Childhood obesity: are genetic differences involved?

Ethnic differences and parental beliefs are important for overweight prevention and management in children: a cross-sectional study in the Netherlands

Background

The prevalence of obesity and overweight is highest among ethnic minority groups in Western countries. The objective of this study is to examine the contribution of ethnicity and beliefs of parents about overweight preventive behaviours to their child’s outdoor play and snack intake, and to the parents’ intention to monitor these behaviours.

Methods

A cross-sectional survey was conducted among parents of native Dutch children and children from a large minority population (Turks) at primary schools, sampled from Youth Health Care registers.

Results

Native Dutch parents observed more outdoor play and lower snack intake in their child and had stronger intentions to monitor these behaviours than parents of Turkish descent. In the multivariate analyses, the parents’ attitude and social norm were the main contributing factors to the parental intention to monitor the child’s outdoor play and snack intake. Parental perceived behavioural control contributed to the child’s outdoor play and, in parents who perceived their child to be overweight, to snacking behaviour. The associations between parents’ behavioural cognitions and overweight related preventive behaviours were not modified by ethnicity, except for perceived social norm. The relationship between social norm and intention to monitor outdoor play was stronger in Dutch parents than in Turkish parents.

Conclusions

As the overweight related preventive behaviours of both children and parents did differ between the native and ethnic minority populations of this study, it is advised that interventions pay attention to cultural aspects of the targeted population. Further research is recommended into parental behavioural cognitions regarding overweight prevention and management for different ethnicities.

Early origins of child obesity: bridging disciplines and phases of development -- September 30--October 1, 2010

This report summarizes a conference: “Early Origins of Child Obesity: Bridging Disciplines and Phases of Development”, held in Chicago on September 30–October 1, 2010. The conference was funded in part by the National Institutes of Health and the Williams Heart Foundation, to achieve the conference objective: forging a next-step research agenda related to the early origins of childhood obesity. This research agenda was to include working with an array of factors (from genetic determinants to societal ones) along a continuum from prenatal life to age 7, with an emphasis on how the developing child deals with the challenges presented by his/her environment (prenatal, parental, nutritional, etc.). The conference offered a unique opportunity to facilitate communication and planning of future work among a variety of researchers whose work separately addresses different periods in early life. Over the span of two days, speakers addressed existing, critical research topics within each of the most-studied age ranges. On the final day, workshops fostered the discussion needed to identify the highest priority research topics related to linking varied early factor domains. These are presented for use in planning future research and research funding.

Can a trial of motivational lifestyle counseling be effective for controlling childhood obesity and the associated cardiometabolic risk factors?

OBJECTIVES

This study was conducted to assess the effectiveness of a simple office-based program for encouraging healthy lifestyle on controlling childhood obesity and associated cardiometabolic risk factors.

METHODS

This non-randomized 24-week lifestyle modification trial was conducted among 457 obese children and adolescents, aged 2-18 years, who had at least one cardiometabolic risk factor in addition to obesity. This trial included three components of exercise, diet education and behavior modification, with all recommendations provided by a pediatrician, two general physicians and a nurse. Instead of strict inhibitory recommendations, healthier lifestyle was encouraged.

RESULTS

Overall 448 (98.04%) of enrolled children completed the trial with a mean age of 9.6 ± 2.9 years. After the trial, the mean of anthropometric measures and cardiometabolic risk factors decreased significantly, the mean high-density lipoprotein cholesterol (HDL-C) increased significantly, and the prevalence of the metabolic syndrome decreased from 20.8% to 1.8%. Triglycerides, LDL-C, diastolic blood pressure and WC had the highest decrease in all age groups, with the most prominent changes in the 14-18-year age group. By each -1SD decline in BMI and WC, risk factors had significant improvement.

CONCLUSION

Motivational office-based counseling can be effective in treatment of childhood obesity and its associated cardio-metabolic risk factors. Such approach can be implemented in the primary health care system; and can be of special concern in low- and middle-income countries with limited human and financial resources. We suggest that expanding the roles of non-physician clinicians such as nurse practitioners can help to increase the amount of time available for such services.

Parental overweight/obesity, social factors, and child overweight/obesity at 7 years of age

BACKGROUND

This study used gender-based analyses to examine whether child overweight/obesity is related to parental overweight/obesity and sociodemographic factors, in a representative population-based cohort of 7-year-old children.

METHODS

Data from the Québec Longitudinal Study of Child Development 1998-2010 was used. Children (n= 1336) were randomly selected from each public health region of Québec. The study was based on face-to-face interviews and a set of questionnaires addressed to mothers and fathers.

RESULTS

Compared to children with no overweight/obese parent, the adjusted odds ratio (OR) of being overweight/obese with two overweight/obese parents was 5 for boys (95% confidence interval [CI]: 2.31-10.85) and 5.87 for girls (95%CI: 2.63-13.12). Gender differences appeared when one parent was overweight/obese. For girls, having either an overweight/obese mother (OR, 3.10; 95%CI: 1.14-8.38) or father (OR, 3.64; 95%CI: 1.68-7.91) significantly increased the odds of being overweight/obese at 7 years. For boys, however, having only an overweight/obese father (OR, 2.05; 95%CI: 1.01-4.16) was related to overweight/obesity, but having only an overweight/obese mother was not related to overweight/obesity at 7 years for boys. In girls, but not in boys, having an immigrant mother also significantly related to overweight/obesity (OR, 2.71; 95%CI: 1.28-5.75) at 7 years, after controlling for other social factors.

CONCLUSIONS

Gender differences in socialization may explain why at 7 years of age, girls' bodyweight is influenced by having even one overweight/obese parent (mother or father), while boys' bodyweight appears to be influenced only by father's overweight/obesity when only one parent is overweight/obese.

Tracking of obesity-related behaviours from childhood to adulthood: A systematic review

Obesity in childhood carries a wide range of physical, psychological and social disbenefits and also increases the risk of adult obesity with its well-recognised, enhanced risk of several common complex diseases as well as adverse socioeconomic and psychosocial sequelae. Understanding the tracking of the two key modifiable behaviours, food consumption and physical activity, between childhood and adulthood may illuminate the childhood determinants of adult obesity and contribute to the development of effective interventions. We performed a systematic review of the available literature on tracking of both physical activity and of dietary intake between childhood and adulthood by searching MEDLINE, EMBASE, CINAHL, PSYCInfo, Google and Google Scholar. For inclusion, studies had to report baseline measurements when the children were less than, or equal to, 18 years and to report follow-up for at least 5 years to any age over 18 years. After removal of duplicates, 9625 search hits were screened by title and/or abstract and 79 potentially relevant papers were identified and full papers obtained. In total 39 papers were included in this analysis. Of these, 11 papers (from 5 studies) reported data on tracking of diet from childhood to adulthood and 28 papers (from 16 studies) reported data on tracking of physical activity or inactivity. Despite the diversity of study design and measurement methodology, we found evidence of tracking of both physical activity and of diet between childhood and adulthood with estimates of strength of tracking of a similar order for both behaviours. Because of the inherent methodological difficulties in quantifying habitual behaviour, it is likely that the reported estimates of strength of tracking under-estimate the true degree of tracking. The evidence of tracking reported here may give greater impetus to the development of interventions aimed to prevent the persistence of obesity from childhood into adulthood and its attendant adverse socioeconomic, psychosocial and health sequelae.

Differences in the heritability of growth and growth velocity during infancy and associations with FTO variants

While the associations of common variants in the FTO gene with obesity have been widely replicated in adults, there is conflicting evidence regarding their effects in infancy. We hypothesize that the genetic influences on growth traits vary during infancy, and that conflicting results may stem from variation in the ages at which FTO associations have been examined. Using longitudinal weight and length data at 0, 1, 3, 6, 9, 12, 18, 24, 30, and 36 months in 917 (444 females, 473 males) family members from the Fels Longitudinal Study, we used a variance components-based approach (SOLAR) to: (i) examine differences in heritability (gene-by-age interaction) in weight, length, relative weight (BMI and ponderal index (PI)) and instantaneous weight and length velocities over the course of infancy, and (ii) test whether a common FTO variant (rs9939609) was associated with infant growth at three ages (maximum trait heritability, birth and 36 months). All heritabilities at birth (of 39-74%) were significant (P < 3.9 × 10(-10)), but changed with age (gene-by-age interaction, P < 0.05). Weight, relative weight, and weight velocity reached maximum heritabilities (of 76-89%) at 6-9 months, while length and length velocity reached maximum heritabilities (of 96-99%) at 18-30 months. We found no association of rs9939609 with growth status or velocity measured at any age (P > 0.11). This study for the first time demonstrates the fluctuation of genetic influences on infant growth, but further work is required to determine which gene variants explain the strong additive genetic effects observed.

Obesidade infantil ontem e hoje: importância da avaliação antropométrica pelo enfermeiro

Estudos comprovam que a incidência de doenças crônicas em adultos está diretamente relacionada à obesidade na infância. Esta investigação teve como objetivo determinar a classificação nutricional infantil e comparar os índices de sobrepeso e obesidade de crianças atendidas em uma Unidade de Saúde de um município do interior paulista nos anos de 1983/1984 e 2003/2004. Os dados relacionados ao crescimento e desenvolvimento infantil foram obtidos dos prontuários. Para classificação do estado nutricional foi adotado o percentil. Para a análise descritiva, foram consideradas as frequências absolutas e percentuais. Os dados foram analisados utilizando-se teste t para comparações das médias. Foi observado maior risco de sobrepeso e diferença significativa no peso de crianças nascidas nos anos de 2003/2004 comparado aos nascidos em 1983/1984. A avaliação antropométrica realizada pelo enfermeiro é de fundamental importância no diagnóstico nutricional infantil para a identificação acurada das anormalidades e definição de estratégias de atuação eficazes.

Methodology matters: IVF versus ICSI and embryonic gene expression

The use of assisted reproduction treatment, especially intracytoplasmic sperm injection (ICSI), is now linked to a range of adverse consequences, the aetiology of which remains largely undefined. Our objective of this study was to determine differences in gene expression of blastocysts generated by ICSI as well as ICSI with artificial oocyte activation (ICSI-A) versus the less manipulative IVF, providing fundamental genetic information that can be used to aid in the diagnosis or treatment of those adversely affected by assisted reproduction treatment, as well as stimulate research to further refine these techniques. Murine blastocysts were generated by ICSI, ICSI-A and IVF, and processed for a microarray-based analysis of gene expression. Ten blastocysts were pooled for each procedure and three independent replicates generated. The data were then processed to determine differential gene expression and to identify biological pathways affected by the procedures. In blastocysts derived by ICSI versus IVF, the expression of 197 genes differed (P < 0.01). In blastocysts derived by ICSI-A versus IVF and ICSI-A versus ICSI, the expression of 132 and 65 genes differed respectively (P < 0.01). Procedural-induced changes in genes regulating specific biological pathways revealed some consistency to known adverse consequences. Detailed investigation of procedure-specific dysfunction is therefore warranted.

Chronic high-fat diet in fathers programs β-cell dysfunction in female rat offspring

The global prevalence of obesity is increasing across most ages in both sexes. This is contributing to the early emergence of type 2 diabetes and its related epidemic. Having either parent obese is an independent risk factor for childhood obesity. Although the detrimental impacts of diet-induced maternal obesity on adiposity and metabolism in offspring are well established, the extent of any contribution of obese fathers is unclear, particularly the role of non-genetic factors in the causal pathway. Here we show that paternal high-fat-diet (HFD) exposure programs β-cell 'dysfunction' in rat F(1) female offspring. Chronic HFD consumption in Sprague-Dawley fathers induced increased body weight, adiposity, impaired glucose tolerance and insulin sensitivity. Relative to controls, their female offspring had an early onset of impaired insulin secretion and glucose tolerance that worsened with time, and normal adiposity. Paternal HFD altered the expression of 642 pancreatic islet genes in adult female offspring (P < 0.01); genes belonged to 13 functional clusters, including cation and ATP binding, cytoskeleton and intracellular transport. Broader pathway analysis of 2,492 genes differentially expressed (P < 0.05) demonstrated involvement of calcium-, MAPK- and Wnt-signalling pathways, apoptosis and the cell cycle. Hypomethylation of the Il13ra2 gene, which showed the highest fold difference in expression (1.76-fold increase), was demonstrated. This is the first report in mammals of non-genetic, intergenerational transmission of metabolic sequelae of a HFD from father to offspring.

Effects of heritability, shared environment, and nonshared intrauterine conditions on child and adolescent BMI

Heritability studies of BMI, based upon twin samples, have identified genetic and shared environmental components of BMI, but have been largely silent about the nonshared environmental factors. Intrauterine factors have been identified as having significant long-term effects on BMI and may be a critical source of nonshared environmental influence. Extant studies based on samples of either unrelated individuals or twins cannot separate the effects of genetics, shared environments, and nonshared intrauterine conditions because the one lacks variation in the degree of relatedness and the other has insufficient variation in intrauterine conditions. This study improves upon these prior studies by using a large, sibling-based sample to examine heritability, shared environmental, and nonshared intrauterine influences on BMI during two age periods in childhood (6-8 years; 12-14 years). The primary interest was in determining the effects of the intrauterine environment on BMI as a component of the nonshared environment and in determining whether there were sex-specific differences in heritability and/or in the intrauterine factors. These were estimated using regression-based techniques introduced by DeFries and Fulker. Heritability of BMI was estimated to be 0.20-0.28 at 6-8 years and 0.46-0.61 at 12-14 years. Differences in heritability were found at 12-14 years between same-sex as compared to mixed-sex pairs. The shared environmental effect was significant at 6-8 years but insignificant at 12-14 years. Differences in birth weight were significant in all groups at 6-8 years suggesting long-term effects of the nonshared intrauterine environment; at 12-14 years, birth weight was no longer significant for girls.

Birth weight, maternal body mass index, and early childhood growth: a prospective birth cohort study in China

BACKGROUND

The relations of birth weight and maternal body mass index (BMI) to overweight remain unresolved. We prospectively examined the relations of birth weight with various anthropometric measures at age 3 to 6 years, the effect of maternal BMI, and the patterns of these relations in an analysis using 9 birth weight categories.

METHODS

The subjects were 210 172 singleton infants born alive with a gestational age ≥ 28 weeks between October 1993 and December 1996; the subjects were followed up in 2000. Birth weight, maternal height and weight, and other relevant information were measured or collected prospectively. Overweight and underweight were defined by using National Center for Health Statistics/World Health Organization reference data. Logistic regression models were used to estimate relative risks. Analyses stratified by quartile of maternal BMI were performed to examine the effects of maternal BMI on the associations of birth weight with overweight and underweight.

RESULTS

Birth weight was linearly associated with height, weight, and BMI at age 3-6 years. Adjustment for maternal BMI did not alter this association. Birth weight was positively associated with overweight and negatively associated with underweight. The relation curves for both overweight and underweight resembled half of a flat parabolic curve. The associations for overweight and underweight were slightly stronger for the highest and lowest quartiles of maternal BMI, respectively.

CONCLUSIONS

Higher birth weight is associated with an increased risk for childhood overweight, and lower birth weight with an increased risk for underweight. The associations between birth weight and early childhood anthropometric growth measures could not explained by maternal BMI.

Prevention of overweight and obesity: how effective is the current public health approach

Obesity is a public health problem that has become epidemic worldwide. Substantial literature has emerged to show that overweight and obesity are major causes of co-morbidities, including type II diabetes, cardiovascular diseases, various cancers and other health problems, which can lead to further morbidity and mortality. The related health care costs are also substantial. Therefore, a public health approach to develop population-based strategies for the prevention of excess weight gain is of great importance. However, public health intervention programs have had limited success in tackling the rising prevalence of obesity. This paper reviews the definition of overweight and obesity and the variations with age and ethnicity; health consequences and factors contributing to the development of obesity; and critically reviews the effectiveness of current public health strategies for risk factor reduction and obesity prevention.

Comparison of various maternal anthropometric indices of obesity for identifying metabolic syndrome in offspring

BACKGROUND

Several maternal anthropometric markers have been associated with the metabolic syndrome (MS) in offspring. The objectives of this study were (1) to determine the association between children's MS and maternal anthropometric markers such as body mass index (BMI), waist circumference (WC), WC/height, weight/sitting height squared, and WC/sitting height and (2) to compare the abilities of these five indices to identify children with MS.

METHODS

Data were collected cross-sectionally from five elementary schools between April 2007 and March 2008. BMI, WC, WC/height, weight/sitting height squared, and WC/sitting height were acquired in mothers and their children. Tanner stage, blood pressure, glucose, lipids, and insulin were measured in children. Criteria analogous to Adult Treatment Panel III for MS were used for children.

RESULTS

Of 624 children (307 boys) 8.96 +/- 1.86 years old, with their mothers being 36.25 +/- 7.14 years old, examined, 107 (17.1%) of children were obese (BMI >95th percentile per Centers for Disease Control and Prevention norms), and 95 (15.2%) were overweight (OW) (85th percentile < or =BMI < 95th percentile). Of the mothers, 109 (30.4%) were obese (BMI > 30 kg/m(2)), and 206 (33.0%) were OW (25 kg/m(2) < BMI < 30 kg/m(2)). Approximately 68% of the children were prepubertal. The prevalence of MS was 3.5% overall: 6.7% in OW and 13.9% in obese children. To determine which marker was a better predictor for MS, a receiver operating characteristics (ROC) curve was generated for the five maternal anthropometric measures, with children's MS as the dichotomous variable. The areas under the ROC curves were 0.697 +/- 0.07 for BMI, 0.698 +/- 0.07 for WC, 0.717 +/- 0.07 for WC/height, 0.725 +/- 0.07 for WC/sitting height, and 0.704 +/- 0.07 for weight/sitting height squared. There was no significant difference between the areas of the five maternal anthropometric markers as predictors of children's MS.

CONCLUSIONS

Measurement of maternal sitting height had no advantages over total height in the prediction of children's MS. All maternal anthropometric measures identified the MS in their children consistent with known familial associations of obesity and type 2 diabetes.

Prevention of overweight and obesity: how effective is the current public health approach

Obesity is a public health problem that has become epidemic worldwide. Substantial literature has emerged to show that overweight and obesity are major causes of co-morbidities, including type II diabetes, cardiovascular diseases, various cancers and other health problems, which can lead to further morbidity and mortality. The related health care costs are also substantial. Therefore, a public health approach to develop population-based strategies for the prevention of excess weight gain is of great importance. However, public health intervention programs have had limited success in tackling the rising prevalence of obesity. This paper reviews the definition of overweight and obesity and the variations with age and ethnicity; health consequences and factors contributing to the development of obesity; and critically reviews the effectiveness of current public health strategies for risk factor reduction and obesity prevention.

Genomic characterization of human adenovirus 36, a putative obesity agent

Increased levels of serum antibody titers against human adenovirus 36 (HAdV-D36) are associated with human obesity and experimental obesity in laboratory animals. While HAdV-D36 has been studied as an infectious agent implicated in obesity for over a decade, the complete genome sequence and its analysis have yet to be reported. A detailed analysis of the genome sequence of HAdV-D36 may be important to understand its role in obesity. Genomic and bioinformatic comparisons with other HAdVs identified differences that suggested unique functions. Global pairwise genome alignment with all sequenced human adenovirus D (HAdV-D) genomes revealed areas of nonconserved sequences in the hexon, E3 CR1 beta, E3 CR1 gamma, and fiber genes. Phylogenetic analysis of all HAdV-D36 proteins confirmed that this virus belongs to species Human adenovirus D. This genomic analysis of HAdV-D36 provides an important tool for comprehending the role that this unique adenovirus may play in human obesity. Low amino acid sequence identity in the E3 CR1 beta and CR1 gamma genes may suggest distinctive roles for these proteins. Furthermore, the predicted molecular models of the HAdV-D36 fiber protein seem to implicate a unique tissue tropism for HAdV-D36.

Genetic influences on blood lipids and cardiovascular disease risk: tools for primary prevention

Genetic polymorphism in human populations is part of the evolutionary process that results from the interaction between the environment and the human genome. Recent changes in diet have upset this equilibrium, potentially influencing the risk of most common morbidities such as cardiovascular diseases, obesity, diabetes, and cancer. Reduction of these conditions is a major public health concern, and such a reduction could be achieved by improving our ability to detect disease predisposition early in life and by providing more personalized behavioral recommendations for successful primary prevention. In terms of cardiovascular diseases, polymorphisms at multiple genes have been associated with differential effects in terms of lipid metabolism; however, the connection with cardiovascular disease has been more elusive, and considerable heterogeneity exists among studies regarding the predictive value of genetic markers. This may be because of experimental limitations, the intrinsic complexity of the phenotypes, and the aforementioned interactions with environmental factors. The integration of genetic and environmental complexity into current and future research will drive the field toward the implementation of clinical tools aimed at providing dietary advice optimized for the individual's genome. This may imply that dietary changes are implemented early in life to gain maximum benefit. However, it is important to highlight that most reported studies have focused on adult populations and to extrapolate these findings to children and adolescents may not be justified until proper studies have been carried out in these populations and until the ethical and legal issues associated with this new field are adequately addressed.

Early risk determinants and later health outcomes: implications for research prioritization and the food supply. Summary of the workshop

The International Life Sciences Institute North American Branch, in conjunction with the International Life Sciences Institute Research Foundation, on 8-9 July 2008, sponsored the workshop "Early Risk Determinants and Later Health Outcomes: Implications for Research Prioritization and the Food Supply." A primary objective was to focus on the relative influence of genetics and environmental factors, particularly in relation to specific nutrients and food components, on determinants of risk within the developmental stages of pregnancy, infancy (0-12 mo), and early childhood (</=5 y of age). A panel of experts concluded the workshop by providing their reactions to the papers presented while attempting to identify the critical time windows and the research gaps and challenges for future research. This was followed by a discussion of how the food industry might assist in the acquisition and translation of the knowledge of the determinants of disease to improve human health.

Can infant feeding choices modulate later obesity risk?

Since the concept of lasting programming effects on disease risk in human adults by the action of hormones, metabolites, and neurotransmitters during sensitive periods of early development was proposed >3 decades ago, ample supporting evidence has evolved from epidemiologic and experimental studies and clinical trials. For example, numerous studies have reported programming effects of infant feeding choices on later obesity. Three meta-analyses of observational studies found that obesity risk at school age was reduced by 15-25% with early breastfeeding compared with formula feeding. We proposed that breastfeeding protects against later obesity by reducing the occurrence of high weight gain in infancy and that one causative factor is the lower protein content of human milk compared with most infant formula (the early protein hypothesis). We are testing this hypothesis in the European Childhood Obesity Project, a double-blind, randomized clinical trial that includes >1000 infants in 5 countries (Belgium, Germany, Italy, Poland, and Spain). We randomly assigned healthy infants who were born at term to receive for the first year infant formula and follow-on formula with higher or lower protein contents, respectively. The follow-up data obtained at age 2 y indicate that feeding formula with reduced protein content normalizes early growth relative to a breastfed reference group and the new World Health Organization growth standard, which may furnish a significant long-term protection against later obesity. We conclude that infant feeding practice has a high potential for long-term health effects, and the results obtained should stimulate the review of recommendations and policies for infant formula composition.

Early determinants of development: a lipid perspective

This article results from an International Life Sciences Institute workshop on early nutritional determinants of health and development. The presentation on lipids focused mainly on the longer-chain products of the essential fatty acids, particularly docosahexaenoic acid (22:6n-3), and cognitive development as among the most studied lipids and outcomes, respectively, in early human nutrition. Because there have been several recent reviews on this topic, the present review takes a broader perspective with respect to both early development and lipids: an expanded research agenda is plausible on the basis of observations from some human studies and from animal studies. Other lipids known to be provided in variable amounts to infants through human milk are cholesterol and gangliosides. Short sections address the current state of knowledge and some questions that could be pursued.

Driving research in infant and children's nutrition: a perspective on industry

As part of the workshop entitled "Early Risk Determinants and Later Health Outcomes: Implications for Research Prioritization and the Food Supply" (8-9 July 2008, Washington, DC), which was cosponsored by the International Life Sciences Institute of North America and the International Life Sciences Institute Research Foundation, representatives of the food industry discussed the practical application of nutrition science. Nutrition plays a key role in guiding health outcomes throughout the life cycle. In particular, the prenatal, postnatal, and early childhood periods are extremely sensitive to the presence of appropriate nutrition. A growing body of evidence shows that early nutrition may program the unborn and the infant's key physiologic systems, including the endocrine, cardiovascular, and central nervous systems, to influence later life outcomes. While scientists in academia continue to explore the multifactorial nature of early risk determinants and later life outcomes at a mechanistic and basic science level, it is important to understand the potential of the infant and child food industries to address questions such as what factors have been noted to drive research in these sectors of the food industry. How can scientists in these industries work alongside the scientists in academia and in government to set priorities, make decisions around these health issues, and translate academic insights into innovative nutritional solutions for the benefit of public health? Given the commitment of the infant and child food industries to deliver scientifically supported early life nutrition, it is easy to understand why this industry would work in partnership with both the scientists in academia and the government to identify a means of addressing the fundamental questions of this workshop.

Early determinants of cardiovascular disease: the role of early diet in later blood pressure control

It is now widely accepted that a gross change in the maternal diet during pregnancy results in offspring with raised blood pressure. More recently, results from human intervention studies and a range of animal experiments have questioned this concept. It thus appears that, when blood pressure is measured directly or by telemetry, the extent to which blood pressure is raised is largely dependent on the magnitude of the postnatal catch-up growth. In addition, such effects can be lost when appropriate corrections are made for current body weight. Consequently, offspring born to nutritionally manipulated mothers can actually have a lower blood pressure than control group offspring. At the same time, studies of the offspring born to contemporary women in developed countries show very little, if any, effect of changes in maternal diet on blood pressure in the offspring when assessed during childhood. In small animal studies, at least, the cardiovascular outcomes linked to small size at birth can differ between the sexes, which may be related in part to differences in kidney function between males and females. With respect to large animal studies, significant effects on blood pressure are less apparent and may relate to the much slower onset of hypertension. The challenge is to use our increased knowledge of the critical windows in early development to optimize later health. One clear priority is the prevention of excess adiposity and to determine how epigenetic mechanisms may provide novel strategies in this regard.

Epigenetic mechanisms for nutrition determinants of later health outcomes

Epigenetic marking on genes can determine whether or not genes are expressed. Epigenetic regulation is mediated by the addition of methyl groups to DNA cytosine bases, of methyl and acetyl groups to proteins (histones) around which DNA is wrapped, and by small interfering RNA molecules. Some components of epigenetic regulation have evolved to permit control of whether maternal or paternal genes are expressed. The epigenetic imprinting of IGF2 expression is an example of maternal and paternal epigenetic marking that modulates fetal growth and fetal size. However, epigenetic regulation also permits the fetus and the infant to adapt gene expression to the environment in which it is growing; sometimes when this adjustment goes awry, the risk of chronic disease is increased. Recent progress in the understanding of nutritional influences on epigenetics suggests that nutrients that are part of methyl-group metabolism can significantly influence epigenetics. During critical periods in development, dietary methyl-group intake (choline, methionine, and folate) can alter DNA and histone methylation, which results in lifelong changes in gene expression. In rodent models, pregnant dams that were fed diets high in methionine, folic acid, and choline produced offspring with different coat colors or with kinked tails. A number of syndromes in humans can be caused by defective epigenetic regulation, including Rett syndrome. There are interesting examples of the effects of nutrition in early life that result in altered health in adults, and some of these could be the result of altered epigenetic regulation of gene expression.

Early risk determinants and later health outcomes: implications for research prioritization and the food supply. Introduction to the workshop

The workshop entitled "Early Risk Determinants and Later Health Outcomes: Implications for Research Prioritization and the Food Supply," reported in this issue, was borne of a quest to consolidate current knowledge on the early determinants of maternal and child health outcomes related to obesity, cardiovascular disease risk, and neurodevelopment. The primary goal was to delineate the relative influence of genetics and environmental factors, particularly in relation to specific nutrients and food components, on determinants of risk within the developmental stages of pregnancy, infancy (0-12 mo), and early childhood up to 5 y of age. A panel of experts was charged with critiquing the evidence presented and with identifying research gaps and challenges for future research, such as when and how the food industry might translate knowledge of the determinants of disease into improvements in human health through food product development.