Patterns of Growth Associated With the Timing of Adiposity Rebound

This study was undertaken to evaluate the effects of age of adiposity rebound (AR) on measures of fat mass between ages 7 and 11 years, maturity, and adiposity in 458 children from a birth cohort studied to age 26 years. Patterns of growth between ages 3 and 26 years and changes in fat mass index between 7 and 11 years in groups with early (<5.5 years for boys and <5 years for girls), average (between 5.5 and 7.5 years for boys and between 5 and 7 years for girls), and late AR (≥7.5 years for boys and ≥7 years for girls) are described. The mean z‐scores for BMI, height, and weight increased between age 3 years and adolescence in the early‐rebound group and decreased in the late‐rebound group. The differences were maintained until adulthood for BMI and weight. Disproportionately high increases in fat mass index during growth (7–11 years), more advanced bone age in boys at age 7 years, and earlier menarche in girls were evident in the early‐rebound group. The relative risks at 26 years of being overweight (BMI 25–29.9 kg/m²) and obese (BMI ≥30 kg/m²) were 2.70 (95% confidence interval (CI): 1.55, 4.66) and 5.91 (95% CI: 3.03, 11.55) respectively, using the average group as the reference. The corresponding relative risks for adult waist girths exceeding international cut points were 2.12 (95% CI: 1.09, 4.13) and 3.32 (95% CI: 1.46, 7.54). Thus, early rebound is associated with increased depositions of fat in middle childhood, and risks associated with early rebound persist at least until early adulthood.     

Long-term changes in body weight, BMI, and adiposity rebound among children and adolescents in the Czech republic

The Czech Republic has undergone rapid political, social, and economic transformation since the late 1980s. While obesity rates among children and adolescents in the Czech Republic have been previously relatively low, this has changed in recent years. Across the past 50 years, body weight, body mass index (BMI)-for-age, and adiposity rebound (AR) (the time when a child reaches the lowest BMI before their BMI gradually begins to increase until adulthood) occurs earlier. The most dramatic changes have been observed among school-aged children, where BMI values have increased at the 50th, 90th, and 97th percentiles. In contrast, adolescent girls appear to be thinner than in the past. The analyses of weight-for-height percentiles indicated that the 50th percentile of the body weight among boys and girls remained similar in nearly all age categories across the past 50 years. Although the growth pattern of children at the 50th percentile has not changed, the 10th and 90th percentiles have expanded. Our findings suggest that the secular trend of increased height, accelerated growth, and earlier maturation is responsible for Czech children experiencing adiposity rebound at earlier ages compared to the past.     

Ethnic Differences in Subcutaneous Adiposity and Waist Girth in Children and Adolescents

The purpose of this study was to examine ethnic differences in adiposity as measured by sum of skinfolds (SKF) and waist circumference (WC) in children and adolescents, after statistical adjustment for the BMI and age. A cross sectional sample of 3,218 (55% white, 49% male) children and adolescents aged 5–18 years who participated in the Bogalusa Heart Study (1992–1994) were included in these analyses. Sex‐specific ANOVAs, adjusted for BMI and age, for each 2‐year age group compared measures of adiposity (SKF and WC) between ethnic groups. No significant differences in the proportions of children and adolescents who were overweight and obese by ethnicity or sex were found. Mean SKF in normal weight (P < 0.0001) and overweight (P < 0.0001) categories was higher for white than black children of both sexes. Across most age categories, white boys and girls had significantly higher SKF than black boys and girls, respectively (P ≤ 0.05). Across most age categories, white boys had significantly higher WC than black boys (P ≤ 0.05) with no difference in the girls, when adjusted for BMI and age. Measures of adiposity in childhood and adolescence were significantly higher in white children compared to black children, when adjusted for BMI and age. Throughout childhood and adolescence, white boys and girls had higher SKF and white boys had higher WC. Differences in adiposity between ethnic groups should be considered in disease risk assessment and stratification as they are observed even for a given BMI level.     

Rate of Fat Gain Is Faster in Girls Undergoing Early Adiposity Rebound

Objective: To determine the changes in body composition (fat and lean mass) occurring in children during adiposity rebound (AR). Research Methods and Procedures: Thirty‐nine girls, 3 to 6 years of age at baseline, underwent yearly DXA scans for 2 years. An additional DXA scan was obtained 4 to 5 years after baseline. Age at AR was determined by modeling, and the velocity of change in height, weight, fat mass, and lean mass was estimated for each child using random coefficient models. Girls with an AR <5 years of age were classified as having an early AR, and those having an AR ≥5 years were classified as late AR. Results: Although body composition was similar at age 5, by age 9, girls with an early AR were significantly taller (3.5% more) and heavier (14.4%), with greater fat mass (50%) and percentage body fat (27%) than girls with a later AR. In addition, more girls were overweight according to BMI (18% vs. 6%) or percentage body fat (29% vs. 11%) at this time, despite no differences at baseline. Annual velocity of fat mass gain was over 2‐fold higher in early compared with late rebounders (17.1% vs. 6.5%, p < 0.0001), with no difference in lean mass velocity (13.1% vs. 12.5%, p = 0.116). Discussion: Differences in BMI during AR were caused specifically by alterations in body fat and not by alterations in lean mass or height. Children undergoing early AR gained fat at a faster rate than children who rebounded at a later age.     

Blood Pressure in Adolescence and Early Adulthood Related to Obesity and Birth Size

Objective: Obesity is an established risk factor for higher systolic (SBP) and diastolic (DBP) blood pressure in adolescence and early adulthood, but birth size may also have a role. We analyzed the effects of adolescent and adult obesity and birth size on BP in the young adult. Research Methods and Procedures: In a prospective longitudinal study, anthropometric measurements were obtained at birth on 67 boys and 67 girls bom in Boston. Their body mass indices (BMI) and BP were recorded 17 years and 30 years later. Results: For women, adolescent and early adult obesity appeared to be the stronger determinants of higher BP, although smaller head and chest circumferences at birth may also be related. We found some evidence of birth (ponderal index [PI] and head circumference) anthropometric influences on age 17 BP levels in boys. By age 30, body mass variables were the dominant predictors of male BP levels. Female BMI at age 17 was positively correlated with birth adiposity (PI), but BMI at 30 was related only to age 17 BMI. Similarly, male BMI at 17 years was higher for those who weighed more at birth, but BMI at 30 years was again related only to age 17 BMI. Discussion: We conclude that adult weight and weight gain are the major determinants of adult BP.     

Age at Puberty and the Emerging Obesity Epidemic

Background

Recent studies have shown that puberty starts at younger ages than previously. It has been hypothesized that the increasing prevalence of childhood obesity is contributing to this trend. The purpose of this study was to analyze the association between prepubertal body mass index (BMI) and pubertal timing, as assessed by age at onset of pubertal growth spurt (OGS) and at peak height velocity (PHV), and the secular trend of pubertal timing given the prepubertal BMI.

Methodology/Principal Findings

Annual measurements of height and weight were available in all children born from 1930 to 1969 who attended primary school in the Copenhagen municipality; 156,835 children fulfilled the criteria for determining age at OGS and PHV. The effect of prepubertal BMI at age seven on these markers of pubertal development within and between birth cohorts was analyzed. BMI at seven years was significantly inversely associated with age at OGS and PHV. Dividing the children into five levels of prepubertal BMI, we found a similar secular trend toward earlier maturation in all BMI groups.

Conclusion/Significance

The heavier both boys and girls were at age seven, the earlier they entered puberty. Irrespective of level of BMI at age seven, there was a downward trend in the age at attaining puberty in both boys and girls, which suggests that the obesity epidemic is not solely responsible for the trend.     

哈萨克族学生体质发育状况的10年比较分析

报道新疆阿勒泰地区1995年2589名城镇7—18岁哈萨克族(哈族)中小学生身高、体重、胸围、坐高、肩宽、骨盆宽6项体质发育指标的调查结果。男女生体质发育指标随年龄增加而增长,各项指标的年均增长值皆为男生大于女生。与1985年比较,哈族学生的身高、体重、胸围皆有不同程度增长。哈族男女生的身高突增年龄仍分别为14岁和10岁,但是其身高增长却不伴有相应比例的坐高增长,女生部分年龄组的肩宽和男女生各年龄组的骨盆宽呈现负增长,提示哈族学生的体型与10年前相比已经开始有所改变。     

Maternal corticotropin-releasing hormone levels during pregnancy and offspring adiposity

Objective: Animal models suggest that fetal exposure to glucocorticoids can program adiposity, especially central adiposity, later in life. We examined associations of maternal corticotropin‐releasing hormone (CRH) levels in the late 2nd trimester of pregnancy, a marker of fetal glucocorticoid exposure, with child adiposity at age 3 years. Research Methods and Procedures: We analyzed data from 199 participants in Project Viva, a prospective cohort study of pregnant women and their children, At age 3 years, the main outcomes were age‐sex‐specific BMI z score and the sum of subscapular (SS) and triceps (TR) skinfold thicknesses to represent overall adiposity, and ratio of SS to TR (SS:TR) to represent central adiposity. Results: Mean (standard deviation) maternal 2nd trimester log CRH was 4.94 (0.56) pg/mL. At age 3, mean (standard deviation) for BMI z score was 0.52 (1.02); for SS + TR, 16.51 (3.94) mm; and for SS:TR, 0.67 (0.17). Log CRH was mildly inversely correlated with birth weight (r = ?0.08), chiefly because of its association with length of gestation (r = ?0.21) rather than fetal growth (r = ?0.004). After adjustment for sociodemographic factors, maternal smoking, BMI, and gestational weight gain, fetal growth, length of gestation, breastfeeding duration, and (for SS:TR only) child's 3‐year BMI, each increment of 1 unit of log CRH was associated with a reduction in BMI z score [?0.43; 95% confidence interval (CI), ?0.73, ?0.14; p = 0.004] and possible reduction in SS + TR (?1.10; 95% CI, ?2.33, 0.14; p = 0.08). In contrast, log CRH was associated with higher SS:TR (0.07; 95% CI, 0.02, 0.13; p = 0.007). Discussion: Fetal exposure to glucocorticoids, although associated with an overall decrease in body size, may cause an increase in central adiposity.     

Birth Weight and Its Relationship to Size Attained and Relative Fat Distribution at 7 to 12 Years of Age

The relationship between birth weight and relative subcutaneous fat distribution at school age was considered in 131 boys and 106 girls 7 to 12 years of age. Relative fat distribution at school age was estimated with the ratio of the subscapular to triceps skinfolds (S/T) for the total sample, and with the ratio of the sum of two trunk (subscapular, midaxillary) to the sum of two extremity (triceps, medial calf) skinfolds (T/E) for subsamples of 102 boys and 63 girls. There were no sex differences in the S/T ratio (mm/mm), boys 0.62 ± 0.15, girls 0.63 ± 0.18; T/E ratio (mm/mm), boys 0.58 ± 0.13, girls 0.59 ± 0.16; and BMI (kg/m²), boys 17.1 ± 2.4, girls 16.9 ± 2.2. Second order partial correlations, controlling for age and the BMI or age and sum of skinfolds, between birth weight and the skinfold ratios are, respectively, ?0.22 and ?0.20 (p<0.01) for S/T and ?0.29 and ?032 (p<0.01) for T/E in girls, and ?0.18 and ?0.17 (p<0.05) for S/T and ?0.06 and ?0.6 for T/E in boys. Though low, the correlations suggest that as birth weight decreases proportionally more subcutaneous fat is accumulated on the trunk than on the extremities, more so in females than in males. Results of stepwise multiple regression analyses indicate that birth weight accounts for from 2% to 8% of the variance in relative subcutaneous fat distribution at school age.     

Obesity and attenuated adiposity rebound in children with congenital hypothyroidism. Normalization of BMI values in adolescents.

An earlier adiposity rebound, suggestive of adult obesity, has been reported in children with congenital hypothyroidism. We undertook this study to evaluate the effect of congenital hypothyroidism on: 1) the timing of adiposity rebound, 2) the long-term prognosis of BMI status, and 3) the factors potentially affecting adiposity in subjects with congenital hypothyroidism. We found that in children with congenital hypothyroidism the BMI values were higher during the first years of life compared to normal population, but subsequently normalized. After the initial rise of BMI, the decline (nadir) and subsequent rise (adiposity rebound), usually occurring in normal children at an age greater than 30 months, was less evident in our group of children with congenital hypothyroidism. The severity of hypothyroidism affected BMI values at 6 and 12, but not at 36 months of age. In conclusion, in children with congenital hypothyroidism, 1) the high BMI values in early childhood normalize in adolescence, and 2) the normally expected BMI fluctuations during the first years of life are attenuated. These findings constitute indirect evidence that thyroid function during fetal and neonatal life affects BMI status during the first years of life.     

Gender-specific growth patterns for stature,sitting height and limbs length in Croatian children and youth (3 to 18 years of age)

In a cross-sectional study of growth, 5,155 children (2,591 females, 2,564 males) from the town of Zagreb (Croatia) were measured. Four traits of linear dimensionality (stature, sitting height, arm and leg lengths) were studied in the age span of 3 to 18 years. A significant average annual increase of all four anthropometric parameters were observed up to 14 and 15 years of age in girls and 16 years of age in boys, showing that girls had a shorter growing period. In the prepubertal period until 9 years of age, gender differences were negligible. At the age of 10, boys were overgrown by girls in all parameters due to the earlier onset of puberty in girls. The growth gains for girls, when compared with those for boys, show a different pattern across variables. The female growth advantage remained in a two years period for the limbs length, but in a three year period for stature and the longest, for 4 years, for sitting height. The male predominance in size had an onset at the age of 13 for the limbs and in the age of 14 for stature and sitting height. The patterns of sexual dimorphism in stature and sitting height during growing years are similar to those observed in other populations of Europe. Growth of Croatian children and youth is very similar to that of the tallest European populations.     

Genetic and environmental contributions to weight, height, and BMI from birth to 19 years of age: an international study of over 12,000 twin pairs

Objective

To examine the genetic and environmental influences on variances in weight, height, and BMI, from birth through 19 years of age, in boys and girls from three continents.

Design and Settings

Cross-sectional twin study. Data obtained from a total of 23 twin birth-cohorts from four countries: Canada, Sweden, Denmark, and Australia. Participants were Monozygotic (MZ) and dizygotic (DZ) (same- and opposite-sex) twin pairs with data available for both height and weight at a given age, from birth through 19 years of age. Approximately 24,036 children were included in the analyses.

Results

Heritability for body weight, height, and BMI was low at birth (between 6.4 and 8.7% for boys, and between 4.8 and 7.9% for girls) but increased over time, accounting for close to half or more of the variance in body weight and BMI after 5 months of age in both sexes. Common environmental influences on all body measures were high at birth (between 74.1–85.9% in all measures for boys, and between 74.2 and 87.3% in all measures for girls) and markedly reduced over time. For body height, the effect of the common environment remained significant for a longer period during early childhood (up through 12 years of age). Sex-limitation of genetic and shared environmental effects was observed.

Conclusion

Genetics appear to play an increasingly important role in explaining the variation in weight, height, and BMI from early childhood to late adolescence, particularly in boys. Common environmental factors exert their strongest and most independent influence specifically in pre-adolescent years and more significantly in girls. These findings emphasize the need to target family and social environmental interventions in early childhood years, especially for females. As gene-environment correlation and interaction is likely, it is also necessary to identify the genetic variants that may predispose individuals to obesity.     

The High Prevalence of Overweight and Obesity in Mexican Children

Objective: To establish the prevalence of overweight and obesity in Mexican children 10 to 17 years of age according to the percentiles from both the Centers of Disease Control and Prevention (CDC) and the International Obesity Task Force (IOTF). Research Methods and Procedures: Heights and weights were measured in children from nationally representative, randomly chosen households in the Mexican National Health Survey 2000. The study population consisted of 7862 boys and 8947 girls, 10 to 17 years of age. Measurements used were the percentage of children in the corresponding BMI categories for overweight and obesity specified by the CDC and the IOTF BMI percentiles. Results: The children were short, with mean Z scores for height by age varying from ? 0.62 ± 1.26 to ?1.12 ± 1.06 in boys and from ?0.45 ± 1.25 to ?1.19 ± 1.12 in girls. CDC‐based overweight prevalences varied by age from 10.8% to 16.1% in boys and 14.3% to 19.1% in girls, with obesity prevalences from 9.2% to 14.7% in boys and 6.8% to 10.6% in girls; these prevalences did not relate to stunting. IOTF‐based excess weight prevalences were similar, with higher overweight rates (boys, 15.4% to 18.8%; girls, 18.4% to 22.3%) but lower obesity rates (boys, 6.1% to 9%; girls, 5.9% to 8.2%). Discussion: Mexican children have one‐half the overweight/obesity prevalences of U.S. Mexican‐American children; however, there are higher rates in Northern Mexico, which is closer to the U.S. These escalating rates of excess weight demand new prevention, as well as management, policies.     

Growth attainments of well-off chandigarh children: A mixed longitudinal study

Distance and velocity pattern of growth for body weight and height of 134 well-off Chandigarh boys aged 9–17 years, and 109 girls aged 9 to 16 years were studied following a mixedlongitudinal growth study design. For both body weight and height pattern-wise, Chandigarh boys showed close similarity with their American counterparts up to about 13 years of age, while girls did so till 12 years. Where after, Chandigarh children remained lighter and shorter than those of American origin and this differential may be explained on racial grounds rather than nutritional ones since all children included in this study remained free from dietary and other health related constraints. Marginally, higher height growth attainments noticed in Chandigarh children in contrast to their other Indian counterparts during initial years of adolescence shows that Chandigarh children are in process of expressing their genetic growth potential to its full which has not yet been fully achieved. The rate (velocity) of weight and height growth in Chandigarh children remained substatially lower than their sex-matched British counterparts throught the period of study. PHV in boys measured 6.4 cm/yr. and 5.4 cm/yr. in girls. It was attained at the age of 11.5 years in girls and 12.5 years in boys. Peak weight velocity in boys averaged 3.7 kg/yr., while it measured 4.6 kg/yr. in girls. In girls (11.5 yr.), PWV too was attained earlier than boys (13.5 yr.) by two years. The shorter height and lighter weight growth attainments noticed in Chandigarh children in contrast to their Western counterparts may be attributed to slower and lesser magnitude peak growth velocities recorded in Chandigarh children. The use of values presented has been recommended to monitor and assess growth attainments of Indian children residing in the Union Territory of Chandigarh.     

Probability of Adult Overweight and Risk Change during the BMI Rebound Period

Objective: To develop a probability chart of adult overweight based on childhood body mass index (BMI) values and to evaluate the BMI change during the BMI rebound period during childhood, in different populations, with the use of risk function curves. Research Methods and Procedures: A longitudinal growth study of 3650 full-term healthy Swedish children followed from birth to 18 years of age. Weight and height values of our subjects were obtained. Results: A probability chart for reaching a BMI > 23 kg/m² at 18 years of age was constructed for boys and girls. For example, a BMI of 18 kg/m² at 4 years of age is associated with 0.70 probability of attaining a BMI > 23 kg/m² at 18 years of age in boys; a BMI of 16 kg/m² at 4 years of age leads to 0.40 probability of having a BMI > 23 kg/m² at 18 years of age in girls. Children with an obvious BMI rebound before 8 years of age have a high risk of being overweight at 18 years of age. There is a clear trend of BMI increase from the 1970s to the 1990s in U.S. children from a parallel dataset, and Hispanic children are at the highest risk of adult overweight. Discussion: The probability chart for adult overweight developed here provides a functional method of defining childhood obesity that is based on the risk of long-term ill health rather than on a certain statistical cut-off point. It will help pediatricians or healthcare workers identify those children who are at a high risk of becoming overweight in adulthood, which will allow clinical intervention at younger ages.     

Physical activity levels of normal-weight and overweight girls and boys during primary school recess

Objective: This study aimed to compare moderate‐to‐vigorous physical activity (MVPA) and vigorous physical activity (VPA) in normal‐weight and overweight boys and girls during school recess. Research Methods and Procedures: Four hundred twenty children, age 6 to 10 years, were randomly selected from 25 schools in England. Three hundred seventy‐seven children completed the study. BMI was calculated from height and weight measurements, and heart rate reserve thresholds of 50% and 75% reflected children's engagement in MVPA and VPA, respectively. Results: There was a significant main effect for sex and a significant interaction between BMI category and sex for the percent of recess time spent in MVPA and VPA. Normal‐weight girls were the least active group, compared with overweight boys and girls who were equally active. Fifty‐one boys and 24 girls of normal weight achieved the 40% threshold; of these, 30 boys and 10 girls exceeded 50% of recess time in MVPA. Eighteen overweight boys and 22 overweight girls exceeded the 40% threshold, whereas 8 boys and 8 girls exceeded the 50% threshold. Discussion: Overweight boys were significantly less active than their normal‐weight male counterparts; this difference did not hold true for girls. Even though nearly double the number of normal‐weight children achieved the 40% of MVPA during recess compared with overweight children, physical activity promotion in school playgrounds needs to be targeted not only at overweight but at other health parameters, as 40 overweight children met the 40% MVPA target proposed for recess.     

Longitudinal study of body weight changes in children: who is gaining and who is losing weight

Cross-sectional studies have reported significant temporal increases in prevalence of childhood obesity in both genders and various racial groups, but recently the rise has subsided. Childhood obesity prevention trials suggest that, on average, overweight/obese children lose body weight and nonoverweight children gain weight. This investigation tested the hypothesis that overweight children lose body weight/fat and nonoverweight children gain body weight/fat using a longitudinal research design that did not include an obesity prevention program. The participants were 451 children in 4th to 6th grades at baseline. Height, weight, and body fat were measured at month 0 and month 28. Each child's BMI percentile score was calculated specific for their age, gender and height. Higher BMI percentile scores and percent body fat at baseline were associated with larger decreases in BMI and percent body fat after 28 months. The BMI percentile mean for African-American girls increased whereas BMI percentile means for white boys and girls and African-American boys were stable over the 28-month study period. Estimates of obesity and overweight prevalence were stable because incidence and remission were similar. These findings support the hypothesis that overweight children tend to lose body weight and nonoverweight children tend to gain body weight.     

Genetic risk for earlier menarche also influences peripubertal body mass index

It is unclear whether earlier age at menarche is associated with higher body mass index (BMI) because they share a common genetic underpinning. We investigated the impact of single nucleotide polymorphisms (SNPs) influencing menarche timing on peripubertal BMI. For 556 Fels Longitudinal Study children (277 boys/279 girls) born 1928–1992, a genetic risk score (GRS₄₂) was computed as the sum of the number of risk alleles in 42 putative menarche SNPs. Serial BMI Z‐scores within ±6.99 years from each individual's age at peak height velocity (Age@PHV) were grouped into seven time points (?6 years, ?4 years, –2 years, Age@PHV, +2 years, +4years, and +6 years). Heritability of BMI ranged from 0.53 to 0.85 across the time points. The effect of GRS₄₂ on BMI Z‐scores at each time point was modeled using variance components‐based procedures. GRS₄₂ had a significant (P < 0.05) effect at every time point; an increase of one risk allele was associated with an increase of 0.03–0.08 BMI Z‐scores. A separate score (GRS₂₉) was computed that excluded 13 of the menarche SNPs previously documented to also influence adiposity; significant main effects were observed at Age@PHV+4 and +6 years. This finding supports a causal effect of advanced sexual development on post‐Age@PHV BMI. Significant positive GRS₄₂ (or GRS₂₉)‐by‐birth year interactions indicate that some genetic influences on BMI have amplified over the 20th century. This gene‐by‐environment interaction also suggests that children with a genetic predisposition to earlier sexual development might avoid elevated BMI through alteration of their nutritional environment. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.     

The Relationship of Childhood Adiposity to Parent Body Mass Index and Eating Behavior

Objective: To better understand risk factors for the development of obesity in early childhood, we examined the association between children's adiposity and their parents' eating behavior and body mass index (BMI). Research Methods and Procedures: Parents of 85 white children 36 months of age (49 boys and 36 girls) completed the Three‐Factor Eating Questionnaire measuring three dimensions of parent eating behavior: disinhibited eating, cognitive restraint of eating, and susceptibility to hunger. Parent BMI (kg/m²) was calculated using self‐reported height and weight. The children's percentage body fat was assessed by dual energy X‐ray absorptiometry analysis. Results: Twenty‐six percent of parents were obese (BMI ≥ 30 kg/m²). Both maternal and paternal BMI were associated with higher scores for disinhibition (r = 0.69 and r = 0.68, p < 0.001), and maternal BMI was also associated with higher scores for hunger (r = 0.51, p < 0.001). There were no significant relationships between children's percentage body fat and parent eating scores, and the correlation between children's percentage body fat and parent BMI was significant only between mothers and daughters (r = 0.35, p = 0.04). Obese parents were no more likely to have a child who was fatter (upper quintile of percentage body fat for gender). Discussion: Among 36 month‐old white children, parent eating behavior was related to parent BMI, but not to children's adiposity. There was only a weak relationship between parent BMI and child adiposity. Despite the aggregation of adiposity within families due to shared genes and environments, children may not express differences in susceptibility to obesity by 3 years of age.     

Trends in Height and BMI of 6‐Year‐Old Children during the Nutrition Transition in Chile

Objective: We analyzed trends in height and BMI and their interaction in 6‐year‐old Chilean children over the last 15 years. Research Methods and Procedures: We calculated height for age z‐score (HAZ), BMI z‐score, prevalence of obesity, underweight, and stunting from cross‐sectional national school‐based annual population surveys in 1987, 1990, 1993, 1996, 2000, and 2002. Using mixed model analysis, we determined the risk of obesity according to height over time as odds ratios (ORs) and 95% confidence interval and the potential influence of height and year of study on BMI z‐score. Results: Over the study period, height increased by 2.8 cm in boys and 2.6 cm in girls, whereas stunting declined from 5% to 2% in both. Tallness increased by ～2%, BMI z‐score increased from +0.3 to +0.65 in boys and to +0.62 in girls, and HAZ increased from ?0.47 in boys and ?0.45 in girls to 0 in 2002. Underweight declined from 4% to 3%, whereas obesity rose from 5% to ～14%. The probability of obesity among tall children was significantly greater than that for normal height children (OR, 2.3 to 3.5). The lowest obesity risk was observed between ?2 and ?1 HAZ. The OR for obesity in the stunted relative to normal height children was variable, ranging from 1.23 to 0.65, whereas it was significant and consistently positive (1.1 to 1.7) for boys and girls when it was compared with the lowest obesity risk according to height. Discussion: Tallness is significantly associated with increased obesity risk in children, while stunting is also associated, but to a lesser degree.