The relationship between stature, growth, and short-term changes in height and weight in normal prepubertal children

Childhood body mass index trajectories and asthma and allergies: A systematic review

BACKGROUND

Previous systematic reviews have focused on associations between single time point measures of Body Mass Index (BMI) and asthma and allergic diseases. As BMI changes dynamically during childhood, examination of associations between longitudinal trajectories in BMI and allergic diseases is needed to fully understand the nature of these relationships.

OBJECTIVE

To systematically synthesise the association between BMI trajectories in childhood (0-18 years) and allergic diseases (asthma, eczema, allergic rhinitis, or food allergies outcomes).

DESIGN

We conducted a systematic review following the PRISMA guidelines, and two independent reviewers assessed the study quality using the ROBINS-E and GRADE tools. A narrative synthesis was performed as the statistical heterogeneity did not allow a meta-analysis.

DATA SOURCES

A search was performed on PubMed and EMBASE databases on 4th January 2023.

ELIGIBILITY CRITERIA

Longitudinal cohort studies assessing the associations between childhood BMI trajectories and allergic diseases were included.

RESULTS

Eleven studies met the inclusion criteria with a total of 37,690 participants between 0 and 53 years of age. Ten studies examined asthma outcomes, three assessed association with allergic rhinitis, two assessed eczema, and one assessed food allergy. High heterogeneity and high risk of bias were observed. Overall, the quality of evidence was very low. Nevertheless, two consistent findings were identified: (1) a persistently high BMI between 6 and 10 years of age may be associated with an increased risk of asthma at 18 years and (2) a rapid increase in BMI in the first 2 years of life may be associated with subsequent asthma.

CONCLUSIONS

Maintaining a normal BMI trajectory during childhood may reduce the risk of asthma. Future research that adequately addresses confounding and includes longer-term follow-up is needed. Moreover, additional studies examining potential associations with eczema, food allergies, and allergic rhinitis outcomes are needed.

Interactions between Growth of Muscle and Stature: Mechanisms Involved and Their Nutritional Sensitivity to Dietary Protein: The Protein-Stat Revisited

Childhood growth and its sensitivity to dietary protein is reviewed within a Protein-Stat model of growth regulation. The coordination of growth of muscle and stature is a combination of genetic programming, and of two-way mechanical interactions involving the mechanotransduction of muscle growth through stretching by bone length growth, the core Protein-Stat feature, and the strengthening of bone through muscle contraction via the mechanostat. Thus, growth in bone length is the initiating event and this is always observed. Endocrine and cellular mechanisms of growth in stature are reviewed in terms of the growth hormone-insulin like growth factor-1 (GH-IGF-1) and thyroid axes and the sex hormones, which together mediate endochondral ossification in the growth plate and bone lengthening. Cellular mechanisms of muscle growth during development are then reviewed identifying (a) the difficulties posed by the need to maintain its ultrastructure during myofibre hypertrophy within the extracellular matrix and the concept of muscle as concentric "bags" allowing growth to be conceived as bag enlargement and filling, (b) the cellular and molecular mechanisms involved in the mechanotransduction of satellite and mesenchymal stromal cells, to enable both connective tissue remodelling and provision of new myonuclei to aid myofibre hypertrophy and (c) the implications of myofibre hypertrophy for protein turnover within the myonuclear domain. Experimental data from rodent and avian animal models illustrate likely changes in DNA domain size and protein turnover during developmental and stretch-induced muscle growth and between different muscle fibre types. Growth of muscle in male rats during adulthood suggests that "bag enlargement" is achieved mainly through the action of mesenchymal stromal cells. Current understanding of the nutritional regulation of protein deposition in muscle, deriving from experimental studies in animals and human adults, is reviewed, identifying regulation by amino acids, insulin and myofibre volume changes acting to increase both ribosomal capacity and efficiency of muscle protein synthesis via the mechanistic target of rapamycin complex 1 (mTORC1) and the phenomenon of a "bag-full" inhibitory signal has been identified in human skeletal muscle. The final section deals with the nutritional sensitivity of growth of muscle and stature to dietary protein in children. Growth in length/height as a function of dietary protein intake is described in the context of the breastfed child as the normative growth model, and the "Early Protein Hypothesis" linking high protein intakes in infancy to later adiposity. The extensive paediatric studies on serum IGF-1 and child growth are reviewed but their clinical relevance is of limited value for understanding growth regulation; a role in energy metabolism and homeostasis, acting with insulin to mediate adiposity, is probably more important. Information on the influence of dietary protein on muscle mass per se as opposed to lean body mass is limited but suggests that increased protein intake in children is unable to promote muscle growth in excess of that linked to genotypic growth in length/height. One possible exception is milk protein intake, which cohort and cross-cultural studies suggest can increase height and associated muscle growth, although such effects have yet to be demonstrated by randomised controlled trials.

Regional Differences in Height, Weight, and Body Composition may Result from Photoperiodic Responses: An Ecological Analysis of Japanese Children and Adolescents

This ecological study examined whether geographical differences in the physique of Japanese children and adolescents can be explained from the perspective of photoperiodicity induced by effective day length (light duration exceeding a certain threshold of illuminance) using prefecture-level anatomical data and Mesh Climatic Data. Multiple regression analysis for height prediction demonstrated that when controlled by weight, effective day lengths of the longest and shortest months were inversely correlated with height distribution. Conversely, for weight prediction, when controlled by height, the effective day lengths of the longest and shortest months were positively correlated with weight distribution. The regression coefficients were greater for the effective day length of the shortest month in both height and weight prediction. This phenomenon where the same two explanatory variables are negatively correlated with height and positively correlated with weight in a significant manner is rare, and there may be no physiological interpretation of this phenomenon other than one based on changes in thyroid hormone signaling. These distribution characteristics are common to the photoperiodicity by which seasonal breeding vertebrates reciprocally switch thyroid hormone signaling according to prior photoperiodic history through epigenetic functions. From these perspectives, thyroid hormone signaling in a certain region was assumed to be activated in summer according to the prior shorter winter day length and inactivated in winter according to the prior longer summer day length. Regarding the prevalence of obesity, the coexistence of longer summer and winter day lengths was thought to set body composition to be short and fat in early adolescence.

Evaluating the seasonality of growth in infants using a mobile phone application

It has been observed that growth velocity of toddlers and school children shows seasonal variation, while such seasonality is unknown in infants. The aim of this study was to examine whether growth velocity (length and weight) of infants differs by seasons. We assessed longitudinal measurement data obtained for 9,409 Japanese infants whose parents used the mobile phone application, "Papatto Ikuji", during the period from January 2014 to October 2017. On average, each infant had 4.8 entries for length and 5.4 entries for weight. The mean daily change in sex- and age-adjusted z-scores between two time points was estimated as the growth velocity during that period: ΔLAZ/day and ΔWAZ/day for length and weight, respectively. We analyzed 20,007 ΔLAZ/day (mean, -0.0022) and 33,236 ΔWAZ/day (mean, 0.0005) measurements, and found that ΔLAZ/day showed seasonal differences with increases during summer. We conducted a multilevel linear regression analysis, in which effects of age, sex, nutrition and season of birth were adjusted, showing significant difference in ΔLAZ/day between winter and summer with a mean ΔLAZ/day difference of 0.0026 (95%CI 0.0015 to 0.0036; P < 0.001). This seasonal difference corresponded to 13% of the average linear growth velocity in 6-month-old infants. A modest effect of nutrition on linear growth was observed with a mean ΔLAZ/day difference of 0.0015 (95%CI 0.0006 to 0.0025; P < 0.001) between predominantly formula-fed infants and breastfed infants. In conclusion, we observed that linear growth, but not weight gain, of Japanese infants showed significant seasonality effects represented by increases in summer and decreases in winter.

Chronobiological Hypothesis about the Association Between Height Growth Seasonality and Geographical Differences in Body Height According to Effective Day Length

Studies on growth hormone therapy in children have shown that height velocity is greater in summer than in winter and that this difference increases with latitude. It is hypothesized that summer daylight is a causative factor and that geographical distribution of body height will approximate the distribution of summer day length over time. This is an ecological analysis of prefecture-level data on the height of Japanese youth. Mesh climatic data of effective day length were collated. While height velocity was greatest during the summer, the height of Japanese youth was strongly and negatively correlated with the distribution of winter effective day length. Therefore, it is anticipated that summer height velocity is greater according to winter day length (dark period). This may be due to epigenetic modifications, involving reversible DNA methylation and thyroid hormone regulation found in the reproductive system of seasonal breeding vertebrates. If the function is applicable to humans, summer height growth may quantitatively increase with winter day length, and height growth seasonality can be explained by thyroid hormone activities that-induced by DNA methylation-change depending on the seasonal difference in day length. Moreover, geographical differences in body height may be caused by geographical differences in effective day length, which could influence melatonin secretion among subjects who spend a significant time indoors.

Seasonal variations in growth and body composition of 8-11-y-old Danish children

BACKGROUND

Earlier studies on seasonality in growth reported the largest height gains during spring and largest body weight gains during autumn. We examined seasonality in height, body weight, BMI, fat mass index (FMI), and fat-free mass index (FFMI) among contemporary Danish 8-11-y olds.

METHODS

A total of 760 children from the OPUS School Meal Study provided >2,200 measurements on height, body weight, and composition between September and June. Average velocities were calculated using change-score analyses based on 3-mo intervals. As a complementary analysis, point velocities derived from estimated growth curves were fitted using semiparametric regression that included covariate adjustment and allowed flexible modeling of the time trend.

RESULTS

Average velocities showed the following trends: height was higher than the average (6.10 cm/y) in January-April. Body weight was below the average (4.02 kg/y) in August-January and above in January-May; BMI (average: 0.49 kg/ m(2)/y) and FFMI (average: 0.17 kg/m(2)/y) showed similar trends. In contrast, FMI was above the average (0.38 kg/m(2)/y) in November-March. Similar trends were seen for point velocities.

CONCLUSION

Our findings suggest seasonality in growth and body composition of Danish children. We recovered the well-known height velocity peak during spring time, but unlike earlier studies, we found coincident peaks in body weight, BMI, and FFMI velocities.

The seasonality of slipped upper femoral epiphysis--meta-analysis: a possible association with vitamin D

We performed a meta-analysis of studies evaluating the seasonality of slipped upper femoral epiphysis (SUFE). In addition we compared the monthly incidences of SUFE at latitudes greater than 40° with the established serum 25-hydroxyvitamin levels for children resident at a comparative latitude. In total 11 relevant studies were identified, involving 7451 cases of SUFE. There was significant variation in the month of onset of SUFE. The degree of variability increased with increasing latitude. The modal month of symptomatic onset was dependent upon latitude. At latitudes greater than 40°, the most common month of onset was August. At latitudes between 20° and 40°, this was earlier in the calendar year, around April. The seasonal variability was statistically significant (p<0.0001 and p<0.005 for latitudes >40° and 20°-40° respectively). The pattern of monthly fluctuation in onset of SUFE very closely mirrored the monthly pattern of variation for serum 25-hydroxyvitamin D3. There was a very strong positive correlation (Spearman rank rho = + 0.8, p = 0.001). There is a monthly variation in incidence of SUFE. The degree of variability increases with increasing latitude. There may be an association with vitamin D. We hypothesise that elevated serum 25-hydroxyvitamin D3 accelerates growth thus rendering the growth plate vulnerable to slippage in analogous manner to the pubertal growth spurt.

Effect of summer daylight exposure and genetic background on growth in growth hormone-deficient children

The response to growth hormone in humans is dependent on phenotypic, genetic and environmental factors. The present study in children with growth hormone deficiency (GHD) collected worldwide characterised gene–environment interactions on growth response to recombinant human growth hormone (r-hGH). Growth responses in children are linked to latitude, and we found that a correlate of latitude, summer daylight exposure (SDE), was a key environmental factor related to growth response to r-hGH. In turn growth response was determined by an interaction between both SDE and genes known to affect growth response to r-hGH. In addition, analysis of associated networks of gene expression implicated a role for circadian clock pathways and specifically the developmental transcription factor NANOG. This work provides the first observation of gene–environment interactions in children treated with r-hGH.

Integrating fundamental concepts of obesity and eating disorders: implications for the obesity epidemic

Physiological mechanisms promote weight gain after famine. Because eating disorders, obesity, and dieting limit food intake, they are famine-like experiences. The development of the concept of meeting an ideal weight was the beginning of increasing obesity. Weight stigma, the perception of being fat, lack of understanding of normal growth and development, and increased concern about obesity on the part of health providers, parents, and caregivers have reinforced each other to promote dieting. Because weight suppression and disinhibition provoke long-term weight increase, dieting is a major factor producing the obesity epidemic. The integrated eating disorder-obesity theory included in this article emphasizes that, contrary to dieters, lifetime weight maintainers depend on physiological processes to control weight and experience minimal weight change.

Child health, its dynamic interaction with nutrition and health memory--evidence from Senegal

Child malnutrition is pervasive in developing countries and anthropometric measures such as weight-for-height and height-for-age have proven reliable indicators of short term malnutrition and stunting. Rather than studying these indicators separately, we look at their interaction and carve out child health dynamics. Considering height-for-age a child's health stock and weight-for-lagged height a proxy for nutritional inputs, we develop a child health production function that features self-productivity of past health stocks and contemporaneous nutritional inputs. We test the model on a Senegalese panel of 271 children between 0 and 5 years employing dynamic panel methods to control for endogeneity in the production function. In line with previous evidence, we find that children can partially catch-up from malnutrition spells. Yet, child health stocks also deplete quickly and need constant updating in the form of nutrition. This demonstrates the importance of health memory and that malnutrition cannot be fought with snapshot interventions. Consequently, sustainable nutrition interventions have to be long term and yield higher returns the earlier they reach children.

Translational neuroendocrinology: control of human growth

Human growth is driven by both basic cell processes as well as hormones, in particular the growth hormone (GH)-insulin-like growth factor (IGF)-1 axis. Understanding how these mechanisms are coordinated is not only critical to achieving a normal growth rate, but also to recognising potential new causes of disordered growth and how they might be treated. We have demonstrated in healthy children that height is gained by periods of rapid growth interspersed by periods of very slow growth or even stasis. We have also shown that a lower order organism, Caenorhabditis elegans, grows in a similar manner. By contrast, secretion of GH from somatotrophs occurs on a daily basis in discrete pulses over a 24-h period. We have used the measurement of GH in urine as a surrogate marker of GH secretion to show that there are rhythms of GH output with frequencies of several days. We then assessed which attributes of these GH profiles were related to growth and found that disorderliness in the GH profile (as measured by approximate entropy) was related to better growth rate. This feature was then tested in the dwarf rat using different GH regimens to introduce variation into the administration of daily GH injections. Better long bone growth was associated with week-to-week or even random dose variation compared to the same amount of GH delivered as a standard daily dose. Understanding the control of growth has implications in clinical practice for modelling GH treatment regimens based on physiological principles.

Probiotics Lactobacillus reuteri DSM 17938 and Lactobacillus casei CRL 431 modestly increase growth, but not iron and zinc status, among Indonesian children aged 1-6 years

Probiotics and milk calcium may increase resistance to intestinal infection, but their effect on growth and iron and zinc status of Indonesian children is uncertain. We investigated the hypotheses that cow milk with added probiotics would improve growth and iron and zinc status of Indonesian children, whereas milk calcium alone would improve growth but reduce iron and zinc status. A 6-mo randomized trial was conducted in low-socioeconomic urban communities of Jakarta. Healthy children (n = 494) were randomly assigned to receive low-lactose milk with a low calcium content of ∼50 mg/d (LC; n = 124), a regular calcium content of ∼440 mg/d (RC group; n = 126), regular calcium with 5 × 10(8) CFU/d Lactobacillus casei CRL 431 (casei; n = 120), or regular calcium with 5 × 10(8) CFU/d Lactobacillus reuteri DSM 17938 (reuteri; n = 124). Growth, anemia, and iron and zinc status were assessed before and after the intervention. Compared with the RC group, the reuteri group had significantly greater weight gain [0.22 (95% CI: 0.02, 0.42) kg], weight-for-age Z-score (WAZ) changes [0.09 (95% CI: 0.01, 0.17)], and monthly weight [0.03 (95% CI: 0.002, 0.05) kg/mo] and height [0.03 (95% CI: 0.01, 0.05) cm/mo] velocities. Casei significantly increased monthly weight velocity [0.03 (95% CI: 0.001, 0.05) kg/mo], but not height. However, the changes in underweight, stunting, anemia prevalence, and iron and zinc status were similar between groups. In conclusion, L. reuteri DSM 17938 modestly improved growth by increasing weight gain, WAZ changes, and weight and height velocity, whereas L. casei CRL 431 modestly improved weight velocity. Independent from probiotics supplementation, regular milk calcium did not affect growth or iron and zinc status.

Evaluation of a multicomponent intervention to improve weight status and fitness in children: Upstarts

BACKGROUND

Many physical activity intervention programs are unable to sustain long-term improvements in activity levels and are often not cost-effective. The aim of this study was to determine if a low-cost school- and community-centered sports coaching program was able to improve health-related fitness in children.

METHODS

Children from three schools in socially deprived areas took part in weekly coaching sessions over two 10 week periods during the school year. Coaching was provided by local community-based sports clubs. Body mass index (BMI), jump height, handgrip strength, and 20 m shuttle run test (20mSRT) performance were assessed before and after each of the two intervention periods, to determine short- and long-term changes in health-related fitness. Age- and sex-normalized z-scores were calculated using normative UK reference data for each measure.

RESULTS

BMI z-score did not change in the short term, as expected, but importantly was significantly lower at the end of the study. Both handgrip and 20mSRT performance scores increased after the first 10 week period. Only improvements in handgrip were maintained for the whole study period. Jump height actually decreased over the entire study period.

CONCLUSION

There were some notable benefits of this novel, cost-effective, naturalistic intervention but future studies should examine seasonal variation and motivational factors as potential confounding variables.

Summer effects on body mass index (BMI) gain and growth patterns of American Indian children from kindergarten to first grade: a prospective study

BACKGROUND

Overweight and obesity are highly prevalent among American Indian children, especially those living on reservations. There is little scientific evidence about the effects of summer vacation on obesity development in children. The purpose of this study was to investigate the effects of summer vacation between kindergarten and first grade on growth in height, weight, and body mass index (BMI) for a sample of American Indian children.

METHODS

Children had their height and weight measured in four rounds of data collection (yielded three intervals: kindergarten, summer vacation, and first grade) as part of a school-based obesity prevention trial (Bright Start) in a Northern Plains Indian Reservation. Demographic variables were collected at baseline from parent surveys. Growth velocities (Z-score units/year) for BMI, weight, and height were estimated and compared for each interval using generalized linear mixed models.

RESULTS

The children were taller and heavier than median of same age counterparts. Height Z-scores were positively associated with increasing weight status category. The mean weight velocity during summer was significantly less than during the school year. More rapid growth velocity in height during summer than during school year was observed. Obese children gained less adjusted-BMI in the first grade after gaining more than their counterparts during the previous two intervals. No statistically significant interval effects were found for height and BMI velocities.

CONCLUSIONS

There was no indication of a significant summer effect on children's BMI. Rather than seasonal or school-related patterns, the predominant pattern indicated by weight-Z and BMI-Z velocities might be related to age or maturation.

TRIAL REGISTRATION

Bright Start: Obesity Prevention in American Indian Children Clinical Trial Govt ID# NCT00123032.

Seasonal variations in physical activity and implications for human health

This review explores the implications of seasonal changes in physical activity for fitness and human health. Photosensitivity and nutrient shortages mediate animal hibernation via the hypothalamus and changes in leptin and ghrelin concentrations. Opportunities for hunting and crop cultivation determine seasonal activity in under-developed human societies, but in developed societies temperature and rainfall are dominant influences, usually over-riding innate rhythms. Both questionnaire data and objective measurements show that many groups from children to the elderly increase their physical activity from winter to spring or summer. Measurements of maximal oxygen intake and muscle strength commonly show parallel seasonal changes. However, potential effects upon body mass and body fat may be counteracted by changes of food intake; subsistence agriculturists sometimes maintain or increase physical activity at the expense of a decrease in body mass. In developed societies, body fat commonly increases during the winter, with parallel changes in blood lipids, blood pressure and blood coagulability; moreover, these changes are not always fully reversed the following summer. Most developed societies show increased all-cause and cardiac mortalities in the winter. Health consequences of seasonal variations in physical activity including an increased vulnerability to cardiac catastrophe and a year-by-year increase in total body fat seem most likely if the average level of physical activity for the year is low. Public health recommendations should underline the importance of maintaining physical activity during adverse environmental conditions by adapting clothing, modifying behaviour and exploiting any available air-conditioned indoor facilities.

Reductions in the energy content of meals served in the Chilean National Nursery School Council Program did not consistently decrease obesity among beneficiaries

In 2001, the Chilean National Nursery Schools Council Program reduced by 10% the energy content (approximately 418.7 kJ) of meals served to children to reduce obesity. We assessed the impact of this measure on obesity and stunting among beneficiaries 2-5 y old. The energy reduction was staggered over 3 y, allowing for a quasi-experimental design involving early (2001), mid (2002), and late (2003) intervention groups. Routine anthropometric measurements (approximately 64,000/y) taken from 1996-2005 were obtained from registries; obesity (BMI-for-age Z-score > or = 2 SD) and stunting (height-for-age Z-score < or = 2 SD) were defined using the 2006 growth standards. Segmented regression analyses were conducted by intervention group to contrast pre- and postintervention trends. Overall, obesity was high (15.9%), with levels consistently higher in fall and winter as reported in other studies. Preintervention obesity trends increased in the early group (P = 0.001) but decreased in the late intervention group (P = 0.02). The impact of the energy reduction on obesity was inconsistent, with reductions in the early group (P < 0.01) but with no change in mid and late intervention groups (P > 0.05). Stunting prevalence was almost as low as in the growth standard (3.2 vs. 2.3%) and decreased preintervention in all groups (P < 0.05). Stunting prevalence increased postintervention (P < 0.05) in all but the late intervention group, where there was no change. Despite a robust design and the ability to detect small seasonal changes in obesity, our analyses showed that the 10% energy reduction did not consistently decrease obesity. The intervention may have slowed improvements in linear growth, but concern is tempered by the near absence of growth failure.

Body mass index in rural first grade schoolchildren: progressive increase in boys

CONTEXT

Childhood overweight is a global health problem. Monitoring of childhood body mass index (BMI) may help identify critical time periods during which excess body weight is accumulated.

PURPOSE

To examine changes in mean BMI and the prevalence of at-risk-for overweight in repeated cross-sectional samples of rural first grade schoolchildren between 1999 and 2004.

METHODS

BMI was determined in 479 first graders from a rural Wyoming school district. BMI and gender-specific BMI-for-age percentiles were determined and evaluated over the 6 years. Children were also classified as normal or at-risk-for overweight according to CDC classification procedures.

FINDINGS

From 1999 to 2004, there was a significant increase in the average BMI of first graders, 15.8+/-2.2 kg/m2 versus 16.8+/-2.2 kg/m2, respectively (P<.05). First grade boys had a progressive increase in BMI from 1999 to 2004 (15.6+/-2.2 kg/m2 compared to 17.3+/-2.2 kg/m2, respectively), but no change was evident for first grade girls. There was an approximate 4-fold increase in the percentage of rural first grade boys classified as at-risk-for overweight between 1999 and 2004.

CONCLUSIONS

A progressive increase in the BMI and the significant increase in prevalence of at-risk-for overweight in rural first grade boys highlight the need for future gender and age group-specific investigations. Focus should be given to primary prevention programs targeting potentially vulnerable time periods when excess weight gain may be occurring.

Seasonal anthropometric cycles in a command economy: the case of Czechoslovakia, 1946-1966

Anthropometric evidence is used to shed light on the living standards in early communist Czechoslovakia (1946-1966). Height and weight variation of adolescent boys exhibit a pattern that is inconsistent with that for a normal healthy population. The hypothesis is proposed that this pattern arose from periodic food supply shortages, most marked in the spring of each year. The boys in the sample display a remarkably slow growth during the spring but catch up over the summer.

Sex differences in the relationships among weight gain, subcutaneous skinfold tissue and saltatory length growth spurts in infancy

As the mechanisms controlling the amount and timing of growth saltations are not well understood, the identification of physiologic coupling in weight and length growth are important for further understanding normal growth biology. Thirty-four healthy infants (13 males, 21 females) participated in a longitudinal growth study during the first year. Weekly weights and s.c. skinfolds (limb and trunk) were analyzed in a growth event-focused study. Coincident analysis tested the null hypothesis of chance concurrence between significant weight gain and saltatory length growth spurts. Logistic regression quantified this relationship and investigated the interaction between incremental weight gain and s.c. skinfolds on length growth spurts. The null hypothesis of random coincidence between weight gain and saltatory length growth was not supported. For girls, significant weight gain and length growth were coupled during the same week and length saltations were 42% more likely during the weeks of significant weight gain, with no interaction from s.c. skinfolds. For boys, length growth saltations were coupled to both previous and concomitant weight gain but were predicted only by previous weight gain, controlling for confounders. Boys were 68% more likely to grow in length the week following significant weight gain, and initial abdominal to suprailiac skinfold ratios conferred a 4-fold increased likelihood of length growth within the week, controlling for confounders. These data generate the hypothesis that a common growth signal cascade couples growth in weight and length/height with a time delay due to sex-specific biology, reflected in a s.c. fat fold interface.

Seasonality of growth response to GH therapy in prepubertal children with idiopathic growth hormone deficiency

OBJECTIVE

Longitudinal growth of children exhibits seasonal variation. In both healthy children and in children with growth hormone (GH) deficiency (GHD) receiving GH therapy, growth rate is maximal during spring and summer. In the present study, we analyzed the growth response to GH therapy in children with GHD as a function of the season when therapy was started.

SUBJECTS AND METHODS

Anthropometric measurements and biochemical analyses of GH secretion status and bone formation were longitudinally assessed in a cohort of 52 prepubertal children with GHD (14 girls, mean age 7.6 years) who were treated with a fixed dose of GH (0.025 mg/kg/day).

RESULTS

Auxological assessments over the 2-year observation period revealed a significantly better growth response to GH therapy in children who started therapy between the spring and summer (group 1) compared with children who started in the autumn or winter (group 2). The difference was largest in the initial 3-month treatment period (35%; P<0.01). The initial better gain in height of group 1 was sustained during the study period. Baseline peak GH levels during stimulation tests and insuin-like growth factor-I levels did not differ between the two groups. However, group 1 had significantly higher bone resorption and formation markers, either at the start or shortly after initiation of GH treatment. This suggests that children with GHD have higher bone turnover during spring and early summer, irrespective of GH therapy.

CONCLUSIONS

In summary, this study suggests that the season of GH initiation is a determinant of the initial growth response to GH replacement in prepubertal children with GHD.

A review of activity indices and end points for clinical trials in children with Crohn's disease

The necessity to include children and adolescents in clinical trials is increasingly recognized. Two recent workshops provided the impetus for pediatric gastroenterologists to develop evidence-based recommendations concerning end points and outcome assessment in cases of pediatric Crohn's disease. The overall goal was to facilitate clinical trial design by standardizing the methodology. This article critically reviews the available assessment tools and provides consensus recommendations for the evaluation of linear growth, disease activity, and health-related quality of life in clinical trials in pediatric Crohn's disease.

A help-line for children. Seasonal variations in issues

The objectives of the study were to describe monthly variations in issues in calls to a help-line for children and adolescents. All 80,983 calls to a Red Cross Help-Line for children in 1991-1997 were included. In 22,698 calls, information about age, sex or issue could be identified. A monthly variation in frequency of calls with peaks in April and November and a correlation with the absolute values of monthly changes in length of day were found. Conversations concerning psychiatric suffering were more frequent in January or February and less frequent than expected in May/June and December. Conversations about sexuality correlated with the frequencies of births in the adult population 9 months later. A spring and fall peak in total calling and a winter peak in calls for depression, anxiety, pain and neglect were described.

Seasonal variation of slipped capital femoral epiphysis in the United States

Seasonal variation in the onset of symptoms of slipped capital femoral epiphysis (SCFE) has been described. The author examined seasonal variation of hospital admissions for SCFE using a national database and compared seasonal variation between the northern and southern United States, between girls and boys, and between black and white children. Significant seasonal variation was found in the North in both boys and girls, but there was less seasonal variation among blacks than among whites. Some seasonal variation was present in the South, but it did not reach the level of statistical significance. Although the cause of seasonal variation in SCFE remains unknown, the effect differs by latitude and skin pigmentation, suggesting a possible link to impaired vitamin D synthesis.

Analysis of polymorphisms of the vitamin D receptor, estrogen receptor, and collagen Ialpha1 genes and their relationship with height in children with bone cancer

PURPOSE

The authors' objectives were to compare height at diagnosis of children with bone tumors with that of Spanish reference children; to analyze the frequency of the genotypes for the polymorphisms of the vitamin D receptor (VDR), estrogen receptor (ER), and collagen Ialpha1 (COLIalpha1) genes in patients and in healthy controls; and to test the relationship between the genetic markers and height.

PATIENTS AND METHODS

Height and weight at diagnosis were measured in 58 osteosarcoma and 36 Ewing sarcoma patients and compared with standards published for Spanish reference children according to sex and age. For the molecular analysis, genetic polymorphisms of the VDR (Fok I, Apa I, and TaqI), ER (Pvu II and XbaI), and COLIalpha1 (Msc I) genes were characterized in 72 osteosarcoma and 53 Ewing sarcomas and in a group of 143 healthy matched children.

RESULTS

Osteosarcoma and Ewing sarcoma patients were significantly taller than Spanish reference children. Osteosarcoma patients showed a significantly higher frequency of the Ff genotype for the Fok I polymorphism (VDR gene) than the control group. The odds ratio for this genotype was 1.78, with an increased relative risk of 78% for heterozygous Ff carriers. Among Ewing sarcoma patients, this same genotype was significantly associated with lower height than homozygotes (FF or ff).

CONCLUSIONS

Children with bone cancer are significantly taller than the reference population, which may be influenced by the genotype for the Fok I polymorphism of the VDR gene.

Short-term changes in growth and urinary growth hormone, insulin-like growth factor-I and markers of bone turnover excretion in healthy prepubertal children

Childhood growth is a non-linear process. To assess whether there is a biochemical correlate of non-linear growth, we have measured free pyridinoline (fPYR) and deoxypyridinoline (fDPYR) excretion in seven healthy prepubertal children, aged 6.1-7.7 years. To examine the link between short-term growth and hormone output, urinary growth hormone (uGH) and insulin-like growth factor-I (uIGF-I) were also measured. Height and weight were measured and a timed overnight urine was collected three times per week from September to July, with results expressed as a weekly change in height (Dheight(w)) or weight (Dweight(w)), and as weekly average hormone or bone marker excretion (uGH(w), uIGF-I(w), fPYR(w), fDPYR(w)). Subject specific SD scores (SDS) were derived for each variable.Dheight(w)and Dweight(w)did not correlate to uGH(w), uIGF-I(w), fPYR(w)or fDPYR(w). Dheight(w)SDS was weakly but significantly correlated to fPYR(w)SDS (r = +0.16;P<0.05) and fDPYR(w)SDS (r = +0.15;P<0.05). The percentage of high frequency (2-4 weeks) variation in uGH(w)excretion, as defined by time series analysis, was correlated with the mean uIGF-I(w)(r = +0.81;P<0.05), which in turn was significantly reduced (92 +/- 38 vs 120 +/- 47 ng;P<0.001) during periods of slow growth (Dheight(w)< 0.05 cm/week). We conclude that in normal children the amount of urinary fPYR, fDPYR, GH and IGF-I does not provide a direct biochemical correlate of growth from week to week. However good growth is associated with a relative increase in fPYR and fDPYR excretion, while poor growth is associated with reduced IGF-I excretion, which in turn is influenced by the temporal secretory pattern of GH over 2-4 weeks.