with delayed TSH rise.

Conclusions:

Simultaneous T4 and TSH measurements at neonatal screening can miss patients affected by central hypothyroidism. However, this screening procedure allows identification of cases of central hypothyroidism with low T4 values and those neonates affected by primary hypothyroidism with delayed TSH rise who we would have missed by using the TSH measure alone.

Renal function and volume of infants born with a very low birth-weight: a preliminary cross-sectional study

AIM

The aim of our study was to compare the function and volumes of kidneys of very low birth-weight (VLBW) and of extremely low birth-weight (ELBW) infants at pre-school ages.

PATIENTS AND METHODS

We did a revision of the neonatal records of infants born in our hospital that weighed < or =1500 g at birth. The children were divided into two groups according to their weight at birth: ELBW (<1000 g) and VLBW (1000-1500 g). At the age of 5.7 +/- 1.4 years, the children underwent clinical, laboratory and ultrasound renal assessments.

RESULTS

Sixty-nine children fulfilled the requirements for the study. The rate of neonatal treatment with aminoglycosides was higher in ELBW preterms. Renal function parameters, i.e. estimated glomerular filtration rate and albuminuria, did not differ between the two groups of children. Urinary alpha1-microglobulin excretion was significantly higher and kidneys were significantly smaller in the ELBW group than in the VLBW group.

CONCLUSION

No impairment or differences in renal parameters were found in pre-school children born ELBW compared with those born with VLBW, except for differences in kidney volume, renal cortical thickness and urinary alpha1-microglobulin excretion. Thus, patients born with ELBW would require a longer follow-up period.

Perinatal nutrient restriction reduces nephron endowment increasing renal morbidity in adulthood: a review

Perinatal malnutrition has been included among the causes of renal disease in adulthood. Here, we consider the relationships between early supply of specific nutrients (such as protein, fat, vitamins and electrolytes) and renal endowment. Prenatal and postnatal nutrition mismatch is also discussed. In addition, this article presents the role of nutrition of both mothers and pre-term infants on nephron endowment, with final practical considerations.

Carbohydrate‐deficient transferrin determined in blood microsamples from healthy newborns by using capillary zone electrophoresis

OBJECTIVE

There is a paucity of studies on quantitative determination of carbohydrate-deficient transferrin (CDT) in newborns. The aim of our study was therefore to determine CDT concentrations in newborns by using capillary zone electrophoresis (CZE).

MATERIAL AND METHODS

Capillary blood was collected from the heels of 28 at-term healthy newborns, simultaneously with the Guthrie card screening. Forty-seven adults were examined as controls. CZE separations were performed with a P/ACE MDQ capillary electropherograph in uncoated fused-silica capillaries using a commercial reagent kit. After iron saturation, the samples were loaded by application of 0.5 psi for 15 s, and separated under 28kV with UV detection. All relevant transferrin (Tf) glycoforms were separated within 7 min. CDT quantification (%CDT) was carried out by calculating the percentage ratio between the sum of the peak areas of CDT-related glycoforms and the sum of peak areas of all Tf glycoforms.

RESULTS

In most cases, good separations of Tf glycoforms were obtained. In the newborns the %CDT was 0.51 versus 0.66 in adults (difference not statistically significant). Trisialo-Tf concentration was significantly lower in newborns (3.20) than in adults (4.11). Furthermore, pentasialo-Tf appeared to be lower in newborns (7.30) than in adults (14.00), but because complete separation of the peaks of tetrasialo- and pentasialo-Tf was not always possible, this finding could not be confirmed statistically.

CONCLUSIONS

CZE showed definite advantages in terms of volume of blood to be collected, simplicity and standardization of analysis and, because of the direct detection of the separated zones, accuracy of quantification. The present study provides the basic information in the search for glycosylation defects in newborns.

Evaluating kidney damage from vesico-ureteral reflux in children

To review the most relevant clinical studies that evaluate kidney damage in children with primary vesico-ureteral reflux (VUR), we reviewed and compared randomized controlled trials and clinical trials from scientific literature. In these studies, vesico-ureteral reflux was diagnosed by voiding cystourethrogram and kidney damage was assessed by either DMSA scan or urography. Relative risk with 95% confidence intervals was calculated using Review Manager Software (The Cochrane Collaboration, 2000). The overall relative risk of kidney damage shown by DMSA scan and urography was statistically higher in children with vesico-ureteral reflux of various degrees than in controls (3.7 times and 2.8 times, respectively). However, in high-grade VUR, the relative risk of congenital kidney damage was 5.6 times that of controls. We conclude that severe VUR is frequently associated with early kidney damage, perhaps with prenatal onset. Progression of kidney damage may depend on the severity of VUR and untreated urinary tract infections. Prevention of congenital kidney damage from severe VUR is possible when there is early intervention, even during fetal growth.

Pelvi-ureteric junction obstruction and renal function after pyeloplasty: a retrospective study in 29 children

AIM

Actually, unilateral obstruction is not indicated for surgery, especially if renal function is unaffected. This retrospective study focused on the renal function after pyeloplasty for unilateral obstruction in children.

METHODS

Twenty-nine children were retrospectively reviewed. To compare the ultrasound readings in patients with different ages, the comparative-length-index (index) of each renal unit (RU) was calculated. MAG3 dynamic scintigraphy was applied to diagnose any obstructions.

RESULTS

Children with left obstruction were younger than children with right obstruction, when surgery was performed. Scintigraphic scan of right RUs with obstruction operated later was a lower at diagnosis than jet of the normal contralateral. Normal scintigraphic scan at diagnosis of left RUs with obstruction operated early revealed that RU was slightly reduced after the operation. At both diagnosis and follow-up the index between obstructed RUs and normal contralateral was comparable, even if it was significantly higher in left obstructed RUs. At follow-up, however, the scintigraphic scan revealed that RUs were more reduced in patients who were treated late.

CONCLUSION

Early pyeloplasty partially safeguard kidney function in children with unilateral obstruction, whose renal function was normal at birth. The reduced kidney function observed before surgery was not proportionally improved after surgery with respect to the contralateral that was not affected.

Therapeutic options in childhood nocturnal enuresis

Monosymptomatic nocturnal enuresis, a heterogeneous condition, is frequently treated in children aged >5 years. Of the various treatment options, enuresis alarm has been widely advocated as being effective for treating nocturnal enuresis, while extracorporeal pelvic floor magnetic stimulation for overactive bladder, urge incontinence and urgency-frequency syndrome has not yet been confirmed by controlled studies as primary treatment for monosymptomatic nocturnal enuresis. Desmopressin, an antidiuretic hormone (ADH) analog, or arginine vasopressin (AVP), can resolve primary nocturnal enuresis by decreasing night-time urine production. Enuretic children requiring either desmopressin or desmopressin plus oxybutynin to achieve dryness have polyuria. Tricyclic antidepressants (i.e. imipramine) are used successfully in enuretic children. Although tricyclics and desmopressin are effective in reducing the number of wet nights, most children relapse after discontinuation of active treatment. Combined therapy (enuresis alarm, bladder training, motivational therapy and pelvic floor muscle training) is more effective than each component alone or than pharmacotherapy. Furthermore, desmopressin combined with alarm therapy has a positive effect on enuresis. Pharmacotherapy can provide early relief of enuresis, while behavioral intervention may lead to greater long-term benefits. The positive effect of achieving dry nights with pharmacotherapy can encourage the child to sustain behavioral therapy.

Genetic analysis carried out on blood-spots of phenylalanine hydroxylase-deficient newborns detected by northeastern Italian neonatal screening

The aim of this work was to perform genetic analysis on 18 different blood-spot samples collected from neonates detected as hyperphenylalaninemic by Northeastern Italian screening program. DNA was extracted from blood-spots. Exons/introns of PAH gene were amplified by polymerase chain reaction (PCR), and PCR products were purified and sequenced with both forward and reverse primers. The most frequent mutations were IVS12nt1g>a (16.7%) and R408W, P281L and L48S (all together 11.1%). As expected, compound heterozygosity was the usual finding; homozygosity was found only in two patients with R158Q and IVS2nt5g>c mutations. The V230I mutation was reported for the first time in Italy. We found six previously described polymorphisms (V245V, IVS4nt47c>t, IVS2nt19t>c, IVS3nt-22c>t, IVS5nt-54a>g, and E280>Q280). To our knowledge, four genotypes were not previously described: R158Q/V230I present in one patient with classical PKU; and L48S/R408Q, A403V/IVS2nt-13t>g, and G272X/V230I present in patients showing HPA phenotype. Most of the mutations were located in the exons 12 and 7 and in exon/intron 2 (83.3% detection of total mutations in PKU or HPA patients of Northeastern Italy). From a practical viewpoint, the genetic analysis of blood-spots collected on Guthrie cards for neonatal screening for PKU could be a simple method to establish the genotype of neonates. Consequently, the genotype/phenotype correlation could lead to a more accurate diagnosis and prognosis for families.

Therapeutic approach in a case of Pearson's syndrome

Mitochondrial cytopathy is a multisystemic disease that requires different pharmacological and specialist approaches; although most therapies are usually of scarce effectiveness. We describe a clinical management of a very young girl with Pearson's syndrome that developed the symptoms of Kearns-Sayre syndrome. Many of symptoms were temporarily improved by the replacement therapy with hydrocortisone introduced to treat the partial adrenal insufficiency. During her life, she showed an ample clinical spectrum of symptoms because of multiple organs involvements: firstly bone marrow and, thereafter, brain, retina, inner ear, and kidney. Partial adrenal insufficiency, rarely described in mitochondrial disorders, was a distinctive characteristic of this case. When our patient was treated with hydrocortisone, in addition to ubiquinone and carnitine, the episodes of decompensation regressed and an improvement of the adrenal insufficiency, but only temporary reversion of the weakness of muscle, ophthalmoplegia and of the fatigue, were testified. Nevertheless, after a brief period of recovery, she developed the de Toni-Debré-Fanconi syndrome and the reappearance of the neurological symptoms.

Nutrient oxidation during moderately intense exercise in obese prepubertal boys

The aim of this study was to measure the nutrient oxidation rate during walking at different speeds and to identify the walking speed associated with the highest fat oxidation rate in a group of prepubertal boys with different levels of adiposity. Twenty-four prepubertal boys (age, 10 +/- 1 yr) with different levels of overweight (body mass index, 25.5 +/- 3.5 kg/m(2); sd score of body mass index, 3.4 +/- 1.1) performed a treadmill test. We measured by indirect calorimetry their respiratory exchange while they walked at speeds of 4, 5, and 6 km/h as well as their maximal oxygen uptake. The fat oxidation rate did not change significantly when the speed of walking was increased, whereas carbohydrate oxidation increased significantly (P < 0.001). A significant (P < 0.05) association was found between adiposity (percent fat mass) and the fat to carbohydrate oxidation ratio during walking at 4, 5, and 6 km/h (r = 0.37, r = 0.37, and r = 0.36, respectively), adjusting for exercise intensity (maximal oxygen uptake, percentage). The lowest fat to carbohydrate oxidation ratio, i.e. the highest fat oxidation/carbohydrate oxidation rate, was found at a walking speed of 4 km/h. Moderately intense exercise promoted the highest fat to carbohydrate oxidation ratio. Increasing the exercise intensity did not promote fat oxidation. Therefore, walking at a speed of 4 km/h is recommended as practicable exercise for obese boys and, consequently, for the treatment of childhood obesity.

Complex glycerol kinase deficiency leads to psychomotor and body-growth failure

Complex glycerol kinase deficiency usually presents with Duchenne muscular dystrophy, glycerol kinase deficiency and adrenal hypoplasia congenital. We describe a follow-up patient with complex glycerol kinase deficiency who had appropriate intrauterine development, but who at 1 month of age manifested severe growth delay and psychomotor retardation. Targeted therapy did not bring about the regression of symptoms: both bodyweight and height were below the 3rd centile until 8 years of age, and his Griffith's Mental Development scale score was 71 at age 5 years.

Neonatal hyperinsulinemic hypoglycemia. Two case reports

Neonatal hyperinsulinemic hypoglycemia must be suddenly and appropriately diagnosed and treated to prevent any further neurological dysfunction and damage. Therefore, we report two cases of our observation. Case 1: birth asphyxia, episodes of hypoglycemia after delivery, hyperinsulinism and reduced IGFBP1 blood concentration. Clinical and laboratory pictures resolved progressively after 8 days of life, perfusions were stopped and the neonate began to suck breast milk. Case 2: negative familial and perinatal history. On the 3rd day of life he developed cyanosis, hypotonia, tremors and hypoglycemia. He was discharged with a diagnosis of cerebral injury and neonatal hypoglycemia. At 1 year of life the child showed progressive and heavy neurological damage. The RMN of the brain showed: enlarged ventricles and liquor spaces around the brain, particularly in the frontal region. Hyperinsulinism was diagnosed in our Clinic. He began pharmacological treatment with Diazoxide that permitted euglycemia. The ammonium was normal and excluded glutamate dehydrogenase deficiency (mutation of GLUD1 gene); Diazoxide responsivity excluded mutations of SUR1 and KIR6.3 genes. At 9 years of life he showed motor and language retardation. Newborns with perinatal history of asphyxia may develop transient hyperinsulinism with absent neurological consequences. Persistent hypoglycemic or epileptic-like episodes, in particular on waking up, after meals or during banal infections, must be studied to reveal hyperinsulinism.

Whole-body protein turnover and resting energy expenditure in obese, prepubertal children

BACKGROUND

Obesity is becoming more frequent in children; understanding the extent to which this condition affects not only carbohydrate and lipid metabolism but also protein metabolism is of paramount importance.

OBJECTIVE

We evaluated the kinetics of protein metabolism in obese, prepubertal children in the static phase of obesity.

DESIGN

In this cross-sectional study, 9 obese children (x +/- SE: 44+/-4 kg, 30.9+/-1.5% body fat) were compared with 8 lean (28+/-2 kg ,16.8+/-1.2% body fat), age-matched (8.5+/-0.2 y) control children. Whole-body nitrogen flux, protein synthesis, and protein breakdown were calculated postprandially over 9 h from 15N abundance in urinary ammonia by using a single oral dose of [15N]glycine; resting energy expenditure (REE) was assessed by indirect calorimetry (canopy) and body composition by multiple skinfold-thickness measurements.

RESULTS

Absolute rates of protein synthesis and breakdown were significantly greater in obese children than in control children (x +/- SE: 208+/-24 compared with 137+/-14 g/d, P < 0.05, and 149+/-20 compared with 89+/-13 g/d, P < 0.05, respectively). When these variables were adjusted for fat-free mass by analysis of covariance, however, the differences between groups disappeared. There was a significant relation between protein synthesis and fat-free mass (r = 0.83, P < 0.001) as well as between protein synthesis and REE (r = 0.79, P < 0.005).

CONCLUSIONS

Obesity in prepubertal children is associated with an absolute increase in whole-body protein turnover that is consistent with an absolute increase in fat-free mass, both of which contribute to explaining the greater absolute REE in obese children than in control children.

Energy intake and energy expenditure in prepubertal males with asthma

This study aimed to measure energy intake (EI) and total energy expenditure (TEE) of asthmatic males and to validate diet history as a method of estimating their energy requirements. EI was assessed by dietary history and TEE by the heart-rate monitoring method in a group of asthmatic and nonasthmatic males. Resting energy expenditure (REE) adjusted for fat-free mass was higher in asthmatic than in nonasthmatic males (5,037 versus 4,839 kJ x day(-1), p<0.05). TEE (93+/-1.8 versus 8.4+/-1.4 MJ x day(-1), respectively; p=NS) and EI (9.2+/-15 versus 8.8+/-15 MJ x day(-1), respectively, p=NS) were not statistically different in asthmatic and nonasthmatic male. EI was not statistically different from TEE in both groups of males. Asthmatic males showed an acceptable agreement between TEE and EI at the individual level (range of agreement: -3.2 to 2.9 MJ x day(-1)), and a good agreement at the group level (95% confidence interval for the bias, - 1.1 to 0.8 MJ x day(-1)). Males with mild-to-moderate asthma have a higher metabolic activity per unit fat-free mass than nonasthmatic males. This increased requirement is apparently well compensated by an adequate energy intake. Diet history is a suitable method for estimating energy requirements in males with mild-to-moderate asthma.

Relationship between physical inactivity and adiposity in prepubertal boys

OBJECTIVE

To study the relationship between the energy expenditure for activity (EEAct), the level of activity and adiposity in a group of 9-year-old boys (n = 28) with different body composition (body weight, 38 +/- 10 kg [range, 23 to 66 kg]; fat mass, 23% +/- 10% [range, 8% to 42%]).

METHODS

Total energy expenditure (TEE) was measured by means of the heart-rate monitoring method. EEAct was calculated as TEE-(REE+0.1 TEE), where REE is the postabsorptive resting energy expenditure and 0.1 TEE corresponds to the postprandial thermogenesis (approximately 10% of TEE).

RESULTS

TEE, REE, and EEAct were 9388 +/- 1859, 5154 +/- 642, and 3295 +/- 1356 l J/day, respectively. Daily time devoted to sedentary and nonsedentary activities averaged 290 +/- 155 minutes (range, 69 to 621) and 534 +/- 150 minutes (range, 180 to 783), respectively. Time spent on sedentary activities was directly proportional to fat mass percentage (r = 0.46; p < 0.05). It was the only variable, among the free-living physical-activity [EEAct, TEE/(REE+0.1 TEE) ratio, time spent in nonsedentary and sedentary activities] variables, which remained significantly in the multiple step-down regression analysis final equation (r = 0.46; p < 0.05).

CONCLUSIONS

The positive relationship between adiposity and time spent on sedentary activities in 9-year-old boys suggests the importance of the role played by muscular activity, at least in the maintenance of obesity in childhood. Prepubertal children should be encouraged to spend less time on sedentary activities to treat and prevent their obesity.

Total and exogenous carbohydrate oxidation in obese prepubertal children

The aim was to explore whether the origin of carbohydrate oxidation (exogenous compared with endogenous carbohydrate) after consumption of a mixed meal was influenced by obesity in children. Ten obese prepubertal children 8 y of age (44.2 +/- 3.6 kg) were studied over 9.5 h and compared with eight normal-weight, matched control children (28.5 +/- 1.6 kg). They were fed a mixed meal containing naturally enriched [13C]carbohydrate (cane sugar and popcorn) providing 55% of the daily energy requirement as measured by 24-h resting metabolic rate. Total carbohydrate oxidation was calculated by indirect calorimetry (hood system) whereas exogenous carbohydrate oxidation was estimated from carbon dioxide production (VCO2), the isotopic enrichment of breath 13CO2, and the abundance of [13C]carbohydrate in the meal ingested. The time course of 13CO2 in breath-measured over 570 min-followed a similar pattern in both groups. Although total carbohydrate oxidation was not significantly different among the two groups, exogenous carbohydrate utilization was significantly greater (P < 0.03) and endogenous carbohydrate oxidation was significantly lower (P < 0.05) in obese compared with control children. In addition, the rate of exogenous carbohydrate oxidation expressed as a proportion of total carbohydrate oxidation was positively related to the body fat of the children (r = 0.68, P < 0.01). The study suggests that in the postprandial phase, a smaller proportion of carbohydrate oxidation is accounted for by glycogen breakdown in obese children. The sparing of endogenous glycogen may result from decreased glycogen turnover already present at an early age.

Total energy expenditure and patterns of activity in 8-10-year-old obese and nonobese children

Total energy expenditure (TEE) and patterns of activity were measured by means of a heart rate (HR)-monitoring method in a group of 8-10-year-old children including 13 obese children (weight, 46 +/- 10 kg; fat mass: 32 +/- 9%) and 16 nonobese children (weight, 31 +/- 5 kg; fat mass, 18 +/- 5%). Time for sleeping was not statistically different in the two groups of children (596 +/- 33 vs. 582 +/- 43 min; p = NS). Obese children spent more time doing sedentary activities (400 +/- 129 vs. 295 +/- 127 min; p < 0.05) and less time in nonsedentary activities (449 +/- 126 vs. 563 +/- 135 min; p < 0.05) than nonobese children. Time spent in moderate or vigorous activity-i.e., time spent at a HR between 50% of the maximal O2 uptake (peak VO2) and 70% peak VO2 (moderate) and at a HR > or = 70% peak VO2 (vigorous)-was not statistically different in obese and nonobese children (88 +/- 69 vs. 52 +/- 35 min and 20 +/- 21 vs. 16 +/- 13 min, respectively; p = NS). TEE was significantly higher in the obese group than in the nonobese group (9.46 +/- 1.40 vs. 7.51 +/- 1.67 MJ/day; p < 0.01). The energy expenditure for physical activity (plus thermogenesis) was significantly higher in the obese children (3.98 +/- 1.30 vs. 2.94 +/- 1.39 MJ/day; p < 0.05). The proportion of TEE daily devoted to physical activity (plus thermogenesis) was not significantly different in the two groups, as shown by the ratio between TEE and the postabsorptive metabolic rate (PMR): 1.72 +/- 0.25 obese vs 1.61 +/- 0.28 non-obese. In conclusion, in free-living conditions obese children have a higher TEE than do nonobese children, despite the greater time devoted to sedentary activities. The higher energy cost to perform weight-bearing activities as well as the higher absolute PMR of obese children help explain this apparent paradox.

Daily energy expenditure in free-living conditions in obese and non-obese children: comparison of doubly labelled water (2H2(18)O) method and heart-rate monitoring

OBJECTIVE

To compare the heart-rate monitoring with the doubly labelled water (2H2(18)O) method to estimate total daily energy expenditure in obese and non-obese children.

DESIGN

Cross sectional study of obese and normal weight children.

SUBJECTS

13 prepubertal children: six obese (4M, 2F, 9.1 +/- 1.5 years, 47.3 +/- 9.7 kg) and seven non-obese (3M, 4F, 9.3 +/- 0.6 years, 31.8 +/- 3.2 kg).

MEASUREMENTS

Total daily energy expenditure was assessed by means of the doubly labelled water method (TEEDLW) and of heart-rate monitoring (TEEHR).

RESULTS

TEEHR was significantly (P < 0.05) higher than TEEDLW in obese children (9.47 +/- 0.84 MJ/d vs 8.99 +/- 0.63 MJ/d) whereas it was not different in non-obese children (8.43 +/- 2.02 MJ/d vs 8.42 +/- 2.30 MJ/d, P = NS). The difference of TEE assessed by HR monitoring in the obese group averaged 6.2 +/- 4.7%. At the individual level, the degree of agreement (difference between TEEHR and TEEDLW +/- 2s.d.) was low both in obese (-0.36, 1.32 MJ/d) and in non-obese children (-1.30, 1.34 MJ/d). At the group level, the agreement between the two methods was good in nonobese children (95% c.i. for the bias:-0.59, 0.63 MJ/d) but not in obese children (0.04, 0.92 MJ/d). Duration of sleep and energy expenditure during resting and physical activity were not significantly different in the two groups. Patterns of heart-rate (or derived energy expenditure) during the day-time were similar in obese and non-obese children.

CONCLUSION

The HR monitoring technique provides an estimation of TEE close to that assessed by the DLW method in non-obese prepubertal children. In comparison with DLW, the HR monitoring method yields a greater TEE value in obese children.

Parental and perinatal factors associated with childhood obesity in north-east Italy

The association between obesity and perinatal, constitutional and social factors was studied in 1363 children (676 males, 687 females) living in six areas of north-east Italy. The children were randomly selected from four age categories (4,8,10 and 12 years of age). After adjustment for age, significant associations between the risk of obesity in the child and their body weight at birth (P < 0.01) and the father's or mother's body mass index (P < 0.001) were found in both genders. When these parental and perinatal variables were included as independent variables in a multiple logistic regression model controlling for the effect of age, parental body mass index and children's birth-weight remained independently associated with childhood obesity. In females, an interaction between birthweight and the mother's body mass index on the prevalence of obesity in childhood was found. In conclusion, parental obesity and birthweight represent major risk factors for obesity among children in north-east Italy.

Elevated energy expenditure and reduced energy intake in obese prepubertal children: paradox of poor dietary reliability in obesity?

The purpose of this study was to assess the validity of two common methods used to assess energy intake. A 3-day weighed dietary record and a dietary history were collected and compared with the total daily energy expenditure (TEE) assessed by the heart rate method in a group of 12 obese and 12 nonobese prepubertal children (mean age 9.3 +/- 1.1 years vs 9.3 +/- 0.4 years). The TEE value was higher in obese than in nonobese children (9.89 +/- 1.08 vs 8.13 +/- 1.39 MJ/day; p < 0.01). Energy intake assessed by the dietary record was significantly lower than TEE in the obese children (7.06 +/- 0.98 MJ/day; p < 0.001) but comparable to TEE in the nonobese children (8.03 +/- 0.99 MJ/day; p = not significant). Energy intake assessed by diet history was lower than TEE in the obese children (8.37 +/- 1.35 MJ/day, p < 0.05) but close to TEE in the nonobese children (8.64 +/- 1.54 MJ/day, p = not significant). These results suggest that obese children underreport food intake and that the dietary record and the diet history are not valid means of assessing energy intake in obese prepubertal children.

Maximal aerobic power during running and cycling in obese and non-obese children

The maximal aerobic capacity while running and cycling was measured in 22 prepubertal children (mean age +/- SD 9.5 +/- 0.8 years): 14 obese (47.3 +/- 10 kg) and 8 non-obese (31.1 +/- 6.1 kg). Oxygen consumption (VO2) and carbon dioxide production were measured by an open circuit method. Steady state VO2 was determined at different levels of exercise up to the maximal power on the cycloergometer (92 W in obese and 77 W in non-obese subjects) and up to the maximal running speed on the treadmill at a 2% slope (8.3 km/h in obese and 9.0 km/h in lean children). Expressed in absolute values, the VO2max in obese children was significantly higher than in controls (1.55 +/- 0.29 l/min versus 1.23 +/- 0.22 l/min, p < 0.05) for the treadmill test and comparable in the two groups (1.4 +/- 0.2 l/min versus 1.16 +/- 0.2 l/min, ns) for the cycloergometer test. When VO2max was expressed per kg fat free mass, the difference between the two groups disappeared for both tests. These data suggest that obese children had no limitation of maximal aerobic power. Therefore, the magnitude of the workload prescribed when a physical activity program is intended for the therapy of childhood obesity, it should be designed to increase caloric output rather than to improve cardiorespiratory fitness.

Energy expenditure during walking and running in obese and nonobese prepubertal children

We measured body composition and energy expenditure during walking and running on a treadmill in 40 prepubertal children: 23 obese children (9.3 +/- 1.1 years of age; 46 +/- 10 kg (mean +/- SD)) and 17 nonobese matched control children (9.2 +/- 0.6 years of age; 30 +/- 5 kg). Energy expenditure was assessed by indirect calorimetry with a standard open-circuit method. At the same speed of exercise, the energy expenditure was significantly (p < 0.01) greater in obese than in control children, in both boys and girls. Expressed per kilogram of body weight or per kilogram of fat-free mass, the energy expenditure was comparable in the two groups. Obese children had a significantly (p < 0.01) larger pulmonary ventilatory response to exercise than did control children. Heart rate was comparable in boys and girls combined but significantly higher (p < 0.05) in obese subjects, if boys and girls were analyzed separately. These data indicate that walking and running are energetically more expensive for obese children than for children of normal body weight. The knowledge of these energy costs could be useful in devising a physical activity program to be used in the treatment of obese children.

Basal energy expenditure in obese and normal weight schoolchildren

The present study was performed using indirect calorimetry to test the hypothesis of a reduction of the basal energy expenditure in obese prepubertal children. The obese and control children studied were comparable regarding age, height and fat-free mass (FFM). Total weight and body fat percentage were significantly greater in the obese children. Plasma insulin and glucagon concentrations were significantly higher in obese than in control children. In the two groups of children the basal metabolic rates (BMRs) were comparable in both absolute values and values adjusted for FFM, age and gender utilizing the multiple regression analysis. The most important variable to predict BMR was FFM, followed by age. BMR was significantly correlated with FFM, both for obese and control children, and also when the two groups were combined. In conclusion, our data do not support the idea that a child's obesity is maintained by increased metabolic efficiency at least in basal conditions.