People who were small at birth and had poor infant growth have an increased risk of adult cardiovascular disease, osteoporosis and type 2 diabetes, particularly if their restricted early growth is followed by increased childhood weight gain. These relations extend across the normal range of birth size in a graded manner, so reduced size is not a prerequisite. In addition larger birth size is associated with risks of obesity and type 2 diabetes. The associations appear to reflect developmental plastic responses made by the fetus and infant based on cues about the environment, influenced by maternal characteristics including diet, body composition, stress and exercise levels. These responses involve epigenetic processes which modify the offspring’s phenotype. Vulnerability to ill-health results if the environment in infancy, childhood and later life is mismatched to the phenotype induced in development, informed by the developmental cues. This mismatch may arise through unbalanced diet or body composition of the mother, or change in lifestyle factors between generations. These insights offer new possibilities for early diagnosis and prevention of chronic disease.
Nutrition; fetal growth; metabolic disease; epigenetics
Fixed genomic variation explains only a small proportion of the risk of adiposity. In animal models, maternal diet alters offspring body composition, accompanied by epigenetic changes in metabolic control genes. Little is known about whether such processes operate in humans.
RESEARCH DESIGN AND METHODS
Using Sequenom MassARRAY we measured the methylation status of 68 CpGs 5′ from five candidate genes in umbilical cord tissue DNA from healthy neonates. Methylation varied greatly at particular CpGs: for 31 CpGs with median methylation ≥5% and a 5–95% range ≥10%, we related methylation status to maternal pregnancy diet and to child’s adiposity at age 9 years. Replication was sought in a second independent cohort.
In cohort 1, retinoid X receptor-α (RXRA) chr9:136355885+ and endothelial nitric oxide synthase (eNOS) chr7:150315553+ methylation had independent associations with sex-adjusted childhood fat mass (exponentiated regression coefficient [β] 17% per SD change in methylation [95% CI 4–31], P = 0.009, n = 64, and β = 20% [9–32], P < 0.001, n = 66, respectively) and %fat mass (β = 10% [1–19], P = 0.023, n = 64 and β =12% [4–20], P = 0.002, n = 66, respectively). Regression analyses including sex and neonatal epigenetic marks explained >25% of the variance in childhood adiposity. Higher methylation of RXRA chr9:136355885+, but not of eNOS chr7:150315553+, was associated with lower maternal carbohydrate intake in early pregnancy, previously linked with higher neonatal adiposity in this population. In cohort 2, cord eNOS chr7:150315553+ methylation showed no association with adiposity, but RXRA chr9:136355885+ methylation showed similar associations with fat mass and %fat mass (β = 6% [2–10] and β = 4% [1–7], respectively, both P = 0.002, n = 239).
Our findings suggest a substantial component of metabolic disease risk has a prenatal developmental basis. Perinatal epigenetic analysis may have utility in identifying individual vulnerability to later obesity and metabolic disease.
We aimed to study the maternal retinal microvasculature at mid-trimester and its relationship with subsequent fetal growth and birth size.
We recruited 732 pregnant women aged 18-46 years in the first trimester with singleton pregnancies. All had retinal photography and fetal scan performed at 26-28 weeks gestation, and subsequent fetal scan at 32-34 weeks gestation. Infant anthropometric measurements were done at birth. Retinal microvasculature was measured using computer software from the retinal photographs.
In multiple linear regression models, each 10 μm narrowing in maternal retinal arteriolar caliber was associated with decreases of 1.36 mm in fetal head circumference at 32-34 weeks gestation, as well as decreases of 1.50 mm and 2.30 mm in infant head circumference and birth length at delivery, respectively. Each standard deviation decrease in maternal retinal arteriolar fractal dimension was associated with decreases of 1.55 mm in fetal head circumference at 32-34 weeks gestation, as well as decreases of 1.08 mm and 46.42 g in infant head circumference and birth weight at delivery, respectively.
Narrower retinal arteriolar caliber and a sparser retinal vascular network in mothers, reflecting a suboptimal uteroplacental microvasculature during mid-pregnancy, were associated with poorer fetal growth and birth size.
Background Early life environments induce long-term changes in neurocognitive development and behaviour. In animal models, early environmental cues affect neuropsychological phenotypes via epigenetic processes but, as yet, there is little direct evidence for such mechanisms in humans.
Method We examined the relation between DNA methylation at birth and child neuropsychological outcomes in two culturally diverse populations using a genome-wide methylation analysis and validation by pyrosequencing.
Results Within the UK Southampton Women’s Survey (SWS) we first identified 41 differentially methylated regions of interest (DMROI) at birth associated with child’s full-scale IQ at age 4 years. Associations between HES1 DMROI methylation and later cognitive function were confirmed by pyrosequencing in 175 SWS children. Consistent with these findings, higher HES1 methylation was associated with higher executive memory function in a second independent group of 200 SWS 7-year-olds. Finally, we examined a pathway for this relationship within a Singaporean cohort (n = 108). Here, HES1 DMROI methylation predicted differences in early infant behaviour, known to be associated with academic success. In vitro, methylation of HES1 inhibited ETS transcription factor binding, suggesting a functional role of this site.
Conclusions Thus, our findings suggest that perinatal epigenetic processes mark later neurocognitive function and behaviour, providing support for a role of epigenetic processes in mediating the long-term consequences of early life environment on cognitive development.
HES1; methylation; neurocognitive development; epigenetic; perinatal
We found that the relatively simple microbiota of young infants shifts predictably to a more mature anaerobic microbiota during infancy and the dynamics of this shift are influenced by environmental factors. In this longitudinal study of 75 infants, we demonstrate high interindividual variability within the normal range of birth outcomes, especially in the rate of microbiota progression. Most had acquired a microbiota profile high in Bifidobacterium and Collinsella by 6 months of age, but the time point of this acquisition was later in infants delivered by caesarean section and those born after a shorter duration of gestation. Independently of the delivery mode and gestation duration, infants who acquired a profile high in Bifidobacterium and Collinsella at a later age had lower adiposity at 18 months of age.
This study shows that the acquisition of the early microbiota is strongly influenced by environmental factors such as the delivery mode and duration of gestation, even in healthy neonates. The composition of the early microbiota has been linked with long-lasting effects on health and disease. Here we show that the rate of acquisition of certain microbiota predicts adiposity at 18 months of age and so potentially the risk of later obesity.
Pregnancy and birth cohorts have been utilised extensively to investigate the
developmental origins of health and disease, particularly in relation to understanding the
aetiology of obesity and related cardiometabolic disorders. Birth and pregnancy cohorts
have been utilised extensively to investigate this area of research. The aim of the
present review was twofold: first to outline the necessity of measuring cardiometabolic
risk in children; and second to outline how it can be assessed. The major outcomes thought
to have an important developmental component are CVD, insulin resistance and related
metabolic outcomes. Conditions such as the metabolic syndrome, type 2 diabetes and CHD all
tend to have peak prevalence in middle-aged and older individuals but assessments of
cardiometabolic risk in childhood and adolescence are important to define early causal
factors and characterise preventive measures. Typically, researchers investigating
prospective cohort studies have relied on the thesis that cardiovascular risk factors,
such as dyslipidaemia, hypertension and obesity, track from childhood into adult life. The
present review summarises some of the evidence that these factors, when measured in
childhood, may be of value in assessing the risk of adult cardiometabolic disease, and as
such proceeds to describe some of the methods for assessing cardiometabolic risk in
Paediatric health; Metabolic disease; Cardiovascular risk; Population studies; DOHaD, developmental origins of health and
; DXA, dual-energy X-ray
; IMT, intima media thickness
; NAFLD, non-alcoholic fatty liver
; PWV, pulse wave velocity
; TNFR, TNF receptor
Background: Early life may be a “critical period” when appetite and regulation of energy balance are programmed, with lifelong consequences for obesity risk. Insight into the potential impact of modifying early-life risk factors on later obesity can be gained by evaluating their combined effects.
Objective: The objective was to examine the relation between the number of early-life risk factors and obesity outcomes among children in a prospective birth cohort (Southampton Women's Survey).
Design: Five risk factors were defined: maternal obesity [prepregnant body mass index (BMI; in kg/m2) >30], excess gestational weight gain (Institute of Medicine, 2009), smoking during pregnancy, low maternal vitamin D status (<64 nmol/L), and short duration of breastfeeding (none or <1 mo). Obesity outcomes examined when the children were aged 4 and 6 y were BMI, dual-energy X-ray absorptiometry–assessed fat mass, overweight, or obesity (International Obesity Task Force). Data were available for 991 mother-child pairs, with children born between 1998 and 2003.
Results: Of the children, 148 (15%) had no early-life risk factors, 330 (33%) had 1, 296 (30%) had 2, 160 (16%) had 3, and 57 (6%) had 4 or 5. At both 4 and 6 y, there were positive graded associations between number of early-life risk factors and each obesity outcome (all P < 0.001). After taking account of confounders, the relative risk of being overweight or obese for children who had 4 or 5 risk factors was 3.99 (95% CI: 1.83, 8.67) at 4 y and 4.65 (95% CI: 2.29, 9.43) at 6 y compared with children who had none (both P < 0.001).
Conclusions: Having a greater number of early-life risk factors was associated with large differences in adiposity and risk of overweight and obesity in later childhood. These findings suggest that early intervention to change these modifiable risk factors could make a significant contribution to the prevention of childhood obesity.
adiposity; childhood obesity; early life; obesity; lifecourse; prevention
Maternal blood pressures in pregnancy is an important determinant of offspring size at birth. However, the relationship between maternal blood pressures and offspring’s size at birth is not consistent and may vary between ethnic groups. We examined the relationship between maternal peripheral and central blood pressures and offspring size at birth in an Asian multi-ethnic cohort, and effect modifications by maternal ethnicity and obesity.
We used data from 713 participants in the Growing Up in Singapore Towards Healthy Outcomes study consisting of pregnant Chinese, Malay and Indian women recruited from two tertiary hospitals between 2009 to 2010. Peripheral systolic and diastolic blood pressures (SBP and DBP), and central SBP and pulse pressure (PP) were measured around 27 weeks of gestation. Biometric parameters at birth were collected from medical records.
After adjusting for maternal and fetal covariates, each 1-SD increase (10.0 mmHg) in central SBP was inversely associated with birth weight (−40.52 g; 95% confidence interval (CI) -70.66 to −10.37), birth length (−0.19 cm; −0.36 to −0.03), head circumference (−0.12 cm; −0.23 to −0.02) and placental weight (−11.16 g; −20.85 to −1.47). A one-SD (11.1 mmHg) increase in peripheral SBP was also associated with lower birth weight (−35.56 g; −66.57 to −4.54). The inverse relations between other blood pressure measures and offspring size at birth were observed but not statistically significant. Higher peripheral SBP and DBP and central SBP were associated with increased odds of low birth weight (defined as weight <2500 g) and small for gestational age (defined as <10th percentile for gestational age adjusted birth weight). Maternal adiposity modified these associations, with stronger inverse associations in normal weight women. No significant interactions were found with ethnicity.
Higher second-trimester peripheral and central systolic pressures were associated with smaller offspring size at birth, particularly in normal weight women. Findings from this study reinforces the clinical relevance of antenatal blood pressure monitoring.
Electronic supplementary material
The online version of this article (doi:10.1186/s12884-014-0403-1) contains supplementary material, which is available to authorized users.
Pregnancy; Blood pressures; Obesity; Birth weight
In vitro fertilisation (IVF) treatment provides an opportunity to study early developmental responses to periconceptional dietary interventions. Retrospective studies have suggested links between preconception diet and fertility, and more recently, a "Mediterranean" diet has been reported to increase pregnancy rates by up to 40%. In addition, a prospective study examining increased intake of omega-3 polyunsaturated fats demonstrated a quickened rate of embryo development after IVF. However, up to now, few prospective randomised controlled trials have investigated the impact of periconceptional dietary interventions on fertility outcomes.
Methods and design
The study is a randomised controlled trial of a dietary intervention consisting of olive oil for cooking, an olive oil based spread, and a daily supplement drink enriched with Vitamin D (10 microgram daily) and marine omega-3 fatty acids (2 g daily) for 6 weeks preconception versus a control diet of sunflower seed oil for cooking, a sunflower oil based spread, and a daily supplement drink without added Vitamin D or marine omega-3 fatty acids. Couples undergoing IVF will be randomised to either the intervention or control group (55 in each arm). The primary endpoint is embryo developmental competency in vitro, measured by validated morphokinetic markers. Secondary outcomes will include the effect of the dietary intervention on the nutritional content of the intrauterine environment.
This approach will enable rigorous examination of the impact of the dietary intervention on early embryo development, together with the influence of the peri-implantation intra-uterine nutritional environment.
Universal and high-risk screening for gestational diabetes mellitus (GDM) has been widely studied and debated. Few studies have assessed GDM screening in Asian populations and even fewer have compared Asian ethnic groups in a single multi-ethnic population.
1136 pregnant women (56.7% Chinese, 25.5% Malay and 17.8% Indian) from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort study were screened for GDM by 75-g oral glucose tolerance test (OGTT) at 26–28 weeks of gestation. GDM was defined using the World Health Organization (WHO) criteria. High-risk screening is based on the guidelines of the UK National Institute for Health and Clinical Excellence.
Universal screening detected significantly more cases than high-risk screening [crude OR 2.2 (95% CI 1.7-2.8)], particularly for Chinese women [crude OR = 3.5 (95% CI 2.5-5.0)]. Pre-pregnancy BMI > 30 kg/m2 (adjusted OR = 3.4, 95% CI 1.5-7.9) and previous GDM history (adjusted OR = 6.6, 95% CI 1.2-37.3) were associated with increased risk of GDM in Malay women while GDM history was the only significant risk factor for GDM in Chinese women (adjusted OR = 4.7, 95% CI 2.0-11.0).
Risk factors used in high-risk screening do not sufficiently predict GDM risk and failed to detect half the GDM cases in Asian women. Asian women, particularly Chinese, should be screened to avoid under-diagnosis of GDM and thereby optimize maternal and fetal outcomes.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2393-14-345) contains supplementary material, which is available to authorized users.
Universal screening; High risk screening; Gestational diabetes; Asians; Ethnic
Maternal vitamin D deficiency has been associated with reduced offspring bone mineral accrual. Retinoid-X Receptor-alpha (RXRA) is an essential cofactor in the action of 1,25(OH)2-vitamin D, and RXRA methylation in umbilical cord DNA has been associated with later offspring adiposity. We tested the hypothesis that RXRA methylation in umbilical cord DNA collected at birth is associated with offspring skeletal development, assessed by dual-energy X-ray absorptiometry, in a population-based mother-offspring cohort (Southampton Women’s Survey). Relationships between maternal plasma 25(OH)-vitamin D concentrations and cord RXRA methylation were also investigated. In 230 children aged 4 years, higher % methylation at 4 out of 6 RXRA CpG sites measured was correlated with lower offspring % bone mineral content (%BMC) (β=−0.02 to −0.04%/SD, p=0.002 to 0.043) and BMC corrected for body size (β=−2.1 to −3.4g/SD, p=0.002 to 0.047), with a further site associated with %BMC only. Similar relationships for %BMC were observed in a second independent cohort (n=64). Maternal free 25(OH)-vitamin D index was negatively associated with methylation at one of these RXRA CpG sites (β=−3.3 SD/unit, p=0.03). In addition to the mechanistic insights afforded by associations between maternal free 25(OH)-vitamin D index, RXRA methylation in umbilical cord DNA, and childhood BMC, such epigenetic marks in early life might represent novel biomarkers for adverse bone outcomes in the offspring.
Epigenetic; methylation; umbilical cord; RXRA; vitamin D; DXA
To assess whether changes in measures of fat distribution and body size during early life are associated with blood pressure at 36 months of age.
Analysis of data collected from a prospective cohort study.
Community-based investigation in Southampton, UK.
761 children with valid blood pressure measurements, born to women participating in the Southampton Women’s Survey.
Primary and secondary outcome measures
Anthropometric measurements were collected at 0, 6, 12, 24 and 36 months and conditional changes between the time points calculated. Blood pressure was measured at 36 months. Factors possibly influencing the blood pressure were assessed using linear regression. All independent variables of interest and confounding variables were included in stepwise multiple regression to identify the model that best predicted blood pressure at 36 months.
Greater conditional gains in abdominal circumference (AC) between 0–6 and 24–36 months were associated with higher systolic and diastolic blood pressures at 36 months (p<0.001). Subscapular skinfold and height gains were weakly associated with higher blood pressures, while greater weight gains between 0–6, 12–24 and 24–36 months were more strongly associated, but the dominant influences were AC gains, particularly from 0–6 to 24–36 months. Thus one SD score increases in AC between 0–6 and 24–36 months were associated with 1.59 mm Hg (95% CI 0.97 to 2.21) and 1.84 mm Hg (1.24 to 2.46) higher systolic blood pressures, respectively, and 1.04 mm Hg (0.57 to 1.51) and 1.02 mm Hg (0.56, 1.48) higher diastolic pressures, respectively.
Conditional gains in abdominal circumference, particularly within 6 months of birth and in the year preceding measurement, were more positively associated with blood pressure at 36 months than gains in other anthropometric measures. Above-average AC gains in early childhood may contribute to adult hypertension and increased cardiovascular disease risk.
Maternal 25-hydroxy-vitamin D [25(OH)D] status in pregnancy has been associated with offspring bone development and adiposity. Vitamin D has also been implicated in postnatal muscle function but little is known about a role for antenatal 25(OH)D exposure in programming muscle development.
We investigated the associations between maternal plasma 25(OH)D status at 34 weeks gestation and offspring lean mass and muscle strength at 4 years of age.
Design and setting
A prospective UK population-based mother-offspring cohort: the Southampton Women’s Survey (SWS).
12583 non-pregnant women were initially recruited into SWS, of which 3159 had singleton pregnancies. 678 mother-child pairs were included in this analysis.
Main Outcomes Measured
At 4 years of age, offspring assessments included hand grip strength (Jamar Dynamometer) and whole body DXA (Hologic Discovery) yielding lean mass and %lean mass. Physical activity was assessed by 7-day accelerometry (Actiheart) in a subset of children (n=326).
Maternal serum 25(OH)D concentration in pregnancy was positively associated with offspring height-adjusted hand grip strength (β=0.10 SD/SD, p=0.013), which persisted after adjustment for maternal confounding factors, duration of breastfeeding and child’s physical activity at 4 years (β=0.13 SD/SD, p=0.014). Maternal 25(OH)D was also positively associated with offspring %lean mass (β=0.11 SD/SD, p=0.006), but not total lean mass (β=0.06, p=0.15). This however did not persist after adjustment for confounding factors (β=0.09 SD/SD, p=0.11).
This observational study suggests that intrauterine exposure to 25(OH)D during late pregnancy might influence offspring muscle development through an effect primarily on muscle strength rather than muscle mass.
vitamin D; grip strength; muscle mass; fetal programming
Individual differences in the temperamental dimension of effortful control are constitutionally based and have been associated with an adverse prenatal developmental environment, with structural brain alterations presenting a potential mechanism. We investigated this hypothesis for anatomically defined brain regions implicated in cognitive and inhibitory motor control.
Twenty-seven 15–16 year old participants with low, medium, or high fetal growth were selected from a longitudinal birth cohort to maximize variation and represent the full normal spectrum of fetal growth. Outcome measures were parent ratings of attention and inhibitory control, thickness and surface area of the orbitofrontal cortex (lateral (LOFC) and medial (MOFC)) and right inferior frontal gyrus (rIFG), and volumetric measures of the striatum and amygdala.
Lower birth weight was associated with lower inhibitory control, smaller surface area of LOFC, MOFC and rIFG, lower caudate volume, and thicker MOFC. A mediation model found a significant indirect effect of birth weight on inhibitory control via caudate volume.
Our findings support a neuroanatomical mechanism underlying potential long-term consequences of an adverse fetal developmental environment for behavioral inhibitory control in adolescence and have implications for understanding putative prenatal developmental origins of externalizing behavioral problems and self-control.
Chronic cardiorespiratory disease is associated with low birthweight suggesting the importance of the developmental environment. Prenatal factors affecting fetal growth are believed important, but the underlying mechanisms are unknown. The influence of developmental programming on bronchial hyperreactivity is investigated in an animal model and evidence for comparable associations is sought in humans. Pregnant Wistar rats were fed either control or protein-restricted diets throughout pregnancy. Bronchoconstrictor responses were recorded from offspring bronchial segments. Morphometric analysis of paraffin-embedded lung sections was conducted. In a human mother-child cohort ultrasound measurements of fetal growth were related to bronchial hyperreactivity, measured at age six years using methacholine. Protein-restricted rats' offspring demonstrated greater bronchoconstriction than controls. Airway structure was not altered. Children with lesser abdominal circumference growth during 11–19 weeks' gestation had greater bronchial hyperreactivity than those with more rapid abdominal growth. Imbalanced maternal nutrition during pregnancy results in offspring bronchial hyperreactivity. Prenatal environmental influences might play a comparable role in humans.
Asymmetry of the neonatal brain is not yet understood at the level of structural connectivity. We utilized DTI deterministic tractography and structural network analysis based on graph theory to determine the pattern of structural connectivity asymmetry in 124 normal neonates. We tracted white matter axonal pathways characterizing interregional connections among brain regions and inferred asymmetry in left and right anatomical network properties. Our findings revealed that in neonates, small-world characteristics were exhibited, but did not differ between the two hemispheres, suggesting that neighboring brain regions connect tightly with each other, and that one region is only a few paths away from any other region within each hemisphere. Moreover, the neonatal brain showed greater structural efficiency in the left hemisphere than that in the right. In neonates, brain regions involved in motor, language, and memory functions play crucial roles in efficient communication in the left hemisphere, while brain regions involved in emotional processes play crucial roles in efficient communication in the right hemisphere. These findings suggest that even at birth, the topology of each cerebral hemisphere is organized in an efficient and compact manner that maps onto asymmetric functional specializations seen in adults, implying lateralized brain functions in infancy.
cerebral asymmetry; structural connectivity network; diffusion tensor imaging; neonates; tractography
Despite the widespread recognition that obesity in pregnant women is associated with adverse outcomes for mother and child, there is no intervention proven to reduce the risk of these complications. The primary aim of this randomised controlled trial is to assess in obese pregnant women, whether a complex behavioural intervention, based on changing diet (to foods with a lower glycemic index) and physical activity, will reduce the risk of gestational diabetes (GDM) and delivery of a large for gestational age (LGA) infant. A secondary aim is to determine whether the intervention lowers the long term risk of obesity in the offspring.
Multicentre randomised controlled trial comparing a behavioural intervention designed to improve glycemic control with standard antenatal care in obese pregnant women.
Inclusion criteria; women with a BMI ≥30 kg/m2 and a singleton pregnancy between 15+0 weeks and 18+6 weeks’ gestation. Exclusion criteria; pre-defined, pre-existing diseases and multiple pregnancy. Randomisation is on-line by a computer generated programme and is minimised by BMI category, maternal age, ethnicity, parity and centre. Intervention; this is delivered by a health trainer over 8 sessions. Based on control theory, with elements of social cognitive theory, the intervention is designed to improve maternal glycemic control. Women randomised to the control arm receive standard antenatal care until delivery according to local guidelines. All women have a 75 g oral glucose tolerance test at 27+0- 28+6 weeks’ gestation.
Primary outcome; Maternal: diagnosis of GDM, according to the International Association of Diabetes in Pregnancy Study Group (IADPSG) criteria. Neonatal; infant LGA defined as >90th customised birth weight centile.
Sample size; 1546 women to provide 80% power to detect a 25% reduction in the incidence of GDM and a 30% reduction in infants large for gestational age.
All aspects of this protocol have been evaluated in a pilot randomised controlled trial, with subsequent optimisation of the intervention. The findings of this trial will inform whether lifestyle mediated improvement of glycemic control in obese pregnant women can minimise the risk of pregnancy complications.
Current controlled trials; ISRCTN89971375.
Study protocol; Pregnancy; Obesity; Complex intervention; Randomised controlled trial; Glycemic index; Physical activity; Gestational diabetes; Large for gestational age
Little is known about preschool-aged children’s levels of physical activity (PA) over the course of the day. Using time-stamped data, we describe the levels and patterns of PA in a population-based sample of four-year-old British children.
Within the Southampton Women’s Survey the PA levels of 593 4-year-old children (51% female) were measured using (Actiheart) accelerometry for up to 7 days. Three outcome measures: minutes spent sedentary (<20 cpm); in light (LPA: ≥20 – 399 cpm) and in moderate-to-vigorous activity (MVPA: ≥400 cpm) were derived. Average daily activity levels were calculated and then segmented across the day (morning, afternoon and evening). MVPA was log-transformed. Two-level random intercept models were used to analyse associations between activity level and temporal and demographic factors.
Children were active for 67% (mean 568.5 SD 79.5 minutes) of their daily registered time on average, with 88% of active time spent in LPA. All children met current UK guidelines of 180 minutes of daily activity. There were no differences in children’s average daily levels of sedentary activity and LPA by temporal and demographic factors: differences did emerge when activity was segmented across the day. Sex differences were largest in the morning, with girls being more sedentary, spending fewer minutes in LPA and 18% less time in MVPA than boys. Children were more sedentary and less active (LPA and MVPA) in the morning if they attended childcare full-time compared to part-time, and on weekend mornings compared to weekdays. The reverse was true for weekend afternoons and evenings. Children with more educated mothers were less active in the evenings. Children were less sedentary and did more MVPA on summer evenings compared to winter evenings.
Preschool-aged children meet current physical activity guidelines, but with the majority of their active time spent in LPA, investigation of the importance of activity intensity in younger children is needed. Activity levels over the day differed by demographic and temporal factors, highlighting the need to consider temporality in future interventions. Increasing girls’ morning activity and providing opportunities for daytime activity in winter months may be worthwhile.
In 1995 the Tucson Children’s Respiratory Study (TCRS) identified clinically distinct phenotypes amongst early wheezers; the Avon Longitudinal Study of Parents And Children (ALSPAC) has recently re-examined these.
To validate statistically derived ALSPAC phenotypes in the Southampton Women’s Survey (SWS) using infant and 6 year lung function, and allergic sensitisation at 1, 3 and 6 years, comparing these with TCRS phenotypes.
Complete 6 year follow-up data were available for 926 children, selected from 1973 infants born to 12,579 women characterised pre-conception. 95 children had V’maxFRC and FEV0.4 measured age 5-14 weeks using rapid compression/raised volume techniques. At 6 years we performed spirometry (n=791), fractional exhaled nitric oxide (FeNO, n=589) and methacholine challenge (n=234). Skin prick testing was performed at 12m, 3 and 6 years (n=1494, 1255, 699, respectively). Using wheeze status questionnaire data at 6m, 12m, 2, 3 and 6 years we classified children into TCRS (never, transient early, persistent, late-onset) and ALSPAC based groups (never, early, transient, intermediate-onset, late-onset, persistent).
Amongst ALSPAC groups, persistent and late-onset wheeze were associated with atopy at 3 and 6 years, whilst intermediate-onset wheeze showed earlier atopic association at 1 year; all three were associated with FeNO at 6 years. Persistent wheezers had lower infant (V’maxFRC p<0.05) and 6 year lung function (FEV1, FEV1/FVC and FEF25-75, p<0.05), whilst late and intermediate-onset wheezers showed no lung function deficits. Transient wheezers were non-atopic but showed persistent lung function deficits (V’maxFRC in infancy, FEV1 and FEF25-75 at 6 years, all p<0.05). Those who wheezed only in the first year (early phenotype) showed no lung function deficits. No associations were seen with 6 years bronchial hyper-responsiveness or infancy FEV0.4.
SWS cohort data validates the statistically derived ALSPAC 6-class model. In particular, lung function and atopy successfully differentiate persistent, late-onset and intermediate-onset wheeze, whilst the Tucson ‘transient early’ wheeze phenotype can be sub-classified into groups that reflect early lung function. Since the 4-class model fails to adequately differentiate phenotypes based on lung function and atopy, we propose that strong consideration be given to using the 6-class paradigm for longitudinal outcome work in wheezing with onset in early life.
Wheeze; asthma; phenotype; lung function; cohort; atopy
We investigated relationships between early growth and proximal femoral geometry at age six years in a prospective population-based cohort, the Southampton Women’s Survey.
In 493 mother-offspring pairs we assessed linear size (individual measure dependent on developmental stage) using high-resolution ultrasound at 11, 19 and 34 weeks gestation (femur length) and at birth, 1, 2, 3, 4 and 6 years (crown-heel length/height). Standard deviation (SD)-scores were created and conditional regression modelling generated mutually independent growth variables. Children underwent hip DXA (Dual X-ray absorptiometry) at 6 years (Hologic Discovery, Hologic Inc., MA); hip structure analysis software yielded measures of geometry and strength.
There were strong associations between early linear growth and femoral neck section modulus (Z) at 6 years, with the strongest relationships observed for femur growth from 19-34 weeks gestation (β=0.26 cm3/SD, p<0.0001), and for height growth from birth to 1 year (β=0.25 cm3/SD, p<0.0001) and 1-2 years (β=0.33 cm3/SD, p<0.0001), with progressively weaker relationships over years 3 (β=0.23 cm3/SD, p=0.0002) and 4 (β=0.10 cm3/SD, p=0.18).
These results demonstrate that growth before age 3 years predicts proximal femoral geometry at six years old. The data suggest critical periods in which there is capacity for long term influence on the later skeletal growth trajectory.
We have demonstrated previously that higher birth weight is associated with greater peak and later-life bone mineral content and that maternal body build, diet, and lifestyle influence prenatal bone mineral accrual. To examine prenatal influences on bone health further, we related ultrasound measures of fetal growth to childhood bone size and density. We derived Z-scores for fetal femur length and abdominal circumference and conditional growth velocity from 19 to 34 weeks’ gestation from ultrasound measurements in participants in the Southampton Women’s Survey. A total of 380 of the offspring underwent dual-energy X-ray absorptiometry (DXA) at age 4 years [whole body minus head bone area (BA), bone mineral content (BMC), areal bone mineral density (aBMD), and estimated volumetric BMD (vBMD)]. Volumetric bone mineral density was estimated using BMC adjusted for BA, height, and weight. A higher velocity of 19- to 34-week fetal femur growth was strongly associated with greater childhood skeletal size (BA: r = 0.30, p < .0001) but not with volumetric density (vBMD: r = 0.03, p = .51). Conversely, a higher velocity of 19- to 34-week fetal abdominal growth was associated with greater childhood volumetric density (vBMD: r = 0.15, p = .004) but not with skeletal size (BA: r = 0.06, p = .21). Both fetal measurements were positively associated with BMC and aBMD, indices influenced by both size and density. The velocity of fetal femur length growth from 19 to 34 weeks’ gestation predicted childhood skeletal size at age 4 years, whereas the velocity of abdominal growth (a measure of liver volume and adiposity) predicted volumetric density. These results suggest a discordance between influences on skeletal size and volumetric density.
EPIDEMIOLOGY; OSTEOPOROSIS; PROGRAMMING; DEVELOPMENTAL ORIGINS
Factors associated with parental awareness of children’s physical activity (PA) levels have not been explored in preschool-aged children. This paper investigates maternal awareness of preschool-aged children’s PA levels and determined correlates associated with maternal overestimation of PA.
Data from the Southampton Women’s Survey, a UK population-based study, were collected March 2006 through June 2009. Daily minutes of moderate-to-vigorous PA (MVPA) were derived using accelerometry in 478 4-year-old children. Mothers who were realistic or overestimated their child’s PA were identified. Log-binomial regression was used to analyse correlates of maternal overestimation of PA levels in children whose mothers perceived them to be active (n = 438).
40.8% of children were classified as inactive: 89.7% of these were perceived to be active by their mothers (over-estimators). These mothers were more likely to think their child sometimes lacked skills required to be physically active (RR (95% CI) = 1.29(1.03-1.63)) and their child was more likely to attend nursery full-time (RR = 1.53(1.14-2.04)). They were less likely to have older children at home (RR = 0.71(0.56-0.90)).
Almost 90% of mothers of inactive preschool-aged children perceive their child to be active. Nursery-school attendance and having older siblings at home may be important to consider when designing behavioural interventions to increase PA in preschool children.
Physical activity; Awareness; Preschool children