Maternal-fetal interactions and birth order influence insulin variable number of tandem repeats allele class associations with head size at birth and childhood weight gain

Polymorphism of the insulin gene (INS) variable number of tandem repeats (VNTR; class I or class III alleles) locus has been associated with adult diseases and with birth size. Therefore, this variant is a potential contributory factor to the reported fetal origins of adult disease. In the population-based Avon Longitudinal Study of Pregnancy and Childhood birth cohort, we have confirmed in the present study the association between the INS VNTR III/III genotype and larger head circumference at birth (odds ratio [OR] 1.92, 95% CI 1.23-3.07; P = 0.004) and identified an association with higher cord blood IGF-II levels (P = 0.05 to 0.0001). The genotype association with head circumference was influenced by maternal parity (birth order): the III/III OR for larger head circumference was stronger in second and subsequent pregnancies (OR 5.0, 95% CI 2.2-11.5; P = 0.00003) than in first pregnancies (1.2, 0.6-2.2; P = 0.8; interaction with birth order, P = 0.02). During childhood, the III/III genotype remained associated with larger head circumference (P = 0.004) and was also associated with greater BMI (P = 0.03), waist circumference (P = 0.03), and higher fasting insulin levels in girls (P = 0.02). In addition, there were interactions between INS VNTR genotype and early postnatal weight gain in determining childhood BMI (P = 0.001 for interaction), weight (P = 0.005), and waist circumference (P = 0.0005), such that in the approximately 25% of children (n = 286) with rapid early postnatal weight gain, class III genotype-negative children among this group gained weight more rapidly. Our results indicate that complex prenatal and postnatal gene-maternal/fetal interactions influence size at birth and childhood risk factors for adult disease.     

Maternal employment and the initiation of breastfeeding

This study examines whether planning to be employed postpartum has an effect on initiation of breastfeeding. Data were collected from questionnaires completed by mothers who were subjects in the prospective, population-based, Avon Longitudinal Study of Pregnancy and Childhood. The mothers of 10,530 full-term singleton infants gave information during pregnancy on their postpartum employment plans and their initial infant feeding methods. Information was also given by 7642 of these mothers on the timing of their postpartum employment plans. Adjusted logistic regression was performed to identify associations between (a) "any" plans to work postpartum and the initiation of breastfeeding, and (b) the timing of the commencement of work postpartum, and the initiation of breastfeeding. A total of 8316 (79%) of the women initiated breastfeeding. The decision to breastfeed was not associated with "any" plans to work postpartum. However, women who planned to commence work prior to 6 wk postpartum were significantly less likely to initiate breastfeeding compared with those not intending to work postpartum. Older, more highly educated women, women who had or were planning to attend childbirth classes, women who were breastfed as infants, women who did not smoke and women who were giving birth to their first child were significantly more likely to initiate breastfeeding. Conclusion: Planning to return to employment prior to 6 wk postpartum reduces the likelihood of initiating breastfeeding. As increasing numbers of mothers are returning to work shortly after the birth of their child, this finding could have implications for maintaining the current level of breastfeeding.     

Stereoacuity at age 3.5 y in children born full-term is associated with prenatal and postnatal dietary factors: a report from a population-based cohort study

BACKGROUND: Observational studies suggested that breast-feeding benefits the visual development of preterm children, which has been attributed to the presence of docosahexaenoic acid (DHA) in breast milk but not most formula milks. Randomized studies showed that preterm children require a dietary supply of DHA in the first few weeks of life for optimal visual development, but it is unclear whether full-term children experience similar benefits from breast milk or DHA supplements. OBJECTIVE: The objective of this study was to compare stereoacuity at age 3.5 y in healthy, full-term children who were breast-fed and in similar children who had not been breast-fed after adjustment for socioeconomic status and maternal diet. DESIGN: Prospectively collected data on maternal diet during pregnancy (including intake of oily fish), the child's diet, and the socioeconomic status of the family were examined. Stereoacuity at age 3.5 y was assessed. RESULTS: Children who had been breast-fed for 4 mo were more likely to achieve high-grade stereopsis, or stereoscopic vision, than were children who had not been breast-fed (adjusted odds ratio: 2.77; 95% CI: 1.54, 4.97). The mother's antenatal blood DHA content was associated with her intake of oily fish (P < 0.0001). Children whose mothers ate oily fish during pregnancy were also more likely to achieve high-grade stereopsis than were children whose mothers did not eat oily fish (adjusted odds ratio: 1.57; 95% CI: 1.00, 2.45). CONCLUSIONS: The results of this study suggest that for full-term infants, breast-feeding is associated with enhanced stereopsis at age 3.5 y, as is a maternal DHA-rich antenatal diet, irrespective of later infant feeding practice.     

Food and nutrient intake in a cohort of 8-month-old infants in the south-west of England in 1993

OBJECTIVE: To investigate food and nutrient intakes in 8-month-old infants. DESIGN: Prospective study. SETTING: Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC), south-west England. SUBJECTS: A total of 1131 singleton Caucasian infants (82% of those invited) from a 10% random sample of ALSPAC, known as Children in Focus (CIF). METHODS: Diet was assessed using a structured 3-day unweighed dietary record. Food and nutrient intakes were compared with intakes from the 6--9 month age group of a British infant feeding survey, which formed part of the National Diet and Nutrition Survey (NDNS). Nutrient intakes were compared with dietary reference values (DRV). RESULTS: Intakes of energy and most nutrients were very similar between CIF and NDNS. The main difference was in the type of fat eaten resulting in a higher polyunsaturated to saturated fatty acid ratio in CIF (0.34) compared with NDNS (0.21). Other differences included the much lower calcium and iodine intakes in CIF compared with the NDNS. Differences in the proportion of consumers of formula and cow's milk accounted for most of the nutrient differences. Energy intakes were similar to the estimated average requirements (EAR), however, breastfed infants were slightly below and non-breastfed were slightly above the EAR. Mean intakes of zinc and vitamin D were below the Reference Nutrient Intakes. CONCLUSIONS: The diets of 8-month-old infants in this study were adequate in most nutrients. Breastfed infants had slightly lower energy intakes than non-breastfed infants.     

Opposing influences of prenatal and postnatal weight gain on adrenarche in normal boys and girls

Associations between low birth weight and higher adrenal androgen secretion before puberty have yet only been reported in case-control studies in girls. We examined the influence of birth weight and early postnatal weight gain on overnight-fasting adrenal androgen and cortisol levels in 770 children from a large normal United Kingdom birth cohort at age 8 yr. In univariate analyses, adrenal androgen levels were inversely related to birth weight sd score in each sex [dehydroepiandrosterone sulfate in boys: regression coefficient (B) = -2.5 microg/dl/SD; 95% confidence interval (CI), -4.7 to -0.2; in girls: B = -3.8 microg/dl/SD; 95% CI, -6.2 to -1.4; androstenedione in boys: B = -0.15 nmol/liter/sd, 95% CI, -0.25 to -0.6; in girls: B = -0.13 nmol/liter/SD; 95% CI, -0.24 to -0.02). In multivariate analyses, both lower birth weight and larger current body weight predicted higher adrenal androgen levels (P < 0.005 for all comparisons). Allowing for current weight, children who showed rapid postnatal weight gain between 0 and 3 yr had higher dehydroepiandrosterone sulfate (P = 0.002) and androstenedione (P = 0.004) levels at 8 yr. In contrast, cortisol levels were unrelated to birth weight or current body size. In summary, the relationship between lower birth weight and higher childhood adrenal androgen levels was continuous throughout the range of normal birth weights, and was similar in boys and girls. Adrenal androgen levels were highest in small infants who gained weight rapidly during early childhood. We suggest that higher adrenal androgen secretion could contribute to links between early growth and adult disease risks, possibly by enhancing insulin resistance and central fat deposition.     

Maternal childhood abuse and offspring adjustment over time

This study addressed the basis for the intergenerational transmission of psychosocial risk associated with maternal childhood abuse in relation to offspring adjustment. The study tested how far group differences in individual change in adjustment over time were explained by differences in exposure to specific environmental risk experiences. Data are drawn from the Avon Longitudinal Study of Parents and Children. Information on mothers' own experience of childhood abuse, offspring adjustment at ages 4 and 7 years, and hypothesized mediators was available for 5,619 families. A residuals scores analysis was used to track children's adjustment over time. Maternal childhood abuse was associated with poorer behavioral trajectories between ages 4 and 7 years. Children of abused mothers were more likely to experience a range of negative life events between ages 4 and 7 years, including changes in family composition, separations from parents, "shocks and frights" and physical assaults. Interim life events, together with antecedent psychosocial risk (maternal antenatal affective symptoms, age 4 parental hostility, age 4 family type) fully mediated the association between maternal childhood abuse and offspring prognosis.The authors express their gratitude to the families who participated in the study. Support for these analyses was provided by a grant from the Medical Research Council. The Avon Longitudinal Study of Parents and Children (ALSPAC) is part of the World Health Organisation initiated European Study of Pregnancy and Childhood, and is supported, among others, by the Wellcome Trust, The Department of Health, The Department of the Environment, and the Medical Research Council. The ALSPAC study team comprises interviewers, computer technicians, laboratory technicians, clerical workers, research scientists, volunteers, and managers who continue to make the study possible.