Associations between maternal physical activity in early and late pregnancy and offspring birth size: remote federated individual level meta-analysis from eight cohort studies.

OBJECTIVE: Evidence on the impact of leisure time physical activity (LTPA) in pregnancy on birth size is inconsistent. We aimed to examine the association between LTPA during early and late pregnancy and newborn anthropometric outcomes. DESIGN: Individual level meta-analysis, which reduces heterogeneity across studies. SETTING: A consortium of eight population-based studies (seven European and one US) comprising 72 694 participants. METHODS: Generalised linear models with consistent inclusion of confounders (gestational age, sex, parity, maternal age, education, ethnicity, BMI, smoking, and alcohol intake) were used to test associations between self-reported LTPA at either early (8-18 weeks gestation) or late pregnancy (30+ weeks) and the outcomes. Results were pooled using random effects meta-analyses. MAIN OUTCOME MEASURES: Birth weight, large-for-gestational age (LGA), macrosomia, small-for-gestational age (SGA), % body fat, and ponderal index at birth. RESULTS: Late, but not early, gestation maternal moderate to vigorous physical activity (MVPA), vigorous activity, and LTPA energy expenditure were modestly inversely associated with BW, LGA, macrosomia, and ponderal index, without heterogeneity (all: I2  = 0%). For each extra hour/week of MVPA, RR for LGA and macrosomia were 0.97 (95% CI: 0.96, 0.98) and 0.96 (95% CI: 0.94, 0.98), respectively. Associations were only modestly reduced after additional adjustments for maternal BMI and gestational diabetes. No measure of LTPA was associated with risk for SGA. CONCLUSIONS: Physical activity in late, but not early, pregnancy is consistently associated with modestly lower risk of LGA and macrosomia, but not SGA. TWEETABLE ABSTRACT: In an individual participant meta-analysis, late pregnancy moderate to vigorous physical activity modestly reduced birth size outcomes.

Breech presentation is associated with lower bone mass and area: findings from the Southampton Women's Survey.

We compared bone outcomes in children with breech and cephalic presentation at delivery. Neonatal whole-body bone mineral content (BMC) and area were lower in children with breech presentation. At 4 years, no differences in whole-body or spine measures were found, but hip BMC and area were lower after breech presentation. INTRODUCTION: Breech presentation is associated with altered joint shape and hip dysplasias, but effects on bone mineral content (BMC), area (BA) and density (BMD) are unknown. METHODS: In the prospective Southampton Women's Survey mother-offspring cohort, whole-body bone outcomes were measured using dual-energy X-ray absorptiometry (DXA) in 1430 offspring, as neonates (mean age 6 days, n = 965, 39 with a breech presentation at birth) and/or at age 4.1 years (n = 999, 39 breech). Hip and spine bone outcomes were also measured at age 4 years. RESULTS: Neonates with breech presentation had 4.2 g lower whole-body BMC (95% CI -7.4 to - 0.9 g, P = 0.012) and 5.9 cm2 lower BA (- 10.8 to - 1.0 cm2, P = 0.019), but BMD was similar between groups (mean difference - 0.007, - 0.016 to 0.002 g/cm2, P = 0.146) adjusting for sex, maternal smoking, gestational diabetes, mode of delivery, social class, parity, ethnicity, age at scan, birthweight, gestational age and crown-heel length. There were no associations between breech presentation and whole-body outcomes at age 4 years, but, in similarly adjusted models, regional DXA (not available in infants) showed that breech presentation was associated with lower hip BMC (- 0.51, - 0.98 to - 0.04 g, P = 0.034) and BA (- 0.67, - 1.28 to - 0.07 cm2, P = 0.03) but not with BMD (- 0.009, - 0.029 to 0.012 g, P = 0.408), or spine outcomes. CONCLUSIONS: These results suggest that breech presentation is associated with lower neonatal whole-body BMC and BA, which may relate to altered prenatal loading in babies occupying a breech position; these differences did not persist into later childhood. Modest differences in 4-year hip BMC and BA require further investigation.

Modifiable risk factors of maternal postpartum weight retention: an analysis of their combined impact and potential opportunities for prevention.

BACKGROUND/OBJECTIVES: Pregnancy triggers a physiological change in weight status. Postpartum weight retention in the childbearing years can substantially alter a woman's weight gain trajectory, with several potential contributing factors identified. Most research has relied on women's recall of pre-pregnancy weight during pregnancy or later, and not considered risk factors in combination. Using measured pre-pregnancy weight, this study aimed to examine the associations of maternal postpartum weight retention with parity, pre-pregnancy BMI, excessive gestational weight gain (GWG), maternal serum vitamin D concentration and dietary Glycaemic Index in early and late pregnancy, and breastfeeding duration, including analysis of the combined impact of potentially modifiable risk factors. SUBJECTS/METHODS: Prospective cohort study of 12 583 non-pregnant women aged 20-34 years in Southampton (UK) who were assessed prior to pregnancy, with those who subsequently became pregnant followed up in early and late gestation, and after delivery (n=2559 in the final sample). Linear regression models examined potential predictors of weight retention in adjusted individual and multivariate analyses, and as a risk factor score. RESULTS: Compared with pre-pregnancy weight, 73% of women retained some weight at 6 months postpartum (mean (s.d.): 3.5 (6.2) kg). In the adjusted multivariate model, women who were primiparous, had a lower pre-pregnancy BMI, excessive GWG, a lower early pregnancy vitamin D concentration and breastfed for <6 months had greater weight retention 6 months postpartum (P<0.05 for all variables). For each additional modifiable risk factor (excessive GWG, low vitamin D concentration in early pregnancy and short breastfeeding duration; scale 0-3), women retained an additional 2.49 kg (95% CI: 2.16, 2.82; P<0.001). CONCLUSIONS: Having a greater number of modifiable risk factors was associated with greater weight retention 6 months postpartum. Initiatives supporting women to target these risk factors in the years prior to, during and after pregnancy could impact on their weight gain trajectory and later risk of adverse weight-related outcomes.

Maternal stress and psychological distress preconception: association with offspring atopic eczema at age 12 months.

BACKGROUND: Perinatal maternal stress and low mood have been linked to offspring atopic eczema. OBJECTIVES: To examine the relation of maternal stress/mood with atopic eczema in the offspring, focusing particularly on stress/psychological distress preconception. METHODS: At recruitment in the UK Southampton Women's Survey, preconception maternal reports of perceived stress in daily living and the effect of stress on health were recorded; in a subsample, psychological distress was assessed (12-item General Health Questionnaire). Infants were followed up at ages 6 (n = 2956) and 12 (n = 2872) months and atopic eczema ascertained (based on UK Working Party Criteria for the Definition of Atopic Dermatitis). At 6 months post-partum, mothers were asked if they had experienced symptoms of low mood since childbirth and completed the Edinburgh Postnatal Depression Scale. RESULTS: Preconception perceived stress affecting health [OR 1.21 (95% CI 1.08-1.35), P = 0.001] and stress in daily living [OR 1.16 (1.03-1.30), P = 0.014] were associated with an increased risk of offspring atopic eczema at age 12 months but not at 6 months, robust to adjustment for potentially confounding variables. Findings were similar for maternal psychological distress preconception. Low maternal mood between delivery and 6 months post-partum was associated with an increased risk of infantile atopic eczema at age 12 months, but no significant association between post-natal mood and atopic eczema was seen after taking account of preconception stress. CONCLUSION AND CLINICAL RELEVANCE: Our data provide novel evidence linking maternal stress at preconception to atopic eczema risk, supporting a developmental contribution to the aetiology of atopic eczema and pointing to potentially modifiable influences.

Higher maternal serum concentrations of nicotinamide and related metabolites in late pregnancy are associated with a lower risk of offspring atopic eczema at age 12 months.

BACKGROUND: Evidence that atopic eczema partly originates in utero is increasing, with some studies linking the risk of developing the condition with aspects of maternal diet during pregnancy. Nicotinamide, a naturally occurring nutrient that is maintained through the dietary intakes of vitamin B3 and tryptophan, has been used in the treatment of some skin conditions including atopic eczema. OBJECTIVE: To examine the relation of maternal serum concentrations of nicotinamide and related tryptophan metabolites to the risk of atopic eczema in the offspring. METHODS: Within the UK Southampton Women Survey, infantile atopic eczema at ages 6 and 12 months was ascertained (modified UK Working Party Criteria for the Definition of Atopic Dermatitis). Maternal serum levels of kynurenine, kynurenic acid, anthranilic acid, tryptophan, nicotinamide and N1-methylnicotinamide were measured in late pregnancy by mass spectrometry (n = 497) and related to the odds ratio of infantile atopic eczema. RESULTS: Maternal nicotinamide and related metabolite concentrations were not associated with offspring atopic eczema at age 6 months. Higher concentrations of nicotinamide and anthranilic acid were, however, associated with a lower risk of eczema at age 12 months (odds ratios 0.69, 95% CI 0.53-0.91/SD change, P = 0.007 and 0.63, 0.48-0.83, P = 0.001, respectively). The associations were robust to adjustment for potentially confounding variables. CONCLUSION AND CLINICAL RELEVANCE: This is the first study linking maternal serum concentrations of nicotinamide and related metabolites to the risk of atopic eczema in the offspring. The findings point to potentially modifiable maternal influences on this complex and highly prevalent condition.

Age at introduction of solid foods and feeding difficulties in childhood: findings from the Southampton Women's Survey.

This study aimed to determine whether age at introduction of solid foods was associated with feeding difficulties at 3 years of age. The present study was carried out using data from the Southampton Women's Survey (SWS). Women enrolled in the SWS who subsequently became pregnant were followed-up during pregnancy and postpartum, and the offspring have been studied through childhood. Maternal socio-demographic and anthropometric data and child anthropometric and feeding data were collected through interviews and self-administered questionnaires. When the children were 3 years of age, mothers/carers rated six potential child feeding difficulty questions on a four-point Likert scale, including one general question and five specific feeding difficulty questions. Age at introduction of solids as a predictor of feeding difficulties was examined in 2389 mother-child pairs, adjusting for child (age last breast fed, sex, gestation) and maternal characteristics (parity, pre-pregnancy BMI, age, education, employment, parenting difficulties, diet quality). The majority of mothers/carers (61 %) reported some feeding difficulties (general feeding difficulty question) at 3 years of age, specifically with their child eating enough food (61 %), eating the right food (66 %) and being choosy with food (74 %). Children who were introduced to solids ≥6 months had a lower risk of feeding difficulties (RR 0·73; 95 % CI 0·59, 0·91, P=0·004) than children who were introduced to solids between 4 and 6 months. No other significant associations were found. There were few associations between feeding difficulties in relation to age at introduction of solid foods. However, general feeding difficulties were less common among infants introduced to solid foods ≥6 months of age.

Diet quality across early childhood and adiposity at 6 years: the Southampton Women's Survey.

BACKGROUND: Poor diet quality in early childhood is inconsistently linked to obesity risk. Understanding may be limited by the use of cross-sectional data and the use of body mass index (BMI) to define adiposity in childhood. OBJECTIVE: The objective of this study is to examine the effects of continued exposure to diets of varying quality across early childhood in relation to adiposity at 6 years. METHODS: One thousand and eighteen children from a prospective UK birth cohort were studied. Diet was assessed using food frequency questionnaires when the children were aged 6 and 12 months, and 3 and 6 years; diet quality was determined according to scores for a principal component analysis-defined dietary pattern at each age (characterized by frequent consumption of fruits, vegetables and fish). At each age, children were allocated a value of 0/1/2 according to third of the distribution (bottom/middle/top) their diet quality score was in; values were summed to calculate an overall diet quality index (DQI) for early childhood (range 0-8). Obesity outcomes considered at 6 years were dual-energy X-ray absorptiometry-assessed fat mass and BMI. RESULTS: One hundred and seven (11%) children had a DQI=0, indicating a consistently low diet quality, 339 (33%) had a DQI=1-3, 378 (37%) had a DQI=4-6 and 194 (19%) had a DQI=7-8. There was a strong association between lower DQI and higher fat mass z-score at 6 years that was robust to adjustment for confounders (fat mass s.d. per 1-unit DQI increase: ß=-0.05 (95% confidence interval (CI): -0.09, -0.01), P=0.01). In comparison with children who had the highest diet quality (DQI=7-8), this amounted to a difference in fat mass of 14% (95% CI: 2%, 28%) at 6 years for children with the poorest diets (DQI=0). In contrast, no independent associations were observed between DQI and BMI. CONCLUSIONS: Continued exposure to diets of low quality across early childhood is linked to adiposity at the age of 6 years.

Placental amino acid transport may be regulated by maternal vitamin D and vitamin D-binding protein: results from the Southampton Women's Survey.

Both maternal 25-hydroxyvitamin D (25(OH)D) concentrations during pregnancy and placental amino acid transporter gene expression have been associated with development of the offspring in terms of body composition and bone structure. Several amino acid transporter genes have vitamin D response elements in their promoters suggesting the possible linkage of these two mechanisms. We aimed to establish whether maternal 25(OH)D and vitamin D-binding protein (VDBP) levels relate to expression of placental amino acid transporters. RNA was extracted from 102 placental samples collected in the Southampton Women's Survey, and gene expression was analysed using quantitative real-time PCR. Gene expression data were normalised to the geometric mean of three housekeeping genes, and related to maternal factors and childhood body composition. Maternal serum 25(OH)D and VDBP levels were measured by radioimmunoassay. Maternal 25(OH)D and VDBP levels were positively associated with placental expression of specific genes involved in amino acid transport. Maternal 25(OH)D and VDBP concentrations were correlated with the expression of specific placental amino acid transporters, and thus may be involved in the regulation of amino acid transfer to the fetus. The positive correlation of VDBP levels and placental transporter expression suggests that delivery of vitamin D to the placenta may be important. This exploratory study identifies placental amino acid transporters which may be altered in response to modifiable maternal factors and provides a basis for further studies.

Physical activity, calcium intake and childhood bone mineral: a population-based cross-sectional study.

UNLABELLED: In a free-living cohort of 4-year old children, mean daily time in moderate-vigorous physical activity and daily calcium intake at 3 years, were positively related to hip bone size and density. Relationships between physical activity and bone indices were stronger when calcium intake was above compared with below median (966 mg/day). INTRODUCTION: We examined the cross-sectional relationships between childhood physical activity, dietary calcium intake and bone size and density. METHODS: Children aged 4 years were recruited from the Southampton Women's Survey. They underwent measurement of bone mass by DXA (Hologic Discovery). Physical activity was assessed by accelerometry (Actiheart, Cambridge Neurotechnology Ltd, Cambridge, UK) for seven continuous days. RESULTS: Four hundred twenty-two children (212 boys) participated. In a cross-sectional analysis, after adjusting for gender, daily mean time(minutes per day) spent in moderate to very vigorous activity (MVPA) was positively related to hip BA (R(2) = 3%, p < 0.001), BMC (R(2) = 4%, p < 0.001), aBMD (R (2) = 3%, p = 0.001) and estimated vBMD (R(2) = 2%, p = 0.01), but not height (r (s) = 0.04, p = 0.42) or weight (r(s) = 0.01, p = 0.76). Mean daily calcium intake (assessed at 3 years old) positively predicted bone indices in those with a calcium intake below the median (966 mg/day), but there was a much attenuated relationship in those above this. These associations persisted after inclusion of total energy, protein and phosphorus in multivariate models. The relationships between MVPA and bone indices were stronger in children with calcium intakes above the median. Thus, for aBMD, the variance explained by MVPA when daily calcium intake was below the median was 2% (p = 0.1) and above median was 6% (p = 0.001). CONCLUSIONS: These results support the notion that adequate calcium intake may be required for optimal action of physical activity on bone development and that improving levels of physical activity and calcium intake in childhood may help to optimise accrual of bone mass.

DNA methylation signatures in cord blood associated with birthweight are enriched for dmCpGs previously associated with maternal hypertension or pre-eclampsia, smoking and folic acid intake.

Many epidemiological studies have linked low birthweight to an increased risk of non-communicable diseases (NCDs) in later life, with epigenetic proceseses suggested as an underlying mechanism. Here, we sought to identify neonatal methylation changes associated with birthweight, at the individual CpG and genomic regional level, and whether the birthweight-associated methylation signatures were associated with specific maternal factors. Using the Illumina Human Methylation EPIC array, we assessed DNA methylation in the cord blood of 557 and 483 infants from the UK Pregnancies Better Eating and Activity Trial and Southampton Women's Survey, respectively. Adjusting for gestational age and other covariates, an epigenome-wide association study identified 2911 (FDR≤0.05) and 236 (Bonferroni corrected p ≤ 6.45×10-8) differentially methylated CpGs (dmCpGs), and 1230 differentially methylated regions (DMRs) (Stouffer ≤0.05) associated with birthweight. The top birthweight-associated dmCpG was located within the Homeobox Telomere-Binding Protein 1 (HMBOX1) gene with a 195 g (95%CI: -241, -149 g) decrease in birthweight per 10% increase in methylation, while the top DMR was located within the promoter of corticotropin-releasing hormone-binding protein (CRHBP). Furthermore, the birthweight-related dmCpGs were enriched for dmCpGs previously associated with gestational hypertension/pre-eclampsia (14.51%, p = 1.37×10-255), maternal smoking (7.71%, p = 1.50 x 10-57) and maternal plasma folate levels during pregnancy (0.33%, p = 0.029). The identification of birthweight-associated methylation markers, particularly those connected to specific pregnancy complications and exposures, may provide insights into the developmental pathways that affect birthweight and suggest surrogate markers to identify adverse prenatal exposures for stratifying for individuals at risk of later NCDs.

Differential relationships between parent-child DXA and pQCT bone measures: Results from the Southampton Women's Survey.

AIM: To investigate the associations between indices of bone health in childhood and corresponding parental measures. METHODS: The Southampton Women's Survey characterised 12,583 non-pregnant women aged 20-34 years; 3158 subsequently had singleton live births. In a subset, dual-energy X-ray absorptiometry (DXA) measurements of bone area (BA), bone mineral content (BMC) and areal bone mineral density (aBMD) lumbar spine and total hip were obtained in the parent/offspring (aged 8-9 years) trios. Another subset of children (aged 6-7 years), and their parents, had peripheral quantitative computed tomography (pQCT; 4% and 38% tibia) measures. Using multivariable linear regression we examined relationships between mother/father and offspring, adjusting for parental age, habitual walking speed and education; offspring age and sex; and the corresponding bone measure in the other parent (ß-coefficients (95%CI) unit/unit for each bone measure). RESULTS: Data were available for 260 trios with DXA and 99 with pQCT. There were positive associations for BA, BMC and aBMD between either parent and offspring. Mother-child associations were of greater magnitude than father-child; for example, mother-child aBMD (ß = 0.26 g·cm-2/g·cm-2 (0.21,0.32)) and father-child aBMD (ß = 0.16 g·cm-2/g·cm-2 (0.11,0.21)), P-difference in ß = 0.007. In the subset with pQCT there was a positive association for mother-offspring 4% tibial total area (ß = 0.33 mm2/mm2 (0.17,0.48)), but little evidence of a father-offspring association (ß = -0.06 mm2/mm2 (-0.17,0.06)). In contrast offspring 38% cortical density was more strongly associated with this measure in fathers (ß = 0.48 mg·cm-3/mg·cm-3 (0.15,0.82)) than mothers (ß = 0.27 mg·cm-3/mg·cm-3 (-0.03,0.56)). In general mother-father differences were attenuated by adjustment for height. CONCLUSIONS: Whilst offspring bone measures are independently associated with those of either parent, the magnitude of the association is often greater for maternal than paternal relationships. These findings are consistent with an in utero influence on offspring growth but might also reflect genetic and/or epigenetic parent of origin effects. SUMMARY: In an established parent-offspring cohort, associations between parent and offspring bone indices were generally greater in magnitude for mother-offspring than father-offspring relationships.

Methods for determining pubertal status in research studies: literature review and opinions of experts and adolescents.

In lifecourse studies that encompass the adolescent period, the assessment of pubertal status is important, but can be challenging. We aimed to identify current methods for pubertal assessment and assess their appropriateness for population-based research by combining a review of the literature with the views of experts in the field. We searched bibliographic databases, extracted data and assessed study quality to inform a workshop with 21 experts. Acceptability of different approaches was explored with a panel of ten adolescents. We screened 11,935 abstracts, assessed 157 articles and summarised results from 38 articles. Combining these with the opinions of experts, self-assessment was found to be a practical method for use in studies where agreement with the gold standard of clinical assessment by physical examination to within one Tanner stage was acceptable. Serial measures of height and foot size accurately indicated timing of the pubertal growth spurt and age at peak height velocity, and were seen as feasible within longitudinal studies. Hormonal and radiological methods did not offer a practical means of assessing pubertal status. Assessment of voice maturation was promising, but needed validation. Young people thought that self-assessment, foot size and voice assessments were acceptable, and preferred an assessor of the same sex for clinical assessment. This review thus informs researchers working in lifecourse and adolescent health, and identifies future directions in order to improve validity of the methods.

Placental volume at 11 weeks is associated with offspring bone mass at birth and in later childhood: Findings from the Southampton Women's Survey.

OBJECTIVES: To investigate associations between placental volume (PV) at 11 weeks' gestation and offspring bone outcomes at birth, 6 years and 8 years. METHODS: 3D ultrasound scanning was used to assess 11 week PV in a subset (n = 236) of the Southampton Women's Survey (a prospective mother-offspring cohort). Maternal anthropometric measures and lifestyle information were obtained pre-pregnancy and at 11 weeks' gestation. Offspring dual-energy x-ray absorptiometry scanning was performed within 2 weeks postnatally and at 6 and 8 years. Linear regression was used to assess associations between PV and bone outcomes, adjusting for offspring age at DXA and sex, and maternal age, height, smoking status, walking speed and triceps skinfold thickness. ß are SD change in bone outcome per SD change in PV. RESULTS: In adjusted models, 11 week PV was positively associated with bone area (BA) at all time points, with evidence of persisting associations with increasing childhood age (birth: n = 80, ß = 0.23 [95%CI = 0.03, 0.42], 6 years: n = 110, ß = 0.17 [-0.01, 0.36], 8 years: n = 85, ß = 0.13 [-0.09, 0.36]). Similar associations between 11 week PV and bone mineral content (BMC) were observed. Associations with size-corrected bone mineral content were weaker at birth but strengthened in later childhood (birth: n = 78, ß = 0.07 [-0.21, 0.35], 6 years: n = 107, ß = 0.13 [-0.08, 0.34], 8 years: n = 71, ß = 0.19 [-0.05, 0.43]). CONCLUSIONS: 11 week PV is associated with DXA bone measures at birth, with evidence of persisting associations into later childhood. Further work is required to elucidate the contributions of placental morphology and function to gestational influences on skeletal development.

Paternal skeletal size predicts intrauterine bone mineral accrual.

BACKGROUND: We have previously demonstrated that maternal body build and lifestyle factors predict neonatal bone mineral accrual. However, the paternal determinants of neonatal bone mass are not known. In this study we explored the relationship between a father's bone mass and that of his offspring. METHODS: A total of 278 pregnancies (142 male and 136 female neonates) were recruited from the Southampton Women's Survey, a unique, well-established cohort of women, aged 20-34 yr, who had been assessed before and during pregnancy. The neonates and their fathers underwent whole body dual-x-ray absorptiometry (DXA) within 2 wk of birth using a Lunar DPX (General Electric Corp., Madison, WI) and Hologic Discovery instrument (Hologic Inc., Bedford, MA), respectively; correlation and regression methods were used to explore the parental determinants of neonatal bone mass. RESULTS: After adjusting the paternal DXA indices for father's age and the neonatal for baby's gestational age and age at DXA scan, there were highly significant positive associations between baby's whole body bone area, bone mineral content, and bone mineral density and the corresponding indices in the father (P = 0.003, 0.0002, 0.046, respectively) among female infants. These relationships were independent of maternal height and fat stores. The associations for male infants with paternal DXA indices did not achieve statistical significance. CONCLUSIONS: The father's skeletal size predicts skeletal size more strongly in female than male offspring, independently of the mother's body build. These data point toward the importance of considering paternal genotype in studies exploring the developmental origins of osteoporotic fracture and raise intriguing mechanistic questions about the gender specificity of influences on intrauterine bone mineral accrual.

Stability of dietary patterns in young women over a 2-year period.

OBJECTIVE: To examine the stability of dietary patterns in young women over a two-year period and to identify factors that influence stability. DESIGN: A food frequency questionnaire was used to assess diet. In a subgroup, this was repeated after 2 years. Questions were asked about major changes to diet over this time. Dietary patterns were identified using principal components analysis and pattern scores were compared at the two time points. The consumption of foods was also examined. The relationship between change in pattern scores and socio-demographic factors and body mass index was assessed. SETTING: The Southampton Women's Survey, a prospective study of diet, health and lifestyle in young women and their influences on fetal growth. SUBJECTS: A subgroup of 94 women from a cohort of 6129 nonpregnant women aged 20-34 years. RESULTS: Two dietary patterns, labelled 'prudent' and 'high energy', were identified. Spearman correlation coefficients between the initial and repeat scores for the prudent and high-energy patterns were 0.81 and 0.64, respectively. Average changes (repeat - initial) were 0.13 and -0.01 SD of initial score. Change in prudent dietary pattern score was influenced by amount of strenuous exercise taken and by changes in partnership status. An increase in high-energy pattern score was associated with lower social class. CONCLUSIONS: Dietary patterns in young women are reasonably stable over a 2-year period. This suggests that dietary patterns identified in the recent past may provide useful information about current dietary patterns.

Parental determinants of neonatal body composition.

BACKGROUND: The prevalence of both childhood and adult obesity is rising in the developed world, and there is increasing interest in its underlying causes. A number of studies suggest a positive relationship between birth weight and childhood body mass index, but less is known about specific prenatal environmental influences on more direct measures of obesity. We used data from the Southampton Women's Survey to investigate parental influences on neonatal body composition ascertained by dual x-ray absorptiometry. METHODS: Participating mothers were characterized in detail (anthropometry, lifestyle, diet) before and during pregnancy; information was also obtained on their partners. The offspring underwent assessment of fat and lean body mass by dual x-ray absorptiometry within 2 wk of birth. Linear regression methods were used to explore the parental determinants of neonatal body composition. RESULTS: Complete data were available for 448 mother-offspring pairs. Taller women and those with higher parity had offspring with increased birth weight, fat, and lean mass (P < 0.05). Mothers who were taller, of greater parity, had greater fat stores, or walked more slowly also had offspring with greater proportionate body fat at birth (all P < 0.05). There was a weaker trend toward lower percentage fat and greater percentage lean in the offspring of mothers who smoked during pregnancy. CONCLUSION: Maternal size, parity, smoking history, walking speed, and fat stores are independent determinants of neonatal body composition. If these influences are shown to have persisting effects on body composition through to adulthood, they point to novel public health interventions early in life to prevent later obesity.

Placental calcium transporter (PMCA3) gene expression predicts intrauterine bone mineral accrual.

Evidence is accruing that environmental exposures during critical periods of early development induce persisting changes in skeletal growth, and alter fracture risk in later life. We have previously demonstrated that placental calcium transport, partly determined by maternal 25-(OH) vitamin D status, may underlie this phenomenon. However, the precise relationship between expression of calcium transport proteins in the human placenta, and neonatal bone mineral accrual in the offspring, remains unknown. Tissue samples from 70 human placentae were fast frozen in liquid nitrogen and stored at -70 degrees C. A quantitative real time reverse transcriptase polymerase chain reaction was used to measure the mRNA expression of PMCA isoforms 1-4, using beta-actin as a control gene. Neonatal whole body bone area, mineral content and areal density (BA, BMC, BMD) were measured within 2 weeks of birth using DXA. PMCA3 mRNA expression predicted BA (r=0.28, p=0.02), BMC (r=0.25, p=0.04), placental weight (r=0.26, p=0.04) and birth weight (r=0.33, p=0.006) of the neonate. In a multivariate model, the relationship between placental PMCA3 expression and neonatal BMC was independent of maternal height, pre-pregnant fat stores, parity, physical activity, smoking, and calcium intake (p<0.05). Expression of the placental calcium transporter PMCA3 mRNA predicts neonatal whole body bone mineral content. This association may explain, in part, the mechanism whereby a mother's 25(OH)-vitamin D stores influence her offspring's bone mass.

Dietary patterns in the Southampton Women's Survey.

OBJECTIVE: Dietary pattern analysis is receiving increasing attention as a means of summarizing the multidimensional nature of dietary data. This research aims to compare principal component analysis (PCA) and cluster analysis using dietary data collected from young women in the UK. DESIGN: Diet was assessed using a 100-item interviewer-administered food frequency questionnaire. PCA and cluster analysis were used to examine dietary patterns. SETTING: Southampton, UK. SUBJECTS: A total of 6125 non-pregnant women aged 20-34 years. RESULTS: PCA identified two important patterns: a 'prudent' diet and a 'high-energy' diet. Cluster analysis defined two clusters, a 'more healthy' and a 'less healthy' cluster. There was a strong association between the prudent diet score and the two clusters, such that the mean prudent diet score in the less healthy cluster was -0.73 standard deviations and in the more healthy cluster was +0.83 standard deviations; the difference in the high-energy diet score between the two clusters was considerably smaller. CONCLUSIONS: Both approaches revealed a similar dietary pattern. The continuous nature of the outcome of PCA was considered to be advantageous compared with the dichotomy identified using cluster analysis. SPONSORSHIP: The study was funded by the Dunhill Medical Trust, the University of Southampton and the Medical Research Council.

Relation of FTO gene variants to fetal growth trajectories: Findings from the Southampton Women's survey.

INTRODUCTION: Placental function is an important determinant of fetal growth, and fetal growth influences obesity risk in childhood and adult life. Here we investigated how FTO and MC4R gene variants linked with obesity relate to patterns of fetal growth and to placental FTO expression. METHODS: Southampton Women's Survey children (n = 1990) with measurements of fetal growth from 11 to 34 weeks gestation were genotyped for common gene variants in FTO (rs9939609, rs1421085) and MC4R (rs17782313). Linear mixed-effect models were used to analyse relations of gene variants with fetal growth. RESULTS: Fetuses with the rs9939609 A:A FTO genotype had faster biparietal diameter and head circumference growth velocities between 11 and 34 weeks gestation (by 0.012 (95% CI 0.005 to 0.019) and 0.008 (0.002-0.015) standard deviations per week, respectively) compared to fetuses with the T:T FTO genotype; abdominal circumference growth velocity did not differ between genotypes. FTO genotype was not associated with placental FTO expression, but higher placental FTO expression was independently associated with larger fetal size and higher placental ASCT2, EAAT2 and y + LAT2 amino acid transporter expression. Findings were similar for FTO rs1421085, and the MC4R gene variant was associated with the fetal growth velocity of head circumference. DISCUSSION: FTO gene variants are known to associate with obesity but this is the first time that the risk alleles and placental FTO expression have been linked with fetal growth trajectories. The lack of an association between FTO genotype and placental FTO expression adds to emerging evidence of complex biology underlying the association between FTO genotype and obesity.