Early growth and cardiovascular disease

Immune function in rural Gambian children is not related to season of birth, birth size, or maternal supplementation status

BACKGROUND

We previously showed that mortality from infectious diseases among young adults in rural Gambia is strongly correlated with the season of their birth. This suggests that early life insults that involve fetal malnutrition, exposure to natural toxins, or highly seasonal infections affecting the infant or pregnant mother cause permanent damage to the immune system. Excess mortality begins after puberty and has a maximal odds ratio of >10 for deaths between ages 25 and 50 y.

OBJECTIVE

We investigated the immune function of children according to birth weight, season of birth, and exposure to maternal dietary supplementation during pregnancy.

DESIGN

Immune function was measured in 472 prepubertal children aged 6.5-9.5 y from 28 villages in rural Gambia. The mothers of these children had been randomly assigned to a high-energy prenatal supplementation program, which significantly increased birth weight. This permitted supplementation status, birth weight, and season of birth to be investigated as exposure variables. The outcome variables tested were naive responses to rabies and pneumococcus vaccines, delayed-type hypersensitivity skin reactions, and mucosal defense (secretory immunoglobulin A and dual-sugar permeability).

RESULTS

Immune responses were strongly related to current age and sex, suggesting a high level of sensitivity, but were not consistently related to birth weight, season of birth, or maternal supplementation (control compared with intervention).

CONCLUSION

Events in early life did not predict a measurable defect in immune response within this cohort of rural Gambian children. It is possible that the early programming of immune function may be mediated through a defect in immunologic memory or early senescence rather than through impairment of early responses.

Abdominal fat and birth size in healthy prepubertal children

BACKGROUND

Studies examining the foetal origins hypothesis suggest that small birth size may be a marker of foetal adaptations that programme future propensity to adult disease. We explore the hypothesis that birth size may relate to fat distribution in childhood and that fat distribution may be a link between birth size and adult disease.

OBJECTIVE

To investigate the relationship between birth size and abdominal fat, blood pressure, lipids, insulin and insulin:glucose ratio in prepubertal children.

DESIGN

Cross-sectional study, based on a birth cohort of consecutive full-term births.

SUBJECTS

Two hundred and fifty-five (137 females) healthy, 7- and 8-y-old children.

MEASUREMENTS

Body composition and abdominal fat was measured by dual energy X-ray absorptiometry. Lipid, glucose and insulin profiles were measured after an overnight fast and an automated BP monitor was used for blood pressure measurements.

RESULTS

There was a negative association between abdominal fat and birth weight s.d. score across a range of normal birth weights (beta=-0.18; 95% CI=-0.31 to -0.04, P=0.009) and a positive association with weight s.d. score at 7/8 y (beta=0.35; 95% CI=0.24 to 0.46, P<0.001). Children who were born with the lowest weight s.d. score and had the greatest weight s.d. score at 7/8 y had significantly more (P<0.001) abdominal fat, as a percentage of total fat (6.53+/-1.3%) than those who had the highest birth weight s.d. score and the lowest weight s.d. score at 7/8 y (4.14+/-0.5%). Similar results were seen if head circumference, but not ponderal index, was used as an indicator of birth size. Increased abdominal fat was associated with higher total cholesterol:HDL cholesterol, higher triglyceride concentration and increased diastolic blood pressure.

CONCLUSIONS

Birth weight independently predicted abdominal fat. Children with the highest amount of abdominal fat were those who tended to be born lighter and gained weight centiles. Increased abdominal fat was associated with precursor risk factors for ischaemic heart disease.

Successes and shortcomings of fetal echocardiography

While it is possible to perform balloon valvuloplasty of a critically stenosed pulmonary valve in the fetus safely, the majority of serious heart conditions remain undiagnosed until after birth. This article addresses the successes and shortcomings of fetal cardiology.

Increased tissue concentrations of arachidonic acid in umbilical artery and placenta in fetal growth retardation

OBJECTIVE

To compare the fatty acid phospholipid composition of the umbilical artery and the placenta in cases of fetal growth retardation (FGR) and of normal growth, as well as in symmetric and asymmetric FGR.

DESIGN

Case-control study.

SETTING

University hospital.

POPULATION

Thirty-nine FGR cases (12 asymmetric, 27 symmetric) and 78 cases with normal growth.

MAIN OUTCOME MEASURES

Thin layer gas-liquid capillary chromatography of phospholipid fatty acids in umbilical artery and placental cotyledons. Newborns were classified as FGR if their weight was under the 10th percentile for our center. FGR was defined as symmetric if the ponderal index was >2.32, and as asymmetric if it was <2.32.

RESULTS

In FGR, arachidonic acid was significantly increased both in placenta (24.05%+/-2.78 vs 22.46%+/-2.93) and in umbilical artery (16.76%+/-2.40 vs 15.58%+/-3.67). Indeed this increase was significantly higher in asymmetric than in symmetric FGR (25.70+/-2.32 vs 23.32+/-2.68 in placenta and 18.06+/-1.46 vs 16.14 +/-2.53 in umbilical artery). On the other hand, in the placenta there were a number of differences in the metabolic ratios analyzed when comparing symmetric and asymmetric FGR, indicating a lower DHA availability and a higher n-6 fatty acid elongation and desaturation in asymmetric FGR.

CONCLUSION

FGR is characterized by an increase in arachidonic acid both in the placenta and umbilical artery phospolipids, probably reflecting a different mobilization from tissue stores. It is speculated that the different arterial composition could be partially responsible for the increased cardiovascular risk of FGR in adulthood. On the other hand the metabolic status of the placenta concerning polyunsaturated fatty acids was very different in symmetric and asymmetric FGR, suggesting a different pathogenesis.

Parental recall of birthweight: a good proxy for recorded birthweight?

Recent evidence suggests potential associations between birthweight and disease in later life. For resource or other reasons recorded birthweight may be unavailable to researchers who have access to uniquely relevant outcome data. The present study examined the validity of parental recall of birthweight. Parents of 1015 males and females aged 12 and 15 years participating in the Young Hearts Study (a cluster random sample of 1015 males and females aged 12 and 15 years from post-primary schools in Northern Ireland) completed a questionnaire which included a question about their child's birthweight. The answer provided was compared with recorded birthweight obtained from archived computerised child health records with a cut-off point for inaccurate reporting set at +/- 227 g (1/2 lb). The influence of social class and weight at birth on accuracy of recall was also determined. A total of 84.8% of parents accurately recalled their child's birthweight to within 227 g. Parents from non-manual occupation social classes recalled birthweight more accurately than those from manual occupation social classes (88.0 vs. 82.6% accurate: chi2 = 4.81, p = 0.03). Parents of low birthweight infants tended to recall their birthweight less accurately than parents of normal weight infants: 76.1% accurate compared to 86.1% accurate: chi2 = 3.54, p = 0.06. Parents of high birthweight infants recalled their birthweight less accurately than parents of normal weight infants: 78.5% accurate: chi2 = 3.94, p = 0.05. In conclusion, parentally recalled birthweight may be a suitable proxy for recorded birthweight for population based research into disease in childhood and adolescence.

Nutritional interventions in cardiovascular disease: new challenges and opportunities

New opportunities for control of cardiovascular disease (CVD) through nutritional interventions can be divided into three areas: nutritional intervention on newly identified causes of CVD; nutritional strategies to more efficiently or equitably employ current, proven interventions; and nutritional approaches to reduce costs and improve effectiveness so that benefits can be expanded to more of the population. Examples of newly identified causes of CVD amenable to nutritional intervention include fetal/early childhood malnutrition and gene-environment interactions. Examples of more efficient or equitable nutritional strategies include better nutrition education for healthcare providers, patient education resources on the Internet, and widely available functional foods or nutriceuticals. Nutritional approaches to improve cost-effectiveness include better availability of foods associated with reduced CVD risk (eg, fruits, vegetables, fish) and supplementation of the American diet. The advances in nutritional strategies described in this monograph have the potential for population-wide CVD risk reduction.

Parental recall of birth weight: how accurate is it?

OBJECTIVE

To assess the accuracy of parental recall of birth weight in a British population and to investigate whether social class and age of the child significantly influence the accuracy of recalled birth weight.

METHODS

A questionnaire was given to parents whose children were participating in a blood pressure study and the hospital records were retrieved to check the birth weight data.

RESULTS

At the time of the study, the children (n = 649) ranged in age from 6 to 15 years. Seventy five per cent of the recalled birth weights were within 50 g of that recorded in the hospital records. No significant associations were found between the difference in birth weights (recalled birth weight minus hospital record) and social class of the parents or age of the child at time of data collection.

CONCLUSION

This large study shows that parental recall of birth weight is good across the social classes and up to 16 years after delivery. There was no evidence of systematic bias, which would prejudice results of studies on the relation of birth weight to adult hypertension.