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

Stillbirth risk and smallness for gestational age according to Hadlock, INTERGROWTH-21st, WHO, and GROW fetal weight standards: analysis by maternal ethnicity and body mass index

BACKGROUND

Appropriate growth charts are essential for fetal surveillance, to confirm that growth is proceeding normally and to identify pregnancies that are at risk. Many stillbirths are avoidable through antenatal detection of the small-for-gestational-age fetus. In the absence of an international consensus on which growth chart to use, it is essential that clinical practice reflects outcome-based evidence.

OBJECTIVE

This study investigated the performance of 4 internationally used fetal weight standards and their ability to identify stillbirth risk in different ethnic and maternal size groups of a heterogeneous population.

STUDY DESIGN

We analyzed routinely collected maternity data from more than 2.2 million pregnancies. Three population-based fetal weight standards (Hadlock, Intergrowth-21st, and World Health Organization) were compared with the customized GROW standard that was adjusted for maternal height, weight, parity, and ethnic origin. Small-for-gestational-age birthweight and stillbirth risk were determined for the 2 largest ethnic groups in our population (British European and South Asian), in 5 body mass index categories, and in 4 maternal size groups with normal body mass index (18.5-25.0 kg/m2). The differences in trend between stillbirth and small-for-gestational-age rates were assessed using the Clogg z test, and differences between stillbirths and body mass index groups were assessed using the chi-square trend test.

RESULTS

Stillbirth rates (per 1000) were higher in South Asian pregnancies (5.51) than British-European pregnancies (3.89) (P<.01) and increased in both groups with increasing body mass index (P<.01). Small-for-gestational-age rates were 2 to 3-fold higher for South Asian babies than British European babies according to the population-average standards (Hadlock: 26.2% vs 12.2%; Intergrowth-21st: 12.1% vs 4.9%; World Health Organization: 32.2% vs 16.0%) but were similar by the customized GROW standard (14.0% vs 13.6%). Despite the wide variation, each standard's small-for-gestation-age cases had increased stillbirth risk compared with non-small-for-gestation-age cases, with the magnitude of risk inversely proportional to the rate of cases defined as small for gestational age. All standards had similar stillbirth risk when the small-for-gestation-age rate was fixed at 10% by varying their respective thresholds for defining small for gestational age. When analyzed across body mass index subgroups, the small-for-gestation-age rate according to the GROW standard increased with increasing stillbirth rate, whereas small-for-gestation-age rates according to Hadlock, Intergrowth-21st, and World Health Organization fetal weight standards declined with increasing body mass index, showing a difference in trend (P<.01) to stillbirth rates across body mass index groups. In the normal body mass index subgroup, stillbirth rates showed little variation across maternal size groups; this trend was followed by GROW-based small-for-gestation-age rates, whereas small-for-gestation-age rates defined by each population-average standard declined with increasing maternal size.

CONCLUSION

Comparisons between population-average and customized fetal growth charts require examination of how well each standard identifies pregnancies at risk of adverse outcomes within subgroups of any heterogeneous population. In both ethnic groups studied, increasing maternal body mass index was accompanied by increasing stillbirth risk, and this trend was reflected in more pregnancies being identified as small for gestational age only by the customized standard. In contrast, small-for-gestation-age rates fell according to each population-average standard, thereby hiding the increased stillbirth risk associated with high maternal body mass index.

Time trends in body height according to educational level. A descriptive study from the Tromsø Study 1979-2016

OBJECTIVES

The objective of our study was to describe time trends in body height according to attained educational level in women and men in Norway.

METHODS

We used previously collected data from six repeated cross-sectional studies in the population based Tromsø Study 1979-2016. Measured body height in cm and self-reported educational level were the primary outcome measures. We included 31 466 women and men aged 30-49 years, born between 1930 and 1977. Participants were stratified by 10-year birth cohorts and allocated into four groups based on attained levels of education. Descriptive statistics was used to estimate mean body height and calculate height differences between groups with different educational levels.

RESULTS

Mean body height increased by 3.4 cm (95% confidence interval (CI) 3.0, 3.8) in women (162.5-165.9 cm) and men (175.9-179.3 cm) between 1930 and 1977. The height difference between groups with primary education compared to long tertiary education was 5.1 cm (95% CI 3.7, 6.5) in women (161.6-166.7 cm) and 4.3 cm (95% CI 3.3, 5.3) in men (175.0-179.3 cm) born in 1930-39. The height differences between these educational groups were reduced to 3.0 cm (95% CI 1.9, 4.1) in women (163.6-166.6 cm) and 2.0 cm (95% CI 0.9, 3.1) in men (178.3-180.3 cm) born in 1970-77.

CONCLUSIONS

Body height increased in women and men. Women and men with long tertiary education had the highest mean body height, which remained stable across all birth cohorts. Women and men in the three other groups had a gradual increase in height by birth cohort, reducing overall height differences between educational groups in our study population.

Growing taller unequally? Adult height and socioeconomic status in Spain (Cohorts 1940–1994)

Socioeconomic inequalities and their evolution in different historical contexts have been widely studied. However, some of their dimensions remain relatively unexplored, such as the role played by socioeconomic status in the trajectory of biological living standards, especially net nutritional status. The main objective of this article is to analyze whether the power of socioeconomic status (SES) to explain differences in the biological dimensions of human well-being (in this case, adult height, a reliable metric for health and nutritional status) has increased or diminished over time. Educational attainment and occupational category have been used as two different proxies for the SES of Spanish men and women born between 1940 and 1994, thus covering a historical period in Spain characterized by remarkable socioeconomic development and a marked increase in mean adult height. Our data is drawn from nine waves of the Spanish National Health Survey and the Spanish sample of two waves of the European Health Interview Survey (ENSE) for the period 1987 to 2017 (N = 73,699 citizens aged 23–47). A multivariate regression analysis has been conducted, showing that, as a whole, height differentials by educational attainment have diminished over time, whereas differences by occupational category of household heads have largely persisted. These results indicate the need for further qualification when describing the process of convergence in biological well-being indicators across social groups. For instance, the progressive enrollment of a greater proportion of the population into higher educational levels may lead us to underestimate the real differences between socioeconomic groups, while other proxies of SES still point to the persistence of such differences.

•

Different SES impact on nutritional status according to SES operationalization.

•

Significant reduction in height differentials by educational attainment over time.

•

Height differentials largely persist by social class over time.

•

Evidence is provided on recent halt of upward intergenerational growth in Spain.

•

Mean cohort height stagnation not due to increases in social groups' differentials.

Adolescent Cranial Volume as a Sensitive Marker of Parental Investment: The Role of Non-material Resources?

Growth of different body parts in humans is sensitive to different resource constraints that are mediated by parental investment. Parental investment can involve the expenditure of material, cognitive, and emotional resources on offspring. Cranial volume, an important predictor of cognitive ability, appears understudied in this context. We asked (1) whether there are associations between growth and family structure, self-reported estimates for resource availability, and sibling number; and (2) whether these constraints relate to head and body growth in a similar manner. We assessed the associations between parental investment, height, and cranial volume in a cross-sectional study of Estonian children (born 1980-87, aged 11-17). Height correlated negatively with the number of siblings but this association became negligible in a model controlling for birthweight, parental heights, and mother's age at birth. Unlike height, cranial volume was unrelated to sibling number, but it was negatively associated with self-reported meat and general resource shortage. Cranial volume was related to family structure and paternal education. Children living with both birth-parents had larger heads than those living in families containing a step-parent. Since these family types did not differ with respect to meat or general resource shortage, our findings suggest that families including both genetic parents provide non-material benefits that stimulate predominantly cranial growth. For the studied developmental period, cranial volume appeared a more sensitive marker of growth constraints than height. The potential of using cranial volume for quantifying physical impact of non-material parental investment deserves further attention.

Childhood adherence to a potentially healthy and sustainable Nordic diet and later overweight: The Norwegian Mother, Father and Child Cohort Study (MoBa)

The New Nordic Diet (NND) is a potentially healthy and sustainable dietary pattern represented by locally available and traditionally consumed foods in the Northern countries. The diet has been commonly examined in adult populations, but less is known regarding its potential associations with overweight/obesity in children. We have previously developed child diet scores measuring compliance to the NND at child age 6 and 18 months and 3 and 7 years. In this study, we aimed to describe child and maternal characteristics and assess potential associations between the age‐specific diet scores and child overweight at 8 years. This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa), including 14,989 mother–child pairs and uses data from the Medical Birth Registry of Norway (MBRN). The scores measured NND compliance as a total score and categorized into low, medium and high NND compliance at each age point. Using logistic regression models, we investigated the association between each age‐specific score and the odds of overweight at 8 years. In crude analyses, adherence to the NND at 6 months was inversely associated with odds of overweight at 8 years in the continuous score (odds ratio = 0.95, 95% CI [0.91, 0.98]) and when comparing high versus low NND adherence (odds ratio = 0.81, 95% CI [0.70, 0.94]). The association was almost entirely attenuated in the adjusted models. In conclusion, child NND adherence up to 7 years of age was not associated with odds of overweight at 8 years in adjusted analyses.

Genetic and environmental influences on human height from infancy through adulthood at different levels of parental education

Genetic factors explain a major proportion of human height variation, but differences in mean stature have also been found between socio-economic categories suggesting a possible effect of environment. By utilizing a classical twin design which allows decomposing the variation of height into genetic and environmental components, we tested the hypothesis that environmental variation in height is greater in offspring of lower educated parents. Twin data from 29 cohorts including 65,978 complete twin pairs with information on height at ages 1 to 69 years and on parental education were pooled allowing the analyses at different ages and in three geographic-cultural regions (Europe, North America and Australia, and East Asia). Parental education mostly showed a positive association with offspring height, with significant associations in mid-childhood and from adolescence onwards. In variance decomposition modeling, the genetic and environmental variance components of height did not show a consistent relation to parental education. A random-effects meta-regression analysis of the aggregate-level data showed a trend towards greater shared environmental variation of height in low parental education families. In conclusion, in our very large dataset from twin cohorts around the globe, these results provide only weak evidence for the study hypothesis.

Social class-specific secular trends in height among 19-year old Polish men: 6th national surveys from 1965 till 2010

The results presented in this study concern the assessment of the secular trend of body height in 10 % a random national sample (N = 134,224) representing all regions of Poland in 8 homogeneous social groups over 45 years in Poland (1965-2010). Very significant political, social and economic changes in Poland occurred in the period studied. The political revolution that began in Poland at the turn of the 1980s and 1990s dramatically changed the picture of social inequalities in the country. It rapidly transformed (in different directions and to a different degree) the economic situation, working conditions, lifestyles and the prestige of particular social classes and professional groups. A positive secular trend was observed in 19-year-old participants in the period analysed in all homogeneous socio-professional groups, however, with different intensity in each group. The highest body height increases in 1965-2010 were observed in the sons of farmers with post-primary father's education (7.77 cm). The lowest were observed among the sons of professionals, only 5.45 cm. Although social distances between extreme socio-economic groups significantly decreased (from 4.89 cm in 1965 to 2.76 cm in 2010), social gradients of body height, despite the improvement in the standards of living of the entire society remained exceptionally stable and unchanged for nearly half a century.

Intergenerational effect of early-life growth on offspring height: Evidence from the Hertfordshire Cohort Study

BACKGROUND

Previous intergenerational (parent to child) and transgenerational (grandparent to grandchild) studies have shown there is a link between parental and offspring birthweight.

OBJECTIVES

The aim was to explore the association between the early-life weight gain of an individual and the adult height of their children and grandchildren.

METHODS

Study participants across three generations of the Hertfordshire Cohort Study (HCS) were included in this study. Health visitors recorded the birthweight (kg) and weight at 1 year (kg) of the original (F0 generation) HCS participants when they were born in Hertfordshire between 1931 and 1939. A conditional infant weight gain score for F0 participants was calculated using birthweight and weight at 1 year, and self-reported height (cm) of their children (F1 generation) and their grandchildren (F2 generation) was obtained from postal questionnaires. Due to the lack of clustering within family lines, linear regression analysis was used to compare intergenerational relationships.

RESULTS

Data were available from 139 F0, 148 F1, and 198 F2 participants. A positive association was found between parental birthweight (F0) and offspring adult height; on average, a 1 kg increase in F0 birthweight was associated with a 2.04 cm increase in F1 adult height (beta 2.04, 95% confidence interval [CI] -0.03, 4.10). A positive association was found between F0 conditional weight gain during the first year of life and offspring (beta 1.53, 95% CI 0.45, 2.62) and grandchild height (beta 1.06, 95% CI 0.03, 2.10). Positive associations were also found between F0 weight at 1 year and offspring (beta 1.83, 95% CI 0.79, 2.87) and grandchild height (beta 0.91, 95% CI -0.10, 1.91).

CONCLUSION

This study demonstrates an association between grandparental weight gain in early life and the heights of their children and grandchildren. The results of these analyses highlight the importance of early-life weight gain on the adult stature of subsequent offspring.

Life-course socioeconomic status and lung function in adulthood: a study in the EPIPorto cohort

OBJECTIVE

This study aims to investigate the association of life-course socioeconomic status (SES) with lung function during adulthood, by exploring the influence of life-course social mobility and of cumulative exposure to low SES.

METHODS

Participants were 1458 individuals from EPIPorto study, a population-based cohort of Portuguese adults. The life-course SES was computed using participants' paternal occupation and own occupation, resulting in four patterns: stable high, upward, downward, stable low. A cumulative life-course SES index was also calculated using the participants' paternal occupation, own education and occupation. Lung function during adulthood was assessed with forced expiratory volume in first second (FEV₁) and forced vital capacity (FVC) percentages predicted (higher percentages are associated with better lung function). Linear regression models were used to estimate beta coefficients and 95% CI for the association of socioeconomic indicators and lung function.

RESULTS

Disadvantaged SES from childhood to adulthood was associated with lower lung function (FEV₁:-6.64%,-10.68;-2.60/FVC:-3.77%,-7.45;-0.08), and the greater the socioeconomic disadvantage, the lower the lung function (FEV₁:-2.56%,-3.98;-1.15/FVC:-1.54%,-2.83;-0.24) among men, independently of marital status and behavioural factors. Among women, SES effects were only observed in those experiencing a stable low life-course SES at older ages (-5.15%,-10.20;-0.09). Men experiencing a downward social mobility presented the lowest lung function, but there was attenuation to the null after accounting for marital status and behavioural factors.

CONCLUSION

A life-course disadvantaged SES is an important predictor of lower lung function during adulthood. Downward social mobility was associated with the lowest lung function among men, although this association was mostly explained by behavioural factors.

Income inequality and social gradients in children's height: a comparison of cohort studies from five high-income countries

BACKGROUND

Health and well-being are better, on average, in countries that are more equal, but less is known about how this benefit is distributed across society. Height is a widely used, objective indicator of child health and predictor of lifelong well-being. We compared the level and slope of social gradients in children's height in high-income countries with different levels of income inequality, in order to investigate whether children growing up in all socioeconomic circumstances are healthier in more equal countries.

METHODS

We conducted a coordinated analysis of data from five cohort studies from countries selected to represent different levels of income inequality (the USA, UK, Australia, the Netherlands and Sweden). We used standardised methods to compare social gradients in children's height at age 4-6 years, by parent education status and household income. We used linear regression models and predicted height for children with the same age, sex and socioeconomic circumstances in each cohort.

RESULTS

The total analytic sample was 37 063 children aged 4-6 years. Gradients by parent education and household income varied between cohorts and outcomes. After adjusting for differences in age and sex, children in more equal countries (Sweden, the Netherlands) were taller at all levels of parent education and household income than children in less equal countries (USA, UK and Australia), with the greatest between-country differences among children with less educated parents and lowest household incomes.

CONCLUSIONS

The study provides preliminary evidence that children across society do better in more equal countries, with greatest benefit among children from the most disadvantaged socioeconomic groups.

The Relation Between Household Food Insecurity and Children's Height in Canada and the United States: A Scoping Review

Household food insecurity is a determinant of health and marker of material deprivation. Although research has shown that food insecurity is associated with numerous adverse health, developmental and nutritional outcomes among children in high-income countries, little is known about its impact on children's height, an important marker of nutritional status and physical development. We reviewed evidence on the relation between experience-based measures of food insecurity and the height of children aged 0-18 y in Canada and the United States. The search, conducted in Embase, Medline, CINAHL, ProQuest, Web of Science, and EconLit from the inception of the databases to October 2017, identified 811 records that were screened for relevance. A total of 8 peer-reviewed studies, 2 from Canada and 6 from the United States, met the inclusion criteria and were summarized. Five studies found no association between food insecurity and children's height. One study found that having taller children in the household predicted more severe food insecurity, whereas 2 studies found that more severe experiences of food insecurity were associated with shorter height among children from ethnic minority populations. These results suggest that household food insecurity may not be associated with height inequalities among children in Canada and the United States, except perhaps in certain high-risk populations. However, the few studies identified for review provide insufficient evidence to determine whether food insecurity is or is not associated with children's height in these countries. Given the importance of optimal linear growth for current and future well-being, it is critical to understand how different modifiable environmental circumstances relate to children's height to help establish priorities for intervention. Families with children are disproportionately affected by food insecurity, and more research explicitly designed to examine the association between household food insecurity and children's height in high-income countries is needed.

Which modifiable prenatal factors mediate the relation between socio-economic position and a child's weight and length at birth?

Although several studies have shown a positive association between socio-economic position and size at birth, not enough is known about the modifiable factors that may be involved. We aimed to investigate whether maternal prepregnancy body mass index (BMI), smoking, diet, and depression during pregnancy mediate the positive association between maternal education and birth size. Weight and length z-scores specific for gestational age and sex were calculated for 1,500 children from the EDEN mother-child cohort. A mediation analysis of the associations between maternal education and birth size was conducted with a counterfactual method, adjusted for recruitment centre, parity, maternal height, and age. In the comparison of children of mothers with low versus intermediate education levels, maternal smoking during pregnancy explained 52% of the total effect of education on birth weight. Similar findings were observed with birth length z-score (37%). The comparison of children of mothers with high versus intermediate education levels yielded a non-significant total effect, which masked opposite mediating effects by maternal BMI and smoking during pregnancy on both birth weight and length. Prepregnancy BMI and maternal smoking during pregnancy mediate the positive association between maternal education and birth weight and length z-scores. These mediators, however, act in opposite directions, thereby masking the extent to which healthy prenatal growth is socially differentiated.

Longitudinal associations between body composition and regional fat distribution and later attained height at school entry among preschool children predisposed to overweight

BACKGROUND/OBJECTIVES

To investigate the associations between indicators of obesity and fat distribution, such as body mass index (BMI), fat mass, and skinfold measures during preschool age, and attained height at school entry.

SUBJECTS/METHODS

The Healthy Start primary intervention study comprised 1100 obesity-prone preschool children from the greater Copenhagen area, with a mean [standard deviation (SD)] age of 4.0 (1.1) years at baseline. Anthropometry was measured by trained health professionals at baseline (preschool age) and follow-up height at school entry was gathered by school nurses. Prospective associations between body fat measures and later attained height were examined using generalized linear models with adjustments for potential confounders.

RESULTS

Greater adiposity at preschool age was directly associated with a higher attained height at follow-up at school-age, when adjusting for confounders. A baseline difference of one BMI unit was associated with a greater attained height of 0.8 cm [(95% confidence interval (CI) 0.5; 1.2]. Furthermore, a difference of 1 mm in the sum of four skinfolds measured at baseline was associated with a greater attained height of 0.1 cm (95% CI 0.03; 0.2) at follow-up. Children with overweight or obesity at baseline attained a significantly higher height of 2.9 (95% CI 1.6; 4.1) cm at follow-up after full adjustment than normal weight children.

CONCLUSIONS

Our results supports that greater adiposity at preschool age is associated with greater tallness. Although a greater height is assumed to be desirable, accelerated growth in childhood may in itself be a risk factor for obesity later in life.

Predicting women's height from their socioeconomic status: A machine learning approach

The social determinants of health literature routinely deploy socio-economic status (SES) as a key factor in accounting for women's height-an established indicator of human welfare at the population level-using traditional regression. However, this literature lacks a systematic identification of the predictive power of SES as well as the possible non-linear relationships between the measures of SES (education, occupation, and material wealth) in predicting variation in women's height. This study aims to evaluate this predictive power. We used the Demographic and Health Surveys (DHS) from 66 low- and middle-income countries (women = 1,273,644), sampled between 1994 and 2016. The analysis consisted of training seven machine-learning algorithms of different function classes and assessing their predictive power out-of-sample, vis-à-vis OLS regression. In an OLS framework, SES accounts for 0.7%, R², of the total variance in women's height (from σ_OLSFix² = 31.82 to σ_OLSSES² = 31.57), adjusting for country, community, and sampling year fixed effects. The country-specific variances range from as low as 25.10 units in Egypt to as high as 74.46 units in Sao Tome and Principe. With the same set of SES measures, the best performing learner, a Bayesian neural net, produces a predictive variance of σ_BnnSES² = 31.52. This is a negligible improvement in variance explained by 0.3% (σ_BnnSES²-σ_OLSSES²). Given our selection of algorithms, our findings indicate no relevant non-linear relationships between SES and women's height, and also the predictive limits of SES. We recommend that scholars report both the average effect of SES on health outcomes as well as its contribution to the variance explained. This will improve our understanding of how key social and economic factors affect health, deepening our understanding of the social determinants of health.

Association between parental socio-demographic factors and declined linear growth of young children in Jakarta

Background: In Indonesia, approximately 35.5% of children under five years old were stunted. Stunting is related to shorter adult stature, poor cognition and educational performance, low adult wages, lost productivity, and higher risk of nutrition-related chronic disease. The aim of this study was to identify parental socio-demographic risk factors of declined linear growth in children younger than 2 years old.Methods: This was a cohort-prospective study between August 2012 and May 2014 at three primary community health care centers (Puskesmas) in Jakarta, Indonesia, namely Puskesmas Jatinegara, Mampang, and Tebet. Subjects were healthy children under 2 years old, in which their weight and height were measured serially (at 6–11 weeks old and 18–24 months old). The length-for-age based on those data was used to determine stature status. The serial measurement was done to detect growth pattern. Parental socio-demographic data were obtained from questionnairesResults: From the total of 160 subjects, 14 (8.7%) showed declined growth pattern from normal to stunted and 10 (6.2%) to severely stunted. As many as 134 (83.8%) subjects showed consistent normal growth pattern. Only 2 (1.2%) showed improvement in the linear growth. Maternal education duration less than 9 years (RR=2.60, 95% CI=1.23–5.46; p=0.02) showed statistically significant association with declined linear growth in children.Conclusion: Mother with education duration less than 9 years was the determining socio-demographic risk factor that contributed to the declined linear growth in children less than 2 years of age.

Socioeconomic differences in children’s growth trajectories from infancy to early adulthood: evidence from four European countries

Background

Height is regarded as a marker of early-life illness, adversity, nutrition and psychosocial stress, but the extent to which differences in height are determined by early-life socioeconomic circumstances, particularly in contemporary populations, is unclear. This study examined socioeconomic differences in children’s height trajectories from birth through to 21 years of age in four European countries.

Methods

Data were from six prospective cohort studies—Generation XXI, Growing Up in Ireland (infant and child cohorts), Millennium Cohort Study, EPITeen and Cardiovascular Risk in Young Finns Study—comprising a total of 49 492 children with growth measured repeatedly from 1980 to 2014. We modelled differences in children’s growth trajectories over time by maternal educational level using hierarchical models with fixed and random components for each cohort study.

Results

Across most cohorts at practically all ages, children from lower educated mothers were shorter on average. The gradient in height was consistently observed at 3 years of age with the difference in expected height between maternal education groups ranging between −0.55 and −1.53 cm for boys and −0.42 to −1.50 cm for girls across the different studies and widening across childhood. The height deficit persists into adolescence and early adulthood. By age 21, boys from primary educated maternal backgrounds lag the tertiary educated by −0.67 cm (Portugal) and −2.15 cm (Finland). The comparable figures for girls were −2.49 cm (Portugal) and −2.93 cm (Finland).

Conclusions

Significant differences in children’s height by maternal education persist in modern child populations in Europe.

Effects of socioeconomic position and social mobility on linear growth from early childhood until adolescence

OBJECTIVE

To assess the effect of socioeconomic position (SEP) in childhood and social mobility on linear growth through adolescence in a population-based cohort.

METHODS

Children born in Cuiabá-MT, central-western Brazil, were evaluated during 1994 - 1999. They were first assessed during 1999 - 2000 (0 - 5 years) and again during 2009 - 2011 (10 - 17 years), and their height-for-age was evaluated during these two periods.Awealth index was used to classify the SEP of each child's family as low, medium, or high. Social mobility was categorized as upward mobility or no upward mobility. Linear mixed models were used.

RESULTS

We evaluated 1,716 children (71.4% of baseline) after 10 years, and 60.6% of the families showed upward mobility, with a higher percentage among the lowest economic classes. A higher height-for-age was also observed among those from families with a high SEP both in childhood (low SEP= -0.35 z-score; high SEP= 0.15 z-score, p < 0.01) and adolescence (low SEP= -0.01 z-score; high SEP= 0.45 z-score, p < 0.01), whereas upward mobility did not affect their linear growth.

CONCLUSION

Expressive social mobility was observed, but SEP in childhood and social mobility did not greatly influence linear growth through childhood in this central-western Brazilian cohort.

Pathways between Socioeconomic Disadvantage and Childhood Growth in the Scottish Longitudinal Study, 1991-2001

Socioeconomically disadvantaged children are more likely to be of shorter stature and overweight, leading to greater risk of obesity in adulthood. Disentangling the mediatory pathways between socioeconomic disadvantage and childhood size may help in the development of appropriate policies aimed at reducing these health inequalities. We aimed to elucidate the putative mediatory role of birth weight using a representative sample of the Scottish population born 1991-2001 (n = 16,628). Estimated height and overweight/obesity at age 4.5 years were related to three measures of socioeconomic disadvantage (mother's education, Scottish Index of Multiple Deprivation, synthetic weekly income). Mediation was examined using two approaches: a 'traditional' mediation analysis and a counterfactual-based mediation analysis. Both analyses identified a negative effect of each measure of socioeconomic disadvantage on height, mediated to some extent by birth weight, and a positive 'direct effect' of mother's education and Scottish Index of Multiple Deprivation on overweight/obesity, which was partly counterbalanced by a negative 'indirect effect'. The extent of mediation estimated when adopting the traditional approach was greater than when adopting the counterfactual-based approach because of inappropriate handling of intermediate confounding in the former. Our findings suggest that higher birth weight in more disadvantaged groups is associated with reduced social inequalities in height but also with increased inequalities in overweight/obesity.

The association between maternal nutrition and lifestyle during pregnancy and 2-year-old offspring adiposity: analysis from the ROLO study

Aim

To examine the association between maternal nutrition and lifestyle factors and offspring adiposity, using baseline and 2-year postpartum follow-up data from a randomised control trial of low glycaemic index diet.

Subject and methods

Food diaries and lifestyle questionnaires were completed during pregnancy and infant feeding and maternal lifestyle questionnaires 2 years postpartum for 281 mother and infant pairs from the ROLO study. Maternal anthropometry was measured throughout pregnancy and infant and maternal anthropometry was measured 2 years postpartum.

Results

Maternal 2 year postpartum body mass index (BMI) was positively associated with offspring BMI-for-age z-score (B = 0.105, p = 0.015). Trimester 2 saturated fat intake was positively associated with offspring subscapular:triceps skinfold ratio (B = 0.018, p = 0.001). Trimester 1 glycaemic index was also positively associated with offspring sum of subscapular and triceps skinfolds (B = 0.009, p = 0.029).

Conclusions

Maternal BMI 2 years postpartum was positively associated with offspring BMI. Pregnancy saturated fat intake was positively and polyunsaturated fat negatively associated with offspring adiposity. While further research is necessary, pregnancy and the postpartum period may be early opportunities to combat childhood obesity.

Electronic supplementary material

The online version of this article (doi:10.1007/s10389-016-0740-9) contains supplementary material, which is available to authorized users.

Socioeconomic variation in height: analysis of National Child Measurement Programme data for England

OBJECTIVE

Short stature is associated with increased risk of ill health and mortality and can negatively impact on an individual's economic opportunity and psychological well-being. The aim of this study was to investigate the association between height and area-level deprivation by ethnic group in children in England.

DESIGN

Cross-sectional analysis of data gathered from the National Child Measurement Programme 2008/2009 to 2012/2013.

PARTICIPANTS/METHODS

Children (n=1 213 230) aged 4-5 and 10-11 years attending state-maintained primary schools in England. Mean height SD score (SDS) (based on the British 1990 growth reference) was calculated for children by Income Deprivation Affecting Children Index as a measure of area-level deprivation. Analyses were performed by sex and age group for white British, Asian and black ethnicities.

RESULTS

For white British children mean height decreased 0.2 SDS between the least and the most deprived quintile. For Asian children the relationship was weaker and varied between 0.08 and 0.18 SDS. For white British boys the magnitude of association was similar across age groups; for Asian boys the magnitude was higher in the age group of 10-11 years and in white British girls aged 10-11 years the association decreased. Height SDS was similar across all levels of deprivation for black children.

CONCLUSIONS

Social inequalities were shown in the height of children from white British and Asian ethnic groups. Further evaluation of height in black children is warranted. Action is needed to reduce inequalities in height by addressing the modifiable negative environmental factors that prevent healthy growth and development of children.

Adult height, nutrition, and population health

In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence.

Connecting the Dots in Childhood Obesity Disparities: A Review of Growth Patterns from Birth to Pre-Adolescence

In this review, we considered how disparities in obesity emerge between birth, when socially disadvantaged infants tend to be small, and later in childhood, when socially disadvantaged groups have high risk of obesity. We reviewed epidemiologic evidence of socioeconomic and racial/ethnic differences in growth from infancy to pre-adolescence. Minority race/ethnicity and lower socioeconomic status was associated with rapid weight gain in infancy but not in older age groups, and social differences in linear growth and relative weight were unclear. Infant feeding practices was the most consistent mediator of social disparities in growth, but mediation analysis was uncommon and other factors have only begun to be explored. Complex life course processes challenge the field of social epidemiology to develop innovative study designs and analytic techniques with which to pose and test challenging yet impactful research questions about how obesity disparities evolve throughout childhood.

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.

The association of the 'additional height index' with atopic diseases, non-atopic asthma, ischaemic heart disease and mortality: a population-based study

OBJECTIVE

Intrauterine growth has been associated with atopic conditions. Growth and adult height have been associated with cardiovascular disease, cancers and mortality but are highly genetic traits. The objectives of the study were as follows: first, to define a height measure indicating an individual's height below or above that which could be expected based on parental height (genetic inheritance) and growth charts. It was named 'the additional height index' (AHI), defined as (attained-expected) height; second, to investigate possible associations of AHI with atopic versus non-atopic health outcomes and with ischaemic heart disease (IHD) and IHD mortality.

DESIGN

General population-based study.

SETTING

Research centre.

PARTICIPANTS

A random sample of 2656 men and women living in greater Copenhagen took part in the MONICA10 study (the Danish monitoring trends and determinants of cardiovascular disease). In total, 1900 participants with information of parental height were selected.

OUTCOME MEASURES

Atopic sensitisation (serum IgE), questionnaire information of atopic dermatitis, rhinoconjunctivitis, asthma or wheezing, and registry-based diagnoses of IHD/IHD mortality from National Registries.

RESULTS

Increasing levels of AHI were inversely associated with non-atopic asthma, non-atopic wheezing, IHD and IHD mortality (IHD-all). For one SD increase of AHI, the OR or HR with CI in adjusted analyses was non-atopic asthma OR=0.52 (0.36 to 0.74), non-atopic wheezing OR=0.67 (0.51 to 0.89), and IHD-all HR=0.89 (0.78 to 1.01). The level of AHI was higher among individuals with atopic dermatitis, allergic rhinoconjunctivitis and atopic sensitisation (all p values <0.001) compared with individuals without those conditions; however, the associations were not confirmed in adjusted analyses.

CONCLUSIONS

Individuals with childhood conditions that led them to attain tallness higher than expected from their parents' height may be at lower risk of non-atopic asthma/wheeze and IHD/IHD mortality but possibly at higher risk of atopic conditions. The measure of tallness below or above the expected height could be a sensitive alternative to normal height in epidemiological analyses.

Grandparental education, parental education and child height: evidence from Hong Kong's "Children of 1997" birth cohort

PURPOSE

Adult height is the sum of growth during fetal, infancy, childhood, and puberty, controlled by different biological factors. In long-term developed Western populations, height is positively associated with socioeconomic position, but less clearly so in recently developing populations. We aimed to elucidate socioeconomic influences on height at different growth phases.

METHODS

We examined the associations of parents' education and grandparents' education with birth weight and height gain z-scores during infancy (birth to <2 years), childhood (2 to <8 years), and puberty (8 to <14 years) adjusted for parents' height using generalized estimating equations in Hong Kong's "Children of 1997" birth cohort (n = 8264).

RESULTS

Parents' education, but not grandparents', was positively associated with birth weight (z-score, 0.07; 95% confidence interval [CI] 0.01-0.12 for grade ≥12 compared with grade ≤9) and height gain during infancy (0.11; 95% CI, 0.05-0.18), adjusted for gender, gestational age, initial size, parity, parents' age, parents' birthplace, and parents' height. Conversely, similarly adjusted, grandparents' education, but not parents', was associated with height gain during childhood (0.11; 95% CI, 0.04-0.18).

CONCLUSIONS

Parental education was associated with fetal and infant, but not childhood, linear growth, suggesting the mechanism underlying socioeconomic influences on height at different growth phases may be contextually specific.

Linear spline multilevel models for summarising childhood growth trajectories: A guide to their application using examples from five birth cohorts

Childhood growth is of interest in medical research concerned with determinants and consequences of variation from healthy growth and development. Linear spline multilevel modelling is a useful approach for deriving individual summary measures of growth, which overcomes several data issues (co-linearity of repeat measures, the requirement for all individuals to be measured at the same ages and bias due to missing data). Here, we outline the application of this methodology to model individual trajectories of length/height and weight, drawing on examples from five cohorts from different generations and different geographical regions with varying levels of economic development. We describe the unique features of the data within each cohort that have implications for the application of linear spline multilevel models, for example, differences in the density and inter-individual variation in measurement occasions, and multiple sources of measurement with varying measurement error. After providing example Stata syntax and a suggested workflow for the implementation of linear spline multilevel models, we conclude with a discussion of the advantages and disadvantages of the linear spline approach compared with other growth modelling methods such as fractional polynomials, more complex spline functions and other non-linear models.

Oppositionality and socioemotional competence: interacting risk factors in the development of childhood conduct disorder symptoms

OBJECTIVES

Oppositional behavior in childhood is a probabilistic risk factor for the subsequent development of more serious conduct problems characteristic of conduct disorder (CD). The capacity to understand the subjective states of others (socioemotional competence) helps regulate antisocial behavior in typical development. We hypothesized that socioemotional competence moderates the developmental relationship between oppositionality and CD symptoms, such that oppositional defiant disorder (ODD) symptoms pose the greatest risk for subsequent CD symptoms in children with poor socioemotional competence.

METHOD

Parent-report data were collected for 6,218 children at 7 and 10 years of age. Bootstrap multiple regression predicting CD symptoms at age 10 was used to test for an interaction between socioemotional competence and ODD symptoms, while also accounting for direct effects and controlling for sex, maternal education, attention-deficit/hyperactivity disorder symptoms, and CD symptoms at 7 years. We further tested whether the interaction applied to both males and females, and to both aggressive and rule-breaking CD symptoms.

RESULTS

A significant interaction was found between ODD and socioemotional competence: the association between oppositionality at 7 years and CD traits at 10 years was strongest for children with poor socioemotional capacities. As predicted, this moderation effect was significant in a model predicting aggression, but it was not significant for rule-breaking CD symptoms.

CONCLUSION

Socioemotional competence moderates the developmental relationship between mid-childhood oppositionality and more serious conduct problems in later childhood. A capacity to understand the subjective states of others may buffer the risk posed by oppositionality for later CD symptoms, including aggression.

Head circumference of infants born to mothers with different educational levels; the Generation R Study

OBJECTIVE

Head circumference (HC) reflect growth and development of the brain in early childhood. It is unknown whether socioeconomic differences in HC are present in early childhood. Therefore, we investigated the association between socioeconomic position (SEP) and HC in early childhood, and potential underlying factors.

METHODS

The study focused on Dutch children born between April 2002 and January 2006 who participated in The Generation R Study, a population-based prospective cohort study in Rotterdam, The Netherlands. Maternal educational level was used as indicator of SEP. HC measures were concentrated around 1, 3, 6 and 11 months. Associations and explanatory factors were investigated using linear regression analysis, adjusted for potential mediators.

RESULTS

The study included 3383 children. At 1, 3 and 6 months of age, children of mothers with a low education had a smaller HC than those with a high education (difference at 1 month: -0.42 SD; 95% CI: -0.54,-0.30; at 3 months: -0.27 SD; 95% CI -0.40,-0.15; and at 6 months: -0.13 SD; 95% CI -0.24,-0.02). Child's length and weight could only partially explain the smaller HC at 1 and 3 months of age. At 6 months, birth weight, gestational age and parental height explained the HC differences. At 11 months, no HC differences were found.

CONCLUSION

Educational inequalities in HC in the first 6 months of life can be mainly explained by pregnancy-related factors, such as birth weight and gestational age. These findings further support public health policies to prevent negative birth outcomes in lower socioeconomic groups.