Commentary: The impact of fetal and infant exposures along the life course

Placental thickness measurement by ultrasonography and its correlation with gestational age of fetus in the manipuri population

Purpose:

The study was done to measure the placental thickness (PT) in pregnant women and find its correlation with the gestational age (GA) of the fetus by ultrasonography. Comparisons were also made with the other fetal biometry parameters, and baseline data were generated with respect to the gestational weeks and placental position.

Materials and Methods:

The study was a cross-sectional one with a sample size of 134 singleton pregnancies. About 11–40 weeks of gestation were studied for the measurement of PT and other fetal parameters. Informed consent was obtained before recording the data on the preformed questionnaire. All measurements were done in mm and during the relaxed phase of the uterus.

Results:

As per the study, PT (in mm) increases with an increase in GA (in weeks) and almost matches it from 12 to 34 weeks of gestation. PT had a strong correlation with GA (r = 0.966). The correlation was statistically significant, with a P < 0.001.

Conclusion:

Thus, the estimation of the thickness of the placenta at the cord insertion site by means of ultrasonography is a relatively simple, safe, and cheap modality for accurate estimation of GA, fetal growth, and placental abnormalities and thus can significantly affect the management and outcome of pregnancy.

Aflatoxin M1in breast-milk of UAE women

A study was undertaken to determine whether breast-milk of mothers from the United Arab Emirates (UAE) contained aflatoxins. One hundred and forty lactating mothers, 55 who had delivered premature infants (<2500 g, </=37 wk gestational age) and 85 who had full-term infants, agreed to participate in the study. Breast-milk was collected during regular feeding of infants in the special care baby unit and postnatal wards using an electric breast pump and ten ml of milk was siphoned off into a zinc-free plastic container for analysis. Aflatoxin M(1) concentration in the breast-milk samples was measured by HPLC. Samples were collected between January 1999 and December 2000. Approximately 66% of the mothers were expatriates and 34% were UAE nationals. Babies' weight, postnatal age, sex, birthweight and gestational age, and mothers' nationality, age and parity were recorded. Overall, 92% of the breast-milk samples contained aflatoxin M(1). Both univariate and multivariate logistic regression analysis failed to show significant correlation between aflatoxin M(1) and gestational age, postnatal age, gender, nationality and clinical condition. Levels of lactose, protein and lipids did not correlate significantly with levels of aflatoxin M(1). The public should be educated about storing food and the hazards of aflatoxin ingestion to reduce the unacceptably frequent presence of aflatoxin in breast-milk.

Placental thickness in the second trimester: a pilot study to determine the normal range

OBJECTIVES

We sought to determine the normal sonographically measured placental thickness in millimeters at the second-trimester scan (18 weeks to 22 weeks 6 days) and determine whether the measurement should be adjusted for gestational age and the placental site.

METHODS

We conducted a cross-sectional observational pilot study involving 114 consecutive patients with singleton pregnancies presenting for routine second-trimester sonography between 18 weeks and 22 weeks 6 days.

RESULTS

The unadjusted overall mean placental thickness was 24.6 (SD, 7.29) mm. The placental thickness was normally distributed. On multivariable analysis, the predicted mean thickness was 6.6 mm (95% confidence interval, 4.4 to 8.8 mm; P < .001) less in anterior compared to posterior or fundal placentas and increased by 0.6 mm (95% confidence interval, -0.5 to 1.7 mm; P = .27) for each week increase in gestation after 18 weeks

CONCLUSIONS

The placental position and possibly gestational age need to be considered when determining placental thickness. Anterior placentas are approximately 7 mm thinner than posterior or fundal placentas. Anterior placentas of greater than 33 mm and posterior placentas of greater than 40 mm should be considered abnormally thick.

Association between birthweight and cognitive function in middle age: the atherosclerosis risk in communities study

PURPOSE

We aimed to examine the relationship of birthweight to cognitive performance in middle aged participants of the Atherosclerosis Risk in Communities Study (ARIC).

METHODS

Cognitive function, assessed by means of three neuropsychological tests-the Delayed Word Recall Test (DWR), the Digit Symbol Subtest of the Wechsler Adult Intelligence Scale-Revised (DSS/WAIS-R), and the Word Fluency (WF) Test, was evaluated in relation to birthweight, as recalled through standardized interviews, by the use of data from the second and fourth follow-up visits of the Atherosclerosis Risk in Communities study cohort (1990-1992 and 1996-1998, respectively). Overall, 6785 participants satisfied the inclusion criteria and were included in the analysis.

RESULTS

After adjusting for adult sociodemographic factors, childhood socioeconomic environment and parental risk factors, and adult anthropometric, health status-related. and behavioral variables, we observed linear trends for the relationship of birthweight to WF scores, although the trend was statistically significant only for those reporting exact birthweights (p for trend = .004). For the other cognitive test results, results were either null or inconsistent with the a priori hypotheses.

CONCLUSIONS

Except for WF in those reporting exact birthweights, our study does not support the notion that birthweight influences cognitive function in adults.

Poverty, near-poverty, and hardship around the time of pregnancy

To describe income levels and the prevalence of major hardships among women during or just before pregnancy. We separately analyzed 2002-2006 population-based postpartum survey data from California's Maternal and Infant Health Assessment (n = 18,332) and 19 states participating in CDC's Pregnancy Risk Assessment Monitoring System (n = 143,452) to examine income and several hardships (divorce/separation, domestic violence, homelessness, financial difficulties, spouse/partner's or respondent's involuntary job loss or incarceration, and, in California only, food insecurity and no social support) during/just before pregnancy. In both samples, over 30% of women were poor (income </=100% of federal poverty level [FPL]) and 20% near-poor (101-200% FPL); and around 60% of low-income (poor or near-poor) women experienced at least one hardship. While hardship prevalence decreased significantly as income increased, many non-low-income women also experienced hardships; e.g., in California, 43% of all women and 13% with incomes >400% FPL experienced one or more hardships. These findings paint a disturbing picture of experiences around the time of pregnancy in the United States for many women giving birth and their children, particularly because 60% had previous births. The high prevalence of low income and of serious hardships during pregnancy is of concern, given previous research documenting the adverse health consequences of these experiences and recognition of pregnancy as a critical period for health throughout the life course. Low income and major hardships around the time of pregnancy should be addressed as mainstream U.S. maternal-infant health and social policy issues.

Measures of placental growth in relation to birth weight and gestational age

Fetal growth depends in part on placental growth. The authors tested placental measures derived from digital images for reliability and to evaluate their association with birth weight and gestational age. A total of 628 women recruited into the Pregnancy, Infection, and Nutrition Study, a prospective cohort study of preterm birth in central North Carolina between 2002 and 2004, delivered singleton liveborn infants after 24 completed weeks' gestation. Novel chorionic plate morphometric parameters captured off digital images of the gross placenta were analyzed as estimators of gestational age and birth weight. Without acknowledgment to placental weight, digitally obtained lateral chorionic plate growth measures accounted for 17 percent of gestational age variance and 35 percent of birth weight variance, overall. Chorionic plate measures accounted for 10 percent of birth weight variance beyond that accounted for by placental weight alone. Among preterm births, 34 percent of gestational age variance and 63 percent of birth weight variance were accounted for by lateral chorionic plate growth measures. Intraclass correlation coefficients for the novel digital measures ranged from 0.96 to 0.98. Reliable digital measures of lateral chorionic plate growth estimate birth weight variance more strongly than gestational age, project variance that is not accounted for by placental weight, and project these outcomes to a greater degree in preterm births than at term.

Correlations of siblings' and mothers' utilisation of primary and hospital health care: a record linkage study in Western Australia

A relationship between maternal and child use of general practitioners (GPs) has been shown to exist for some time, however, the reasons for this relationship are not clear and the extent to which this relationship extends to tertiary care is unknown. The aim of this study was to examine the relationships between the utilisation of health care by siblings and mothers over a 14 year period. A retrospective cohort study of 756 mothers and their 1494 children up to age 14 years was conducted in three general practices in Western Australia. Medicare claims and hospital morbidity records for 1984-1997 were linked using deterministic and probabilistic matching. Generalised Estimating Equations and correlations were used to examine the relationships between the utilisation of primary and hospital health care by family members. Significant correlations were found between hospital admissions of all participants and their GP visits, specialist visits, pathology and diagnostic imaging combined and hospital length of stay. There was a strong association between siblings' use of GPs. A child's rate of GP attendance increased with that of its mother. There was a weak but significant relationship between siblings' use of hospitals, and a child's hospital admission rate increased with that of its mother. It is concluded that there is a strong relationship between siblings' use of GPs and a weaker but still significant association between the hospital admissions of siblings. As expected, there were strong associations between mother and child visits to GPs. There was also an association between a mother's use of hospital and that of her children. This finding reduces the plausibility that the relationships found between utilisation of health care by siblings and mothers can be explained entirely by behavioural factors, and suggests the presence of intergenerational correlation of morbidity.

Postweaning exposure to aflatoxin results in impaired child growth: a longitudinal study in Benin, West Africa

Aflatoxins are dietary contaminants that are hepatocarcinogenic and immunotoxic and cause growth retardation in animals, but there is little evidence concerning the latter two parameters in exposed human populations. Aflatoxin exposure of West African children is known to be high, so we conducted a longitudinal study over an 8-month period in Benin to assess the effects of exposure on growth. Two hundred children 16-37 months of age were recruited from four villages, two with high and two with low aflatoxin exposure (50 children per village). Serum aflatoxin-albumin (AF-alb) adducts, anthropometric parameters, information on food consumption, and various demographic data were measured at recruitment (February) and at two subsequent time points (June and October). Plasma levels of vitamin A and zinc were also measured. AF-alb adducts increased markedly between February and October in three of the four villages, with the largest increases in the villages with higher exposures. Children who were fully weaned at recruitment had higher AF-alb than did those still partially breast-fed (p < 0.0001); the major weaning food was a maize-based porridge. There was no association between AF-alb and micronutrient levels, suggesting that aflatoxin exposure was not accompanied by a general nutritional deficiency. There was, however, a strong negative correlation (p < 0.0001) between AF-alb and height increase over the 8-month follow-up after adjustment for age, sex, height at recruitment, socioeconomic status, village, and weaning status; the highest quartile of AF-alb was associated with a mean 1.7 cm reduction in growth over 8 months compared with the lowest quartile. This study emphasizes the association between aflatoxin and stunting, although the underlying mechanisms remain unclear. Aflatoxin exposure during the weaning period may be critical in terms of adverse health effects in West African children, and intervention measures to reduce exposure merit investigation.

A life course approach to diet, nutrition and the prevention of chronic diseases

OBJECTIVE

To briefly review the current understanding of the aetiology and prevention of chronic diseases using a life course approach, demonstrating the life-long influences on the development of disease.

DESIGN

A computer search of the relevant literature was done using Medline-'life cycle' and 'nutrition' and reviewing the articles for relevance in addressing the above objective. Articles from references dated before 1990 were followed up separately. A subsequent search using Clio updated the search and extended it by using 'life cycle', 'nutrition' and 'noncommunicable disease' (NCD), and 'life course'. Several published and unpublished WHO reports were key in developing the background and arguments.

SETTING

International and national public health and nutrition policy development in light of the global epidemic in chronic diseases, and the continuing nutrition, demographic and epidemiological transitions happening in an increasingly globalized world. RESULTS OF REVIEW: There is a global epidemic of increasing obesity, diabetes and other chronic NCDs, especially in developing and transitional economies, and in the less affluent within these, and in the developed countries. At the same time, there has been an increase in communities and households that have coincident under- and over-nutrition.

CONCLUSIONS

The epidemic will continue to increase and is due to a lifetime of exposures and influences. Genetic predisposition plays an unspecified role, and with programming during fetal life for adult disease contributing to an unknown degree. A global rise in obesity levels is contributing to a particular epidemic of type 2 diabetes as well as other NCDs. Prevention will be the most cost-effective and feasible approach for many countries and should involve three mutually reinforcing strategies throughout life, starting in the antenatal period.

Birth weight and cognitive development in adolescence: causal relationship or social selection?

Using data from the National Longitudinal Survey of Adolescent Health (Add Health), I investigate the relationship between birth weight and cognitive development among adolescents aged 12-17. Initial OLS regression models reveal a significant, positive relationship between low birth weight and verbal ability. Controlling for demographic, socioeconomic, and other adolescent characteristics modifies, but does not eliminate, this relationship. Additional models that stratify the sample by parental education illustrate the greater importance of other family and adolescent characteristics for cognitive development in adolescence, and a diminished role of birth weight. In the final section of the paper, fixed effects models of non-twin full siblings indicate no significant association between birth weight and verbal ability, suggesting that traditional cross-sectional models overstate the influence of birth weight for cognitive development in adolescence.

Determinants of aflatoxin exposure in young children from Benin and Togo, West Africa: the critical role of weaning

BACKGROUND

Dietary exposure to high levels of the fungal toxin, aflatoxin, occurs in West Africa, where long-term crop storage facilitates fungal growth.

METHODS

We conducted a cross-sectional study in Benin and Togo to investigate aflatoxin exposure in children around the time of weaning and correlated these data with food consumption, socioeconomic status, agro-ecological zone of residence, and anthropometric measures. Blood samples from 479 children (age 9 months to 5 years) from 16 villages in four agro-ecological zones were assayed for aflatoxin-albumin adducts (AF-alb) as a measure of recent past (2-3 months) exposure.

RESULTS

Aflatoxin-albumin adducts were detected in 475/479 (99%) children (geometric mean 32.8 pg/mg, 95% CI: 25.3-42.5). Adduct levels varied markedly across agro-ecological zones with mean levels being approximately four times higher in the central than in the northern region. The AF-alb level increased with age up to 3 years, and within the 1-3 year age group was significantly (P = 0.0001) related to weaning status; weaned children had approximately twofold higher mean AF-alb adduct levels (38 pg AF-lysine equivalents per mg of albumin [pg/mg]) than those receiving a mixture of breast milk and solid foods after adjustment for age, sex, agro-ecological zone, and socioeconomic status. A higher frequency of maize consumption, but not groundnut consumption, by the child in the preceding week was correlated with higher AF-alb adduct level. We previously reported that the prevalence of stunted growth (height for age Z-score HAZ) and being underweight (weight for age Z-score WAZ) were 33% and 29% respectively by World Health Organziation criteria. Children in these two categories had 30-40% higher mean AF-alb levels than the remainder of the children and strong dose- response relationships were observed between AF-alb levels and the extent of stunting and being underweight.

CONCLUSIONS

Exposure to this common toxic contaminant of West African food increases markedly following weaning and exposure early in life is associated with reduced growth. These observations reinforce the need for aflatoxin exposure intervention strategies within high-risk countries, possibly targeted specifically at foods used in the post-weaning period.

Nutrition before birth, programming and the perpetuation of social inequalities in health

The need to explain social inequalities in health has led to the theory that chronic disease is due, in part, to a legacy of adverse experiences in early life. Epidemiological studies show consistently that individuals who are small at birth have an increased risk of cardiovascular disease in adulthood. There is growing consensus that this association reflects a causal relationship and is not simply the product of bias or confounding. The concept of programming is invoked as the biological mechanism; birth size is thus a proxy for fetal programming. Recent findings suggest that fetal programming interacts with the post-birth environment. The adverse exposures that are thought to underlie and potentiate programming cluster in socially patterned ways, thus creating substantial inequalities in health. Experiments in animals demonstrate that nutritional interventions before or during pregnancy can produce programming phenomena in the offspring, sometimes without an impact on birth size. However, the extent to which maternal nutrition contributes to programming in contemporary developed countries is uncertain.

Ambient neighbourhood noise and children's mental health

OBJECTIVES

To investigate the relation between typical ambient noise levels (highway, rail, road) and multiple mental health indices of school children considering psychosocial and biological risk factors as potential moderators.

METHODS

With a two stage design strategy (representative sample and extreme sample) two cross sectional samples (n=1280; n=123) of primary school children (age 8-11) were studied. Individual exposure to noise at home was linked with two indices of mental health (self reporting by the child on a standard scale and rating by the teacher of classroom adjustment on a standard scale). Noise exposure was modelled firstly according to Austrian guidelines with the aid of a geographical information system and then calibrated and corrected against measurements from 31 locations. Information on potential confounders and risk factors was collected by mothers and controlled in regression modelling through a hierarchical forward stepping procedure. Interaction terms were also analysed to examine subgroups of children at risk-for example, low birth weight and preterm birth.

RESULTS

Noise exposure was significantly associated in both samples with classroom adjustment ratings. Child self reported mental health was significantly linked to ambient noise only in children with a history of early biological risk (low birth weight and preterm birth).

CONCLUSIONS

Exposure to ambient noise was associated with small decrements in children's mental health and poorer classroom behaviour. The correlation between mental health and ambient noise is larger in children with early biological risk.