Examining the temporal relationships between childhood obesity and asthma

Childhood obesity has become an issue of increasing concern to health researchers and policymakers in the United States. One important chronic health condition linked to obesity is pediatric asthma. Although researchers have speculated that both conditions may have common origins, the majority of research in this area has focused on a unidirectional relationship between obesity and later asthma. However, much of the literature is limited by its reliance on cross-sectional data and its failure to examine the possibility that asthma may influence weight fluctuations through changes in physical and sedentary activity. Using data from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K), I explore the bidirectional relationships between childhood obesity and asthma. The results in this paper suggest that past asthma levels are positively correlated with changes in BMI and the onset of obesity. However, only new onset asthma is positively correlated with subsequent changes in BMI. The potential mechanisms are unclear, as I find little evidence that asthma is structurally related to changes in physical or sedentary activity over time. When testing the prevailing hypothesis that obesity is related to subsequent asthma, I find that lagged weight status is strongly related to asthma prevalence levels but that the onset of overweight or obesity is not associated with the subsequent onset of asthma. These results suggest that the onset of asthma may be related to subsequent weight gain over time.     

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.     

Family mealtimes: A contextual approach to understanding childhood obesity

There has been a growing interest in the role that shared family mealtimes may play in promoting the health and well-being of children. Families that regularly eat their main meal together four or more times a week are more likely to have children who do better in school, are of average weight, less likely to use drugs and alcohol at an early age, and consume more fruits and vegetables. The mere fact that families eat together does not address the process by which shared family mealtimes may protect children from unhealthy weight gain. Just as there is no simple explanation for the rising rates of obesity, the link between shared family mealtimes and childhood obesity is a complex one including socioeconomic and cultural context. In this paper, we provide an overview of how shared family mealtimes are embedded in a socio-cultural context that may either support or derail healthy eating patterns for children and youth. Evidence from an observational study of 200 family mealtimes demonstrates the complex interplay between socio-economic factors, family mealtime behaviors, and child obesity status. Families who had a child of healthy weight spent more time engaged with each other during the meal, expressed more positive communication, and considered mealtimes more important and meaningful than families who had a child who was overweight or obese. Using a cumulative risk model, it was found that the combination of family level and neighborhood risk factors predicted child overweight status. Recommendations are made for future research directions and policies directed toward families living in diverse economic circumstances.     

Socioeconomic position at different stages of the life course and its influence on body weight and weight gain in adulthood: a longitudinal study with 13-year follow-up

Socioeconomic inequalities in body weight have been demonstrated in numerous cross-sectional studies; however, little research has investigated these inequalities from a life course and longitudinal perspective. We examined the association between child- and adulthood socioeconomic position (SEP) and BMI and overweight/obesity in 1991 (baseline) and changes in BMI and the prevalence of overweight and obesity between 1991 and 2004. Data from the 1991 and 2004 waves of the longitudinal Dutch GLOBE study were used. Participants (n = 1,465) were aged 40-60 years at baseline. BMI was calculated from self-reported height and weight collected by postal questionnaire. Retrospective recall of father's occupation was used as childhood socioeconomic indicator, and adulthood SEP was measured by the occupation of the main income earner of the household. The findings showed that among women, childhood SEP exerted a greater influence on body weight than SEP in adulthood: at baseline, women from disadvantaged backgrounds in childhood had a higher BMI and were more likely to be overweight or obese, and they gained significantly more weight between baseline and follow-up. In contrast, adult SEP had a greater impact than childhood circumstances on men's body weight: those from disadvantaged households had a higher mean BMI and were more likely to be overweight or obese at baseline, and they gained significantly more weight between 1991 and 2004. The findings suggest that exposure to disadvantaged circumstances at critically important periods of the life course is associated with body weight and weight gain in adulthood. Importantly, these etiologically relevant periods differ for men and women, suggesting gender-specific pathways to socioeconomic inequalities in body weight in adulthood.     

Supermarket access and childhood bodyweight: Evidence from store openings and closings

Retail food environment is increasingly considered in relation to obesity. This study investigates the impacts of access to supermarkets, the primary source of healthy foods in the United States, on the bodyweight of children. Empirical analysis uses individual-level panel data covering health screenings of public schoolchildren from Arkansas with annual georeferenced business lists, and utilizes the variations of supermarket openings and closings. There is little overall impact in either case. However, supermarket openings are found to reduce the BMI z-scores of low-income children by 0.090 to 0.096 standard deviations. Such impact remains in a variety of robustness exercises. Therefore, improvement in healthy food access could at least help reduce childhood obesity rates among certain population groups.     

Genes and the intergenerational transmission of BMI and obesity

This paper compares the strength of intergenerational transmission of body mass index (BMI) and obesity in a sample of adoptees relative to a matched sample of biological children with similar observable characteristics. We find that BMI and obesity are strongly correlated among biological parent-child pairs, but there are no significant intergenerational associations in these health traits among adoptive parent-child pairs. The intergenerational elasticity of BMI for children to their parents is 0.2 in the matched biological sample, but indistinguishable from zero for adopted children with a standard error more than three times as large as the coefficient. Under reasonable assumptions, these findings indicate that the intergenerational transmission of BMI and obesity occurs primarily through genetic mechanisms. Additional analyses of transmission rates by parental gender and among step-parents and step-children support this conclusion. The role of determinants of BMI and obesity in the household environment in relation to our findings is discussed. Given the negative consequences of obesity on earnings and other economic measures, our results suggest that the genetic transmission of weight problems contributes substantially to intergenerational persistence in economic outcomes.     

Development of Overweight in Children in Relation to Parental Weight and Socioeconomic Status

The purpose of the study was to test the hypothesis that socioeconomic status (SES) moderates the association between parental weight and changes in BMI from childhood to early adolescence. Participants included 428 twin children from 100 families with obese parents (“obese families”) and 114 sociodemographically matched families with normal‐weight parents (“lean families”) who were assessed in their homes (age = 4.4). Follow‐up study was conducted 7 years later (age = 11.2) on 346 children (81%). Complete data were available for 333 children. Family SES was indexed with maternal education. Children's weights and heights were measured to calculate BMI s.d. scores based on 1990 British norms. Overweight was defined as >91st BMI centile. In children with obese parents, BMI s.d. scores increased from 0.51 at age 4 to 1.06 at age 11. In children with lean parents, BMI s.d. scores decreased from 0.11 to 0.05. Prevalence of overweight remained stable from age 4 to 11 in children with lean parents (8% to 9%), but it more than doubled in children with obese parents (17% to 45%). There was a significant interaction between parental weight and family SES (P < 0.01), so that in children with lean parents there was no SES difference in the BMI status from age 4 to 11; however, in children with obese parents, the increase in adiposity was significantly greater in lower SES families. These results suggest that parental leanness confers significant protection against development of overweight in children regardless of family SES, while parental obesity is an adverse prognostic sign, especially in lower SES families.     

Body mass index and employment status: A new look

Earlier literature has usually modelled the impact of obesity on employment status as a binary choice (employed, yes/no). I provide new evidence on the impact of obesity on employment status by treating the dependent variable as a as a multinomial choice variable. Using data from a representative English survey, with measured height and weight on parents and children, I define employment status as one of four: working; looking for paid work; permanently not working due to disability; and, looking after home or family. I use a multinomial logit model controlling for a set of covariates. I also run instrumental variable models, instrumenting for Body Mass Index (BMI) based on genetic variation in weight. I find that BMI and obesity significantly increase the probability of “not working due to disability”. The results for the other employment outcomes are less clear. My findings also indicate that BMI affects employment through its effect on health. Factors other than health may be less important in explaining the impact of BMI/obesity on employment.     

Parental obesity moderates the relationship between childhood appetitive traits and weight

Objective:

In this study, the independent and combined associations between childhood appetitive traits and parental obesity on weight gain from 0 to 24 months and body mass index (BMI) z‐score at 24 months in a diverse community‐based sample of dual parent families (n = 213) were examined.

Design and Methods:

Participants were mothers who had recently completed a randomized trial of weight loss for overweight/obese postpartum women. As measures of childhood appetitive traits, mothers completed subscales of the Children's Eating Behavior Questionnaire, including Desire to Drink (DD), Enjoyment of Food (EF), and Satiety Responsiveness (SR), and a 24‐h dietary recall for their child. Heights and weights were measured for all children and mothers and self‐reported for mothers' partners. The relationship between children's appetitive traits and parental obesity on toddler weight gain and BMI z‐score were evaluated using multivariate linear regression models, controlling for a number of potential confounders.

Results:

Having two obese parents was related to greater weight gain from birth to 24 months independent of childhood appetitive traits, and although significant associations were found between appetitive traits (DD and SR) and child BMI z‐score at 24 months, these associations were observed only among children who had two obese parents. When both parents were obese, increasing DD and decreasing SR were associated with a higher BMI z‐score.

Conclusions:

The results highlight the importance of considering familial risk factors when examining the relationship between childhood appetitive traits on childhood obesity.     

Maternal employment and childhood obesity in Russia

Existing research on childhood obesity shows that rising maternal employment is associated with increases in child weight. This paper aims to estimate the effect of maternal employment on childhood obesity in Russia, where obesity has been spreading quickly over the last 20 years. To address the endogeneity of maternal employment and estimate its effect on the weight outcomes of older siblings, I use plausibly exogenous variation in childcare enrolment for the youngest child in the household as an instrumental variable for maternal employment. Based on the Russian Longitudinal Monitoring Survey (RLMS-HSE), the results show that maternal employment leads to an increase in children’s BMI and in their probabilities of becoming overweight and obese. In exploring the potential underlying mechanisms, I find that maternal employment is related to less physical activity, to a higher probability of either watching TV or playing video games, and to poorer dietary habits among children.     

Bodyweight and human capital development: Assessing the impact of obesity on socioemotional skills during childhood in Chile

This article analyzes the effect of bodyweight on socioemotional skills for children aged two to 12 years in Chile. Using an instrumental variable approach and a representative survey, we show that both BMI and obesity are causality related to children’s socioemotional development, even after assuming that our instrument is imperfect. Although we did not find significant differences between boys and girls, we do identify heterogeneous effects by age: the weight penalty for girls starts earlier than for boys. Our findings suggest that early interventions for childhood obesity not only might generate positive impacts on children’s health, but also a greater accumulation of non-cognitive human capital in the future.     

Do additional SNAP benefits matter for child weight?: Evidence from the 2009 benefit increase

We know that youth who live in low-income households tend to have lower nutritional health outcomes—including higher rates of obesity—when compared to their higher-income counterparts. The Supplemental Nutrition Assistance Program (SNAP) is the largest U.S. federal nutrition program and has been found to improve food security and to serve as an income support. It is less clear how SNAP may affect obesity in low-income youth. From a policy perspective, it is essential to understand how the largest federal nutrition assistance program influences the health of children and adolescents. We use the exogenous increase in SNAP benefits that was a part of the American Recovery and Reinvestment Act (ARRA) to identify how a change in benefits is linked with obesity in youth. We find evidence that the ARRA increase in SNAP benefits is associated with healthier weight outcomes in three of the four age groups examined. SNAP-eligible toddlers are less likely to be overweight and adolescents are less likely to be obese. These findings can help policy makers understand how additional SNAP benefits from the Families First Coronavirus Response Act may influence weight outcomes in children and adolescents.     

Peer effects of obesity on child body composition

This study investigates whether peer obesity is a driver of individual weight changes in public school children and whether the impact of peer effects changes as children age. Quantifying peer effects is important for understanding the social determinants of obesity and for planning effective school wellness policies. However, the extant empirical research on peer effects is limited due to difficulties in separating causal influences from confounding factors. This study overcomes some of these difficulties by using a within-school, across-cohort empirical design to separate confounding factors at the individual, school and school-grade level for over one million public school children. The results show that increases a one standard deviation increase in average classmate body mass index (BMI) leads to a modest but meaningful increase of 0.395 standard deviation increase in a child's own BMI. Peer-effects are highest (0.813) for children in Kindergarten and decline with age. These findings suggest that the critical time for school-grade level intervention may be in the earliest ages of childhood development.     

Does smoking affect body weight and obesity in China?

An inverse relationship between smoking and body weight has been documented in the medical literature, but the effect of cigarette smoking on obesity remains inconclusive. In addition, the evidence is mixed on whether rising obesity rates are an unintended consequence of successful anti-smoking policies. This study re-examines these relationships using data from China, the largest consumer and manufacturer of tobacco in the world that is also experiencing a steady rise in obesity rates. We focus on the impact of the total number of cigarettes smoked per day on individuals’ body mass index (BMI) and on the likelihood of being overweight and obese. Instrumental variables estimation is used to correct for the endogeneity of cigarette smoking. We find a moderate negative and significant relationship between cigarette smoking and BMI. Smoking is also negatively related to being overweight and obese, but the marginal effects are small and statistically insignificant for being obese. Quantile regression analyses reveal that the association between smoking and BMI is quite weak among subjects whose BMIs are at the high end of the distribution but are considerably stronger among subjects in the healthy weight range. Ordered probit regression analyses also confirm these findings. Our results thus reconcile an inverse average effect of smoking on body weight with the absence of any significant effect on obesity. From a policy perspective these findings suggest that, while smoking cessation may lead to moderate weight gain among subjects of healthy weight, the effects on obese subjects are modest and should not be expected to lead to a large increase in obesity prevalence rates.     

A Longitudinal Study of Income Differences in the Height-BMI Relation among U.S. Children Ages 6 to 14

Previous work has shown a positive height-obesity association in U.S. children that is more pronounced in those from lower-income families than in those from higher-income families. That work has been limited to cross-sectional analysis. This study evaluates income differentials in the inter-temporal associations between childhood height and obesity in U.S. children ages 6 to 14. Pooled samples of 9,670 female and 10,110 male children from the U.S. Early Childhood Longitudinal Study—Kindergarten Cohort (ECLS-K) were evaluated in multilevel mixed effects models. The results indicated a modest height-income interaction such that the concurrent height-obesity association was weaker at higher incomes. This strengthened into adolescence for females and weakened for males. With respect to height growth, for lower-income males, being shorter before the typical start of the growth spurt (≈ 9 years) and experiencing faster later growth (between 11 and 14 years) were attributes less strongly associated with subsequent obesity. There were no indicated income interactions with height growth in females.     

Food Choices and Consequences for the Nutritional Status: Insights into Nutrition Transition in an Hospital Community

Introduction

Although economic development is generally accompanied by improvements in the overall nutritional status of the country’s population the ‘nutritional transition’ often involves a shift to high energy diets and less exercise with negative consequences. This pilot study was done to examine if education of parents operates at the household level to influence dietary choices and the nutritional status of children in a small community of hospital workers.

Material and Methods

3 groups of persons with varying skill and education levels participated. Weighed food logs were used in all households to calculate ‘adult equivalent’ per-capita-consumption. Nutrients were calculated using nutrients calculator software. BMI was used to classify children as underweight, normal weight and overweight.

Results

128 individuals participated from 30 families included 47 children. 10 children (21%) were underweight, 29 (62%) were normal and 8 (17%) were overweight. Energy consumption was highest in families with overweight children 2692 +/-502 compared to 2259 +/-359 in families with normal weight and 2031+/-354 in the family of underweight children. These differences were statistically significant. 42% underweight children belonged to Class 1 at the lowest skill level and there were no overweight children in this group. Most of the overweight children belonged to Class 2. In Class 3 there were no underweight children and the majority was normal weight children.

Conclusion

Underweight children came from the poorer households. Per capita intake of the family as a whole correlated well with BMI in the children. There was increased obesity in middle income families belonging to Class 2—probably in families who move up the scale from deprivation. Nutritional status in children correlated mostly with maternal education status.     

Parent predictors of child weight change in family based behavioral obesity treatment

Family based behavioral treatment for overweight and obese children includes parenting skills targeting the modification of child eating and activity change. The purpose of this study was to examine parenting skills and parent weight change as predictors of child weight change in a sample of 80 parent/child dyads who were enrolled in a family based behavioral weight loss program for childhood obesity. Eighty overweight and obese children and their parents who enrolled in treatment in two sites were included in the study. Variables included those related to parent modeling (parent BMI), home food environment, parenting (parent and child report), and demographics. Results suggested that parent BMI change was a significant predictor of child weight, in that a reduction of 1 BMI unit in the parent was associated with a 0.255 reduction in child BMI. None of the other variables were significant in the final model. This study is consistent with other research showing that parent weight change is a key contributor to child weight change in behavioral treatment for childhood obesity. Researchers and clinicians should focus on encouraging parents to lose weight to assist their overweight and obese child in weight management.     

Effects of the built environment on childhood obesity: The case of urban recreational trails and crime

We study the effects of urban environment on childhood obesity by concentrating on the effects of walking trails and crime close to children's homes on their BMI and obesity status. We use a unique dataset, which combines information on recreational trails in Indianapolis with data on violent crimes and anthropomorphic and diagnostic data from children's clinic visits between 1996 and 2005. We find that having a trail near a home reduces children's weight. However, the effect depends on the amount of nearby violent crimes. Significant reductions occur only in low crime areas and trails could have opposite effects on weight in high crime areas. These effects are primarily among boys, older children, and children who live in higher income neighborhoods. Evaluated at the mean length of trails this effect for older children in no crime areas would be a reduction of 2 lb of the body weight. Falsification tests using planned trails instead of existing trails, show that trails are more likely to be located in areas with heavier children, suggesting that our results on effects of trails represent a lower bound.     

新疆贫困地区维吾尔族农民肥胖与血脂异常相关性研究

肥胖及血脂异常研究很少涉及低收入地区。本研究分析了新疆低收入地区维吾尔族农民体质指数(BMI)、超重及肥胖与多种血脂分子异常的关系,探讨贫困地区筛查高危人群的适宜策略。在新疆喀什农村对3 286名年龄≥18岁个体(男1 585人,女1 701人) 进行问卷检查、体格检查及多项血脂分子的检测。数据采用Pearson相关性、ROC、Logistic回归等统计学分析。结果显示,在男女性中,随着BMI的增加,甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDLC)的血浓度呈现递增趋势（P<0.01）;男/女性TG、LDLC、TC血浓度均与BMI有显著相关性(P<0.01)。单项或多项血脂异常率均随BMI增加而上升;同一个体2个血脂指标同时异常的高危组合分别是TG+HDLC(高密度脂蛋白胆固醇)和TC+TG。Logistic联合多变量ROC曲线分析表明, 单项指标HDLC(AUC=089)在血脂异常诊断中的权重最高;而组合指标TG+HDLC(AUC=095)的权重高于其它任何组合。单因素Logistic回归分析发现,超重和肥胖是代谢综合征相关血脂指标TG、TC和HDLC异常的危险因素(P<0.05)。上述结果表明,在南疆农村贫困维吾尔族人群中,男女性超重与肥胖者均与血脂指标异常升高相关;HDLC、TG和 TC 任意两个指标同时异常,为血脂异常的高危状态。肥胖伴有“TG+HDLC”异常升高可能是血脂异常相关疾病的“集合危险因素”,在贫困地区具有临床筛查参考价值。