Childhood circumstances and anthropometry: The Boyd Orr cohort

Design and Control of a Single-Leg Exoskeleton with Gravity Compensation for Children with Unilateral Cerebral Palsy

Children with cerebral palsy (CP) experience reduced quality of life due to limited mobility and independence. Recent studies have shown that lower-limb exoskeletons (LLEs) have significant potential to improve the walking ability of children with CP. However, the number of prototyped LLEs for children with CP is very limited, while no single-leg exoskeleton (SLE) has been developed specifically for children with CP. This study aims to fill this gap by designing the first size-adjustable SLE for children with CP aged 8 to 12, covering Gross Motor Function Classification System (GMFCS) levels I to IV. The exoskeleton incorporates three active joints at the hip, knee, and ankle, actuated by brushless DC motors and harmonic drive gears. Individuals with CP have higher metabolic consumption than their typically developed (TD) peers, with gravity being a significant contributing factor. To address this, the study designed a model-based gravity-compensator impedance controller for the SLE. A dynamic model of user and exoskeleton interaction based on the Euler-Lagrange formulation and following Denavit-Hartenberg rules was derived and validated in Simscape^™ and Simulink^® with remarkable precision. Additionally, a novel systematic simplification method was developed to facilitate dynamic modelling. The simulation results demonstrate that the controlled SLE can improve the walking functionality of children with CP, enabling them to follow predefined target trajectories with high accuracy.

A quantitative synthesis study on body mass index and associated factors among adult men and women in Switzerland

Excess weight is caused by multiple factors and has increased sharply in Switzerland since the 1990s. Its consequences represent a major challenge for Switzerland, both in terms of health and the economy. Until now, there has been no cross-dataset overview study on excess weight in adults in Switzerland. Therefore, our aim was to conduct the first synthesis on excess weight in Switzerland. We included all existing nationwide Swiss studies (eight total), which included information on body mass index (BMI). Mixed multinomial logistic regression analyses were performed to assess the associations between different socio-demographic, lifestyle cofactors and the World Health Organization (WHO) categories for BMI. Along with lifestyle factors, socio-demographic factors were among the strongest determinants of BMI. In addition, self-rated health status was significantly lower for underweight, pre-obese and obese men and women than for normal weight persons. The present study is the first to synthesise all nationwide evidence on the importance of several socio-demographic and lifestyle factors as risk factors for excess weight. In particular, the highlighted importance of lifestyle factors for excess weight opens up the opportunity for further public health interventions.

The role of body height as a co-factor of excess weight in Switzerland

Object

Excess weight (Body Mass Index [BMI] ≥25.0 kg/m²) is a major health issue worldwide, including in Switzerland. For high‐income countries, little attention has been paid to body height in context of excess weight. The aim of this study is to assess the importance of body height as a co‐factor for excess weight in multiple large nationwide data sets.

Data and methods

In this comparative study, we included the largest nationwide and population‐based studies in the fields of public health, nutrition and economics for Switzerland, as well as data of the medical examination during conscription for the Swiss Armed Forces, which contained information on BMI and, if possible, waist‐to‐height‐ratio (WHtR) and waist‐to‐hip‐ratio (WHR).

Results

The multinomial logistic regressions show that the probability of belonging to the excess weight category (BMI ≥25.0 kg/m²) decreased with increasing height in both sexes inall contemporary data sets. This negative association was shown to be constant, only among conscripts measured in the 1870s the association was positive, when increasing height was associated with a higher BMI. The negative association not only emerge in BMI, but also in WHtR and WHR.

Conclusion

Our results emphasize the importance of body height as a co‐factor of excess weight, suggesting a clear negative association between height and BMI, WHtR and WHR. Evidence indicates that both early‐life environmental exposures and alleles associated with height may contribute to these associations. This knowledge could serve as further starting points for prevention programs in the field of public health.

Obstetric dimensions of the female pelvis are less integrated than locomotor dimensions and show protective scaling patterns: Implications for the obstetrical dilemma

OBJECTIVES

The "obstetrical dilemma" hypothesis assumes that the modern human female pelvis serves two discrete functions: obstetrics and locomotion. We investigate whether these differing functions create observable patterns of morphological covariation and whether those patterns differ by height, weight, and age. This allows evaluation of evidence for canalization and phenotypic plasticity relevant to obstetric and locomotor function among a living female population.

METHODS

Landmarks (N = 86) were collected and inter-landmark distances were calculated (N = 36) on the pelvis and proximal femur of CT scans of living women aged 20 to 90 years (M = 93) receiving a routine CT scan. Partial least squares and relative SD of eigenvalues analyses were used to evaluate integration overall and within locomotor and obstetric modules, respectively. Ordinary Least Squared regression was used to evaluate scaling relationships between inter-landmark distances and height, weight, and age.

RESULTS

The obstetric pelvis was significantly less internally integrated than the locomotor pelvis. Many obstetric measurements were constrained in absolute terms relative to height; shorter women had relatively larger birth canal dimensions, and several key obstetric dimensions showed relative freedom from height. Lower weight women had some relatively larger obstetric and locomotor dimensions. Regarding age, younger women showed a few relatively larger outlet dimensions.

CONCLUSIONS

This study suggests that the obstetric pelvis and the locomotor pelvis function are morphologically distinct, with the obstetric pelvis showing relatively greater flexibility. These relationships between relative constraints support the hypothesis that the modern female pelvis shows evidence of both canalization and phenotypic plasticity in obstetric and locomotor structures.

Secular changes in limb lengths and proportions from 1952 to 2011 in children, adolescents, and young adults from Kolkata (India)

OBJECTIVES

The aim of the study was to investigate the intergenerational changes of upper and lower limb lengths as well as the values of the upper, lower limb, and intermembral indicators of children, adolescents, and young adults from Kolkata (India) between 1952 to 1966 and 2005 to 2011.

METHODS

The analysis was based on the results of anthropometric measurements of 7488 Bengali children, adolescents, and young adults. They were included in three cross-sectional surveys, carried out in 1955 to 1966, 1982 to 1983 (only males), and 2005 to 2011. The upper and lower limb lengths were obtained and the upper and lower limb indicators, as well as an intermembral index, were calculated. The differences between the cohorts were assessed using two-way ANOVA.

RESULTS

Positive, statistically significant, secular trends regarding the length of the lower and upper limbs as well as the value of the lower limb index were observed. Negative intergenerational changes were noted for the values of the upper limb indicator and intermembral index, suggesting that the secular increase of the length of the upper limbs was less pronounced than those of the body height and lower limbs length.

CONCLUSIONS

The secular increase regarding the lower limbs length was associated with the socioeconomic progress of the country, but the length of the upper limbs was less sensitive for those factors. It is also important to mention that there is still very little information on those characteristics in general, which further proves the need for similar studies.

Surname-inferred Andean ancestry is associated with child stature and limb lengths at high altitude in Peru, but not at sea level

OBJECTIVES

Native Andean ancestry gives partial protection from reduced birthweight at high altitude in the Andes compared with European ancestry. Whether Andean ancestry is also associated with body proportions and greater postnatal body size at altitude is unknown. Therefore, we tested whether a greater proportion of Andean ancestry is associated with stature and body proportions among Peruvian children at high and low altitude.

METHODS

Height, head circumference, head-trunk height, upper and lower limb lengths, and tibia, ulna, hand and foot lengths, were measured in 133 highland and 169 lowland children aged 6 months to 8.5 years. For highland and lowland groups separately, age-sex-adjusted anthropometry z scores were regressed on the number of indigenous parental surnames as a proxy for Andean ancestry, adjusting for potential confounders (maternal age and education, parity, altitude [highlands only]).

RESULTS

Among highland children, greater Andean ancestry was negatively associated with stature and tibia, ulna, and lower limb lengths, independent of negative associations with greater altitude for these measurements. Relationships were strongest for tibia length: each additional Andean surname or 1,000 m increase at altitude among highland children was associated with 0.18 and 0.65 z score decreases in tibia length, respectively. Anthropometry was not significantly associated with ancestry among lowland children.

CONCLUSIONS

Greater Andean ancestry is associated with shorter stature and limb measurements at high but not low altitude. Gene-environment interactions between high altitude and Andean ancestry may exacerbate the trade-off between chest dimensions and stature that was proposed previously, though we could not test this directly.

A life course approach to cardiovascular aging

A life course approach in epidemiology investigates the biological, behavioral and social pathways that link physical and social exposures and experiences during gestation, childhood, adolescence and adult life, and across generations, to later-life health and disease risk. We illustrate how a life course approach has been applied to cardiovascular disease, highlighting the evidence in support of the early origins of disease risk. We summarize how trajectories of cardiometabolic risk factors change over the life course and suggest that understanding underlying 'normal' or 'healthy' trajectories and the characteristics that drive deviations from such trajectories offer the potential for early prevention and for identifying means of preventing future disease.

Increasing parental age at childbirth is associated with greater insulin sensitivity and more favorable metabolic profile in overweight adult male offspring

OBJECTIVE

To assess the effect of parental age at childbirth on insulin sensitivity and other metabolic outcomes in overweight middle-aged males.

METHODS

We studied 73 men aged 46.0±5.4 years, who were overweight (body mass index, BMI 25-30 kg/m(2) ) but otherwise healthy. Insulin sensitivity was assessed by the Matsuda method from an oral glucose tolerance test. Other assessments included dual-energy X-ray absorptiometry-derived body composition, lipid profile, 24-hour ambulatory blood pressure, and carotid intima-media thickness. Maternal and paternal ages were highly correlated (r = 0.71; P < 0.0001), and the main parameter of interest in this study was the mean parental age at childbirth (MPAC), calculated as the average of maternal and paternal ages.

RESULTS

Increasing MPAC was associated with a continuous increase in insulin sensitivity (β = 0.193; P = 0.008), as well as reductions in insulin resistance (HOMA-IR; β = -0.064; P = 0.011), fasting insulin (β = -0.221; P = 0.018) and fasting glucose (β = -0.030; P = 0.033) concentrations. Increasing MPAC was also associated with reductions in night time systolic (β = -0.500; P = 0.020) and diastolic (β = -0.325; P = 0.047) blood pressure, as well as with improved (greater) nocturnal diastolic blood pressure dipping (β = 0.413; P = 0.046). Subgroup analyses on participants of European descent (n = 64) showed that increasing MPAC was associated with reduced carotid intima-media thickness (β = -0.008; P = 0.018) and lower low-density lipoprotein cholesterol concentrations (β = -0.042; P = 0.028).

CONCLUSIONS

Increasing parental age at childbirth was associated with a more favorable metabolic phenotype in overweight middle-aged males. However, it is unknown whether the effect was maternal, paternal, or both. Future studies on the effects of parental age at childbirth on the metabolism of males and females across the BMI range are required.

Socioeconomic differences in childhood length/height trajectories in a middle-income country: a cohort study

BACKGROUND

Socioeconomic disadvantage is associated with shorter adult stature. Few studies have examined socioeconomic differences in stature from birth to childhood and the mechanisms involved, particularly in middle-income former Soviet settings.

METHODS

The sample included 12,463 Belarusian children (73% of the original cohort) born in 1996-1997, with up to 14 stature measurements from birth to 7 years. Linear spline multi-level models with 3 knots at 3, 12 and 34 months were used to analyse birth length and growth velocity during four age-periods by parental educational achievement (up to secondary school, advanced secondary/partial university, completed university) and occupation (manual, non-manual).

RESULTS

Girls born to the most (versus least) educated mothers were 0.43 cm (95% confidence interval (CI): 0.28, 0.58) longer at birth; for boys, the corresponding difference was 0.30 cm (95% CI: 0.15, 0.46). Similarly, children of the most educated mothers grew faster from birth-3 months and 12-34 months (p-values for trend ≤ 0.08), such that, by age 7 years, girls with the most (versus least) educated mothers were 1.92 cm (95% CI: 1.47, 2.36) taller; after controlling for urban/rural and East/West area of residence, this difference remained at 1.86 cm (95% CI: 1.42, 2.31), but after additionally controlling for mid-parental height, attenuated to 1.10 cm (95% CI: 0.69, 1.52). Among boys, these differences were 1.95 cm (95% CI: 1.53, 2.37), 1.89 cm (95% CI: 1.47, 2.31) and 1.16 cm (95% CI: 0.77, 1.55), respectively. Additionally controlling for breastfeeding, maternal smoking and older siblings did not substantively alter these findings. There was no evidence that the association of maternal educational attainment with growth differed in girls compared to boys (p for interaction = 0.45). Results were similar for those born to the most (versus least) educated fathers, or who had a parent with a non-manual (versus manual) occupation.

CONCLUSIONS

In Belarus, a middle-income former Soviet country, socioeconomic differences in offspring growth commence in the pre-natal period and generate up to approximately 2 cm difference in height at age 7 years. These associations are partly explained by genetic or other factors influencing parental stature.

TRIAL REGISTRATION

Current Controlled Trials: NCT01352247 assigned 9 Sept 2005; ClinicalTrials.gov. Identifier: NCT01561612 received 20 Mar 2012.

Relationships between neonatal weight, limb lengths, skinfold thicknesses, body breadths and circumferences in an Australian cohort

Background

Low birth weight has been consistently associated with adult chronic disease risk. The thrifty phenotype hypothesis assumes that reduced fetal growth impacts some organs more than others. However, it remains unclear how birth weight relates to different body components, such as circumferences, adiposity, body segment lengths and limb proportions. We hypothesized that these components vary in their relationship to birth weight.

Methods

We analysed the relationship between birth weight and detailed anthropometry in 1270 singleton live-born neonates (668 male) from the Mater-University of Queensland Study of Pregnancy (Brisbane, Australia). We tested adjusted anthropometry for correlations with birth weight. We then performed stepwise multiple regression on birth weight of: body lengths, breadths and circumferences; relative limb to neck-rump proportions; or skinfold thicknesses. All analyses were adjusted for sex and gestational age, and used logged data.

Results

Circumferences, especially chest, were most strongly related to birth weight, while segment lengths (neck-rump, thigh, upper arm, and especially lower arm and lower leg) were relatively weakly related to birth weight, and limb lengths relative to neck-rump length showed no relationship. Skinfolds accounted for 36% of birth weight variance, but adjusting for size (neck-rump, thigh and upper arm lengths, and head circumference), this decreased to 10%. There was no evidence that heavier babies had proportionally thicker skinfolds.

Conclusions

Neonatal body measurements vary in their association with birth weight: head and chest circumferences showed the strongest associations while limb segment lengths did not relate strongly to birth weight. After adjusting for body size, subcutaneous fatness accounted for a smaller proportion of birth weight variance than previously reported. While heavier babies had absolutely thicker skinfolds, this was proportional to their size. Relative limb to trunk length was unrelated to birth weight, suggesting that limb proportions at birth do not index factors relevant to prenatal life.

Childhood height and birth weight in relation to future prostate cancer risk: a cohort study based on the copenhagen school health records register

BACKGROUND

Adult height has been positively associated with prostate cancer risk. However, the exposure window of importance is currently unknown and assessments of height during earlier growth periods are scarce. In addition, the association between birth weight and prostate cancer remains undetermined. We assessed these relationships in a cohort of the Copenhagen School Health Records Register (CSHRR).

METHODS

The CSHRR comprises 372,636 school children. For boys born between the 1930s and 1969, birth weight and annual childhood heights-measured between ages 7 and 13 years-were analyzed in relation to prostate cancer risk. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI).

RESULTS

There were 125,211 males for analysis, 2,987 of who were subsequently diagnosed with prostate cancer during 2.57 million person-years of follow-up. Height z-score was significantly associated with prostate cancer risk at all ages (HRs, 1.13 to 1.14). Height at age 13 years was more important than height change (P = 0.024) and height at age 7 years (P = 0.024), when estimates from mutually adjusted models were compared. Adjustment of birth weight did not alter the estimates. Birth weight was not associated with prostate cancer risk.

CONCLUSIONS

The association between childhood height and prostate cancer risk was driven by height at age 13 years.

IMPACT

Our findings implicate late childhood, adolescence, and adulthood growth periods as containing the exposure window(s) of interest that underlies the association between height and prostate cancer. The causal factor may not be singular given the complexity of both human growth and carcinogenesis.

Sibling configuration predicts individual and descendant socioeconomic success in a modern post-industrial society

Growing up with many siblings, at least in the context of modern post-industrial low fertility, low mortality societies, is predictive of relatively poor performance on school tests in childhood, lower levels of educational attainment, and lower income throughout adulthood. Recent studies further indicate these relationships hold across generations, so that the descendants of those who grow up with many siblings are also at an apparent socioeconomic disadvantage. In this paper we add to this literature by considering whether such relationships interact with the sex and relative age of siblings. To do this we utilise a unique Swedish multigenerational birth cohort study that provides sibling configuration data on over 10,000 individuals born in 1915–1929, plus all their direct genetic descendants to the present day. Adjusting for parental and birth characteristics, we find that the ‘socioeconomic cost’ of growing up in a large family is independent of both the sex of siblings and the sex of the individual. However, growing up with several older as opposed to several younger siblings is predictive of relatively poor performance on school tests and a lower likelihood of progression to tertiary education. This later-born disadvantage also holds across generations, with the children of those with many older siblings achieving lower levels of educational attainment. Despite these differences, we find that while individual and descendant income is negatively related to the number of siblings, it is not influenced by the relative age of siblings. Thus, our findings imply that the educational disadvantage of later-born children, demonstrated here and in numerous other studies, does not necessarily translate into reduced earnings in adulthood. We discuss potential explanations for this pattern of results, and consider some important directions for future research into sibling configuration and wellbeing in modern societies.

Birth order progressively affects childhood height

BACKGROUND

There is evidence suggesting that first-born children and adults are anthropometrically different to later-borns. Thus, we aimed to assess whether birth order was associated with changes in growth and metabolism in childhood.

METHODS

We studied 312 healthy prepubertal children: 157 first-borns and 155 later-borns. Children were aged 3-10 years, born 37-41 weeks gestation, and of birth weight appropriate-for-gestational-age. Clinical assessments included measurement of children's height, weight, fasting lipid and hormonal profiles and DEXA-derived body composition.

RESULTS

First-borns were taller than later-borns (P < 0·0001), even when adjusted for parents' heights (0·31 vs 0·03 SDS; P = 0·001). There was an incremental height decrease with increasing birth order, so that first-borns were taller than second-borns (P < 0·001), who were in turn taller than third-borns (P = 0·007). Further, among sibling pairs both height SDS (P = 0·009) and adjusted height SDS (P < 0·0001) were lower in second- vs first-born children. Consistent with differences in stature, first- (P = 0·043) and second-borns (P = 0·003) had higher IGF-I concentrations than third-borns. Both first- (P < 0·001) and second-borns (P = 0·004) also had reduced abdominal adiposity (lower android fat to gynoid fat ratio) when compared with third-borns. Other parameters of adiposity and blood lipids were unaffected by birth order.

CONCLUSIONS

First-borns were taller than later-born children, with an incremental height reduction from first to third birth order. These differences were present after correction for genetic height, and associated to some extent with alterations in plasma IGF-I. Our findings strengthen the evidence that birth order is associated with phenotypic changes in childhood.

Associations between arterial oxygen saturation, body size and limb measurements among high-altitude Andean children

Objectives

The relative influences of hypoxia and other environmental stressors on growth at altitude remain unclear. Previous work demonstrated an association between peripheral arterial oxygen saturation (S_pO₂) and anthropometry (especially tibia length) among Tibetan and Han children at altitude. We investigated whether similar associations exist among Andeans, and the patterning of associations between S_pO₂ and anthropometry.

Methods

Stature, head-trunk height, total upper and lower limb lengths, zeugopod (ulna and tibia) and autopod (hand and foot) lengths were measured in Peruvian children (0.5–14 years) living at >3000 m altitude. S_pO₂ was measured by pulse oximetry. Anthropometry was converted to internal z scores. Correlation and multiple regression were used to examine associations between anthropometry z scores and S_pO₂, altitude, or S_pO₂ adjusted for altitude since altitude is a major determinant of variation in S_pO₂.

Results

S_pO₂ and altitude show weak, significant correlations with zeugopod length z scores and still weaker significant correlations with total upper and lower limb length z scores. Correlations with z scores for stature, head-trunk height, or autopod lengths are not significant. Adjusted for altitude, there is no significant association between anthropometry and S_pO₂.

Conclusions

Associations between S_pO₂ or altitude and total limb and zeugopod length z scores exist among Andean children. However, the relationships are relatively weak, and while the relationship between anthropometry and altitude may be partly mediated by S_pO_2, other factors that covary with altitude (e.g., socioeconomic status, health) are likely to influence anthropometry. The results support suggestions that zeugopod lengths are particularly sensitive to environmental stressors. Am. J. Hum. Biol., 25:629–636, 2013. © 2013 Wiley Periodicals, Inc.

Increasing maternal age is associated with taller stature and reduced abdominal fat in their children

BACKGROUND

Maternal age at childbirth continues to increase worldwide. We aimed to assess whether increasing maternal age is associated with changes in childhood height, body composition, and metabolism.

METHODS

277 healthy pre-pubertal children, born 37-41 weeks gestation were studied. Assessments included: height and weight corrected for parental measurements, DEXA-derived body composition, fasting lipids, glucose, insulin, and hormonal profiles. Subjects were separated according to maternal age at childbirth: <30, 30-35, and >35 years.

RESULTS

Our cohort consisted of 126 girls and 151 boys, aged 7.4 ± 2.2 years (range 3-10); maternal age at childbirth was 33.3 ± 4.7 years (range 19-44). Children of mothers aged >35 and 30-35 years at childbirth were taller than children of mothers aged <30 years by 0.26 (p = 0.002) and 0.23 (p = 0.042) SDS, respectively. There was a reduction in childhood BMISDS with increasing maternal age at childbirth, and children of mothers aged >35 years at childbirth were 0.61 SDS slimmer than those of mothers <30 years (p = 0.049). Children of mothers aged 30-35 (p = 0.022) and >35 (p = 0.036) years at childbirth had abdominal adiposity reduced by 10% and 13%, respectively, compared to those in the <30 group. Children of mothers aged 30-35 years at childbirth displayed a 19% increase in IGF-I concentrations compared to offspring in <30 group (p = 0.042). Conversely, IGF-II concentrations were lower among the children born to mothers aged 30-35 (6.5%; p = 0.004) and >35 (8.1%; p = 0.005) compared to those of mothers aged <30 years. Girls of mothers aged 30-35 years at childbirth also displayed improved HOMA-IR insulin sensitivity (p = 0.010) compared to girls born to mothers aged <30 years.

CONCLUSIONS

Increasing maternal age at childbirth is associated with a more favourable phenotype (taller stature and reduced abdominal fat) in their children, as well as improved insulin sensitivity in girls.

Low birth weight does not predict the ontogeny of relative leg length of infants and children: an allometric analysis of the NHANES III sample

Previous research links both low birth weight (LBW) and relative leg length (RLL) to a similar set of adult pathologies, including type II diabetes, coronary vascular disease, and some cancers. Historically, LBW has been frequently used as a broad indicator of the quality of the intrauterine environment, while RLL has been considered a sensitive measure of childhood environmental quality. While these observations have been taken to suggest that these measures reflect independent exposures at different life-stages, their mutual association with a similar set of later pathologies makes this assumption less certain than it may have previously seemed. Nationally representative data from the Third National Health and Nutrition Examination Survey (NHANES III) are used to test the hypothesis that LBW predicts reductions in the development of leg length relative to stature. After controls for important socioeconomic exposures that might confound measurement of such a relationship, we find statistical and biological evidence that variation in birth weight and variation in the development of leg length relative to stature (RLL) are independent. The results suggest that these two measures may represent independent information on prenatal and postnatal environmental quality.

Influence of maternal and paternal IQ on offspring health and health behaviours: evidence for some trans-generational associations using the 1958 British birth cohort study

PURPOSE

Individuals scoring poorly on tests of intelligence (IQ) have been reported as having increased risk of morbidity, premature mortality, and risk factors such as obesity, high blood pressure, poor diet, alcohol and cigarette consumption. Very little is known about the impact of parental IQ on the health and health behaviours of their offspring.

METHODS

We explored associations of maternal and paternal IQ scores with offspring television viewing, injuries, hospitalisations, long standing illness, height and BMI at ages 4 to 18 using data from the National Child Development Study (1958 birth cohort).

RESULTS

Data were available for 1446 mother-offspring and 822 father-offspring pairs. After adjusting for potential confounding/mediating factors, the children of higher IQ parents were less likely to watch TV (odds ratio (95% confidence interval) for watching 3+ vs. less than 3hours per week associated with a standard deviation increase in maternal or paternal IQ: 0.75 (0.64, 0.88) or 0.78 (0.64, 0.95) respectively) and less likely to have one or more injuries requiring hospitalisation (0.77 (0.66, 0.90) or 0.72 (0.56, 0.91) respectively for maternal or paternal IQ).

CONCLUSIONS

Children whose parents have low IQ scores may have poorer selected health and health behaviours. Health education might usefully be targeted at these families.

Social inequalities in height: persisting differences today depend upon height of the parents

Background

Substantial increases in height have occurred concurrently with economic development in most populations during the last century. In high-income countries, environmental exposures that can limit genetic growth potential appear to have lessened, and variation in height by socioeconomic position may have diminished. The objective of this study is to investigate inequalities in height in a cohort of children born in the early 1990s in England, and to evaluate which factors might explain any identified inequalities.

Methods and Findings

12,830 children from The Avon Longitudinal Study of Parents and Children (ALSPAC), a population based cohort from birth to about 11.5 years of age, were used in this analysis. Gender- and age-specific z-scores of height at different ages were used as outcome variables. Multilevel models were used to take into account the repeated measures of height and to analyze gender- and age-specific relative changes in height from birth to 11.5 years. Maternal education was the main exposure variable used to examine socioeconomic inequalities. The roles of parental and family characteristics in explaining any observed differences between maternal education and child height were investigated.

Children whose mothers had the highest education compared to those with none or a basic level of education, were 0.39 cm longer at birth (95% CI: 0.30 to 0.48). These differences persisted and at 11.5 years the height difference was 1.4 cm (95% CI: 1.07 to 1.74). Several other factors were related to offspring height, but few changed the relationship with maternal education. The one exception was mid-parental height, which fully accounted for the maternal educational differences in offspring height.

Conclusions

In a cohort of children born in the 1990s, mothers with higher education gave birth to taller boys and girls. Although height differences were small they persisted throughout childhood. Maternal and paternal height fully explained these differences.

Socioeconomic inequalities in height, leg length and trunk length among children aged 6.5 years and their parents from the Republic of Belarus: evidence from the Promotion of Breastfeeding Intervention Trial (PROBIT)

BACKGROUND

Lower socioeconomic position is associated with shorter stature, in particular shorter leg length, but the magnitude of these associations in non-Western countries has received little attention.

AIM

To examine socioeconomic differentials in height, leg and trunk length in 6.5 year olds from the Republic of Belarus and compare these to differentials in parental height.

METHODS

Multivariable linear regression was used to examine associations in a cohort of 13 889 children.

RESULTS

Children from non-manual households were 1.0 cm (95% confidence interval: 0.7-1.3 cm) taller than those from manual households. Mothers and fathers from non-manual backgrounds were 0.7 cm (0.5-0.8) and 1.8 cm (1.6-2.0) taller than those from manual backgrounds, respectively. Associations with higher parental educational attainment were similar. The magnitudes of the associations of socioeconomic position with leg length were similar to those with trunk length. Adjusting for mid-parental height and number of older siblings attenuated associations markedly.

CONCLUSIONS

In Belarus, similar socioeconomic differentials in height were observed in both children and their parents. Among children, height differentials were partly explained by mid-parental height and number of older siblings. Leg length was not a more sensitive indicator of childhood socioeconomic conditions than trunk length.

Physical stature and method-specific attempted suicide: cohort study of one million men

Adult height, a marker of early-life environment, has been sporadically associated with suicide risk. We have examined adult height and attempted suicide risk in a cohort of 1,102,293 Swedish men and, in fully-adjusted analyses, found decreasing stepwise associations between height and attempted suicides by any means and most specific means.

Secular changes and predictors of adult height for 86 105 male and female members of the Thai Cohort Study born between 1940 and 1990

Background

Height trends can be useful indicators of population health but, despite Thailand's rapid socioeconomic development since the 1950s, few studies have examined accompanying secular changes in adult height or the effects of the transition on the heights of rural versus urban populations. This study therefore sought to document average heights in different age groups of rural and urban Thais and to investigate factors associated with attained height.

Methods

Data from 86 105 Thai Cohort Study participants was used to estimate mean heights for men and women in different birth year groups. Simple regression was used to calculate the change in height per decade of birth year among those based in rural or urban locations as children. Multiple linear regression was used to investigate effects of other childhood factors on height.

Results

Overall, average heights were found to have increased by approximately 1 cm per decade in those born between 1940 and 1990. However, the rate of increase was 0.4–0.5 cm per decade greater among urban-based Thais compared with those from the countryside. Parental education levels, household assets, birth size, sibling number, birth rank and region of residence were also significantly associated with adult height.

Conclusions

These data suggest a marked secular increase in Thai heights in the second half of the 20th century probably reflecting improved childhood health and nutrition over this time. Rural-born Thais, who benefited to a lesser extent from the changes, may face future health challenges with greater risks of, among other things, obesity and its health consequences.

Socioeconomic differences in childhood growth trajectories: at what age do height inequalities emerge?

Background

Socioeconomic differentials in adult height are frequently observed, but the age at which these inequalities emerge and the patterns they follow through childhood are unknown.

Subjects and Methods

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), height trajectories from birth to 10 years (N=12366) were modelled. Individual trajectories were estimated using mixed-effects models. Differences in trajectories by socioeconomic position (SEP) were investigated.

Results

There was a clear gradient in birth length across categories of maternal education; average birth length in boys was 0.41 cm lower in the lowest maternal education category compared with the highest, which is 0.9% of the average birth length for the highest SEP category (equivalent results for girls 0.65 cm, 1.3%). Socioeconomic differences in childhood growth were small, and only resulted in minimal widening of the height inequality with increasing age. By the age of 10 years, the mean difference between children in the lowest and highest maternal education categories was 1.4 cm for boys and 1.7 cm for girls; similar proportionate differences to those seen at birth (1.0% for boys and 1.2% for girls). Patterns were the same when father's education or household occupational social class were used to measure SEP.

Conclusions

The socioeconomic differential in height during childhood in this cohort of children born in the UK in the 1990s arises largely through inequalities in birth length, with small increases in the inequality from differences in growth in later childhood.

Leg length, body proportion, and health: a review with a note on beauty

Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature x 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility.

Childhood stature and adult cancer risk: the Boyd Orr cohort

Cancer risk in adulthood may be influenced by aspects of childhood diet. In the absence of direct dietary data, indirect measures of childhood diet and nutritional status, such as anthropometric measurements, may be useful in investigating diet-cancer associations. Previous studies suggest that taller adults may have increased cancer risk. Peak growth for different anthropometric measures occurs at different times and so differential associations with cancer risk may indicate periods of development that are particularly important in determining future risk. 2,642 traced members of the Boyd Orr cohort had measures of foot length, shoulder breadth, height, and leg length made when they were aged 2-14 years; trunk length was derived from the difference between overall height and leg length. Subjects were followed-up over 59 years to determine all-cause (n = 547) and site-specific (n = 97 for lung, 69 breast, 59 colorectal, 33 prostate, 320 not related to smoking) cancer deaths and registrations. There were no strong associations between childhood anthropometric measurements and adult cancer risk. Odds ratios (ORs) were broadly consistent with a slight increase in risk with increasing childhood stature but no single measure was of particular importance. The strongest associations were seen for breast cancer (OR per standard deviation increase in foot length: 1.16 (95% CI: 0.90, 1.51), shoulder breadth: 1.16 (0.91, 1.49) and trunk: 1.26 (1.00, 1.60), and prostate cancer (OR for foot length: 1.22 (0.86, 1.75)). There was little effect of adjustment for confounding factors and very limited evidence that associations differed with measures made prior to the onset of puberty (comparing the associations in children aged <8 vs. 8+ years). There was no evidence that any of the five indicators of childhood growth was more strongly related to cancer risk than the other measures.