A longitudinal study of the physical growth of Japanese infants.

In order to clarify the characteristics of the physical growth of Japanese infants up to 1 year of age, the data of 3183 infants from 53 hospitals in Japan were collected. Percentile values were calculated from the measurement of body weight, recumbent length, and head circumference, with some additional data interpolated to fill the gaps in the measurements. Compared to the National Center for Health Statistics (NCHS) standard, the recumbent length and head circumference of these infants were smaller throughout the observation period, while body weight was larger at 0-6 months of age, and smaller at 8-12 months of age. The cases were divided into five groups according to birth weight, to examine the influence of foetal growth. The 50th percentile curves of each group were parallel and the intervals between the 3rd and 97th percentile curves in each group became wider in the first 6 months of life, up to the interval of 2.20-3.18 Kg. There was no significant difference in body weight among three groups according to feeding methods, in any age period.     

Structure of monthly increments of length, weight and head circumference in the first year: a pure longitudinal study of 200 Wroc?aw infants

One hundred boys and 100 girls born in Wroc?aw, Poland from 1973 to 1975 were measured every month during the first year of life and every three months during the second. Body length and weight and head circumference were examined. The statistics of values of the traits and their increments and some of the correlation coefficients are given in the tables.     

A longitudinal study of growth in length and weight of Punjabi infants in Chandigarh, India

One hundred and fifty-four Punjabi infants (86 male, 68 female) were followed longitudinally and their lengths and weights measured each month during the first year of life. Monthly distance and velocity means for their weight and crown-heel length with the respective standard deviations are presented. The general pattern of growth is characterized by a period of rapid initial increase followed by a period of slower increment during the second half of infancy. Length velocity decreased from birth onwards, but weight velocity shows a peak at around 1.5 months, followed by a decline.     

Sleep difficulties in infants at risk for developmental delays: a longitudinal study

Objectives We compared the sleep of infants at risk forneuromotor delays to that of infants without such risks, andexamined the predictive validity of risk indicators to the developmentof sleep problems. Methods Conveniently recruitedinfants (n = 142) were assessed for neuromotor achievementsand sleep behaviors at 4–6 months and 10–12 monthsof age. Assessment tools were the Harris Infant Neuromotor Testand Morrell's Infant Sleep Questionnaire. Based on a cumulativerisk index, three groups were defined: higher risk (n = 28),lower risk (n = 42), and no risk (n = 72). Results Atboth ages, the sleep scores were similar among the groups. Inthe no risk and lower risk group, sleep difficulties decreasedwith age, while for infants in the higher risk group, more difficultieswere reported over time. Overall, the neuromotor attainmentswere not related to sleep fragmentation or settling difficulties. Conclusions Ina diverse sample of infants, with and without risks for developmentaldelays, overall, sleep patterns were similar. It appears thatthe neuromotor achievements are not associated with sleep-wakeregulation, as measured by caregivers’ report.     

Quantitative assessment of right and left reaching movements in infants: a longitudinal study from 6 to 36 months

This longitudinal study aimed to explore the early presence and developmental pattern of laterality in reaching kinematics and its relationship to side use. In order to do so, 3-D kinematic measurements as well as 2-D video recordings of right-left reaching movements were successively carried out for 17 infants at the ages of 6, 9, 12, and 36 months. Additional investigations of hand preference were made at 36 months. As four infants were prematurely born, their outcomes were compared to those of the fullterm participants. While most of the infants in the early ages showed a rather inconsistent preference in terms of frequency and distributions of right-left side use, the analyses of reaching kinematics revealed a more consistent pattern of fewer movements units (MUs) and straighter right-sided reaching for the majority of infants at all tested ages. However, reaching kinematics from the preterm infants were generally more variable and less side consistent. It is proposed that the development of human handedness originates from an early right arm rather than hand preference in that representations of asymmetry in bilateral projections (involved in arm movements) developmentally precede contralateral projections (involved in refined hand/finger movements).     

Sibling similarity in annual growth increments in schoolchildren from a rural community in Oaxaca, Mexico

Sibling similarity in annual growth increments was analysed in schoolchildren, aged 6-13 years, from a Zapotec-speaking, subsistence agricultural community in the Valley of Oaxaca in southern Mexico. Sibling correlations for 44 brother-brother, 44 sister-sister, and 110 unlike sex pairs were computed for 17 dimensions holding constant environmental effects, age difference between siblings, and the growth status of each sibling for the dimension. Correlations are negative or close to zero. The lack of similarity between siblings in annual growth increments perhaps reflects age-specific variation in a genotype-environment interaction with chronic undernutrition, the important mediating environmental variable.     

A longitudinal study of gamma-interferon production by peripheral blood mononuclear cells from breast- and bottle-fed infants.

Production of gamma-interferon (gamma-IFN) in vitro by peripheral blood mononuclear cells (PBMC) from 15 breast-fed and 15 bottle-fed infants has been studied from birth to 9 months of age and compared with production by adult cells. Using a Terasaki plate microculture system with serum-free medium, PBMC were stimulated with staphylococcal enterotoxin A (SEA) and gamma-IFN production was assessed by an immunoradiometric assay. Cord blood mononuclear cells (CBMC) and PBMC from all infants secreted large quantities of gamma-IFN. The levels secreted did not change significantly with age over the 9 months of the study, nor did they differ from the levels secreted by adult cells. Cells from the bottle-fed infants secreted slightly more gamma-IFN than cells from breast-fed infants, but this difference was not significant. These results indicate that the potential for PBMC to secrete gamma-IFN in vitro is fully developed at birth in full-term infants and cannot therefore be further influenced by subsequent breast- or bottle-feeding. In addition, the greater susceptibility of infants than adults to certain bacterial and viral infections cannot be attributed to a deficiency in the potential of infant cells to secrete gamma-IFN in vitro.     

Multi-level modelling of longitudinal child growth data from the Birth-to-Twenty Cohort: a comparison of growth models

Background: Different structural and non-structural models have been used to describe human growth patterns. However, few studies have compared the fitness of these models in an African transitioning population.

Aim: To find model(s) that best describe the growth pattern from birth to early childhood using mixed effect modelling.

Subjects and methods: The study compared the fitness of four structural (Berkey-Reed, Count, Jenss-Bayley and the adapted Jenss-Bayley) and two non-structural (2nd and 3rd order Polynomial) models. The models were fitted to physical growth data from an urban African setting from birth to 10 years using a multi-level modelling technique. The goodness-of-fit of the models was examined using median and maximum absolute residuals, Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC).

Results: There were variations in how the different models fitted to the data at different measurement occasions. The Jenss-Bayley and the polynomial models did not fit well to growth measurements in the early years, with very high or very low percentage of positive residuals. The Berkey-Reed model fitted consistently well over the study period.

Conclusion: The Berkey-Reed model, previously used and fitted well to infancy growth data, has been shown to also fit well beyond infancy into childhood.     

A longitudinal study of prospective control in catching by full-term and preterm infants

Prospective control when catching moving toys was studied longitudinally in full-term and preterm infants between the ages of 22 and 48 weeks. The toy’s distance and time to the catching place and its velocity were explored as possible timing strategies used by infants to start their hand movement. The aim of the study was to find evidence for a shift in timing strategy and whether there were differences between full-term and preterm infants. In addition, it was investigated how infants continuously guided their hands to the toy and whether this guidance was influenced by their use of timing strategy. The toy approached the infants from the side with different constant velocities and constant accelerations. Results showed that there was little difference between full-term and preterm infants’ use of timing strategies. Initially, infants used a distance- or velocity-strategy, possibly causing them to have many unsuccessful catches. After a shift to a time-strategy, infants appeared to increase the number of successful catches and performed longer and more functional tau-couplings between the hand and the toy. One preterm infant did not switch to a time-strategy, and frequently missed the moving toy. The same infant also showed less functional tau-coupling with non-controlled collisions between the hand and the toy. More follow-up research is needed to investigate whether problems with extracting the relevant perceptual information for action could be an early indication of later perceptuo-motor difficulties.     

A longitudinal study of growth in Newcastle upon Tyne adolescents

White Newcastle upon Tyne schoolchildren born in 1962 were examined at approximately half-yearly intervals from 9 to 17 years of age. During the last year of compulsory education losses to follow-up became selective with respect to socio-economic background, and the results reported here are restricted to 564 boys and 669 girls seen regularly between the ages of 10 and 15 years at least. Newcastle adolescents were slightly shorter and lighter than the London children on whom Tanner's British Standards were based. The longitudinal pattern of skinfold changes in boys was different from that observed in girls. Differences in height attained between occupational groups were well established by the age of five years, and the same was true of differences between family-size groups for children with fathers in manual occupations. It is inferred that differences in height between occupational and family-size groups resulted more from differences in leg than in trunk length. At age 15, the correlations of height attained with maternal height were 0.42 and 0.43, and with birthweight 0.25 and 0.28, for boys and girls respectively. Adjustment, by regression, of heights attained for birthweight, age at peak height velocity and maternal height diminished differences between occupational and family-size groups. After such adjustment, heights significantly lower than average were found only among subjects with fathers in unskilled manual occupations and with large families. Among subjects with fathers in manual occupations, subscapular and triceps skinfolds and arm circumference decreased significantly with increasing family size.     

Genetic and environmental influences on growth from late childhood to adulthood: a longitudinal study of two Finnish twin cohorts

Objectives: Human growth is a complex process that remains insufficiently understood. We aimed to analyze genetic and environmental influences on growth from late childhood to early adulthood. Methods: Two cohorts of monozygotic and dizygotic (same sex and opposite sex) Finnish twin pairs were studied longitudinally using self‐reported height at 11–12, 14, and 17 years and adult age (FinnTwin12) and at 16, 17, and 18years and adult age (FinnTwin16). Univariate and multivariate variance component models for twin data were used. Results: From childhood to adulthood, genetic differences explained 72–81% of the variation of height in boys and 65–86% in girls. Environmental factors common to co‐twins explained 5–23% of the variation of height, with the residual variation explained by environmental factors unique to each twin individual. Common environmental factors affecting height were highly correlated between the analyzed ages (0.72–0.99 and 0.91–1.00 for boys and girls, respectively). Genetic (0.58–0.99 and 0.70–0.99, respectively) and unique environmental factors (0.32–0.78 and 0.54–0.82, respectively) affecting height at different ages were more weakly, but still substantially, correlated. Conclusions: The genetic contribution to height is strong during adolescence. The high genetic correlations detected across the ages encourage further efforts to identify genes affecting growth. Common and unique environmental factors affecting height during adolescence are also important, and further studies are necessary to identify their nature and test whether they interact with genetic factors. Am. J. Hum. Biol., 2011. © 2011Wiley‐Liss, Inc.     

Model fitting to early childhood length and weight data from the fels longitudinal study of growth

Length and weight data from 3 months to 6 years of age from 466 participants in the Fels Longitudinal Study of Growth were used to fit the Jenss non-linear growth curve. Six (1%) of the Fels participants had extremely outlying values for length parameters, and 20 (4%) had outlying values for weight parameters. The general pattern in the outliers is for average or below average size in infancy, followed by unusually rapid growth or weight gain in childhood. This outlier pattern is associated with significantly higher mean stature or weight at 18 years of age. The results for the majority of the participants are similar to those found in 229 children from the Harvard Growth Study, except for the non-linear intercept for length and the linear intercept for weight. Significant sex differences have not previously been reported for Jenss parameters, perhaps because previous applications have used much smaller sample sizes.     

Family resemblance for Preece-Baines growth curve parameters in the fels longitudinal growth study

The Preece-Baines Model 1 (PB1) nonlinear regression equation was fit to serial stature measurements from 456 participants in the Fels Longitudinal Growth Study. The resulting model parameters and derived biological parameters, such as age, stature, and velocity at take-off (TO) and peak velocity (PV) are analyzed for family resemblance in 228 nuclear families through estimation of familial correlations and path coefficients. Significant family resemblance was found for all of the growth parameters. Transmissibility estimates ranged from 41%–71%, suggesting that some of the factors controlling the timing and shape of the adolescent growth spurt are transmitted from parent to child. Significant gender effects were found in sibling resemblance, with brother-brother pairs more similar than other pairs for age at TO and PV and sister-sister pairs more alike for stature at TO and PV and for velocity at PV. © 1993 Wiley-Liss, Inc.     

Type A behavior: a longitudinal study from childhood to adulthood

In a longitudinal study of a sample of Swedish males and females (n = 170), Type A-related behavior at age 13 was related to the scores on an abbreviated Type A scale based on JAS which was administered when the same subjects were 27 years old. Aggression, Motor Hyperactivity, Overambition, and Overachievement measured at age 13 were used as predictors in a multiple regression analysis, with Type A score at age 27 as the dependent variable. The following results were obtained: 1) for men the multiple correlation was 0.41 (p less than 0.01), with Aggression and Overambition accounting for most of the prediction, and b) for women the multiple correlation was 0.36 (p less than 0.05), with Motor Hyperactivity accounting for most of the prediction. It was concluded that Type A-related behavior could be identified rather early and that it shows an unexpected degree of stability over a period of 14 years.     

Genetics of pre-pubertal growth: A longitudinal study of Japanese twins

Background: Genetic factors explain a major part of the variation of adult stature, but little is still known on the genetics of growth, especially in non-Caucasian populations.

Aim: To analyse the quantitative genetics of pre-pubertal growth in Japanese children.

Subjects and methods: Data from birth until 11 years of age were collected on 349 complete twin pairs based on previously recorded height measures. The data were analysed using two different multivariate models by the Mx statistical package.

Results: No major sex differences were found and thus boys and girls were analysed together. Since 1 year of age, genetic factors explained from 42–71% and environmental factors shared by co-twins from 14–33% of the variation of height. Genetic continuity of height was high and 75% of the genetic variance was shared since 1 year of age. Environmental factors affecting height showed weaker correlations between early and late childhood than genetic factors.

Conclusion: Growth from early to late childhood is largely regulated by the same set of genes. However, also environmental factors shared by co-twins are important for growth. Identifying specific environmental factors affecting growth has potentially important public health implications, even in an affluent society such as Japan.     

Influence of environment on speech-sound discrimination: findings from a longitudinal study

Event-related potentials (ERPs) from 134 children were obtained at 3 and 8 years of age and recorded to a series of consonant-vowel speech syllables and their nonspeech analogues. The HOME inventory was administered to these same children at 3 and 8 years of age and the sample was divided into 2 groups (low vs. high) based on their HOME scores. Discriminant functions analyses using ERP responses to speech and non-speech analogues successfully classified HOME scores obtained at 3 and 8 years of age and discriminated between children who received low vs. high levels of stimulation for language and reading.     

Reading kanji without semantics: Evidence from a longitudinal study of dementia

The effects of the degenerative disease process on patterns of oral reading and reading comprehension of Japanese kanji words were investigated longitudinally in 3 demented patients, based on repeated administration of the 50-item Kanji Pronunciation-Comprehension Test (K.P.C.T.) and a battery of tests assessing a variety of cognitive abilities including semantic memory. On the K.P.C.T., all 3 patients showed essentially perfect oral reading until the very advanced stage of the disease process, which was in marked contrast to the progressive deterioration of their ability to comprehend the same set of words. These findings, consistent with some interpretation of lexical nonsemantic reading in English-speaking neurological patients, suggest the existence of an independent orthography-to-phonology transcoding procedure for kanji words. An interesting discrepancy in the pattern of word pronunciation performance, however, was noted between the Japanese patients (co-existence of near normal word naming and progressive deterioration of comprehension) and the Englishspeaking demented patients with analogous “nonsemantic reading” (emergence of regularisation errors in exception words relatively early in the disease process). Possible explanations and hypotheses for this discrepancy are presented.