[Body mass index charts of Algerian children and adolescents (6-18 years)]. / Courbes de l'indice de masse corporelle d'enfants et adolescents algériens (6­18 ans).

The body mass index (BMI) is widely accepted as a measure of overweight and obesity in children. There are no BMI reference charts for Algerian children and adolescents. The purpose of this study was to construct BMI percentile curves appropriate for children aged 6-18 years in Algeria. The weight and height of 7772 (54.9% girls) healthy schoolchildren from Constantine (eastern Algeria) were measured in 2008/2009. Weight and height for age curves based on the same sample were published previously. The BMI for age percentile curves were estimated in girls and boys separately using the LMS smoothing method. In both sexes, the median BMI increased with age. Girls had lower BMI values than boys before the age of 10 years but they were higher after this age until 18 years of age. Within the study population, the prevalence of overweight (including obesity) and obesity in girls and boys together was 13.7% and 3.0%, respectively, according to the International Obesity Task Force (IOTF) and 16.9% and 4.9% according to the World Health Organization (WHO) (2007). The median BMI curves of Algerian girls and boys were generally lower than those observed in other Arab countries. Compared with other references, the median BMI values of girls were lower than those of a Belgian Flemish population and WHO 2007 until 14 years of age and higher than the French reference between 7 and 18 years of age. The BMI values of Algerian boys were close to the Belgian (Flemish population), French and WHO 2007 references between 6 and 9 years of age and generally lower thereafter. These BMI curves are complementary to the height and weight charts published previously for the assessment of growth in children and adolescents. They were developed according to international guidelines and could serve as a national reference. They could be used as a complement to the 0- to 5-year-old WHO 2006 standards.

[Weight and height local growth charts of Algerian children and adolescents (6-18 years of age)]. / Courbes de poids et de taille d'enfants et adolescents algériens âgés de 6 à 18 ans.

Measurements of height and weight provide important information on growth and development, puberty, and nutritional status in children and adolescents. The aim of this study was to develop contemporary reference growth centiles for Algerian children and adolescents (6-18 years of age). A cross-sectional growth survey was conducted in government schools on 7772 healthy schoolchildren (45.1% boys and 54.9% girls) aged 6-18 years in Constantine (eastern Algeria) in 2008. Height and weight were measured with portable stadiometers and calibrated scales, respectively. Smooth reference curves of height and weight were estimated with the LMS method. These height and weight curves are presented together with local data from Arab countries and with the growth references of France, Belgium (Flanders), and the World Health Organization (WHO) 2007. In girls, median height and weight increased until 16 and 17 years of age, respectively, whereas in boys, they increased through age 18 years. Between ages 11 and 13 years (puberty), girls were taller and heavier than boys. After puberty, boys became taller than girls, by up to 13 cm by the age of 18 years. Median height and weight of Algerian boys and girls were generally intermediate between those observed in other Arab countries. They were higher than the French reference values up to the age of 13 years and lower than Belgian and WHO reference values at all ages. The present study provides Algerian height- and weight-for-age growth charts, which should be recommended as a national reference for monitoring growth and development in children and adolescents.

Growth of Belgian and Norwegian children compared to the WHO growth standards: prevalence below -2 and above +2 SD and the effect of breastfeeding.

BACKGROUND: New national growth references have been published in Belgium and Norway. The WHO recommends universal use of their 2006 Child Growth Standards based on data from breastfed children. OBJECTIVE: To compare the growth of Belgian and Norwegian children with the WHO standards. PARTICIPANTS: 6985 children 0-5 years of age from Belgium and Norway. DESIGN: Proportion of children below -2 SD and above +2 SD of the WHO standards was calculated for length/height, weight, body mass index and head circumference. Average SD scores of exclusively breastfed children of non-smoking mothers were compared with national reference data and with the WHO standards. RESULTS: Generally, the number of Belgian and Norwegian children below -2 SD lines of the WHO standards was lower and above +2 SD higher than expected. The largest differences were for head circumference (0.97% Belgian and 0.18% Norwegian children below -2 SD, 6.55% Belgian and 6.40% Norwegian children above +2 SD) and the smallest for length/height (1.25% Belgian and 1.43% Norwegian children below -2 SD, 3.47% Belgian and 2.81% Norwegian children above +2 SD). The growth pattern of breastfed children of non-smoking mothers was in both countries more alike the local national growth references than the WHO standards. CONCLUSIONS: There are significant deviations in the proportion of children outside normal limits (±2 SD) of the WHO standards. This was true for all children, including those who were exclusively breastfed. Hence, adoption of the WHO growth charts could have consequences for clinical decision-making. These findings advocate the use of national references in Belgium and Norway, also for breastfed children.

References for growth and pubertal development from birth to 21 years in Flanders, Belgium.

BACKGROUND: Due to the secular trend in length and height, growth references need to be updated regularly. Reference charts that were until recently used in Belgium are based on samples collected more than 30 years ago, and references for body mass index (BMI) and pubertal development have not been established before. AIMS: To establish contemporary cross-sectional reference charts for height, weight, BMI, head circumference, and pubertal development from birth to 21 years of age, based on a representative sample of children from Flanders, Belgium. SUBJECTS AND METHODS: 15 989 healthy subjects of Belgian origin, 0-25 years of age, were measured in 2002-2004. Growth curves were fitted with the LMS method, and percentiles for the pubertal development were estimated with generalized additive models on status quo data from 8690 subjects aged 6-22 years of age. RESULTS: A positive secular trend in height and weight is observed in children above 5 years of age. Adult median height has increased by 1.2 cm/decade in boys and 0.8 cm/decade in girls; median weight by 0.9 kg/decade in boys, and 1.0 kg/decade in girls, and the weight distribution became more skewed. The BMI curve is comparable to that of other populations, except for higher percentiles. This reflects the increasing prevalence of overweight and obesity. Median age at menarche (13.0 years) has not advanced any more over the past 50 years. Median ages at menarche and B2 in girls and G2 or T4 in boys are comparable to other West European estimates, but approximately 10% enter G2/T4 before 9 years of age. CONCLUSIONS: The ongoing secular trend in height and weight makes growth charts previously used in Belgium obsolete. New representative charts for growth and pubertal development are introduced. For weight monitoring, it is advised that the now-available BMI growth charts are used.

Multifactorial analysis of a mixed-longitudinal sample of Indian siblings: Age and sex effects on heritability.

The aim of the present study was to examine the heritability of 11 traits in a mixed-longitudinal sample of Indian siblings, and to determine whether heritability estimates vary during the growth period and whether they are influenced by sex. The sample consisted of 245 brothers and 213 sisters from 138 nuclear families living in a semi-urban area in Kolkata, India. The age ranged between 5 and 19 years. The traits were standardised for age and sex using standard deviation scores (SDS) produced by the LMS method (Cole, T.J., 1988. Fitting smoothed centile curves to reference data. J. R. Stat. Soc. A 151, 385-418). The standard deviation scores were analysed by PCA. The two factors with eigenvalues above 1 explained 77.3% of the variance; they showed a high level of pleiotropism present among the studied traits and represented body lengths (PC1) and body weight and breadths (PC2). The heritability between all types of siblings (irrespective of sex) for the PC1 and PC2 was estimated. The heritability between various pairs of siblings showed variations along the whole ontogenetic period studied. During the childhood and pre-pubertal period, heritability between brothers, brother-sister pairs and any sibling pairs was mostly constant, with small and non-significant variations. All the pairs showed the lowest degree of heritability during puberty for PC1 but not for PC2, with significant changes of heritability estimates between adolescence and adulthood, in most of the analysed sibling pairs and in both PC factors. The highest heritability was generally observed at the end of the examined growth period in all pairs. A significant effect of sex on heritability was only detected for PC2 at 11 years of age.

Overweight and obesity in Norwegian children: secular trends in weight-for-height and skinfolds.

AIM: The prevalence of overweight and obesity in paediatric populations has been rapidly increasing in many countries over the past decades. The aims of the present study were to provide new data on weight-for-height and skinfolds, and to compare these to growth references for children between 3 and 17 years, collected in the same city between 1971 and 1974. MATERIAL: The present study is based on cross-sectional data of 4115 children (2086 boys and 2029 girls) aged 4-15 years measured in 2003-6. RESULTS: Overall, 18.0% of the boys and 20.1% of the girls were above the 90th weight-for-height percentile of the 1971-1974 references, 8.0% and 7.2% were above the 97.5th percentile, indicating an upward shift in weight-for-height. An even more prominent increase was observed for skinfold thicknesses; for triceps skinfolds about 30% of the boys and 28% of the girls were above the 90th percentile of the 1971-1974 references, and corresponding values for subscapular skinfolds were 26.5% and 25.9%. Using international cut-off values for body mass index, the overall prevalence of overweight and obesity was 12.5% and 2.1% in boys, and 14.8% and 2.9% in girls. CONCLUSIONS: Our study has demonstrated a significant increase in weight-for-height in Norwegian children over the last 30 years, and that these changes are caused by an increase in fat tissue, as shown by skinfold measurements. The current prevalence of overweight and obesity is comparable to recent estimates from most Western and Northern European countries.

Heritability variations of morphometric traits in West Bengal (India) children aged 4-19 years: a mixed-longitudinal growth study.

BACKGROUND: Longitudinal and semi-longitudinal growth studies on siblings reflecting heritability changes during growth are very scarce. Moreover, studies of variables other than height, weight and BMI are virtually non-existent. AIM: The study compared changes in the heritability of six body lengths, four body breadths, and three indices between ages 4 and 19 years on the basis of a mixed-longitudinal sample of siblings, and examined whether heritability estimates change during the growth period. The data consisted of 238 brothers and 214 sisters from 134 middle-class nuclear families living in Kolkata (India). The analysis of sibling correlation was performed by maximum likelihood. The age-related patterns of heritabilities of the various traits were described by a cubic spline. RESULTS: The heritability was very high and significant in most traits, and at all considered ages. Mean heritability in the 10 morphometric traits was 69.3%, which was higher than the heritability values for the three indices. CONCLUSIONS: These results confirmed the existence of age-related trends in heritability of the considered morphometric traits. The sharp decline of the heritabilities at adolescence in most of the morphometric traits, and the acromio-iliac index in particular, may be due to the large inter-individual variation in the age at which the adolescent growth spurt is reached in both sexes.

Age trends of sibling resemblance for height, weight and BMI during growth in a mixed longitudinal sample from Sarsuna-Barisha, India.

BACKGROUND: Even though some studies have considered that sibling resemblance remains constant throughout the life cycle, several investigations emphasize the importance of age and its interactions with genetic and environmental factors in determining sibling similarity in several bodily traits. In fact, the study of age changes in familial resemblance is of great importance for the analysis of certain sources of variation observed in growth processes. AIM: The study examined sibling resemblance for height, weight and body mass index (BMI) in a mixed longitudinal sample from West Bengal, ages 2-19 years, in order to analyse the variations with age of the sibling resemblance for these phenotypes during growth. SAMPLE AND METHODS: Two hundred and forty-five brothers and 213 sisters from 138 middle-class nuclear families living in a semi-urban area of South Kolkata, India were analysed. The analysis of sibling resemblance was performed through correlations estimated by the maximum-likelihood method. The patterns of different trends of sibling resemblance with age were examined by fitting a cubic non-linear regression to the observed correlations. RESULTS: The results show clear variations with age in the sibling resemblance for the traits height and weight, though to a lesser extent for BMI. In general, we found the highest correlation values during the period of infancy, a remarkable decrease during puberty, and a trend of increase towards the end of the growth cycle. CONCLUSION: The study confirms the effect of age on the degree of similarity among siblings for height, weight and BMI in the sample. The sharp decline of correlation at adolescence can be interpreted in terms of the individual variation in age of reaching the adolescent growth spurt.

Influence of hOGG1, XRCC1 and XRCC3 genotypes on biomarkers of genotoxicity in workers exposed to cobalt or hard metal dusts.

Identification of genetic polymorphisms responsible for reduced DNA repair capacity may allow better cancer prevention. We examined whether variations in genes involved in base-excision (hOGG1, XRCC1) and double strand break (XRCC3) DNA repair contribute to inter-individual differences in genotoxic effects induced in the lymphocytes of 21 cobalt (Co) exposed, 26 hard metal (WC-Co) exposed and 26 matched control male workers. Genotyping was performed by PCR-RFLP. DNA single strand breaks and alkali-labile sites were measured by the alkaline Comet assay. Chromosomal rearrangements resulting from chromosome loss or acentric fragments were assessed as micronucleated mononucleates (MNMC) and binucleates (MNCB) with the cytokinesis-block micronucleus test. Urinary 8-hydroxydeoxyguanosine (8-OHdG) levels were used as an indicator of systemic oxidative DNA damage. A significantly higher frequency of MNMC was observed in WC-Co exposed workers with variant hOGG1(326) genotype. Multivariate analysis performed with genotypes, age, exposure status, type of plant, smoking and their interaction terms as independent variables indicated that MNMC and Comet tail DNA (TD) were influenced by genetic polymorphisms. In the exposed and total populations, workers variant for both XRCC3 and hOGG1 had elevated MNMC frequencies. Further studies will demonstrate whether genotyping for hOGG1 and XRCC3 polymorphisms is useful for a better individual monitoring of workers.

Growth patterns and final height in congenital adrenal hyperplasia due to classical 21-hydroxylase deficiency. Results of a multicenter study.

BACKGROUND: Longitudinal growth and bone age (BA) development are the most important clinical parameters for monitoring adequate glucocorticoid replacement in children with congenital adrenal hyperplasia (CAH). AIM OF THE STUDY: To analyze the growth pattern of patients treated for CAH of the salt wasting (SW) and simple virilizing (SV) clinical forms; to evaluate final height as compared to reference data and individual target height; to evaluate the course of BA development. PATIENTS AND METHODS: A large database of 598 patients with CAH was created in 5 Central European countries and growth data of 341 treated patients with 21-hydroxylase deficiency were analyzed retrospectively. The patients were of Caucasian origin. Centiles were constructed in a cross-sectional manner and an additional longitudinal analysis was performed in order to evaluate the pubertal growth spurt by applying particular statistical methods (Preece-Baines model). RESULTS: The growth of SW CAH patients was impaired in infancy and early childhood (0-3 years of age), but followed normal patterns in childhood until puberty. In contrast, children with SV CAH had normal patterns of growth in infancy and early childhood and were considerably taller than healthy references during childhood. In the longitudinal study, peak height velocity in both boys and girls was normal, but it occurred at an earlier age than in the standard population. The final height of patients with CAH was reduced in comparison to both the reference and the individual target height. No correlations were found between final height and age at the start of the therapy in SV patients or between final height and year of birth. BA was advanced in both types of CAH, but more accelerated in SV patients. CONCLUSION: Characteristic growth patterns for treated SV and SW CAH children were identified, with a normal pubertal growth spurt and reduced final height being observed.

Height velocity in Argentinean girls with Turner's syndrome.

Height velocities from birth to maturity derived from 1,049 height increments measured over intervals 0.85-1.15 years were studied from a sample of 187 patients with Turner's syndrome (TS) diagnosed on the basis of karyotype. Length of follow up in each girl varied from 1.0 to 11.0 years. Cross-sectional analysis showed a relatively stable growth velocity during pubertal ages. However, longitudinal analysis of individual growth curves showed the existence of a small growth spurt in 37 out of 47 girls with available data during pubertal years. Mean peak height velocity (PHV) of this spurt was 5.7 cm/year, SD 1.34; mean age at PHV was 12.66 years, SD 1.70. Selected percentiles were calculated using the least mean squares (LMS) method. Results show that a small growth spurt in girls with TS may be more frequent than previously thought.

Longitudinal growth study of male Japanese junior high school athletes.

The aim of this study was to establish the pattern of adolescent growth in height of male Japanese athletes, and to compare their growth with appropriate controls. The sample consisted of 126 baseball, 39 basketball, 83 soccer, and 53 volleyball players, and 36 nonathletes. The data were collected retrospectively in six public schools in Fukui Prefecture of Western Japan between 1970 and 1987. All subjects were measured at yearly intervals between the age of 6 and 18 years. The total number of measurement occasions for the 337 subjects amounted to 4,134. Athletes trained between 13 and 18 h/week. Individual growth patterns were determined by fitting Preece Baines model I to each individual's serial data. Various biological parameters were derived from the fitted curves. The results indicated that the average growth pattern of these adolescent athletes did not differ substantially from the control group. Volleyball players were significantly taller at 18 years (+3 cm) than the nonathletes (Student's t-test, P < 0.05). Soccer players showed a slight tendency towards late maturation with age at take-off and at peak velocity about half a year later than in nonathletes (Student's t-test, P < 0.05). The 2.3 cm gain in body height due to the later onset of the pubertal growth spurt in soccer players was counterbalanced by a 0.7 cm smaller prepubertal height and a 0.9 cm smaller adolescent gain, so that they ended up slightly, but not significantly, taller than the controls (+0.7 cm). The small differences in growth pattern observed between the nonathletes and the various sports suggest that, in contrast with top-level athletes, body size and maturation rate were not important selective factors in the various groups of athletes of the present study.

Genetic analysis of growth curve parameters of body weight, height and head circumference.

A sample of 681 Israeli boys and girls, including 355 regular siblings (SB), 112 pairs of dizygotic (DZ) and 51 pairs of monozygotic (MZ) twins, was measured for body weight (WT), length (HT) and head circumference (HC) at birth and during the first year of life. The Count model with three parameters was chosen as the best fitting and most parsimonious function to approximate growth of the studied traits. The curves' fitting parameters were estimated for WT, HT and HC for each individual. To test the assumption that there is a genetic source influencing the pattern of growth for each trait, familial correlations between parameter estimates were computed for MZ, DZ twins and SB. In all instances MZ twins showed the highest within-pair correlation in parameters of growth (from 0.58 to 0.86), while SB showed the lowest ones (from 0.10 to 0.70). Variance decomposition analysis was used to simultaneously assess the contribution of gender, gestational age, additive genetic factor, common sibs and common intrauterine environmental effects on total variance of each studied trait separately. All these sources of variation were statistically significant, though the effect of intrauterine environment played a substantial role in early stages of child physical development, explaining from 18.1% to 70.6% of the total variance of the growth curve parameters. Further analyses are needed to clarify how this environment affects child growth and for how long.

Age variations in sibling correlations for height, sitting height and weight.

Familial correlations for height, sitting height and weight have been studied in a sample of 1278 siblings for the Biscay province (Basque Country), aged 4+ to 24+ years. The data have been internally standardized according to sex and age of individuals. The degree of resemblance among sibling has been expressed by intraclass correlation coefficients. The total sample has been divided into three age categories: < 12 years, 12-15 years, and > or = 15 years, in order to examine the effect of age on sibling correlations. In general, changes with age have been observed: sibling correlations for height show a clear upward trend through the considered growth period, reaching a value of 0.48 from 15 years of age. Intra-correlations for weight show a slight downward trend with age. Sitting height shows a rather low correlation before 12 years of age, but equally high values in the other two ranges of age (0.48 and 0.47, respectively). This study confirms that the sibling resemblance for the analysed trait fluctuated through the growth period--height and sitting height showing similar patterns of variation with age--and that, after puberty, the degree of genetic determination is higher for bone measurements than for weight.

Secular changes in growth and maturation: an update.

Secular changes in growth and maturation in recent decades have been reviewed for various populations. The secular increase in attained height during the growth period is continuing in most countries, but has slowed down. The increase in adult stature over the past decades has varied between 0.3 and 3.0 cm/decade. The secular trend in the tempo of growth (earlier menarche and peak height velocity, and shortening of the growth cycle) has come to a halt in some populations, but is continuing or has been reversed in others. The secular trend in attained height and in the tempo of growth is usually more pronounced in children from low socioeconomic backgrounds, in those with poorly educated parents or in those from rural areas. It is concluded that updates of growth standards are required in all populations. More marked secular changes appear to occur in the lower height centiles, which may have direct implications on the future definition of 'short stature' in a population.

Socioeconomic factors and growth during childhood and early adolescence in Jena children.

The influence of socioeconomic parameters (number of children in the family, birth order of subject, professional status of the father, education of the mother) and background characteristics (birth length, birth weight and age of the mother at birth of the child) of growth in body height in children from 4 to 12 years of age was investigated. The analysis is based on data from a longitudinal growth survey, which started with 207 children (98 males and 109 females) from Jena (Germany) in 1985. Multiple regression analysis was used to estimate the degree of relationship between height and the social or background factors. In this study no differences in growth between children of different social groups were found. Variation in height of girls was mainly affected by the biological factor length at birth of the child.

Secular changes in growth.

Secular changes in growth have occurred in almost all industrialized countries during the last century. Almost all of the secular increase seen in adult height occurs during childhood. These changes can be considered to be indicators of the changes in the nutritional, hygienic and health status of a population. The secular trend in adult height has slowed down since the second world war, but is still continuing in most industrialized countries.

Determinants of growth in body length from birth to 6 years of age: A longitudinal study of Lublin children.

The effect of determinants of growth in body length from birth to 6 years of age were studied in a longitudinal sample of 59 male and 70 female infants from Lublin, Poland. Structural equation modeling (SEM) was used to study the effects of gender of the child, occupation of the parents, the educational level of the parents, per capita income, the stature of the parents, and the weight of the mother on body length at birth and at 1, 2, 3, and 6 years of age. Significant sex differences in length were observed at birth and during the first 2 years of postnatal life, but not in the period between 3 and 6 years of age. Socioeconomic status (SES), expressed as a latent variable in the SEM, was not related to body length at birth but was significantly related to body length during infancy and, to a lesser extent, to body length during childhood. Paternal stature was not related to body length at birth and during infancy, but was significantly related to body length from 3 years onwards. Maternal stature was significantly related to body length at birth and at 1 year of age, but not thereafter, while maternal weight was significantly related to body length at birth only. © 1996 Wiley-Liss, Inc.

Genetic variance in the pattern of the growth curve for height: a longitudinal analysis of male twins.

Genetic aspects of the pattern of growth and of short-term variations in growth velocity for height were studied in a sample of 44 MZ and 42 DZ twin pairs from the Wroclaw Longitudinal Twin Study. The data consists of serial measurements of height, taken between 8.5 years of age and adulthood. The intra-pair resemblance of the pattern of attained height was quantified by means of the average Euclidean distance coefficient and the coefficient of shape difference, calculated on the raw height-for-age data. Comparison of these resemblance coefficients between the two types of twins indicated that the growth curves of MZ twins are closer to each other, and more similar in shape, than those of DZ twins. The shape of the growth curve was further characterized by a set of biological parameters, derived from Preece Baines model I (PB) fitted to each subject's serial growth data. Genetic analysis of these parameters, according to the model of Christian, Won Kang and Norton (1974), revealed a strong genetic component in the variance of size at particular milestones in the growth process (height at take-off, at peak velocity and at adulthood), and also in the timing of the growth process (age at take-off and at peak velocity). Height velocity at take-off and peak height velocity were also strongly genetically determined. Finally, short-term variations in growth velocity were analysed on the basis of the profiles of the residuals, obtained by the PB fits to each subject's serial measurements of height. Resemblance coefficients were calculated for the profiles of residuals. The results revealed a significantly greater similarity of profile shapes of the residuals in MZ twins than in DZ twins, strongly suggesting that there is a genetic component in the short-term variations of growth velocity.