Early growth and childhood obesity: a historical cohort study

Association between early weight gain and later adiposity in Sri Lankan adolescents

Early growth pattern is increasingly recognized as a determinant of later obesity. This study aimed to identify the association between weight gain in early life and anthropometry, adiposity, leptin, and fasting insulin levels in adolescence. A cross-sectional study was conducted in 366 school children aged 11-13 years. Weight, height, and waist circumference (WC) were measured. Fat mass (FM) was assessed using bioelectrical impedance analysis. Blood was drawn after a 12-h fast for insulin and leptin assay. Birth weight and weight at 6 months and at 18 months were extracted from Child Health Development Records. An increase in weight SD score (SDS) by ≥0.67 was defined as accelerated weight gain. Linear mixed-effects modeling was used to predict anthropometry, adiposity, and metabolic outcomes using sex, pubertal status, accelerated weight gain as fixed factors; age, birth weight, and family income as fixed covariates, and school as a random factor. Children with accelerated weight gain between birth and 18 months had significantly higher body mass index (BMI) SDS, WC SDS, height SDS, %FM, fat mass index (FMI), fat free mass index (FFMI), and serum leptin levels in adolescence. Accelerated weight gain between 6 and 18 months was associated with higher BMI SDS, WC SDS, %FM, and FMI, but not with height SDS or FFMI. Accelerated weight gain at 0-6 months, in children with low birth weight, was associated with higher height SDS, BMI SDS, WC SDS, %FM, and FMI; in children with normal birth weight, it was associated with BMI SDS, WC SDS, height SDS, and FFMI, but not with %FM or FMI. Effects of accelerated weight gain in early life on anthropometry and adiposity in adolescence varied in different growth windows. Accelerated weight gain during 6-18 months was associated with higher FM rather than linear growth. Effects of accelerated weight gain between 0 and 6 months varied with birth weight.

Infant Weight and Length Growth Trajectories Modeled Using Superimposition by Translation and Rotation Are Differentially Associated with Body Composition Components at 3 and 7 Years of Age

OBJECTIVE

To evaluate how infant weigh and length growth trajectories associate with body composition at 3 and 7 years because previous studies have noted that rapid infant weight gain increases risk for high body mass index (BMI) in children.

STUDY DESIGN

There were 322 children enrolled at 3 years of age with dual x-ray absorptiometry body composition data and pediatrician growth data for 0-2 years of age who were included in analysis. Superimposition by translation and rotation modeling was used to characterize infant weight and length trajectories in terms of size, tempo and velocity measures. Associations of these measures with fat mass, lean mass, percent body fat, bone mineral content, BMI z-score, and overweight prevalence at 3 and 7 years of age were determined.

RESULTS

Infant growth trajectories differed by sex, race, and breastfeeding status. Higher overall weight size and weight velocity from 0 to 2 years of age were associated positively with all age 3 body composition and anthropometry outcomes. However, longer length size from 0 to 2 years of age was associated independently with higher bone mineral content and lean mass, but lower percent body fat, BMI z-score, and a lower odds of overweight at 3 years of age. By 7 years of age, later than average infant weight tempo was also associated with lower fat mass, lean mass, and BMI z-score.

CONCLUSIONS

Greater average weight size and greater weight velocity in infancy are markers for greater overall body size at 3 and 7 years of age. However, longer average lengths and later weight gain tempo between 0 and 2 years of age may help to establish a leaner body composition by 3 and 7 years of age.

Rapid growth in early childhood associated with young adult overweight and obesity--evidence from a community based cohort study

BACKGROUND

Rapid weight gain in early life may increase the risk of overweight and obesity in adulthood. We investigated the association between the rate of growth during early childhood and the development of overweight and obesity in young adults.

METHODS

We used a prospective cohort study of 2077 young adults who were born between 1981 and 1984 in Brisbane, Australia and had anthropometry measurements available at birth, 6 months, 5 years, 14 years and 21 years of age. The associations of rate of early growth with body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) and their categories at 21 years were studied using multivariate analysis.

RESULTS

We found that rapid weight gain [> + 0.67 standard deviation score (SDS)] in the first 5 years of life was associated with young adults' overweight status (BMI: adjusted OR = 2.35, 95% CI, 1.82-3.03; WC: adjusted OR = 2.20, 95% CI, 1.65-2.95). We also observed that slow weight gain in the first 5 years of age (< -0.67 SDS) was inversely associated with overweight (BMI: OR = 0.62, 95% CI, 0.45-0.84). Such associations were not found with WHR. Rapid weight gain in the first 6 months of life increased the risk of overweight as defined by BMI (adjusted OR = 1.13, 95% CI, 0.86-1.49) and WC (adjusted OR = 1.24, 95% CI, 0.92-1.67), but these associations were not statistically significant.

CONCLUSION

Rapid weight gain in the first 5 years of life in children increased their risk of a higher BMI and WC in young adulthood, in contrast slow weight gain was inversely associated with weight status at 21 years.

Associations of family and neighborhood socioeconomic characteristics with longitudinal adiposity patterns in a biracial cohort of adolescent girls

Although many studies have examined the relationship of adiposity with neighborhood socioeconomic context in adults, few studies have investigated this relationship during adolescence. Using 10-year annual measurements of body mass index, expressed as z-scores (BMIz), obtained from 775 black and white participants of the National Heart, Lung, and Blood Institute Growth and Health Study, a prospective cohort study of girls from pre- to postadolescence, we used multilevel modeling to investigate whether family socioeconomic status (SES) and neighborhood socioeconomic characteristics (measured by census-tract median family income) explain variation in BMIz trajectory parameters. Analyses controlled for pubertal maturation. We found that lower SES was associated with higher overall levels of BMIz for both white and black girls. Additionally, lower-SES black girls had a more sustained increase in BMIz during early adolescence and reached a higher peak compared to higher-SES black girls and to white girls. Neighborhood income was associated with BMIz trajectory for black girls only. Unexpectedly, among black girls, living in higher-income neighborhoods was associated with higher overall levels of BMIz, controlling for SES. Our findings suggest that neighborhood socioeconomic characteristics may affect adolescent BMIz trajectories differently in different racial/ethnic groups.

Longitudinal changes in infant body composition: association with childhood obesity

BACKGROUND

Rapid weight gain in infancy has been established as a risk factor for the development of later obesity.

OBJECTIVE

We aimed to investigate the role of changes in infant body composition (assessed via total body electrical conductivity) on the development of overweight/obesity in mid-childhood.

METHODS

Fifty-three term infants were evaluated at birth, three times during infancy and in mid-childhood. Logistic regression was used to determine associations between rates of total weight gain, fat mass gain and lean mass gain during infancy and later overweight/obesity (defined as body mass index [BMI] ≥85th percentile), adjusted for birth weight and parent education.

RESULTS

At follow-up (age 9.0 ± 1.8 years), 30% were overweight/obese. More rapid total weight gain from 0 to 4 months was associated with twofold odds (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.05-3.74, P = 0.04) of overweight/obesity in mid-childhood. From 0 to 8 months, more rapid weight gain was associated with nearly fivefold odds (OR 4.76, 95% CI 1.05-21.5, P = 0.04), and more rapid fat mass gain was associated with eightfold odds (OR 8.03, 95% CI 1.11-58.2, P = 0.04) of later overweight/obesity.

CONCLUSION

This exploratory study suggests that rapid weight gain, especially fat mass gain, in earlier infancy predisposes to mid-childhood overweight/obesity.

Utilising infant growth to predict obesity status at 5 years

AIM

This study determines if an early life growth pattern in healthy infants can predict obesity at age 5.

METHODS

Randomly selected from all healthy children born from 1997 to 2001 in a Midwestern US Health Maintenance Organization; growth patterns from birth to 5 years were described for children who were categorised by obesity classification at 5 years into normal weight (n = 61), overweight (n = 47), obese (n = 41) and morbidly obese (n = 72) cohorts using World Health Organization body mass index (BMI) criteria. A retrospective longitudinal analysis based on weighted least squares was performed on BMI by age (1 week; 2, 4, 6, 9, 12, 15 and 18 months; and 2, 3, 4 and 5 years). Graphs of the longitudinal repeated measures analysis of variance of means allowed identification of the earliest significant divergence of a cohort's average BMI pattern from other cohorts' patterns.

RESULTS

Distinctions in growth patterns and BMIs were evident before 1-year post-birth. Children who were obese or morbidly obese at 5 years demonstrated a BMI pattern that differed from children who were normal weight at 5 years.

CONCLUSIONS

Identifying obesity development in early life may assist with prevention of later obesity. The results merit future study. An early life BMI growth pattern is clinically important because it permits discrimination of those who do and do not fit a normal weight pattern, guiding individualised interventions in the first year of life while precursors of later health are still forming.

The effect of social deprivation on clinical outcomes and the use of treatments in the UK cystic fibrosis population: a longitudinal study

BACKGROUND

Poorer socioeconomic circumstances have been linked with worse outcomes in cystic fibrosis. We assessed whether a relation exists between social deprivation and individual's clinical and health-care outcomes.

METHODS

We did a longitudinal registry study of the UK cystic fibrosis population younger than 40 years (8055 people with 49337 observations for weight, the most commonly collected outcome, between Jan 1, 1996, and Dec 31, 2009). We assessed data for weight, height, body-mass index, percent predicted forced expiratory volume in 1 s (%FEV1), risk of Pseudomonas aeruginosa colonisation, and the use of major cystic fibrosis treatment modalities. We used mixed effects models to assess the association between small-area deprivation and clinical and health-care outcomes, adjusting for clinically important covariates. We give continuous outcomes as mean differences, and binary outcomes as odds ratios, comparing extremes of deprivation quintile.

FINDINGS

Compared with the least deprived areas, children from the most deprived areas weighed less (standard deviation [SD] score -0·28, 95% CI -0·38 to -0·18), were shorter (-0·31, -0·40 to -0·21, and had a lower body-mass index (-0·13, -0·22 to -0·04), were more likely to have chronic P aeruginosa infection (odds ratio 1·89, 95% CI 1·34 to 2·66), and have a lower %FEV1 (-4·12 percentage points, 95% CI -5·01 to -3·19). These inequalities were apparent very early in life and did not widen thereafter. On a population level, after adjustment for disease severity, children in the most deprived quintile were more likely to receive intravenous antibiotics (odds ratio 2·52, 95% CI 1·92 to 3·17) and nutritional treatments (1·78, 1·44 to 2·20) compared with individuals in the least deprived quintile. Patients from the most disadvantaged areas were less likely to receive DNase or inhaled antibiotic treatment.

INTERPRETATION

In the UK, children with cystic fibrosis from more disadvantaged areas have worse growth and lung function compared with children from more affluent areas, but these inequalities do not widen with advancing age. Clinicians consider deprivation status, as well as disease status, when making decisions about treatments, and this might mitigate some effects of social disadvantage.

FUNDING

Medical Research Council (UK).

Association of rapid weight gain during early childhood with cardiovascular risk factors in Japanese adolescents

Background

Because of the lack of relevant data, we investigated the association between rapid weight gain (RWG) during early childhood and cardiovascular risk factors in Japanese adolescents.

Methods

The source population comprised 2285 adolescents aged 13 to 14 years enrolled in any public school in Fukuroi City, Japan during 2008, 2009, or 2010. Since there are no private schools in this city, almost all adolescents who lived in the city went to 1 of these schools. We obtained data on blood pressure (BP), serum lipids, and anthropometry during adolescence, as well as anthropometry at birth, age 1.5 years, and age 3 years, from the Maternal and Child Health Handbook for 1624 children. RWG was defined as a change in body-weight standard deviation score greater than 0.67 from age 0 to 1.5 years or from age 1.5 to 3 years.

Results

After adjusting for confounding factors, adolescents who had RWG from 0 to age 1.5 years or from age 1.5 to 3 years were more likely to be overweight. Adolescents who had RWG during both periods were more likely to be overweight (odds ratio [OR], 6.37; 95% CI, 3.06–13.24), have unfavorable lipid concentrations (OR, 2.03; 95% CI, 1.15–3.58), and have high BP (OR: 2.36, 95% CI: 1.34–4.13). The associations with unfavorable lipid concentrations and high BP disappeared after further adjusting for current body mass index.

Conclusions

RWG during early childhood predicts unfavorable lipid concentrations and high BP in Japanese adolescents, and this relationship is mediated by body mass index in later life.

Weight status of European preschool children and associations with family demographics and energy balance-related behaviours: a pooled analysis of six European studies

This study aimed to (i) gain insight in the prevalence of overweight indices in European preschoolers (4-7 years); (ii) identify energy balance-related behaviours associated with overweight/obesity; and (iii) identify children at risk for overweight/obesity. Secondary analyses of six European data sets were conducted according to standardized protocols. Based on objectively measured height and weight, prevalence of overweight and obesity across the countries ranged from 8% to 30% and 1% to 13%, respectively, with highest rates in Southern European countries (i.e. Spain and Greece). Positive associations between sedentary behaviours and overweight indices were found. Physical activity and dietary behaviours were not associated, possibly because of methodological limitations. Children of parents with high body mass index or low socioeconomic status were at increased risk of overweight/obesity. In conclusion, large differences in prevalence of overweight and obesity among preschoolers across Europe were observed. Future obesity prevention interventions in preschoolers should target screen time giving specific attention to children from overweight and/or low socioeconomic status parents. There is a need for high methodological quality studies, preferably with a long-term prospective design using sensitive, valid and reliable measures of behaviours, assessing whether and which physical activity and dietary behaviours are associated with overweight in preschoolers.

Predictors of obesity in childhood, adolescence, and adulthood in a birth cohort

To determine how characteristics of pregnancy, birth, and early infancy are related to offspring obesity at three critical developmental periods. Mothers were followed through pregnancy and 10-15 years after. Offspring data were obtained through medical record review. Maternal and offspring characteristics were examined to predict obesity in childhood (ages 4-5 years), adolescence (ages 9-14 years), and early adulthood (ages 19-20 years). The original cohort included 802 children born to 795 women. Children who were twins, who had died, or whose mothers had died were excluded (n=25). Medical records of 68.5% of the remaining 777 children documented a height and weight at childhood, adolescence, or early adulthood. Relative risks (RRs) to predict obesity at early adulthood were 12.3 for childhood and 45.1 at adolescence. RRs were also significant to predict obesity at early adulthood between the mother's obesity at prepregnancy (RR=6.4), 4-5 years postpregnancy (RR=6.3), and 10-15 years postpregnancy (RR=6.2). Excluding these variables from the multivariate models and adjusting by gender, birth insurance, and mother's marital status at delivery, the best model to predict obesity at childhood included birth weight, weight gain in infancy, and delivery type. At adolescence, it included maternal pregnancy smoking status, gestational weight gain, and weight gain in infancy, and in early adulthood, included maternal pregnancy smoking status, gestational weight gain, and birth weight. Maternal pregnancy smoking status, gestational weight gain, and weight gain in infancy have long-term effects on offspring. Maternal obesity is the strongest predictor of obesity at all times studied.

Body size and growth in 0- to 4-year-old children and the relation to body size in primary school age

Excess weight in early life is believed to increase susceptibility to obesity, and in support of such theory, excess weight and fast weight gain in early childhood have been related to overweight later in life. The aim of this study was to review the literature on body size and growth in 0- to 4-year-old children and the association with body size at age 5-13 years. In total, 43 observational studies on body size and/or growth were included, of which 24 studies had been published in 2005 or later. Twenty-one studies considered body size at baseline, and 31 studies considered growth which all included assessment of weight gain. Eight (38%) studies on body size, and 15 (48%) on weight gain were evaluated as high-quality studies. Our results support conclusions in previous reviews of a positive association between body size and weight gain in early childhood, and subsequent body size. Body size at 5-6 months of age and later and weight gain at 0-2 years of age were consistently positively associated with high subsequent body size. Results in this review were mainly based on studies from developed Western countries, but seven studies from developing countries showed similar results to those from developed countries.

Early-life determinants of overweight and obesity: a review of systematic reviews

The aim of this paper was to review the evidence for early-life (from conception to 5 years of age) determinants of obesity. The design is review of published systematic reviews. Data sources included Medline, Embase, Web of Science, Cochrane Library, CINAHL, PsycINFO. Identification of 22 eligible reviews from a database of 12,021 independent publications. Quality of selected reviews assessed using the Assessment of Multiple Systematic Reviews score. Articles published after the reviews were used to confirm results. No review was classified as high quality, 11 as moderate and 11 as low. Factors associated with later overweight and obesity: maternal diabetes, maternal smoking, rapid infant growth, no or short breastfeeding, obesity in infancy, short sleep duration, <30 min of daily physical activity, consumption of sugar-sweetened beverages. Other factors were identified as potentially relevant, although the size of their effect is difficult to estimate. Maternal smoking, breastfeeding, infant size and growth, short sleep duration and television viewing are supported by better-quality reviews. It is difficult to establish a causal association between possible determinants and obesity, and the relative importance of each determinant. Future research should focus on early-life interventions to confirm the role of protective and risk factors and to tackle the high burden obesity represents for present and future generations.

Risk factors for childhood obesity at age 5: analysis of the millennium cohort study

Background

Weight at age 5 is a predictor for future health of the individual. This study examines risk factors for childhood obesity with a focus on ethnicity.

Methods

Data from the Millennium Cohort study were used. 17,561 singleton children of White/European (n = 15,062), Asian (n = 1,845) or African (n = 654) background were selected. Logistic regression and likelihood ratio tests were used to examine factors associated with obesity at age 5. All participants were interviewed in their own homes. The main exposures examined included; Birth weight, sedentary lifestyle, family health behaviours, ethnicity, education and income.

Results

Children with a sedentary lifestyle, large at birth, with high risk family health behaviours (overweight mothers, smoking near the child, missing breakfast) and from a family with low income or low educational attainment, were more likely to be obese regardless of ethnicity. Feeding solid food before 3 months was associated with obesity in higher income White/European families. Even when controlling for socioeconomic status, ethnic background is an important independent risk factor for childhood obesity [Odds ratio of obesity; was 1.7 (95%CI: 1.2-2.3) for Asian and 2.7 (95%CI: 1.9-3.9) for African children, compared to White/European]. The final adjusted model suggests that increasing income does not have a great impact on lowering obesity levels, but that higher academic qualifications are associated with lower obesity levels [Odds of obesity: 0.63 (95%CI: 0.52-0.77) if primary carer leaves school after age 16 compared at age 16].

Conclusions

Education of the primary carer is an important modifiable factor which can be targeted to address rising obesity levels in children. Interventions should be family centred supporting and showing people how they can implement lifestyle changes in their family.

Accelerated growth in early life and obesity in preschool Chilean children

In Chile, childhood obesity rates are high. The purpose of this article is to compare BMI growth characteristics of normal (N), overweight (OW), and obese (OB) 5-year olds from 0 to 5 years and explore the influence of some prenatal factors on these patterns of growth. The study was done on a retrospective cohort of 1,089 5-year olds with birth weight >2,500 g. Weight and height were obtained from records at nine occasions (0-36 months); at 52 and 60 months, we measured them. At 60 months, children were classified as N, OW, and OB. At each age, BMI and z-score of BMI (BMI Z) differences were compared among groups. The influence of birth weight, pre-pregnancy BMI, and prenatal variables (weight gain, smoking, and presence of diabetes and preeclampsia) on BMI Z differences between N and OB was also explored. Adiposity rebound (AR) was not observed for the N, although for the OW, it occurred approximately 52 months and for the OB at approximately 24 months. BMI Z differences between N and OB were significant from birth, but were greatest between 6-12 and 36-52 months. Additional adjustment by birth weight, pre-pregnancy BMI, and prenatal variables decreased the BMI Z differences for the first 24 months with virtually no effect after this age. Accelerated growth in OB children from post-transition countries occurs immediately after birth, much earlier than the AR. The influence of prenatal factors on adiposity acquisition may extend at most until 2 years of life, although BMI gains thereafter are more related to postnatal variables.

Contribution of early weight gain to childhood overweight and metabolic health: a longitudinal study (EarlyBird 36)

BACKGROUND

Early weight gain (0-5 years) is thought to be an important contributor to childhood obesity and consequently metabolic risk. There is a scarcity of longitudinal studies in contemporary children reporting the impact of early weight gain on metabolic health.

OBJECTIVE

We aimed to assess the impact of early weight gain on metabolic health at 9 years of age.

METHOD

Two hundred thirty-three children (134 boys, 99 girls) with a gestational age of >37 weeks were assessed at birth, 5 years of age, and 9 years of age. Measures included weight SD scores at each time point and excess weight gained (Delta weight SD score) between them. The outcome measure included composite metabolic score (sum of internally derived z scores of insulin resistance, mean blood pressure, triglyceride level, and total cholesterol/high-density lipoprotein cholesterol ratio).

RESULTS

Weight SD score increased by 0.29 SD score in girls and 0.26 SD score in boys from 0 to 5 years of age and by 0.03 SD score in girls and 0.11 SD score in boys from 5 to 9 years of age. Weight SD score correlated poorly to moderately before 5 years of age but strongly after 5 years of age. Birth weight SD score predicted (girls/boys) 2.4%/0% of the variability in composite metabolic score at 9 years of age. Adding Delta weight SD score (0-5 years old) contributed (girls/boys) 11.2%/7.0% to the score, and adding Delta weight SD score (5-9 years old) additionally contributed (girls/boys) 26.4%/16.5%. Importantly, once weight SD score at 9 years of age was known, predictive strength was changed little by adding Delta weight SD score.

CONCLUSIONS

Most excess weight before puberty is gained before 5 years of age. Weight at 5 years of age bears little relation to birth weight but closely predicts weight at 9 years of age. Single measures of current weight are predictive of metabolic health, whereas weight gain within a specific period adds little. A single measure of weight at 5 years of age provides a pointer to future health for the individual. If metabolic status at 9 years of age means future risk, diabetes/cardiovascular prevention strategies might better focus on preschool-aged children, because the die seems to be largely cast by 5 years of age, and a healthy weight early in childhood may be maintained at least into puberty.

Pediatric overweight or obesity: does the label really matter?

PURPOSE

To discuss the issue of early identification of overweight and obesity in infants and young children and provide some clinical recommendations based on the current evidence and the World Health Organization's (WHO) newly released guidelines for growth and development.

DATA SOURCES

Comparison of the growth charts from the WHO and the Centers for Disease Control as well as current literature.

CONCLUSIONS

Although healthcare providers and the general public recognize overweight and obesity as serious problems, there is still disagreement on what constitutes obesity in infants and young children and when and how to intervene. More research on interventions and outcomes is particularly needed.

IMPLICATIONS FOR PRACTICE

The primary care provider deals with the sequelae of obesity on a daily basis. Some recommendations are provided for nurse practitioners who care for infants and children based on current evidence and expert opinion.

Symposium on ‘Intervention policies for deprived households’ Policy initiatives to address low-income households' nutritional needs in the UK

Members of low-income households in the UK are more likely to have patterns of food and nutrient intakes that are less inclined to lead to good health outcomes in the short and long term. Health inequalities, including the likelihood of child and adulthood obesity, have long been documented in the UK and show little sign of improving so far, despite 10 years of attention from a government that has committed itself to addressing them. Following the Acheson Inquiry into Inequalities in Health (1998) in England a number of initiatives to tackle inequalities in food and diet were established, both nationally and within the devolved nations of Scotland, Wales and Northern Ireland. Nevertheless, until recently, there has been no overall strategic policy addressing the food and nutritional needs of low-income households. The present paper reviews how the problems have been constructed and understood and how they have been addressed, briefly drawing on recent evaluations of food and nutrition policies in Scotland and Wales. The contemporary challenge is to frame cross-cutting policy initiatives that move beyond simple targeting and local actions, encompass a life-course approach and recognise both the diversity of households that fall into ‘low-income’ categories and the need for ‘upstream’ intervention.

Postnatal weight and height growth velocities at different ages between birth and 5 y and body composition in adolescent boys and girls

BACKGROUND

Rapid weight gain in the first years of life is associated with adult obesity. Whether there are critical windows for this long-term effect is unclear.

OBJECTIVE

The objective was to study anthropometric measures in adolescence by sex according to weight and height growth velocities at different ages between birth and 5 y.

DESIGN

Anthropometric measures, including fat and fat-free mass by bipodal impedancemetry, were measured in 468 adolescents aged 8-17 y. We retrospectively collected early infancy data and individually estimated weight and height growth velocities in 69.4% of them using a mathematical model. Associations between birth variables, growth velocities, and anthropometric measures in adolescence were studied.

RESULTS

Weight growth velocity at 3 mo was associated with overweight (odds ratio for a 1-SD increase: 1.52; 95% CI: 1.04, 2.22), fat mass, and waist circumference in adolescence in both sexes and with fat-free mass in boys (r = 0.29, P < 0.001) but not in girls (r = -0.01, NS). Weight growth velocities after 2 y were associated with all anthropometric measures in adolescence, in both sexes. Between 6 mo and 2 y, weight growth velocities were significantly associated only with adolescent height in boys; in girls, associations with fat mass in adolescence were weaker.

CONCLUSION

Our results support the hypothesis of 2 critical windows in early childhood associated with the later risk of obesity: up to 6 mo and from 2 y onward. The study of the determinants of growth during these 2 periods is of major importance for the prevention of obesity in adolescence.

Breastfeeding helps explain racial and socioeconomic status disparities in adolescent adiposity

OBJECTIVES

Studies suggest that breastfeeding is protective for later obesity; however, this association has not held among all racial and socioeconomic status groups. Racial and socioeconomic status differences in breastfeeding behavior have also been noted. In this study, we formally test whether breastfeeding mediates the relationship between race and socioeconomic status with adolescent adiposity.

METHODS

Data were analyzed from 739 black and white 10- to 19-year-old adolescents who participated in a large, school-based study. Parents provided information on parental education, used to measure socioeconomic status, and whether the child was breastfed as an infant. BMI was used to measure adolescent adiposity and was analyzed as a continuous measure (BMI z score) using linear regression and categorically (BMI > or = 85th and > or = 95th percentile) using logistic regression.

RESULTS

Black adolescents and those without a college-educated parent were less likely to have been breastfed for > 4 months. Race and parental education were each independent predictors of BMI z score and of having BMI > or = 85th percentile or BMI > or = 95th percentile. When added to the model, being breastfed for > 4 months was also independently associated with lower BMI z score and lower odds of having BMI > or = 85th percentile or BMI > or = 95th percentile. Inclusion of being breastfed for > 4 months resulted in a 25% decrease in racial and parental education differences in adolescent BMI z score, supporting partial mediation. CONCLUSIONS; Having been breastfed for > 4 months was associated with lower adolescent BMI z score and lower odds of having a BMI > or = 85th percentile or BMI > or = 95th percentile, independent of race or parental education. Furthermore, these analyses suggest that being breastfed for > 4 months partially explains the relationship between social disadvantage and increased adiposity. Increasing breastfeeding duration could result in lower adolescent adiposity for all racial and socioeconomic status groups and potentially minimize socioeconomic disparities in adiposity.

Microcirculation in obesity: an unexplored domain

Obesity is traditionally linked to diabetes and cardiovascular diseases. Very recent experimental, clinical and epidemiological, sometimes provocative, data challenge this automaticity by showing that not the amount but the distribution of fat is the important determinant. Moderate abdominal fat accumulation may thus be more harmful than even consequent overweight. In view of the worldwide burden of obesity, factors leading to it in children and young adults must urgently be identified. Since obesity is a very complex cardiometabolic situation, this will require to focus investigations on uncomplicated obese subjects and adequate animal models. The recent discovery of intergenerational transmissions of obesity risk factors and also the key role played by gestational and perinatal events (epigenetic factors) give rise to completely new concepts and research avenues. Considering the potential close relationship between microcirculation and tissue metabolism, demonstrations of structural and/or functional abnormalities in microvascular physiology very early in life of subjects at risk for obesity might provide a solid basis for further investigations of such links. Microcirculation(arterioles, capillaries and venules) is conceivably a key compartment determining over one or several decades the translation of genetic and epigenetic factors into fat accumulation. Available animal models should serve to answer this cardinal question.

The aetiology of childhood obesity: a review

Whilst the prevention of childhood obesity is the only viable, enduring, cost-effective solution to the obesity epidemic, effective methods for it remain elusive. Furthermore, strategies to influence obesogenic environments remain relatively unexplored. In order to be able to develop powerful population-level interventions and public health policies to prevent childhood obesity, it is important to understand its aetiology and those environments that are most amenable to measurable change. First, the present paper considers why we should be concerned about obesity in children, from both the perspective of the increased health risk to the individual and the high economic cost of treatment of obesity and related diseases, highlighting why the prevention of childhood obesity is important. Next, the determinants of health behaviour and the obesogenic environment are explored, which helps us to understand why the aetiology is so complex and that potential causal factors should not be considered in isolation, as the interaction between these factors is also important. The paper then considers the multi-factorial aetiology of childhood obesity and the rationale for the increasing trends in obesity that are evident, in order to understand what is changing in society and our children's behaviour that is triggering the positive energy balance leading to obesity. The review emphasises the need for multi-level approaches if we truly want to prevent childhood obesity. It also serves to highlight that there is a need to extend the current research base in order to build a well-founded framework to form the basis of a strategy for the prevention of childhood obesity.

Parent overweight predicts daughters' increase in BMI and disinhibited overeating from 5 to 13 years

OBJECTIVE

To assess whether parental overweight status and disinhibited overeating are predictive of daughters' accelerated weight gain and disinhibited overeating.

RESEARCH METHODS AND PROCEDURES

Participants were part of a longitudinal study of girls (N = 197) and their parents. Measured height and weight were used to calculate BMI [weight (kilograms)/height (meters)(2)]. Parents' disinhibited eating behavior was assessed using the Eating Inventory. Girls' disinhibited eating was assessed using a behavioral protocol to measure eating in the absence of hunger. Girls were classified based on parental overweight at study entry into four groups: neither, mother only, father only, or both parents overweight.

RESULTS

Girls with both parents overweight had the most rapid increases in BMI from 5 to 13 years of age; BMI increased most slowly among the neither parent overweight group, with intermediate increases in BMI among mother only and father only overweight groups. Daughters with both parents overweight at study entry were eight times more likely to be overweight at age 13, controlling for daughters' weight at age 5. Girls with both parents overweight had higher levels of disinhibited eating across all ages than all other groups. Although girls in all parental weight status groups showed increases in disinhibited eating over time, girls with both parents overweight had larger increases in disinhibited eating over time compared with all other groups.

DISCUSSION

Girls growing up in families differing in parental overweight had divergent developmental trajectories for BMI and disinhibited overeating. Findings reveal the need to focus prevention efforts on overweight parents of young children.

Differential parental weight and height contributions to offspring birthweight and weight gain in infancy

BACKGROUND

Parental weight and height correlate with offspring birthweight and weight gain, suggesting genetic and environmental influences on fetal growth. The differential contributions of the mother's and father's height and weight to birthweight, or weight gain in infancy, remain unclear and were examined using data from the UK Millennium Cohort Study.

METHODS

We calculated z-scores for birthweight and conditional weight gain to age 9 months (weight gain adjusted for birthweight) for 6811 term white singleton infants living with natural parents, using the British 1990 growth reference. We also calculated parental height and weight z-scores. The effects of parental size on birthweight and weight gain were analysed using multivariable regression, with a novel reparameterization to test for differences in effect size between mother and father.

RESULTS

Maternal weight had a far greater influence than paternal weight on birthweight [coefficient for the difference between parents (95% CI): 0.15 (0.100.20)], while parental height contributions were similar [0.03 (-0.02 to 0.07)]. Weights and heights of mothers and fathers contributed equally to infant weight gain [difference coefficients -0.03 (-0.09 to 0.02) and 0.02 (-0.03 to 0.07), respectively].

CONCLUSIONS

The influences of parental height and weight on birthweight and infant weight gain are similar for the two parents, with the exception of the influence of weight on birthweight where the mother is much more influential than the father. Parental size associations with infant growth result from a complex combination of genetic and environmental influences. This novel reparameterization of parental anthropometry is applicable to other studies examining parental influences on offspring size and growth across the life course.

Little evidence for early programming of weight and insulin resistance for contemporary children: EarlyBird Diabetes Study report 19

OBJECTIVE

The aim of this study was to evaluate whether adaptive responses made to the uterine or very early infant environment are affecting the current metabolic health of young children in the United Kingdom.

METHODS

Participants were 300 healthy children and their parents from the EarlyBird Diabetes Study cohort. Children were recruited from randomly selected schools at 5 years of age. Retrospective measures were maternal prepregnancy weight (n = 230), maternal fasting glucose levels at 28 weeks of pregnancy (n = 27), birth weight, and infant weight at ages 3 and 6 weeks. Prospective measures were insulin resistance, height, weight, and percentage of body fat (sum of 5 skinfold measurements) at ages 5, 6, 7, and 8 years.

RESULTS

Maternal third-trimester fasting glucose levels were associated positively with birth weight but were not associated with either weight or insulin resistance for the same children at 8 years. Birth weight was unrelated to insulin resistance at 8 years. There were no relationships between weight change in the first weeks of life and weight, percentage of fat, or insulin resistance at 8 years. Longer breastfeeding correlated inversely, although weakly, with percentage of body fat for boys only. Current weight was correlated with insulin resistance at 8 years.

CONCLUSIONS

For these contemporary children, neither the gestational environment nor early postnatal growth predicted insulin resistance, which was best predicted by current weight. There was no evidence that predictive adaptive responses made by the fetus or infant affected the child's weight or insulin resistance later in childhood.

Rapid infancy weight gain and subsequent obesity: systematic reviews and hopeful suggestions

In a systematic review, we identified 21 separate studies with data on the association between rapid infancy weight gain, up to age 2 y, and subsequent obesity risk. Uniformly all studies reported significant positive associations. We transformed the reported effect sizes to a standard infancy weight gain exposure, and found that further differences in study design accounted for much of the variation in risk. An accompanying paper by Melinda Yeung reminds us that there are benefits of postnatal catch-up growth in certain populations, and suggests that genetic and nutritional factors could moderate the unhealthy translation of rapid infancy weight gain to visceral fat and insulin resistance. Further evidence is needed, and we will need to rigorously test the benefits and risks of any interventions. However, the concept of "healthy" rapid catch-up infancy growth is an attractive prospect.

CONCLUSION

Rapid infancy weight gain is consistently associated with increased subsequent obesity risk, but the predictive ability of different weight gain cut-offs needs to be tested.