Combination of low birth weight and high adult body mass index: at what age is it established and what are its determinants?

Paternal obesity induces subfertility in male offspring by modulating the oxidative stress-related transcriptional network

BACKGROUND/OBJECTIVE

The effects of fathers' high-fat diet (HFD) on the reproductive health of their male offspring (HFD- F1) remain to be elucidated. Parental obesity is known to have a negative effect on offspring fertility, but there are few relevant studies on the effects of HFD-F1 on reproductive function.

METHODS

We first succeeded in establishing the HFD model, which provides a scientific basis in the analysis of HFD-F1 reproductive health. Next, we assessed biometric indices, intratesticular cellular status, seminiferous tubules and testicular transcriptomic homeostasis in HFD-F1. Finally, we examined epididymal (sperm-containing) apoptosis, as well as antioxidant properties, motility, plasma membrane oxidation, DNA damage, and sperm-egg binding in the epididymal sperm.

RESULTS

Our initial results showed that HFD-F1 mice had characteristics similar to individuals with obesity, including higher body weight and altered organ size. Despite no major changes in the types of testicular cells, we found decreased activity of important genes and noticed the presence of abnormally shaped sperm at seminiferous tubule lumen. Further analysis of HFD-F1 testes suggests that these changes might be caused by increased vulnerability to oxidative stress. Finally, we measured several sperm parameters, these results presented HFD-F1 offspring exhibited a deficiency in antioxidant properties, resulting in damaged sperm mitochondrial membrane potential, insufficient ATP content, increased DNA fragmentation, heightened plasma membrane oxidation, apoptosis-prone and decreased capacity for sperm-oocyte binding during fertilization.

CONCLUSION

HFD- F1 subfertility arises from the susceptibility of the transcriptional network to oxidative stress, resulting in reduced antioxidant properties, motility, sperm-egg binding, and elevated DNA damage. Schematic representation of the HFD-F1 oxidative stress susceptibility to subfertility. Notably, excessive accumulation of ROS surpasses the physiological threshold, thereby damaging PUFAs within the sperm plasma membrane. This oxidative assault affects crucial components such as mitochondria and DNA. Consequently, the sperm's antioxidant defense mechanisms become compromised, leading to a decline in vitality, motility, and fertility.

Consequences of Paternal Nutrition on Offspring Health and Disease

It is well established that the maternal diet during the periconceptional period affects the progeny’s health. A growing body of evidence suggests that the paternal diet also influences disease onset in offspring. For many years, sperm was considered only to contribute half of the progeny’s genome. It now appears that it also plays a crucial role in health and disease in offspring’s adult life. The nutritional status and environmental exposure of fathers during their childhood and/or the periconceptional period have significant transgenerational consequences. This review aims to describe the effects of various human and rodent paternal feeding patterns on progeny’s metabolism and health, including fasting or intermittent fasting, low-protein and folic acid deficient food, and overnutrition in high-fat and high-sugar diets. The impact on pregnancy outcome, metabolic pathways, and chronic disease onset will be described. The biological and epigenetic mechanisms underlying the transmission from fathers to their progeny will be discussed. All these data provide evidence of the impact of paternal nutrition on progeny health which could lead to preventive diet recommendations for future fathers.

Diet-Induced Modification of the Sperm Epigenome Programs Metabolism and Behavior

Globally, obesity has reached epidemic proportions. The rapidly increasing numbers of overweight people can be traced back to overconsumption of energy-dense, poor-quality foods as well as physical inactivity. This development has far-reaching and costly implications. Not only is obesity associated with serious physiological and psychological complications, but mounting evidence also indicates a ripple effect through generations via epigenetic changes. Parental obesity could induce intergenerational and transgenerational changes in metabolic and brain function of the offspring. Most research has focused on maternal epigenetic and gestational effects; however, paternal contributions are likely to be substantial. We focus on the latest advances in understanding the mechanisms of epigenetic inheritance of obesity-evoked metabolic and neurobiological changes through the paternal germline that predict wide-ranging consequences for the following generation(s).

Maternal smoking, genetic susceptibility, and birth-to-adulthood body weight

BACKGROUND

Maternal smoking (MS) is associated with low birthweight (BW) but adult obesity in offspring, however, it remains unknown whether it modifies offspring's genetic susceptibility to obesity on BW, adult body weight, and birth-to-adulthood body weight tracking pattern.

METHODS

This study included 246,759 UK Biobank participants with information on MS, BW (kg), adult body weight and BMI (kg/m²). Individual polygenetic score (PGS) was created on the basis of 97 BMI-associated genetic loci. We calculated individual birth-to-adulthood percentile change, and body weight tracking patterns that combined BW levels (<2.5, 2.5-4.0, and ≥4.0 as low, normal and high BW [LBW, NBW, and HBW]) and adulthood obesity status (≥30 as obesity [OB] and <30 as non-obesity [NOB]), including LBW-to-OB, LBW-to-NOB, NBW-to-OB, NBW-to-NOB, HBW-to-OB, and HBW-to-NOB.

RESULTS

Participants exposed to MS had a 0.108 kg lower BW (95% CI, -0.114 to -0.102), a 1.418 kg higher adult body weight (95% CI, 1.291-1.545), and a 6.91 greater percentile increase of body weight from birth to adulthood (95% CI, 6.62-7.21), compared with those nonexposed (all P < 0.001). In comparison to participants of NBW-to-NOB, MS was associated with an approximately twofold higher risk of LBW-to-OB (odds ratio [OR] 1.98, 95% CI 1.87-2.10), and a reduced likelihood of HBW-to-NOB (0.85, 95% CI 0.82-0.88). The increases in BW, adult body weight, and birth-to-adulthood percentile change per increment of 10 BMI-PGS were 0.021 vs. 0.012, 2.50 vs. 2.11, and 4.03 vs. 3.55, respectively, for participants exposed vs. nonexposed to MS (all P_interaction < 0.05).

CONCLUSION

Our results indicate that exposure to MS is associated with an increased risk of transition from low BW-to-adulthood obesity, and reduced likelihood of change from high BW-to-normal adult body weight. MS may modify the relation of genetic susceptibility to obesity and body weight in offspring.

The impact of pre and perinatal lifestyle factors on child long term health and social outcomes: a systematic review

To understand the full extent of the impact of a trial, it is important to consider the long-term consequences of outcomes beyond the trial follow-up period, especially for early year's interventions. A systematic review of the literature associated with the long-term consequences of four key outcomes from the Building Blocks trial, specifically, low birth weight, smoking during pregnancy, interval to subsequent pregnancy and A&E attendance or inpatient admission was conducted. These factors were guided by the funders, the Department of Health, as being of particular interest in the UK context. Relevant studies were identified from a number of sources including large databases, reference checking and citation searching. The search yielded 3665 papers, 43 of which were considered appropriate for inclusion. Of these, 29 were relating to smoking during pregnancy, 13 to low birth weight, 0 to A&E attendances during early childhood and 1 to short (< 2 years) interval to subsequent pregnancy. Consistent associations were found between maternal smoking during pregnancy and the effects this has on children's health, educational attainment and likelihood of engaging in problem behaviour and criminal activity in later life. Low birth weight was also found to impact on children's long-term health and cognitive development. Subsequent pregnancies within two years of the previous birth were linked with increased likelihood of pre-term birth and neonatal death. Only minimal evidence was identified regarding the consequences of a short interval to second pregnancy and of child A&E and outpatient attendances. Given that these outcomes have been identified by the UK Department of Health as of particular interest for UK benefit, investment of research in these areas is recommended to establish a clearer picture of both short and long-term consequences.

Incidence and Prevalence of Childhood Obesity in Tehran, Iran in 2011

BACKGROUND

The aim of this study was to determine the incidence and prevalence of obesity in Tehranian children.

METHODS

Data from children participated in Tehran Lipid and Glucose Study (TLGS) were evaluated. Cut off points for definition of obesity was the CDC's standard thresholds of the 95th percentile and 85th percentile for overweight. Prevalence, annual incidence of obesity, cumulative incidence over 10 year and the incidence density (cases per person-years) totally were calculated.

RESULTS

The annual incidence of obesity was 1.9 and 3.4% per year in the first 3 yr and decreased to 0.9 and 2.5% in the last 3 yr of follow-up in girls and boys, respectively. Incidence density rates were in line with cumulative incidence, with a rate of 20.7 per 1000 person-years between the ages of 5.6 and 15.5 yr. The prevalence of obesity was higher among children who had obese parents (P=0.03). Among all ages, across the quartiles of parents' BMI, the prevalence of obesity increased with rising in paternal (P=0.001) or maternal BMI (P=0.004). Physical activity of mothers affected the prevalence of obesity in children at mean ages of 5.3 and 9.1 yr. Across quartiles of mother's physical activity, from heavy to light, the prevalence of obesity increased among children, from 4.4% to 5.9% in children, aged 5.3 (P=0.02) and from 11.6% to 13.0% in children, aged 9.1 yr (P=0.03).

CONCLUSION

Prevalence of obesity among children increased with age. Cumulative incidence of obesity in children who were overweight at baseline was much higher than other children.

Male birthweight, semen quality and birth outcomes

STUDY QUESTION

What are the relations among birthweight (BW), semen parameters and birth outcomes in a population-based sample?

SUMMARY ANSWER

BW is unrelated to semen parameters, which are in turn unrelated to birth outcomes.

WHAT IS KNOWN ALREADY

In clinical settings, there has been suggestion that semen parameters are related to BW when comparing fertile and infertile men; however, findings have been less clear in more general populations.

STUDY DESIGN, SIZE, DURATION

Questionnaire data and semen samples were collected at baseline from 427 male participants of the population-based Longitudinal Investigation of Fertility and the Environment (LIFE) prospective cohort study from 2005 to 2009, who were followed prospectively to assess pregnancy outcomes among 226 singleton births.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Men of at least 18 years of age who were married or in a committed relationship and trying to conceive were eligible for participation; physician-diagnosed infertility was an exclusion criterion. Participants were recruited from two geographic areas and semen samples were analyzed for 34 quality parameters categorized as general, motility, morphology, sperm head and sperm chromatin structure using methods including computer-aided semen analysis integrated visual optical system and sperm chromatin structure assay. Linear and mixed models were used for statistical analysis of the relations between men's BW, semen parameters, and BW, gestational age at delivery, birth length, head circumference and ponderal index of singleton births.

MAIN RESULTS AND THE ROLE OF CHANCE

No association was observed between male BW and semen parameters or birth outcomes. Few associations were observed between semen parameters and birth outcomes, and the observed statistically significant associations were isolated and without a consistent pattern that would suggest an association between BW and birth outcomes.

LIMITATIONS, REASONS FOR CAUTION

Men's BW was self-reported and may be subject to some imprecision. Semen analysis was performed the day after collection, an approach that impacts the assessment of motility and that may limit inference from our analyses of motility measures. In addition, inclusion criteria for selection into the cohort limits generalizability to generally healthy couples trying to conceive and without known subfertility.

WIDER IMPLICATIONS OF THE FINDINGS

Despite suggestions from prior studies of male in utero exposures impacting BW and male reproductive health, there appears to be little support for such relations in this generally healthy population.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (N01-HD-3-3355, N01-HD-3-3356 and NOH-HD-3-3358). The authors report no competing interests, and a Memo of Understanding with the National Institute of Occupational Safety and Health (NIOSH) for semen analysis.

TRIAL REGISTRATION NUMBER

Not applicable.

The role of marriage in the causal pathway from economic conditions early in life to mortality

This paper analyzes the interplay between early-life conditions and marital status, as determinants of adult mortality. We use individual data from Dutch registers (years 1815-2000), combined with business cycle conditions in childhood as indicators of early-life conditions. The empirical analysis estimates bivariate duration models of marriage and mortality, allowing for unobserved heterogeneity. Results show that conditions around birth and school going ages are important for marriage and mortality. Men typically enjoy a protective effect of marriage, whereas women suffer during childbearing ages. However, having been born under favorable economic conditions reduces female mortality during childbearing ages.

Environmental epigenetic inheritance through gametes and implications for human reproduction

BACKGROUND

Traditional studies focused on DNA as the heritable information carrier that passes the phenotype from parents to offspring. However, increasing evidence suggests that information, that is independent of the DNA sequence, termed epigenetic information, can be inherited between generations. Recently, in our lab, we found that prediabetes in fathers increases the susceptibility to diabetes in offspring through gametic cytosine methylation changes. Paternal prediabetes changed overall methylation patterns in sperm, and a large portion of differentially methylated loci can be transmitted to pancreatic islets of offspring up to the second generation. In this review, we survey the extensive examples of environmentally induced epigenetic inheritance in various species, ranging from Caenorhabditis elegans to humans. We focus mainly on elucidating the molecular basis of environmental epigenetic inheritance through gametes, which is an emerging theme and has important implications for explaining the prevalence of obesity, type 2 diabetes and other chronic non-genetic diseases, which is also important for understanding the influence of environmental exposures on reproductive and overall health in offspring.

METHODS

For this review, we included relevant data and information obtained through a PubMed database search for all English language articles published up to August 2014 which included the term 'environmental epigenetic inheritance' and 'transgenerational epigenetic inheritance'. We focused on research papers using animal models including Drosophila, C. elegans, mouse and rat. Human data were also included.

RESULTS

Evidence from animal models suggests that environmental epigenetic inheritance through gametes exists in various species. Extensive molecular evidence suggests that epigenetic information carriers including DNA methylation, non-coding RNAs and chromatin proteins in gametes play important roles in the transmission of phenotypes from parents to offspring.

CONCLUSIONS

Given the large number of experimental evidence from various organisms, it is clear that parental environmental alterations can affect the phenotypes of offspring through gametic epigenetic alterations. This more recent thinking based on new data may have implications in explaining the prevalence of obesity, type 2 diabetes and other chronic non-genetic diseases. This also implies that, in the near future, epigenetic factors which are heritable should be regarded important in determining the risk of certain diseases. Moreover, identification of epigenetic markers in gametes (polar body or sperm) may hold great promise for predicting susceptibility to and preventing certain non-genetic diseases in offspring, as well as providing indications on parental environmental exposures.

High-fat diet aggravates glucose homeostasis disorder caused by chronic exposure to bisphenol A

Epidemiological findings on the association between bisphenol A (BPA, 2,2-bis-(4-hydroxyphenyl)propane) exposure and type 2 diabetes mellitus (T2DM) are paradoxical. In animal studies, BPA has been shown to disrupt pancreatic function and blood glucose homeostasis even at a reference 'safe' level during perinatal period. In this study, we explored the effects of long-term paternal exposure to a 'safe' level of BPA on parents themselves and their offspring. Adult male genitor rats fed with either standard chow diet (STD) or high-fat diet (HFD) were treated respectively with either vehicle or BPA (50 μg/kg per day) for 35 weeks. The male rats treated with vehicle or BPA for 21 weeks were then used as sires, and the adult female rats were fed with STD during the gestation and lactation. Offspring rats were weaned on postnatal day 21 and fed with STD in later life. Metabolic parameters were recorded on the adult male rats and their adult offspring. BPA exposure disrupted glucose homeostasis and pancreatic function, and HFD aggravated these adverse effects. However, BPA exposure did not alter body weight, body fat percentage, or serum lipid. In addition, the paternal BPA exposure did not cause adverse reproductive consequence or metabolic disorder in the adult offspring. Our findings indicate that chronic exposure to a predicted 'safe' dose of BPA contributes to glucose metabolic disorders, and that HFD aggravates these adverse effects in paternal rats.

Paternal high-fat diet consumption induces common changes in the transcriptomes of retroperitoneal adipose and pancreatic islet tissues in female rat offspring

We previously showed that paternal high-fat diet (HFD) consumption programs β-cell dysfunction in female rat offspring, together with transcriptome alterations in islets. Here we investigated the retroperitoneal white adipose tissue (RpWAT) transcriptome using gene and pathway enrichment and pathway analysis to determine whether commonly affected network topologies exist between these two metabolically related tissues. In RpWAT, 5108 genes were differentially expressed due to a paternal HFD; the top 5 significantly enriched networks identified by pathway analysis in offspring of HFD fathers compared with those of fathers fed control diet were: mitochondrial and cellular response to stress, telomerase signaling, cell death and survival, cell cycle, cellular growth and proliferation, and cancer. A total of 187 adipose olfactory receptor genes were down-regulated. Interrogation against the islet transcriptome identified specific gene networks and pathways, including olfactory receptor genes that were similarly affected in both tissues (411 common genes, P<0.05). In particular, we highlight a common molecular network, cell cycle and cancer, with the same hub gene, Myc, suggesting early onset developmental changes that persist, shared responses to programmed systemic factors, or crosstalk between tissues. Thus, paternal HFD consumption triggers unique gene signatures, consistent with premature aging and chronic degenerative disorders, in both RpWAT and pancreatic islets of daughters.

Perinatal programming of neuroendocrine mechanisms connecting feeding behavior and stress

Feeding behavior is closely regulated by neuroendocrine mechanisms that can be influenced by stressful life events. However, the feeding response to stress varies among individuals with some increasing and others decreasing food intake after stress. In addition to the impact of acute lifestyle and genetic backgrounds, the early life environment can have a life-long influence on neuroendocrine mechanisms connecting stress to feeding behavior and may partially explain these opposing feeding responses to stress. In this review I will discuss the perinatal programming of adult hypothalamic stress and feeding circuitry. Specifically I will address how early life (prenatal and postnatal) nutrition, early life stress, and the early life hormonal profile can program the hypothalamic-pituitary-adrenal (HPA) axis, the endocrine arm of the body's response to stress long-term and how these changes can, in turn, influence the hypothalamic circuitry responsible for regulating feeding behavior. Thus, over- or under-feeding and/or stressful events during critical windows of early development can alter glucocorticoid (GC) regulation of the HPA axis, leading to changes in the GC influence on energy storage and changes in GC negative feedback on HPA axis-derived satiety signals such as corticotropin-releasing-hormone. Furthermore, peripheral hormones controlling satiety, such as leptin and insulin are altered by early life events, and can be influenced, in early life and adulthood, by stress. Importantly, these neuroendocrine signals act as trophic factors during development to stimulate connectivity throughout the hypothalamus. The interplay between these neuroendocrine signals, the perinatal environment, and activation of the stress circuitry in adulthood thus strongly influences feeding behavior and may explain why individuals have unique feeding responses to similar stressors.

Association of birth order with cardiovascular disease risk factors in young adulthood: a study of one million Swedish men

Background

Birth order has been suggested to be linked to several cardiovascular disease (CVD) risk factors, but the evidence is still inconsistent. We aim to determine the associations of birth order with body mass index (BMI), muscle strength and blood pressure. Further we will analyse whether these relationships are affected by family characteristics.

Methods

BMI, elbow flexion, hand grip and knee extension strength and systolic and diastolic blood pressure were measured at conscription examination in 1 065 710 Swedish young men born between 1951 and 1975. The data were analysed using linear multivariate and fixed effects regression models; the latter compare siblings and account for genetic and social factors shared by brothers.

Results

Fixed effect regression analysis showed that birth order was inversely associated with BMI: second and third born had 0.8% and 1.1% (p<0.001) lower BMI than first-born, respectively. The association pattern differed among muscle strengths. After adjustment for BMI, first-born presented lower elbow flexion and hand grip strength than second-born (−5.9 N and −3.8 N, respectively, p<0.001). Knee extension strength was inversely related to birth order though not always significantly. The association between birth order and blood pressure was not significant.

Conclusions

Birth order is negatively associated with BMI and knee extension strength, positively with elbow flexion and hand grip strength, and is not associated with blood pressure among young men. Although the effects are small, the link between birth order and some CVD risk factors is already detectable in young adulthood.

Parental smoking and vascular damage in their 5-year-old children

BACKGROUND

The relation between smoke exposure in early life, the prenatal period in particular, and the vascular development of young children is largely unknown.

METHODS

Data from the birth cohort participating in the WHISTLER-Cardio study were used to relate the smoking of parents during pregnancy to subsequent vascular properties in their children. In 259 participating children who turned 5 years of age, parental smoking data were updated and children's carotid artery intima-media thickness (CIMT) and arterial wall distensibility were measured by using ultrasonography.

RESULTS

Children of mothers who had smoked throughout pregnancy had 18.8 μm thicker CIMT (95% confidence interval [CI] 1.1, 36.5, P = .04) and 15% lower distensibility (95% CI -0.3, -0.02, P = .02) after adjustment for child's age, maternal age, gender, and breastfeeding. The associations were not found in children of mothers who had not smoked in pregnancy but had smoked thereafter. The associations were strongest if both parents had smoked during pregnancy, with 27.7 μm thicker CIMT (95% CI 0.2, 55.3) and 21% lower distensibility (95% CI -0.4, -0.03).

CONCLUSION

Exposure of children to parental tobacco smoke during pregnancy affects their arterial structure and function in early life.

Birth weight and subsequent risk of obesity: a systematic review and meta-analysis

This report describes the association between birth weight (BW) and obesity. Screening of 478 citations from five electronic databases resulted in the inclusion of 33 studies, most of medium quality. The meta-analysis included 20 of these published studies. The 13 remaining articles did not provide sufficient dichotomous data and were systematically reviewed, revealing results consistent with the meta-analysis. Our results revealed that high BW (>4000 g) was associated with increased risk of obesity (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.91-2.24) compared with subjects with BW ≤ 4000 g. Low BW (<2500 g) was associated with decreased risk of obesity (OR, 0.61; 95% CI, 0.46-0.80) compared with subjects with BW ≥ 2500 g. However, when two studies exhibited selection bias were removed, the results indicated no significant association between low BW and obesity (OR, 0.77; 95% CI, 0.58-1.04). Sensitivity analyses showed that differences in the study design, sample size and quality grade of the study had an effect on the low BW/obesity association, which low BW was not associated with the risk of obesity in cohort studies, studies with large sample sizes and studies with high quality grades. Pooled results were similar when normal birth weight (2500-4000 g) was used as the reference category. Subgroup analyses based on different growth and developmental stages (pre-school children, school children and adolescents) also revealed that high BW was associated with increased risk of obesity from childhood to early adulthood. No significant evidence of publication bias was present. These results suggest that high BW is associated with increased risk of obesity and may serve as a mediator between prenatal influences and later disease risk.

Small birth size, adult overweight, and risk of acute myocardial infraction

BACKGROUND

The association between small size at birth and increased risk of cardiovascular disease in adulthood is well established. This relationship is commonly interpreted according to the "thrifty phenotype hypothesis," which states that the association is generated by a mismatch between fetal and postnatal nutrition. Empirical support for an interaction between impaired fetal growth and later overnutrition is, however, sparse and partly conflicting.

METHODS

The Stockholm Heart Epidemiology Program is a population-based case-control study of risk factors for acute myocardial infarction (MI); data were available for 1058 cases and 1478 controls. Using logistic regression, we studied the effect of size at birth, and its interactive effect with body mass index (BMI), at 3 occasions in adulthood, on the risk of MI. Biologic interaction was estimated with the synergy index.

RESULTS

Very low birth weight for gestational age was associated with increased risk of MI (odds ratio [OR] = 2.0; 95% confidence interval [CI] = 1.4-2.9; attributable fraction = 5%). In nonfatal cases, adjustment for waist-hip ratio, insulin resistance, blood pressure, and lipids reduced the point estimate somewhat. Low birth weight for gestational age in combination with high BMI at the time of the MI produced an OR of 10.8 (3.6-31.8) for MI compared with normal birth weight and normal BMI; the synergy index was 6.5 (95% CI = 1.8-24.0).

CONCLUSIONS

The synergism between small size at birth and high adult BMI supports the thrifty phenotype hypothesis. However, this mechanism seems to pertain to only a small fraction of the acute MI cases, implying minor public health importance.

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.

Peso ao nascer e obesidade em crianças e adolescentes: uma revisão sistemática

OBJETIVO: Verificar o nível de evidência científica e epidemiológica da hipótese de associação entre peso ao nascer e sobrepeso/obesidade na infância e na adolescência, a partir de revisão sistemática da literatura. MÉTODO: Foi realizada revisão sistemática nas bases MedLine/Pubmed, Scielo-Brasil e Lilacs. Adaptou-se a escala de Downs & Black para avaliar a qualidade metodológica dos catorze artigos selecionados. Os artigos foram classificados em duas categorias de análise, de acordo com o índice de desenvolvimento humano do país onde o estudo foi realizado: a) peso ao nascer e sobrepeso/obesidade em países com desenvolvimento humano elevado; e b) peso ao nascer e sobrepeso/obesidade em países com desenvolvimento humano elevado, mas ainda ascendente, e com desenvolvimento humano médio. RESULTADOS: Em ambas as categorias predominou a associação entre elevado peso ao nascer e sobrepeso/obesidade. Além disso, na primeira categoria, um dos sete artigos mostrou que o baixo peso ao nascer foi preditor de maior percentual de gordura corporal e abdominal. Na segunda categoria, três artigos mostraram associação do catch-up growth com sobrepeso/obesidade, e um mostrou o baixo peso ao nascer como fator protetor do sobrepeso (incluindo obesidade). Foram capturados quatro artigos brasileiros, dentre os quais dois não identificaram associação estatisticamente significativa entre peso ao nascer e sobrepeso/obesidade. CONSIDERAÇÕES FINAIS: O elevado peso ao nascer apareceu associado ao sobrepeso/obesidade na maioria dos artigos. Há necessidade de se continuar investigando sobre a associação entre o baixo peso ao nascer e sobrepeso/obesidade.

Understanding the potency of stressful early life experiences on brain and body function

Early life experiences have powerful effects on the brain and body lasting throughout the entire life span and influencing brain function, behavior, and the risk for a number of systemic and mental disorders. Animal models of early life adversity are providing mechanistic insights, including glimpses into the fascinating world that is now called "epigenetics" as well as the role of naturally occurring alleles of a number of genes. These studies also provide insights into the adaptive value as well as the negative consequences, of early life stress, exposure to novelty, and poor-quality vs good-quality maternal care. Animal models begin to provide a mechanistic basis for understanding how brain development and physiological functioning is affected in children exposed to early life abuse and neglect, where there is a burgeoning literature on the consequences for physical health and emotional and cognitive development. An important goal is to identify interventions that are likely to be most effective in early life and some guidelines are provided.

Maternal smoking during pregnancy and child overweight: systematic review and meta-analysis

OBJECTIVE

Perform a systematic review of studies reporting on the association between maternal prenatal cigarette smoking and child overweight.

DESIGN

Meta-analysis of observational studies.

DATA SOURCES

Medline search and review of reference lists among studies published through June 2006.

REVIEW METHODS

Included studies reported an association between maternal smoking during pregnancy and risk of overweight among children at least 2 years of age. We did not include in the meta-analysis studies that provided only a continuous measure of adiposity, although those studies are discussed separately.

RESULTS

Based on results of 84 563 children reported in 14 observational studies, children whose mothers smoked during pregnancy were at elevated risk for overweight (pooled adjusted odds ratio (OR) 1.50, 95% CI: 1.36, 1.65) at ages 3-33 years, compared with children whose mothers did not smoke during pregnancy. The pooled estimate from unadjusted odds ratios (OR 1.52, 95% CI: 1.36, 1.69) was similar to the adjusted estimate, suggesting that sociodemographic and behavioral differences between smokers and nonsmokers did not explain the observed association. Although we observed evidence for publication bias, simulating a symmetric set of studies yielded a similar estimate (OR 1.40, 95% CI: 1.26, 1.55).

CONCLUSIONS

Prenatal smoking exposure appears to increase rates of overweight in childhood. In parts of the world undergoing the epidemiologic transition, the continuing increase in smoking among young women could contribute to spiraling increases in rates of obesity-related health outcomes in the 21st century.

Physiology and neurobiology of stress and adaptation: central role of the brain

The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging. Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms. Beyond the "flight-or-fight" response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body ("allostatic load"). Yet, hormones associated with stress protect the body in the short-run and promote adaptation ("allostasis"). The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids. Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course. Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging. The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses. As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience.

Size at birth and growth trajectories to young adulthood

Few studies in developing countries follow growth trajectories from birth to adulthood. Such studies are important because size at birth and postnatal growth affect risk of chronic disease in adulthood. This study examines the inter-relationships of maternal factors during pregnancy, infant birth weight and length, early postnatal growth, and young adult height, weight, BMI, and skinfold thicknesses, with particular attention to patterns of growth associated with increased chronic disease risk. Women were recruited in pregnancy, and offspring were followed from birth to age 21 in the community-based Cebu (Philippines) Longitudinal Health and Nutrition Survey. Birth weight and length are independently, positively associated with height, BMI and sum of skinfolds in young adult males and females, and inversely associated with the subscapular to triceps ratio in males only. The effects of size at birth on adult size were modified by birth order, and remained significant after adjusting for maternal nutritional status, socioeconomic status at birth and throughout the growth period, and maturation. Early postnatal growth was strongly influenced by BMI at birth, with rapid early infant weight gain associated with thinness. The growth pattern of the at-risk group most often associated with increased risk of chronic disease (small at birth, relatively heavy as an adult), was characterized by more rapid growth in the first 4 postnatal months. The high level of inter-relatedness of maternal nutrition in pregnancy, prenatal growth, and postnatal growth emphasizes the need to consider the full growth trajectory in studies of developmental origins of adult disease.

Inheritance of six anthropometric traits in Vaidyas of West Bengal, India

BACKGROUND

Anthropometric traits are important quantitative traits used by biological anthropologists. Surprisingly little is known about their pattern of inter-generational transmission, probably due to lack of use of developed statistical analysis in previous studies.

AIM

The present study is an attempt to approach the problem of the inheritance of anthropometric traits through advanced statistical applications.

SUBJECTS AND METHODS

Measurements of 824 individuals from 200 families including two generations were collected from Barasat, West Bengal. The study includes age correction by regression, familial correlation, heritability estimation and segregation analyses.

RESULTS

Results showed that there is strong involvement of the familial component in variation of anthropometric traits. The magnitude of heritability (h2= 57-83%) also supports their strong genetic basis. The results indicated that additive genes are not the only contributing factor; the effect of environment is considerable and that of dominant genes not negligible. Due to genetic interaction with the local environment (specific for each trait), heritabilities vary from one trait to another. Length measurements have higher heritability than breadth measurements. Segregation analysis revealed that either the additive or dominant major gene (MG) is responsible for this effect, which follows simple Mendelian transmission. Beside this, the possibility of the existence of an additional minor gene cannot be discarded.

CONCLUSION

Anthropometric traits have a genetic basis but their mode of inheritance is quite complex in nature. There is evidence of major gene effect (along with polygenes) with Mendelian transmission.

Sib-size, birth order and risk of overweight in junior high school students in Japan: results of the Toyama Birth Cohort Study

OBJECTIVE

To investigate whether there is a relationship between sib-size, birth order and the risk of overweight in junior high school students.

METHOD

Sib-size, birth order, height and weight of subjects and their parents, and other lifestyle factors were obtained through a questionnaire survey conducted between June and July 2002 from 7,959 junior high students in Toyama prefecture, Japan. Logistic regression analysis was performed to examine the associations. Boys and girls were analyzed separately.

RESULTS

Boys from three-child families showed a significantly lower risk of overweight than only boys (odds ratio (OR)=0.66, p=0.010), and girls from larger families have a significantly lower risk than only girls (p for trend=0.001). Compared to middle-born girls, only girls have a significantly higher risk of overweight (OR=2.22, p<0.001). The risk of overweight in boys was significantly lower with increasing number of elder sibling or sister. However, increasing of any one sibling almost had the same risk reduction effect on the risk of overweight in girls (OR ranged from 0.74 to 0.76, p<=0.001).

CONCLUSION

Children without siblings are the ones most at risk for overweight, especially in girls. Birth order and sib-size are possible risk factors for the development of overweight and obesity.

Does the primary school attended influence self-reported health or its risk factors in later life? Aberdeen Children of the 1950s Study

BACKGROUND

Adult health and its determinants are influenced by the environment in childhood. The school attended is known to affect the health behaviours of pupils while still at school. Little is known about the long-term influence of school attended on health.

METHODS

A total of 7,095 respondents (mean age 47 years) to a follow-up questionnaire who attended primary school in Aberdeen, UK, provided information on self-reported health; self-reported high blood pressure; GHQ-4; smoking status; alcohol intake; and obesity. Variance partition coefficients (VPCs) summarized the variation in adult health outcomes and behaviours across schools. Multilevel logistic regression was used to estimate the contribution of school to variation in the outcomes taking into account individual-level and school-level factors.

RESULTS

There was some variation across schools in the proportion of adults reporting poor self-rated health (VPC = 0.020) and smoking (0.019). Higher VPCs were found for factors potentially confounded with school: paternal social classes (I&II) (0.45) and gender (0.44). Age at leaving secondary education (0.28) and income (0.10) varied across schools. The effects of primary school diminished after adjusting for individual-level childhood risk factors. The further addition of adult risk factors attenuated these childhood effects. After full adjustment there was no effect of the primary school attended for high blood pressure, current smoking, alcohol intake, and obesity, and negligible effects for the other outcomes.

CONCLUSIONS

Contrary to our expectations, we found little evidence of any relationship between primary school and adult self-reported health or behaviour. This is surprising given the extent to which characteristics known to be associated with adult health were clustered within schools.