Developmental trajectories of overweight during childhood: role of early life factors

Body mass index (BMI) trajectories from birth to 11.5 years: relation to early life food intake

Recent research has shown that the pattern of change over time, or trajectory, of body mass index (BMI) varies among children. However, the factors that underlie the heterogeneity in these trajectories remain largely unexplored. Our aim was to use a growth mixture model to empirically identify classes of BMI trajectories (from birth to 11.5 years) and examine the effects of breastfeeding, introduction of solids, as well as food and nutrient intake at 18 months on these BMI trajectories. We identified three BMI growth trajectories between birth and age 11.5 years, separately in boys and girls. Breastfeeding duration less than six months and the early introduction of solids did not adversely influence BMI trajectories in our sample but high intakes of meat, particularly high fat varieties, and high intakes of carbohydrate at age around 18 months were associated with a high BMI trajectory in boys. It is not clear whether these dietary factors confer a direct risk of higher BMI in childhood or are markers for other dietary patterns that are present early and/or develop through childhood and contribute to higher BMI.

The associations between maternal pre-pregnancy body mass index or gestational weight change during pregnancy and body mass index of the child at 3 years of age

OBJECTIVE

To estimate the associations between maternal pre-pregnancy body mass index (BMI) or gestational weight change (GWC) during pregnancy and offspring BMI at 3 years of age, while taking several pre-and postnatal factors into account.

DESIGN

The Norwegian Mother and Child Cohort Study is a population-based pregnancy cohort study of women recruited from all geographical areas of Norway.

SUBJECTS

The study includes 31 169 women enrolled between 2000 and 2009 through a postal invitation sent to women at 17-18 weeks of gestation. Data collected from 5898 of the fathers were included. MAIN OUTCOME MESURES: Offspring BMI at 3 years was the main outcome measured in this study.

RESULTS

Mean maternal pre-pregnancy BMI was 24.0 kg m(-2) (s.d. 4.1), mean GWC in the first 30 weeks of gestation was 9.0 kg (s.d. 4.1) and mean offspring BMI at 3 years of age was 16.1 kg m(-2) (s.d. 1.5). Both maternal pre-pregnancy BMI and GWC were positively associated with mean offspring BMI at 3 years of age. Pre-pregnancy BMI and GWC also interacted, and the strength of the interaction between these two factors was strongly associated with the increase in offspring BMI among mothers who gained the most weight during pregnancy and had the highest pre-pregnancy BMI. Our findings show that results could be biased by not including pre-pregnant paternal BMI.

CONCLUSION(S)

This large population-based study showed that both maternal pre-pregnancy BMI and GWC were positively associated with mean offspring BMI at 3 years of age.

Classifying developmental trajectories over time should be done with great caution: a comparison between methods

OBJECTIVE

In the analysis of data from longitudinal cohort studies, there is a growing interest in the analysis of developmental trajectories in subpopulations of the cohort under study. There are different advanced statistical methods available to analyze these trajectories, but in the epidemiologic literature, most of those are never used. The purpose of the present study is to compare five statistical methods to detect developmental trajectories in a longitudinal epidemiological data set.

STUDY DESIGN AND SETTING

All five statistical methods (K-means clustering, a "two-step" approach with mixed modeling and K-means clustering, latent class analysis [LCA], latent class growth analysis [LCGA], and latent class growth mixture modeling [LCGMM]) were performed on a real-life data set and two manipulated data sets. The first manipulated data set contained four different linear developments over time, whereas the second contained two linear and two quadratic developments.

RESULTS

For the real-life data set, all five classification methods revealed comparable trajectories. Regarding the manipulated data sets, LCGA performed best in detecting linear trajectories, whereas none of the methods performed well in detecting a combination of linear and quadratic trajectories. Furthermore, the optimal solution for LCA and LCGA contained more classes compared with LCGMM.

CONCLUSION

Although LCGA and LCGMM seem to be preferable above the more simple methods, all classification methods should be applied with great caution.

Predicting academic and cognitive outcomes from weight status trajectories during childhood

OBJECTIVE

To identify childhood body mass index (BMI) trajectories and to describe their association with subsequent academic and cognitive outcomes.

STUDY DESIGN

Prospective cohort: Height and weight measured annually from 4 to 7 years. A mixture of regressions approach grouped children into BMI trajectories (n=1959 children; n=5754 BMI measures). Academic outcomes included teacher-rated progress and achievement. Cognitive outcomes measured by Kaufman's Assessment Battery for Children. Academic and cognitive outcomes were regressed according to BMI trajectories, controlling for family and individual covariates. Subjects drawn from Quebec Longitudinal Study of Child Development (Canada), a 1998 birth cohort (n=2120).

RESULTS

Four clusters of BMI trajectories emerged: two healthy weight groups, one overweight group and one low weight group. Relative to healthy weight, belonging to the overweight or low weight clusters was negatively associated with cognitive and academic outcomes. With the exception of the low weight cluster, this relationship was insignificant in the adjusted model.

CONCLUSIONS

Results suggest that during childhood being overweight does not increase risk for poor educational outcomes. Instead, being underweight may the increase risk for poorer cognitive outcomes. Further group-based trajectory modeling (GBTM) for BMI development over time is needed to confirm results.

Trajectories of growth in body mass index across childhood: Associations with maternal and paternal employment

Research links mothers' employment to higher body mass index (BMI), a measure of weight-for-height, among their children. However, how maternal employment patterns relate to their children's BMI trajectories, and the role that fathers' employment plays in when and at what rate children grow, remain unclear. With data on children from 2 to 15 years of age living in two-parent families from the U.S. NICHD's Study of Early Child Care and Youth Development (N = 1107), individual growth models are used to describe American children's BMI trajectories as predicted by maternal and paternal employment characteristics. Results indicate that, by age 15, children's BMIs are, on average, nearly one-half of a standard deviation above recommended levels, and the majority of growth occurs during the preschool period. The duration of maternal employment, and combined measures of maternal and paternal employment duration, are both associated with higher child BMI across childhood. Associations are small but cumulative. Notably, the association between the duration of time children lived in dual-earner families and child BMI is larger than that between maternal employment duration alone and children's BMI, which is strongest during the preschool period. Combined measures of maternal and paternal employment intensity, defined as the number of periods both parents worked 35 or more hours per week, are associated with higher child BMI during the preschool period only. Findings highlight the importance of taking into account both parents' employment characteristics in investigating children's physical development.

Trajectories of BMI from early childhood through early adolescence: SES and psychosocial predictors

OBJECTIVES

This study examined the ways in which body mass index (BMI) percentile - an identified risk factor for overweight and cardiovascular disease in adulthood - develops from birth through early adolescence. In addition, we examined whether psychosocial factors, such as parenting style and maternal depression, mediated the link between socio-economic status (SES) and BMI growth. Design. Data were obtained from phases 1-3 of the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (SECCYD) - a longitudinal study that followed children from 10 communities in the United States from birth to age 11.

METHODS

We applied growth mixture models to identify distinct subtypes of BMI development. Within these models, we performed between- and within-class mediation analyses to examine whether SES predicted class membership or differences in development within each class via maternal depression and parenting styles.

RESULTS

Results identified three prototypic trajectories of BMI percentile growth, elevated, steady increase, and stable. We found evidence for both between- and within-class mediation, suggesting multiple pathways by which SES can affect BMI development.

CONCLUSIONS

These findings add to the research that suggests that being in a family with a low SES is associated with falling into patterns of development characterized by early and lasting increases in BMI relative to one's peers, and that this association is partly accounted for by maternal depression and parenting styles.

STATEMENT OF CONTRIBUTION

What is already known? Past research has found evidence that patterns of childhood overweight are impacted by socioeconomic status through psychosocial factors like parenting and depression. This evidence is often limited to individual points in time where neglectful, permissive, and authoritarian parenting and higher levels of maternal depression are associated with higher levels of overweight status among children from infancy to adolescence. However, little research has linked together whether the children who receive non-authoritative parenting and are overweight in infancy are the same children who are overweight in adolescence. WHAT DOES THIS STUDY ADD?: • Evidence for 3 different prototypes of BMI percentile growth over the course of childhood approaching adolescence. • Adds complexity re the influence of parenting styles as an influence on patterns of weight gain. • Buttresses existing research as to early and lasting effects of SES on patterns of BMI.

Gestational weight gain and predicted changes in offspring anthropometrics between early infancy and 3 years

OBJECTIVE

To determine how gestational weight gain (GWG), categorized using the 2009 Institute of Medicine recommendations, relates to changes in offspring weight-for-age (WAZ), length-for-age (LAZ) and weight-for-length z-scores (WLZ) between early infancy and 3 years.

METHODS

Women with singleton infants were recruited from the third cohort of the Pregnancy, Infection, and Nutrition Study (2001-2005). Term infants with at least one weight or length measurement during the study period were included (n = 476). Multivariable linear mixed effects regression models estimated longitudinal changes in WAZ, LAZ and WLZ associated with GWG.

RESULTS

In early infancy, compared with infants of women with adequate weight gain, those of women with excessive weight gains had higher WAZ, LAZ and WLZ. Excessive GWG ≥ 200% of the recommended amount was associated with faster rates of change in WAZ and LAZ and noticeably higher predicted mean WAZ and WLZ that persisted across the study period.

CONCLUSIONS

GWG is associated with significant differences in offspring anthropometrics in early infancy that persisted to 3 years of age. More longitudinal studies that utilize maternal and paediatric body composition measures are necessary to understand the nature of this association.

Developmental trajectories of overweight and obesity of US youth through the life course of adolescence to young adulthood

OBJECTIVE

To detect subgroups with different risks at different ages to develop overweight and obese during the adolescence-young adulthood period.

DESIGN

Accelerated longitudinal design and developmental trajectory analysis were used. The likelihoods to become overweight (body mass index [BMI] >25 kg/m(2)) and obese (BMI >30 kg/m(2)) were assessed across the life course from the ages of 12 to 28 years.

SUBJECTS

Adolescent participants aged 12-17 years (n = 4119) identified in the National Longitudinal Survey of Youth 1997 at baseline were followed up to 2008.

RESULTS

SEVEN OVERWEIGHT RISK GROUPS (WG) WERE DETECTED FOR MALE AND FEMALE SAMPLES RESPECTIVELY, OF WHICH FIVE WERE CLOSELY RELATED TO EACH OF THE FOLLOWING FIVE PERIODS: (a) middle-school ages (19.7% and 12.6% for male and female, respectively), (b) high-school ages (11.4% and 13.6%, respectively), (c) college ages (12.6% and 9.1%, respectively), (d) post-college ages (11.8% and 10.0%, respectively), and (e) work-family-formation ages (11.0% and 12.9%, respectively); two were nonperiod-specific groups: a permanent low-risk group for both sexes (27.3% for male, 36.4% for female), a growing-risk group for males (6.2%), and a self-limiting risk group for females (5.4%, with the likelihood increasing with age, which peaked at the age of 21 years, and then declined). Likewise, six obesity risk groups (OG) were detected, of which four corresponded to the first four high-risk WG groups. The risk groups were relatively independent of race and educational attainment.

CONCLUSIONS

Findings of this study imply that five risk groups for weight gain like five consecutive "tests" exist from middle-school period to work-and-family formation. Failure to pass any of these tests in the life course could lead to overweight or obese status. Further research needs to study life-course-specific factors and mechanisms for more effective weight control.

Childhood body mass index trajectories: modeling, characterizing, pairwise correlations and socio-demographic predictors of trajectory characteristics

BACKGROUND

Modeling childhood body mass index (BMI) trajectories, versus estimating change in BMI between specific ages, may improve prediction of later body-size-related outcomes. Prior studies of BMI trajectories are limited by restricted age periods and insufficient use of trajectory information.

METHODS

Among 3,289 children seen at 81,550 pediatric well-child visits from infancy to 18 years between 1980 and 2008, we fit individual BMI trajectories using mixed effect models with fractional polynomial functions. From each child's fitted trajectory, we estimated age and BMI at infancy peak and adiposity rebound, and velocity and area under curve between 1 week, infancy peak, adiposity rebound, and 18 years.

RESULTS

Among boys, mean (SD) ages at infancy BMI peak and adiposity rebound were 7.2 (0.9) and 49.2 (11.9) months, respectively. Among girls, mean (SD) ages at infancy BMI peak and adiposity rebound were 7.4 (1.1) and 46.8 (11.0) months, respectively. Ages at infancy peak and adiposity rebound were weakly inversely correlated (r = -0.09). BMI at infancy peak and adiposity rebound were positively correlated (r = 0.76). Blacks had earlier adiposity rebound and greater velocity from adiposity rebound to 18 years of age than whites. Higher birth weight z-score predicted earlier adiposity rebound and higher BMI at infancy peak and adiposity rebound. BMI trajectories did not differ by birth year or type of health insurance, after adjusting for other socio-demographics and birth weight z-score.

CONCLUSIONS

Childhood BMI trajectory characteristics are informative in describing childhood body mass changes and can be estimated conveniently. Future research should evaluate associations of these novel BMI trajectory characteristics with adult outcomes.

Trajectories of weight disturbances during adolescence in relation to gender in a Swedish cohort

AIM

To explore developmental trajectories among adolescents of thinness and overweight in relation to gender.

METHODS

A group-based procedure was used to determine patterns of weight disturbances in a school-based sample of 3020 Swedish adolescents followed from age 11 to 18. A sensitivity analysis was performed to compensate for an increasing number of missing height and weight data after grade 8.

RESULTS

Six trajectories represented the best description of developmental weight disturbances with the exception of thinness among boys, which was best described by four trajectories. Concerning thinness, 5.9% of girls and 4.2% of boys developed this condition during the study period, while 1.9% of girls and 3.0% of boys recovered from their initial thinness. For overweight, (including obesity) 1.5% of girls and 3.1% of boys developed this weight disturbance during the study period, while 10.1% of girls and 9.3% of boys recovered from overweight/obesity. Non-reporting of height and weight was biased towards an underestimation of the true prevalence of overweight and obesity in girls and of thinness in boys.

CONCLUSIONS

Developmental trajectories provide a novel method to describe the dynamics of weight disturbances during adolescence. Similar patterns were found for overweight and thinness in boys and girls but group sizes varied between genders. Non-reporting of height and weight was found in a gender-specific pattern.

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.

Childhood antecedents to adult cardiovascular disease

Through research in the prevention and treatment of adult diseases, it has become clear that many adult diseases have their origins in childhood. As illustrated in this review, these antecedents are largely a function of the nutrition, physical activity, and habits of developing children. There is also increasing evidence that chronic and toxic levels of stress can play a significant role not only in the development of mental and behavioral conditions but in the developmental pathways that lead to a number of chronic physical health conditions. Internists, family medicine physicians, and medicine-pediatrics physicians generally are comfortable managing patients with a number of cardiovascular risk factors or conditions. Although pediatric clinical guidelines have recommended universal screening for hypertension since 1977 and targeted screening for dyslipidemia since 1992 and type 2 DM since 2000, this screening is not yet common practice in general pediatrics. As the population of children and youth with risk factors for metabolic syndrome--hypertension, dyslipidemia, and type 2 DM--increases as a result of the obesity epidemic, pediatricians will have to screen routinely, and diagnose and treat these conditions in the primary care setting. Pediatric residency programs and continuing medical education programs will have to provide knowledge and clinical training in the management of these conditions before primary care pediatricians are comfortable treating children and youth with multiple cardiovascular conditions.

Excessive gestational weight gain predicts large for gestational age neonates independent of maternal body mass index

OBJECTIVE

To determine the effects of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on large-for-gestational-age (LGA) birth weight (≥90th % ile).

METHODS

We examined 4321 mother-infant pairs from the Ottawa and Kingston (OaK) birth cohort. Multivariate logistic regression (controlling for gestational and maternal age, pre-pregnancy weight, parity, smoking) were performed and odds ratios (ORs) calculated.

RESULTS

Prior to pregnancy, a total of 23.7% of women were overweight and 16.2% obese. Only 29.3% of women met GWG targets recommended by the Institute of Medicine (IOM), whereas 57.7% exceeded the guidelines. Adjusting for smoking, parity, age, maternal height, and achieving the IOM's recommended GWG, overweight (OR 1.99; 95%CI 1.17-3.37) or obese (OR 2.64; 95% CI 1.59-4.39) pre-pregnancy was associated with a higher rate of LGA compared to women with normal BMI. In the same model, exceeding GWG guidelines was associated with higher rates of LGA (OR 2.86; 95% CI 2.09-3.92), as was parity (OR 1.49; 95% CI 1.22-1.82). Smoking (OR 0.53; 95%CI 0.35-0.79) was associated with decreased rates of LGA. The adjusted association with LGA was also estimated for women who exceeded the GWG guidelines and were overweight (OR 3.59; 95% CI 2.60-4.95) or obese (OR 6.71; 95% CI 4.83-9.31).

CONCLUSION

Pregravid overweight or obesity and gaining in excess of the IOM 2009 GWG guidelines strongly increase a woman's chance of having a larger baby. Lifestyle interventions that aim to optimize GWG by incorporating healthy eating and exercise strategies during pregnancy should be investigated to determine their effects on LGA neonates and down-stream child obesity.

Changes in body mass during elementary and middle school in a national cohort of kindergarteners

OBJECTIVE

To analyze changes in BMI, according to gender and race/ethnicity, in a nationally representative cohort of children in the United States during their elementary and middle school years to identify critical periods of excess BMI gains.

METHODS

The Early Childhood Longitudinal Study-Kindergarten Class monitored a nationally representative cohort of kindergarten students over 9 years (1998-2007). Height and weight measurements were available for 4240 white, 640 black, and 1070 Hispanic children in kindergarten and 1st, 3rd, 5th, and 8th grades. In each wave, we estimated the proportions of children with BMI values in each quartile of the Centers for Disease Control and Prevention reference-population distribution according to gender and race/ethnicity. We conducted nonparametric tests of differences in BMI distributions over time within racial/ethnic groups and across racial/ethnic groups in each wave. Piecewise linear growth models were estimated to test for specific time periods during which the largest gains in BMI percentiles occurred.

RESULTS

Overall, nearly 40% of children started kindergarten with a BMI in the top quartile of the growth charts (BMI > 75th percentile). This proportion increased significantly during the elementary school years, and the largest gains were between 1st and 3rd grades (5.8 percentage points), but there was no further increase during middle school. Increases in BMI percentiles over time were most notable among Hispanic children and black girls.

CONCLUSIONS

The early school years might be a critical time for excess BMI gains, even among children with normal BMI values at kindergarten entry.

Body mass index trajectories from adolescence to midlife: differential effects of parental and respondent education by race/ethnicity and gender

OBJECTIVES

Race/ethnicity and education are among the strongest social determinants of body mass index (BMI) throughout the life course, yet we know relatively little about how these social factors both independently and interactively contribute to the rate at which BMI changes from adolescence to midlife. The purpose of this study is to (1) examine variation in trajectories of BMI from adolescence to midlife by mothers' and respondents' education and (2) determine if the effects of mothers' and respondents' education on BMI trajectories differ by race/ethnicity and gender.

DESIGN

We used nationally representative data from the National Longitudinal Survey of Youth. Our sample included white (n=4433), black (n=2420), and Hispanic (n=1501) respondents. Self-reported height and weight were collected on 16 occasions from 1981 to 2008. We employed two-level linear growth models to specify BMI trajectories.

RESULTS

Mothers' education was inversely associated with BMI and BMI change among women. Among men, mothers' education was inversely associated with BMI; these educational disparities persisted for whites, diminished for blacks, and widened for Hispanics. Respondents' education was inversely associated with BMI among women, but was positively associated with the rate of BMI change among black women. Respondents' education was inversely associated with BMI among white and Hispanic men, and positively associated with BMI among black men. These educational disparities widened for White and Black men, but narrowed for Hispanic men.

CONCLUSIONS

Our results suggest that by simultaneously considering multiple sources of stratification, we can more fully understand how the unequal distribution of advantages or disadvantages across social groups affects BMI across the life course.

Maternal behaviors during pregnancy impact offspring obesity risk

This study investigated the effects of maternal changes during pregnancy in diet, exercise, and psychosocial factors on offspring weight parameters at birth and 6 months. In overweight/obese (OW/OB; n = 132) mothers, greater % kcal from sweets early in pregnancy was the strongest, independent predictor of higher weight for age (WFA) (beta = 0.19; P = 0.004), higher odds of macrosomia (OR = 1.1 (1.0-1.2); P = 0.004) and WFA >90th percentile at birth (OR = 1.2 (1.1-1.3); P = 0.002) and higher WFA at 6 months (beta = 0.30; P = 0.002). In normal weight (n = 153) mothers, higher intake of soft drinks was the strongest predictor of higher offspring WFA at birth (beta = 0.16; P = 0.04) but not at 6 months. Prenatal physical activity, depressive symptoms, and sleep-related variables did not significantly predict offspring weight outcomes. Mothers' eating behaviors during pregnancy, especially intake of sweets in OW/OB mothers, may have a lasting effect on child weight.

Mexican American birthweight and child overweight: unraveling a possible early life course health transition

Mexican American children have a weight distribution that categorizes them as relatively healthy at birth but relatively unhealthy by age 3. This early life course transition in health based on weight raises the question of whether Mexican American children "outgrow" the epidemiologic paradox of favorable birth outcomes despite social disadvantage or whether their birthweight distribution places them on trajectory for overweight in childhood. We address this question using newly available 9-year follow-up data from the Fragile Families and Child Wellbeing birth cohort study linked to pre-natal medical records. We systematically investigate the roles of birthweight, pre-natal factors, and childhood factors in explaining racial/ethnic differences in childhood overweight. Our main finding is that Mexican American children do outgrow the paradox: Their rates of childhood overweight are higher than expected given their birthweight distribution. Observed pre-natal and childhood factors do not explain the elevated rates of overweight among Mexican American children.

Trajectories of overweight among US school children: a focus on social and economic characteristics

Much of the research examining the patterns, timing, and socioeconomic characteristics of child overweight has been limited by the lack of longitudinal nationally representative data with sufficiently large or diverse samples. We used the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K), a nationally representative sample of US kindergartners, to identify three distinct patterns of weight gain from kindergarten through eighth grade. The largest group (boys: 59%, girls: 55%) was characterized as having consistently normal weight whereby BMI percentile remained below the 85th percentile. The remaining children (boys: 41%, girls: 45%) fell either into a class characterized as always overweight/at risk of overweight (boys: 27%, girls: 25%) or gradually becoming overweight/at risk for overweight (boys: 15%, girls 20%). We found some evidence that the relationship between socioeconomic status and children's health may operate differently across gender. Among girls, low parental income and education were both significant risk factors for the gradual onset of overweight after beginning Kindergarten. Parental income or changes in parental income were not related to boys' risk of developing overweight after entering Kindergarten; only parents' education. We found that while children of immigrants display higher levels of overweight/at risk for overweight at each grade level, the children of immigrant parents who have had less exposure to the US were more likely to experience early and sustained overweight throughout elementary and middle school, particularly among boys. High rates of overweight as early as kindergarten, combined with race/ethnic differences suggest that interventions should focus on pre-school children's environments.

Is there a healthy foreign born effect for childhood obesity in the United States?

Objective of the study was to explore factors associated with early childhood obesity and assess whether having a foreign born mother is protective against childhood obesity. Data sources include 9 months and 4 years parent interviews and direct assessments of possessive children's weight and height (4 years) or length (9 months) from the Early Childhood Longitudinal Study-Birth Cohort. Subjects were children with anthropometric measures who lived with their mothers (n = 9,700 at 9 months and 8,200 at 4 years). Overweight is defined as a weight-for-length ratio at or above the 95th percentile at 9 months; obesity is defined as a body mass index at or above the 95th percentile at 4 years. The prevalence of overweight/obesity was 15.4% at 9 months and 18.0% at 4 years. After adjustment for potential confounders, having a foreign-born mother was not associated with the odds of overweight at 9 months or 4 years. At 9 months and 4 years, low birth weight, pre-pregnancy weight and weight gain during pregnancy were protective of overweight. In addition to these factors, at 4 years, excessive weight gain in the first 9 months was the strongest predictors for obesity. Living in a safe neighborhood and ever having breastfed were protective against obesity. Having a foreign born mother is not protective of early childhood obesity. A focus on health of women prior to conception and on women's and infants' health in the perinatal period are key to addressing childhood obesity.

Pre-pregnancy and pregnancy predictors of obesity

Obesity has progressively become a global epidemic that constitutes one of the biggest current health problems worldwide. Pregnancy is a risk factor for excessive weight gain. Factors that may predict development of obesity in later life mainly include gestational weight gain, pre-pregnancy nutritional status, age, parity and race. Change in lifestyle factors, such as eating habits, enrollment in physical activity, smoking and duration of lactation, in addition to the above factors, may also contribute to the development of obesity but are still not fully understood. Women who retain more body weight after pregnancy have, in general, larger pregnancy body weight gain, higher pre-pregnancy body mass index, marked weight changes in previous pregnancies, lactate slightly less and stop smoking during pregnancy to a larger extent. In addition, irregular eating habits and decreased leisure time activity after delivery influence postpartum weight retention. Taking into consideration the epidemic of obesity, with all its adverse long-term consequences, there is an increasing need to promote counseling before, during and after pregnancy on the role of diet and physical activity in reproductive health.

Lifecourse childhood adiposity trajectories associated with adolescent insulin resistance

OBJECTIVE

In light of the obesity epidemic, we aimed to characterize novel childhood adiposity trajectories from birth to age 14 years and to determine their relation to adolescent insulin resistance.

RESEARCH DESIGN AND METHODS

A total of 1,197 Australian children with cardiovascular/metabolic profiling at age 14 years were studied serially from birth to age 14 years. Semiparametric mixture modeling was applied to anthropometric data over eight time points to generate adiposity trajectories of z scores (weight-for-height and BMI). Fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were compared at age 14 years between adiposity trajectories.

RESULTS

Seven adiposity trajectories were identified. Three (two rising and one chronic high adiposity) trajectories comprised 32% of the population and were associated with significantly higher fasting insulin and HOMA-IR compared with a reference trajectory group (with longitudinal adiposity z scores of approximately zero). There was a significant sex by trajectory group interaction (P < 0.001). Girls within a rising trajectory from low to moderate adiposity did not show increased insulin resistance. Maternal obesity, excessive weight gain during pregnancy, and gestational diabetes were more prevalent in the chronic high adiposity trajectory.

CONCLUSIONS

A range of childhood adiposity trajectories exist. The greatest insulin resistance at age 14 years is seen in those with increasing trajectories regardless of birth weight and in high birth weight infants whose adiposity remains high. Public health professionals should urgently target both excessive weight gain in early childhood across all birth weights and maternal obesity and excessive weight gain during pregnancy.

Prenatal cocaine exposure and childhood obesity at nine years

Little is known about the association between prenatal cocaine exposure and obesity. We tested whether prenatal cocaine exposure increases the likelihood of obesity in 561 9-year-old term children from the Maternal Lifestyle Study (MLS). Overall, 21.6% of children met criterion for obesity (body mass index [BMI] ≥ 95th percentile, age and sex-specific). While there was no overall cocaine effect on obesity, multivariate logistic analysis revealed that children exposed to cocaine but not alcohol were 4 times more likely to be obese (OR 4.11, CI 2.04-9.76) than children not exposed to either drug. No increase in obesity prevalence was found in children exposed to alcohol but not cocaine (OR 1.08, CI .59-1.93) or both (OR 1.21, CI 0.66-2.22). Alcohol exposure may attenuate the effect of cocaine exposure on obesity. Increased obesity associated with cocaine but not alcohol exposure was first observed at 7 years. BMI was also elevated from 3 to 9 years in children exposed to cocaine but not alcohol, due to increasing weight but normal height. Prenatal exposure to cocaine may alter the neuroendocrine system and metabolic processes resulting in increased weight gain and childhood obesity.

Predicting the risk of newborn children to become overweight later in childhood: the PIAMA birth cohort study

OBJECTIVE

To develop a decision rule by which children with a high risk to develop overweight can be distinguished at birth from children at low risk.

DESIGN, SETTING AND PARTICIPANTS

Data of 1 687 Dutch children born in 1996/1997 who participated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) longitudinal birth cohort study were analysed. Perinatal candidate predictors of overweight at 8 years of age were selected and a prediction model was developed using stepwise model selection based on the Akaike Information Criterion (AIC). The prediction model was internally validated using resampling techniques. Outcome measure. Overweight at the age of 8 years.

RESULTS

A total of 13.9% (n = 253) of the children were overweight at 8 years of age. Independent positive predictors of overweight were paternal and maternal body mass index, female gender, smoking in the parental house, birth weight and hospital delivery. From the model, a decision rule was derived by which an overweight score could be calculated. Of the children with an overweight score below 89.45, only 2.7% were overweight at the age of 8, whereas in children with an overweight score above 105.02 the prevalence of overweight was 35.4%.

CONCLUSION

The risk of overweight at the age of 8 years can be predicted with six characteristics that are available at birth. The decision rule developed in this study may help to target early preventive measures against overweight in high-risk children.

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.

Body mass trajectories through adulthood: results from the National Longitudinal Survey of Youth 1979 Cohort (1981-2006)

BACKGROUND

Most studies describing change in body mass through adulthood model an 'average' trajectory bearing the same functional form in the underlying population. Latent-class growth modelling has revealed the presence of several underlying body mass/obesity trajectory groups among children and adolescents, but has not been applied to capture adult body mass trajectories. We apply the technique to identify adult body mass trajectory groups, risk factors for group membership and (time-varying) modifiers of trajectory level within each group, and assess association between group membership and important health outcomes in midlife.

METHODS

Body mass trajectory groups, from age 18 to 49 years, were identified using latent-class growth modelling based on the National Longitudinal Survey of Youth 1979 (n = 9681). Role of gender, race/ethnicity and age cohort as risk factors for group membership, and of highest grade of education completed, years of urban living, years in employment, years in poverty and years married as modifiers of trajectory level was evaluated.

RESULTS

Four trajectory groups, 'normal weight', 'overweight', 'late adulthood obesity' and 'early adulthood obesity' were identified. Males, Blacks and those born later had higher odds of being in the three latter groups. More education and years married lowered the trajectory within each group. The prevalence of most health outcomes was lowest in the 'normal weight' group, somewhat greater in the 'overweight' group, greater again in the 'late adult obesity group' and highest in the 'early adulthood obesity' group.

CONCLUSION

Regular body mass index screening and monitoring in early adult life may identify a person as belonging to one of these four groups early, and allow the individual and health-care providers opportunities to initiate behavioural or other interventions better tailored to the specific group.

Associations Between Mothers' and Their Children's Weights at 4 Years of Age

OBJECTIVES: To examine the importance of maternal weight characteristics as predictors of overweight (BMI ≥85th percentile and <95th percentile) and obesity (BMI ≥ 95th percentile) in offspring at age 4 years. METHODS: Chi-square and logistic regression analyses were conducted on a sample of 321 mother/child pairs from an earlier observational cohort study on mothers' postpartum weight retention. RESULTS: Maternal early pregnancy BMI and infant birth weight were each positively and significantly (p <0.05) associated with increased risk of obesity in offspring at age 4 years. A significant interaction was found between these two variables in predicting children's risk of obesity. It was driven by the high proportion of obese children among obese women who had infants weighing < 3 kg at birth. Net gestational weight gain was not associated with obesity risk in children, but was positively associated with infant birth weight among normal weight and overweight women. CONCLUSIONS: Reducing maternal BMI in the preconception period among overweight and obese women and preventing excessive weight gain in pregnancy for all women appear to be appropriate strategies to address the childhood obesity epidemic.

Association of maternal gestational weight gain with short- and long-term maternal and child health outcomes

OBJECTIVE

The purpose of this study was to investigate the associations between gestational weight gain (GWG) and small- and large-for-gestational-age (SGA, LGA), cesarean delivery, child overweight, and maternal postpartum weight retention in a diverse sample of women in the Unites States.

STUDY DESIGN

We estimated associations between GWG (continuous and within categories defined by the Institute of Medicine), maternal prepregnancy body mass index, and each outcome in 4496 births in the National Longitudinal Survey of Youth 1979, which was a prospective cohort.

RESULTS

GWG (kilograms) was associated with decreased risk of SGA and increased risk of LGA, cesarean delivery, postpartum weight retention, and child overweight independent of maternal demographic and pregnancy characteristics. Gain above the Institute of Medicine guidelines was associated with decreased risk of SGA and increased risk of all other outcomes.

CONCLUSION

Excessive gain may have long-term consequences for maternal and child body size, but the benefits of lower gain must be balanced against risk of SGA.

Maternal metabolism and obesity: modifiable determinants of pregnancy outcome

BACKGROUND

Obesity among pregnant women is highly prevalent worldwide and is associated in a linear manner with markedly increased risk of adverse outcome for mother and infant. Obesity in the mother may also independently confer risk of obesity to her child. The role of maternal metabolism in determining these outcomes and the potential for lifestyle modification are largely unknown.

METHODS

Relevant studies were identified by searching PubMed, the metaRegister of clinical trials and Google Scholar without limitations. Sensitive search strategies were combined with relevant medical subject headings and text words.

RESULTS

Maternal obesity and gestational weight gain have a significant impact on maternal metabolism and offspring development. Insulin resistance, glucose homeostasis, fat oxidation and amino acid synthesis are all disrupted by maternal obesity and contribute to adverse outcomes. Modification of lifestyle is an effective intervention strategy for improvement of maternal metabolism and the prevention of type 2 diabetes and, potentially, gestational diabetes.

CONCLUSIONS

Maternal obesity requires the development of effective interventions to improve pregnancy outcome. Strategies that incorporate a detailed understanding of the maternal metabolic environment and its consequences for the health of the mother and the growth of the child are likely to identify the best approach.

Maternal smoking during pregnancy and offspring obesity: meta-analysis

BACKGROUND

Recent reports have suggested that maternal smoking may increase the risk of development of obesity in the unborn child in later life, but relatively few cohort studies have been done on the relationship between maternal smoking during pregnancy and future development of metabolic syndrome.

METHODS

A systematic review and meta-analysis of observational studies reporting effect estimates and 95% confidence intervals (95%CI) was conducted on the association between maternal smoking during pregnancy and obesity of future offspring.

RESULTS

Seventeen papers were identified from 444 English-language papers (key word search: maternal smoking and obesity) in PubMed. All papers showed a positive association between maternal smoking during pregnancy and childhood obesity. The meta-analysis, using the DerSimonian-Laird method, found the association to be statistically significant. In association with maternal smoking during pregnancy and body mass index with more than 95%CI in the offspring aged 3-33 years, the pooled odds ratio calculated from 16 of these 17 studies was 1.64 (95%CI: 1.42-1.90). After adjustment for publication bias, the pooled adjusted odds ratio was 1.52 (95%CI: 1.36-1.70). In addition, confounders of maternal obesity, low social status, low birthweight and not being breast-fed seemed to be risk factors for offspring obesity.

CONCLUSION

Maternal smoking during pregnancy may cause future obesity and metabolic syndrome.

O desmame precoce afeta o ganho de peso e a composição corporal em camundongos adultos?

OBJETIVO: Avaliar o efeito do desmame precoce sobre o ganho de peso e a composição corporal de camundongos adultos jovens. MÉTODOS: Camundongos Swiss Webster, machos, foram desmamados precocemente (14º dia de vida) ou amamentados até o 21º dia de vida (grupo controle). Após o desmame, os animais foram alimentados com ração elaborada para roedores em crescimento até o 63º dia de vida, quando então foram sacrificados. RESULTADOS: O peso corporal dos animais do grupo desmamado de forma precoce foi significantemente maior no 28º, 35º e no 63º dias de vida em relação ao grupo controle (p<0,05). Porém, o consumo de ração não diferiu entre os grupos. A concentração sérica de proteínas totais, albumina e ferro, bem como a concentração hepática, muscular e cerebral de proteínas, ácido desoxirribonucléico e a relação proteína/ácido ribonucléico, não diferiram significantemente entre os grupos. O grupo desmamado precocemente apresentou maior quantidade absoluta de massa magra, lipídeos, proteínas e cinzas, em comparação ao grupo controle (p<0,05). A quantidade relativa de umidade, lipídeos, massa magra, proteínas e cinzas não diferiu entre os grupos. CONCLUSÃO: O desmame precoce, associado à ingestão de ração elaborada para roedores em crescimento, resultou em aumento do ganho de peso, porém não afetou a composição corporal de camundongos adultos.

A low alpha-linolenic intake during early life increases adiposity in the adult guinea pig

Background

The composition of dietary fatty acids (FA) during early life may impact adult adipose tissue (AT) development. We investigated the effects of α-linolenic acid (ALA) intake during the suckling/weaning period on AT development and metabolic markers in the guinea pig (GP).

Methods

Newborn GP were fed a 27%-fat diet (w/w %) with high (10%-ALA group), moderate (2.4%-ALA group) or low (0.8%-ALA group) ALA content (w/w % as total FA) until they were 21 days old (d21). Then all animals were switched to a 15%-fat diet containing 2% ALA (as total FA) until 136 days of age (d136).

Results

ALA and docosapentaenoic acid measured in plasma triglycerides (TG) at d21 decreased with decreasing ALA intake. Total body fat mass was not different between groups at d21. Adipose tissue TG synthesis rates and proliferation rate of total adipose cells, as assessed by ²H₂O labelling, were unchanged between groups at d21, while hepatic de novo lipogenesis was significantly 2-fold increased in the 0.8%-ALA group. In older GP, the 0.8%-ALA group showed a significant 15-%-increased total fat mass (d79 and d107, p < 0.01) and epididymal AT weight (d136) and tended to show higher insulinemia compared to the 10%-ALA group. In addition, proliferation rate of cells in the subcutaneous AT was higher in the 0.8%-ALA (15.2 ± 1.3% new cells/5d) than in the 10%-ALA group (8.6 ± 1.7% new cells/5d, p = 0.021) at d136. AT eicosanoid profiles were not associated with the increase of AT cell proliferation.

Conclusion

A low ALA intake during early postnatal life promotes an increased adiposity in the adult GP.

Understanding infant feeding beliefs, practices and preferred nutrition education and health provider approaches: an exploratory study with Somali mothers in the USA

The objective of this study was to explore Somali mothers' beliefs and practices around infant feeding and education, towards developing a culturally informed infant nutrition curriculum for health providers. Four focus groups were conducted to explore: (1) beliefs about infant feeding, hunger and ideal weight; (2) feeding practices; (3) nutrition education approaches; and (4) provider/mother interactions. Thirty-seven Somali mother participants identified the following themes within these topics: (1) strategies for assessing hunger, satiety and when to feed; shared beliefs that plump babies are healthy, leading to worry about infant weight; (2) context of breast milk adequacy, difficulties breastfeeding and environmental and cultural barriers to breastfeeding, leading to nearly universal early supplementation with formula; (3) preferred education approaches include provider visits with interpreters, Somali language educational materials and advice from older, experienced family members; and (4) desired health provider skills include: listening, explaining, empathy, addressing specific concerns, repeating important information, offering preventive advice and sufficient visit time. This study presents knowledge about Somali beliefs and practices that can directly guide discussions with these families. Given that these infants appear on a trajectory towards obesity, influencing infant feeding practices in the Somali community is a good upstream approach to preventing obesity. These findings will underpin a new infant nutrition curriculum for health providers.

Developmental trajectories of girls' BMI across childhood and adolescence

This study describes qualitatively distinct trajectories of BMI change among girls participating in a longitudinal study of non-Hispanic, white girls (n = 182) and their parents, assessed at daughters' ages 5, 7, 9, 11, 13, and 15 years. Height, weight, body fat, fasting blood glucose and lipids, blood pressure, waist circumference, and pubertal status were measured, and participants self-reported dietary, physical activity, and television (TV) viewing patterns. Growth mixture models were used to model heterogeneity in girls' BMI trajectories over 10 years. Statistical support was strongest for four distinct BMI trajectories: (i) upward percentile crossing (UPC; n = 25, 14%); (ii) delayed downward percentile crossing (DDPC; n = 37, 20%); (iii) 60th percentile tracking (60PT; n = 52, 29%); and (iv) 50th percentile tracking (50PT; n = 68, 37%). Girls in the UPC group had more metabolic risk factors at age 15 years, even after adjusting for concurrent weight status. Girls in the UPC group had mothers with the highest BMIs at study entry and were breast-fed for a shorter duration. This novel approach for examining differences in growth trajectories revealed four distinct BMI trajectories that predicted adolescent metabolic health outcomes in girls. The present study provides support for BMI monitoring in girls and for the potential utility of combining data on BMI tracking with data on familial characteristics for the early identification of girls at elevated risk for obesity and metabolic syndrome.

Youth BMI trajectories: evidence from the NLSY97

We examined heterogeneity in BMI trajectory classes among youth and variables that may be associated with trajectory class membership. We used data from seven rounds (1997-2003) of the 1997 National Longitudinal Survey of Youth (NLSY97), a nationally representative, longitudinal survey of people born between 1980 and 1984 who were living in the United States in 1997. The analyses were based on an accelerated longitudinal design. General growth mixture modeling implemented in Mplus (version 4.1) was used to identify subtypes of youth BMI growth trajectories over time. Four distinct youth BMI trajectories were identified. Class 1 includes youth at high risk for becoming obese by young adulthood (at age 12 and 23, approximately 67 and 90%, respectively, are classified as obese, and almost 72% will have had a BMI>or=40 at some time during this developmental period). Class 2 includes youth at moderate-to-high risk (at age 12 and 23, approximately 55 and 68%, respectively, are classified as obese). Class 3 includes youth at low-to-moderate risk (i.e., at age 12 and 23, approximately 8 and 27%, respectively, are classified as obese). Class 4 includes youth at low risk (few of these youth are obese at any age during this developmental period). These results highlight the importance of considering heterogeneity in BMI growth among youth and early interventions among those most at risk of the adverse health consequences of excess weight.

Intrauterine exposure to environmental pollutants and body mass index during the first 3 years of life

OBJECTIVE

We investigated the association between body mass index (BMI) standard deviation score (SDS) and prenatal exposure to hexachlorobenzene, dichlorodiphenyldichloroethylene (DDE), dioxin-like compounds, and polychlorinated biphenyls (PCBs).

METHODS

In this prospective birth cohort study, we assessed a random sample of mother-infant pairs (n = 138) living in Flanders, Belgium, with follow-up until the children were 3 years of age. We measured body mass index as standard deviation scores (BMI SDS) of children 1-3 years of age as well as pollutants measured in cord blood.

RESULTS

DDE correlated with BMI SDS, with effect modification by maternal smoking and the child's age. At 1 year, children of smoking mothers had higher BMI SDS than did children of nonsmoking mothers. At 3 years, this difference was reduced because of the faster rate of decline in BMI SDS in the former group. This relationship held except for children with high levels of DDE. DDE had a small effect on BMI SDS at 3 years of age in children of nonsmoking mothers (difference in BMI SDS for DDE concentrations between the 90th and 10th percentiles = 0.13). On the other hand, smoking enhanced the relation between DDE and BMI SDS at 3 years (difference in BMI SDS for DDE concentrations between the 90th and 10th percentiles = 0.76). Increasing concentrations of PCBs were associated with higher BMI SDS values at all ages (parameter estimate = 0.003 +/- 0.001; p = 0.03).

CONCLUSION

In this study we demonstrated that intrauterine exposure to DDE and PCBs is associated with BMI during early childhood. Future studies are warranted to confirm our findings and to assess possible mechanisms by which these pollutants could alter energy metabolism.

Prenatal smoking prevalence ascertained from two population-based data sources: birth certificates and PRAMS questionnaires, 2004

OBJECTIVES

This study provided a population-based estimate of the prevalence of smoking during pregnancy by combining information from two data sources: birth certificates (BCs) and a self-administered questionnaire.

METHODS

We analyzed data from 39,345 women who delivered live births in one of 24 states and responded to a questionnaire from the Pregnancy Risk Assessment Monitoring System (PRAMS), an ongoing, state- and population-based surveillance system. We compared prevalence of smoking during pregnancy based on the BC, the PRAMS questionnaire, and the two data sources combined. Data were weighted to represent all women delivering live births in each of the 24 states during 2004.

RESULTS

The combined estimate indicated that 15.1% of women reported smoking during pregnancy, whereas the BCs alone reported 10.4% and the PRAMS questionnaires alone reported 13.4%.

CONCLUSIONS

Based on the combined BC and PRAMS questionnaire data, the number of infants exposed to tobacco in-utero may be 31% higher than is currently reported on the BCs. Combining the data from the two different sources led to higher ascertainment of prenatal smoking.

Maternal gestational weight gain and offspring weight in adolescence

OBJECTIVE

To study associations of maternal gestational weight gain with offspring weight status in adolescence.

METHODS

We surveyed 11,994 adolescents aged 9-14 years enrolled in the Growing Up Today Study cohort and their mothers, members of the Nurses' Health Study II. We used multivariable linear and logistic regression to study associations of gestational weight gain with offspring adiposity.

RESULTS

Mean (standard deviation) gestational weight gain was 31.5 (11.2) pounds, and offspring body mass index (BMI) z score (BMI standardized for age and sex) was 0.15 (1.0) units; 6.5% of adolescents were obese (BMI 95th percentile or higher) (BMI is calculated as weight [kg]/[height (m)]2). Gestational gain was linearly associated with adolescent adiposity: compared with 20-24 pounds, gain less than 10 pounds was associated with child BMI z score 0.25 units lower (95% confidence interval [CI] -0.47 to -0.04), and gain 45 pounds or more with BMI z score 0.18 units higher (95% CI 0.11-0.25). Compared with women with adequate gain according to 1990 Institute of Medicine guidelines, women with excessive gain had children with higher BMI z scores (0.14 units, 95% CI 0.09-0.18) and risk of obesity (odds ratio 1.42, 95% CI 1.19-1.70). The predicted prevalence of term low birth weight declined modestly across the range of gain (2% for gain less than 10 pounds, 1% for gain 45 pounds or more), whereas term high birth weight increased dramatically with higher gain (10% for gain less than 10 pounds, 35% for gain of 45 pounds or more).

CONCLUSION

Gestational weight gain is directly associated with BMI and risk of obesity in adolescence. Revised gestational weight-gain guidelines should account for influences on child weight.

LEVEL OF EVIDENCE

II.

Prevalence and risk factors for overweight and obesity in a population of Italian schoolchildren: a longitudinal study

Prevalence of childhood overweight and obesity have dramatically increased worldwide in the last decades. Overweight and obesity are the result of a complex interaction between genetic and environmental factors. The aim of our longitudinal study was to assess the prevalence of overweight and obesity in a population of Italian schoolchildren followed for 2 years and to identify main risk factors for obesity onset and persistence in childhood. We enrolled 632 children (males /females= 345/287), aged 3 to 8 yr.Weight and height were measured at time 0, 1 (1 yr later), and 2 (2 yr later). Overweight and obesity were defined using body mass index (BMI) (Italian growth charts). Data collected included: birth weight, gestational age,maternal weight gain during pregnancy, breast feeding, parents' BMI, educational level, and occupation type. At time 0, 1, and 2 the prevalence of overweight was 22%, 22%, and 25%, respectively, and the prevalence of obesity was 7%, 8%, and 8%, respectively. During follow-up 62%of children remained normal weight, 24% was always overweight or obese, 9% became overweight, while only 5% of overweight subjects became normal weight. Male gender, maternal weight gain during pregnancy >10 kg, parental overweight/obesity were positively associated with the presence of overweight during the entire follow-up. On the contrary, being small for gestational age at birth was negatively related to persistence of overweight. No influence was found for being breastfed, for parental low educational level, and manual occupation. A large prevalence of overweight/obesity was observed in Italian schoolchildren. Gender, maternal weight gain during pregnancy, and parents' BMI were the strongest predictors of the persistence of child overweight and obesity.

Maternal weight gain during pregnancy and child weight at age 3 years

OBJECTIVES

To determine the importance of pregnancy weight gain as a predictor of overweight (Body Mass Index [BMI] >85th percentile) in offspring at age 3 years and if its influence varies by maternal BMI.

METHODS

Chi-square and logistic regression analyses were conducted on a sample of 208 mother-child pairs from an earlier observational cohort study on postpartum weight retention.

RESULTS

In the final reduced regression model, maternal early pregnancy BMI was positively and significantly associated with overweight in offspring, as were birth weight above the sample median of 3,600 g and maternal smoking during pregnancy (P < or = 0.01). In addition, a significant interaction was found between maternal BMI and gestational weight gain (P = 0.03). The risk of offspring overweight that is associated with 5 excess pounds of net pregnancy weight gain increases with maternal BMI.

CONCLUSIONS

Excess pregnancy weight gain is associated with increased risk of child overweight at age 3 years and its impact is greater among high and obese BMI women than it is in normal BMI women. Reducing maternal BMI in the preconception period in overweight women and preventing excessive weight gain in pregnancy for all women appear to be appropriate strategies to address the childhood obesity epidemic.

Prenatal nicotine exposure changes natural and drug-induced reinforcement in adolescent male rats

Clinical studies have demonstrated an increased incidence of substance misuse and obesity in adolescents whose mothers smoked during pregnancy. Although dopamine systems that mediate natural and drug-induced reinforcement have been shown in animal studies to be altered by gestational nicotine treatment, it is not clear whether there are concomitant changes in reinforcement sensitivity. To test whether prenatal nicotine exposure influences sensitivity to natural and drug rewards, timed pregnant rats were implanted with osmotic minipumps delivering saline or nicotine (3 mg/kg/day) from gestational day 4 to 18. Male offspring were tested as adolescents, on postnatal day 32, for operant responding maintained by sucrose pellets or i.v. cocaine (200 or 500 mug/kg per injection). Cocaine-induced stereotypy and c-fos mRNA expression in cortex and striatum were also examined. Complex changes in reward circuitry were observed in the offspring of nicotine-exposed dams. Nicotine-exposed adolescents did not self-administer the low dose of cocaine, but, at the higher dose, exhibited significantly greater cocaine intake and c-fos mRNA expression in nucleus accumbens than did controls. In contrast, control animals showed significantly greater drug-induced stereotypy at both cocaine doses. Operant responding maintained by sucrose was also influenced by gestational nicotine exposure. At a fixed ratio (FR) 1 schedule, although the number of pellets eaten by the two experimental groups was equivalent, more pellets were left uneaten by nicotine-exposed offspring. At FR2 and FR5 schedules, the responding maintained by sucrose pellets was lower in nicotine-exposed offspring. These findings suggest that nicotine exposure during gestation may induce changes in both natural and drug reward pathways.

Physical activity, sedentary behaviour and energy balance in the preschool child: opportunities for early obesity prevention

Prevalence of obesity in preschool children has increased dramatically in recent years. The preschool years (age 3–6 years) have been regarded as critical for the programming of energy balance, via the concept of early ‘adiposity rebound’. Children who undergo early adiposity rebound are at increased risk of later obesity. Recent evidence suggests that associations between timing of adiposity rebound and later obesity may not reflect programming, but might denote that ‘obesogenic’ growth trajectories are often established by the preschool period. Studies of objectively-measured physical activity and sedentary behaviour in preschool children show that levels of physical activity are typically low and sedentary behaviour high. The review of evidence presented here is supportive of the hypothesis that physical activity is protective against obesity in the preschool period, and that sedentary behaviour, particularly television viewing, is obesogenic. Definitive evidence on dose–response relationships between physical activity, sedentary behaviour and obesity remain unclear. Dose–response evidence could be obtained fairly readily by intervention and longitudinal observational studies that use accelerometry in preschool children. The generalisability of much of the evidence base is limited and there is a need for research on the influence of physical activity and sedentary behaviour in the preschool years in the aetiology of obesity in the developing world.

Ecological differences in weight, length, and weight for length of Mexican American children in the WIC program

PURPOSE

Examine factors common in the environments of children who obtain services from a WIC program to determine if differences in ecological/environmental factors can be found in the children who differ in weight, length, and weight for length.

DESIGN AND METHODS

Cross-sectional study of 300 children, 100 each who were stunted, normal weight for length, or overweight. Instruments used were NCATS, ARSMA II, 24-hr diet recall, and Baecke Activity Questionnaire.

RESULTS

Significant differences were present in children's diet, parents' BMI, parents' generation in United States, parents' activity levels, and maternal-child relationship.

PRACTICE IMPLICATIONS

Encourage parents to adopt family approaches to encourage normal body size in children.

Association between family divorce and children's BMI and meal patterns: the GENDAI Study

The aim of this work was to explore the associations between family factors, including divorce, and children's overweight as well as eating and physical activity patterns in a population-based sample of healthy school-aged children. In this cross-sectional study, 1,138 children (53% girls; age: 11.2 +/- 0.7 years) from elementary schools in the Attica region participated. Their parents provided sociodemographic information, including their marital status. Overweight status classification was based on weight and height measurements and BMI evaluation. Children completed a physical activity checklist and a questionnaire on meal patterns and eating behaviors. The Eating Style score was calculated: the higher the score, the more frequent a child was engaged in less-structured feeding practices promoting food intake for reasons other than hunger. Analysis revealed significant association between family divorce and children's overweight: compared with children of married parents, those of divorced had significantly higher BMI levels (20.0 +/- 3.6 kg/m(2) vs. 21.3 +/- 3.4 kg/m(2), respectively, P = 0.007). Controlling for socioeconomic and physical activity factors, divorce remains a significant predictor of a higher BMI, along with older age, higher father's and mother's BMI, less children in the family, and more minutes of daily screen time. Children who had experienced a divorce in their family also reported higher Eating Style score, even after adjusting for potential confounders. In conclusion, in this sample of fifth and sixth graders, unfavorable family circumstances have been associated with children's overweight, as well as with aspects of their eating behavior, namely eating style in relation to conditions around food consumption and hunger, independent of other socioeconomic factors.

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.