Rise of plasma ghrelin with weight loss is not sustained during weight maintenance

Objective: Ghrelin is postulated to be an orexigenic signal that promotes weight regain after weight loss (WL). However, it is not known whether this putative effect of ghrelin is sustained after weight stabilization. The objective of this study was to investigate the relationship of plasma ghrelin concentrations to active WL and weight maintenance in obese subjects. Research Methods and Procedures: This study was a randomized clinical trial, with a 12‐month follow‐up period. Obese Mexican‐American women matched for age and BMI were randomized to a 12‐month WL program (n = 25) or no intervention (controls, n = 23). Interventions included diet, exercise, and orlistat. Body weight and fasting ghrelin, leptin, insulin, and glucose concentrations were measured at baseline and 6 and 12 months. Results: The WL group lost 8.5% of body weight after 6 months and maintained the new weight for the next 6 months. Ghrelin concentrations increased significantly at 6 months but returned to baseline at 12 months. Baseline ghrelin concentrations were directly related to the degree of WL achieved after 12 months. Controls experienced no change in BMI or ghrelin levels. There were no associations between plasma ghrelin and leptin or insulin concentrations. Discussion: Consistent with previous results, ghrelin rises in response to WL, perhaps as a counterregulatory mechanism. However, the present results indicate that ghrelin concentrations return to baseline with sustained weight maintenance, suggesting that its effects are unlikely to regulate long‐term energy balance. Baseline ghrelin concentrations are related to the degree of WL that can be achieved by active weight reduction.     

Prevalence of overweight among Baltimore City schoolchildren and its associations with nutrition and physical activity

Objective: To determine the prevalence of overweight and at‐risk‐for‐overweight in schoolchildren from Baltimore City. Research Methods and Procedures: Ten schools within city limits were randomly selected from each tertile of income, using eligibility for free school lunch as a proxy. A total of 209 third grade students from eight public schools in Baltimore City were surveyed in May 2000. Anthropometric data including height, weight, subscapular and triceps skinfold thickness, and percentage body weight from bioelectrical impedance were collected. Nutrition‐related knowledge, attitudes, and behaviors were assessed using a validated questionnaire. Physical activity was assessed by questionnaire. Results: Based on International Obesity Taskforce reference values for BMI‐for‐age, 20.7% of girls and 17.2% of boys were overweight (BMI > 95th percentile) and 15.3% of girls and 14.1% of boys were at‐risk‐for‐overweight (BMI between the 85th and 95th percentiles). The prevalence of overweight and at‐risk‐for‐overweight did not vary by self‐reported physical activity levels or by nutrition‐related knowledge and behaviors. Discussion: The high prevalence of overweight and at‐risk‐for‐overweight in this sample of inner‐city children from Baltimore City highlights a need for targeted preventive and treatment interventions.     

Prevalence of overweight and obesity in 2- to 6-year-old Italian children

Objective: To assess the prevalence of overweight and obesity in 2‐ to 6‐year‐old Italian children and to compare the prevalence between the north and the south of the country. Research Methods and Procedures: This was a cross‐sectional study of 2150 subjects (M/F: 1137/1013), 5.36 ± 0.83 years of age. The sampling areas were Verona (north Italy) and Messina (south Italy). We used definitions of overweight and obesity using BMI values, with cut‐off values proposed by the International Obesity Task Force. Results: The prevalence of overweight was 16.6% (males: 13.9%, females: 19.6%), and it was higher in the south (males: 17.8%, females: 22.4%) than in the north (males: 11.3%, females: 17.9%). The prevalence of obesity was 8.0% (males: 8.3%, females: 7.7%), and it was higher in the south (males: 12.3%, females: 10.7%) than in the north (males: 5.7%, females: 5.8%). Using the Centers for Disease Control reference charts, the prevalence of overweight and obesity of Italian children was close to that reported in children living in the United States (32% vs. 32.7%, respectively). Discussion: The prevalence of overweight and obesity in young Italian children is very high, and it is rapidly growing. In the south of the country, the prevalence is higher than in the north.     

Mendelian randomization supports causality between overweight status and accelerated aging

It is reported that overweight may lead to accelerated aging. However, there is still a lack of evidence on the causal effect of overweight and aging. We collected genetic variants associated with overweight, age proxy indicators (telomere length, frailty index and facial aging), etc., from genome-wide association studies datasets. Then we performed MR analyses to explore associations between overweight and age proxy indicators. MR analyses were primarily conducted using the inverse variance weighted method, followed by various sensitivity and validation analyses. MR analyses indicated that there were significant associations of overweight on telomere length, frailty index, and facial aging (β = −0.018, 95% CI = −0.033 to −0.003, p = 0.0162; β = 0.055, 95% CI = 0.030–0.079, p < 0.0001; β = 0.029, 95% CI = 0.013–0.046, p = 0.0005 respectively). Overweight also had a significant negative causality with longevity expectancy (90th survival percentile, β = −0.220, 95% CI = −0.323 to −0.118, p < 0.0001; 99th survival percentile, β = −0.389, 95% CI = −0.652 to −0.126, p = 0.0038). Moreover, the findings tend to favor causal links between body fat mass/body fat percentage on aging proxy indicators, but not body fat-free mass. This study provides evidence of the causality between overweight and accelerated aging (telomere length decreased, frailty index increased, facial aging increased) and lower longevity expectancy. Accordingly, the potential significance of weight control and treatment of overweight in combating accelerated aging need to be emphasized.     

Factors affecting prevalence of overweight among 12- to 17-year-old urban adolescents in Hyderabad, India

Objective: The problem of overweight and obesity is not confined only to developed countries but is also widely prevalent in developing countries. The objective of this study was to assess the prevalence of overweight and obesity as defined by the International Obesity Task Force (IOTF) among school‐age children in Hyderabad, India, and identify its associated factors. Research Methods and Procedures: A cross‐sectional and institutional study, adopting a multistage stratified cluster sampling procedure, was carried out during 2003 on adolescents 12 to 17 years of age of both sexes from Hyderabad, India. Results: The overall prevalence of overweight was 6.1% [95% confidence interval (CI): 4.2, 8.0] among boys and 8.2% among girls (CI: 6.0, 10.4); 1.6% and 1.0% were obese, respectively. The prevalence was significantly higher (p < 0.05) among adolescents who watched television ≥3 h/d (10.4%) or belonged to a high socioeconomic background (14.9%, p < 0.001), whereas it was significantly lower among those participating regularly in outdoor games ≥6 h/wk (3.1%, p < 0.004) and household activities ≥3 h/d (4.7%, p < 0.001). The logistic regression analysis revealed that the prevalence of overweight was 4 times higher among the adolescents of high socioeconomic status [odds ratio (OR): 4.1; CI: 2.25, 7.52], 3 times higher in those not participating in outdoor games (OR: 2.75; CI: 1.56, 4.72), and 1.92 times higher in those watching television ≥3 h/d (OR: 1.92; CI: 1.16, 3.18). Discussion: This study confirmed the findings of earlier studies carried out in Western countries and emphasizes that regular physical exercise, doing household activities, regulated television viewing, and healthy eating behaviors could contribute to controlling overweight and obesity.     

Physical activity correlates in adolescent girls who differ by weight status

Objective: This study compared correlates of physical activity (PA) among African‐American and white girls of different weight groups to guide future interventions. Research Methods and Procedures: Participants were 1015 girls (mean age, 14.6 years; 45% African‐American) from 12 high schools in South Carolina who served as control subjects for a school‐based intervention. Post‐intervention measures obtained at the end of ninth grade were used. PA was measured using the Three‐Day PA Recall, and a questionnaire measured social‐cognitive and environmental variables thought to mediate PA. Height and weight were measured, and BMI was calculated. Girls were stratified by race and categorized into three groups, based on BMI percentiles for girls from CDC growth charts: normal (BMI < 85th percentile), at risk (BMI, 85th to 94th percentile), and overweight (BMI ≥ 95th percentile). Girls were further divided into active and low‐active groups, based on a vigorous PA standard (average of one or more 30‐minute blocks per day per 3‐day period). Mixed‐model ANOVA was used to compare factors among groups, treating school as a random effect Results: None of the social‐cognitive or environmental variables differed by weight status for African‐American or white girls. Perceived behavioral control and sports team participation were significantly higher in girls who were more active, regardless of weight or race group. In general, social‐cognitive variables seem to be more related to activity in white girls, whereas environmental factors seem more related to activity in African‐American girls. Discussion: PA interventions should be tailored to the unique needs of girls based on PA levels and race, rather than on weight status alone.     

An exploratory study of cardiac function and oxygen uptake during cycle ergometry in overweight children

Objective: Obesity has been proposed to negatively impact cardiac function in overweight (OW) individuals. The relationship between diastolic dysfunction and oxygen uptake (V?o ₂) kinetics is equivocal. This exploratory investigation evaluated the relationship between resting left ventricular function and V?o ₂ kinetics during cycle ergometry in OW and non‐overweight (NO) children and adolescents. Research Methods and Procedures: Fourteen OW (>85 percentile for BMI for age and gender) children, 10 boys and 4 girls (age, 11.7 ± 1.9 years; body mass, 80.6 ± 45.5 kg) and 10 NO children (4 boys, 6 girls) volunteered to participate in the study (age, 12.5 ± 2.1 years; body mass, 45.8 ± 13.8 kg). Resting cardiovascular structure and function were assessed using spectral Doppler echocardiography. All subjects underwent two sub‐maximal exercise stages on a cycle ergometer (3 minutes unloaded and 5 minutes at 50 W, both at a cadence of 50 rpm). Respiratory data were measured on a breath‐by‐breath basis at both workloads and the mean response time (MRT) was calculated. Results: Analysis of the MRT data demonstrated that there were no significant differences between OW and NO (OW, 52.6 ± 11.7 seconds vs. NO, 45.6 ± 7.4 seconds). Significant correlations (p < 0.05) were obtained between MRT V?o ₂ and echocardiographic‐derived mitral valve inflow pressure half‐time (r = 0.55) and between MRT V?o ₂, and mitral valve inflow deceleration time (r = 0.55). Discussion: The evidence from this research suggests a possible link between left ventricular diastolic function at rest and oxygen uptake kinetics during sub‐maximal exercise in OW and NO children and adolescents.     

Parental misclassification of child overweight/obese status: The role of parental education and parental weight status

Childhood overweight and obesity is a major public health challenge for policymakers in many countries. As the most common supervisors of children’s activities, parents have a potentially important role to play in obesity prevention. However, a precondition for parents to improve their children’s diets, encourage them to be more physically active, or take them to see a doctor about their weight is for the parent to first recognize that their child is overweight or obese. This paper examines the extent of parental misclassification of child weight status, and its correlates, focusing on the role of parental education and the parent’s own obesity status. We find evidence that, among non-obese parents, those who are better-educated report their child’s weight status more accurately, but among obese parents, the better-educated are 45.18% more likely than parents with lower secondary education to give a false negative report of their child’s overweight/obesity; this may reflect social desirability bias.     

Four-year follow-up of school-based intervention on overweight children: the KOPS study

Objective: To evaluate the 4‐year outcome of a school‐based health promotion on weight status as part of the Kiel Obesity Prevention Study (KOPS). Research Methods and Procedures: Within a cluster‐sampled quasi‐randomized controlled trial, 1764 children at 6 and 10 years of age were assessed between 1996 and 2005 in 32 primary schools in Kiel, North Germany. Six nutrition units followed by 20‐minute running games were performed within the first year at school. Prevalence, incidence, and remission of overweight were main outcome measures. Results: The 4‐year change in BMI was +11.6%, with increases in prevalence of overweight and obesity from 5.2% to 11.1% and 3.9% to 5.1%, respectively. Cumulative 4‐year incidence of overweight and obesity was 9.2% and 3.1%, respectively. Intervention had no effect on mean BMI. The effect on prevalence was significant in children from families with high socioeconomic status [odds ratio (OR), 0.35; 95% confidence interval (CI), 0.14 to 0.91] and marginally significant in children of normal‐weight mothers (OR, 0.57; 95% CI, 0.33 to 1.00). Cumulative 4‐year incidence of overweight was lower only in intervention children from families with high socioeconomic status (OR, 0.26; 95% CI, 0.07 to 0.87). Remission of overweight was most pronounced in children of normal‐weight mothers (OR, 5.43; 95% CI, 1.28 to 23.01). Prevalence of underweight was unchanged. The intervention had minor but favorable effects on lifestyle. Discussion: A school‐based health promotion has sustainable effects on remission and incidence of overweight; it was most pronounced in children of normal‐weight mothers and children from families with high socioeconomic status. There was no effect on obesity. The data argue in favor of additional measures of prevention.     

Psychological status and weight-related distress in overweight or at-risk-for-overweight children

Objective: To associate psychological status, weight‐related distress, and weight status during childhood in overweight or at‐risk‐for‐overweight children. Research Methods and Procedures: We associated self‐report of depression, trait anxiety, and weight‐related distress (body size dissatisfaction and weight‐related peer teasing after controlling for the effects of weight) in 164 children (black 35%; age 11.9 ± 2.5 years; girls 51%) who were overweight or at‐high‐risk‐for‐overweight and were not seeking weight loss. Results: Overall, heavier children reported more psychological and weight‐related distress. Black children reported more anxiety and body size dissatisfaction than white children, despite equivalent weights. However, psychological distress was not significantly associated with weight in white children. Girls reported more weight‐related distress than boys. Depression was associated with weight‐related teasing in all predictive models, except in the model using only black subjects. Trait anxiety was associated with report of peer teasing when using all subjects. Depression was also significantly associated with children's report of body size dissatisfaction in models using all subjects, only girls, or white subjects, but not in analyses using only boys or black subjects. For boys peer teasing was associated with body size dissatisfaction. In models including only black children, depression and trait anxiety were not significantly associated with either report of peer teasing or body size dissatisfaction. Discussion: Regardless of race or sex, increasing weight is associated with emotional and weight‐related distress in children. However, associations of psychological status, weight, and weight‐related distress differ for girls and boys, and for black and white children.     

Moderate exercise and bright light treatment in overweight and obese individuals

Objective: Increased physical activity is important given the concern over the growing rates of obesity. The aim of this study is to conduct a controlled investigation of the effects of bright light therapy and exercise on weight loss and body composition in overweight and obese individuals. Research Methods and Procedures: Twenty‐five overweight and obese subjects were assigned to 6 weeks of moderate exercise with or without bright light treatment. Outcome measure included changes in body mass and body composition and ratings of mood, seasonality, and sleep. Results: Body weight decreased significantly with exercise in subjects in the light and non‐light treatment groups, but the change was not significantly different between the groups. Similar results were found for BMI. With exercise, body fat decreased significantly only in the light treatment group. There was a significant effect of the interaction of group by time on body fat composition, but the group by time interaction failed to reach statistical significance for body weight and BMI. Mood scores improved significantly with exercise in the light group, but no significant changes were noted regarding sleep. Discussion: This preliminary study is the first to show that addition of bright light treatment to a 6‐week moderate exercise program can alter body composition by significantly reducing body fat. The reduction in body fat mass is of particular importance, because visceral fat has been particularly implicated as a major factor in the development of the metabolic syndrome. This study is an important step toward finding ways to maximize the effects of exercise.     

Trends in overweight from 1980 through 2001 among preschool-aged children enrolled in a health maintenance organization

Objective: To examine overweight trends over a 22‐year period among preschool‐aged children from primarily middle‐income families enrolled in a health maintenance organization. Research Methods and Procedures: From well‐child care visits to a Massachusetts health maintenance organization, we randomly selected one visit per child per calendar year, yielding a study sample of 120,680 children seen at 366,109 visits from 1980 through 2001. Using multivariate logistic regression models accounting for repeated observations of individual children across years, we estimated trends in prevalence of overweight (weight‐for‐length/height ≥ 95th percentile) and at‐risk‐for‐overweight (85th to 95th percentile). Results: Over the 22‐year study period, the observed prevalence of overweight increased from 6.3% to 10.0% and at‐risk‐for‐overweight increased from 11.1% to 14.4%. These increases were evident among all groups of children including infants < 6 months of age. Overall, the adjusted odds ratios were 1.21 per decade (95% confidence interval, 1.17 to 1.25) for overweight and 1.06 per decade (95% confidence interval, 1.03 to 1.08) for at‐risk‐for‐overweight. Discussion: Rates of overweight are increasing in very young children, even infants, from primarily middle‐class families.     

Maternal employment and childhood overweight in Germany

A widespread finding among studies from the US and the UK is that maternal employment is correlated with an increased risk of child overweight, even in a causal manner, whereas studies from other countries obtain less conclusive results. As evidence for Germany is still scarce, the purpose of this study is to identify the effect of maternal employment on childhood overweight in Germany using two sets of representative micro data. We further explore potential underlying mechanisms that might explain this relationship. In order to address the selection into maternal full-time employment, we use an instrumental variable strategy exploiting the number of younger siblings in the household as an instrument. While the OLS models suggest that maternal full-time employment is related to a 5 percentage point higher probability of the child to be overweight, IV estimates indicate a 25 percentage points higher overweight probability due to maternal full-time employment. Exploring various possible pathways, we find that maternal full-time employment promotes unhealthy dietary and activity behavior which might explain the positive effect of maternal employment on child overweight to some extent. Although there are limitations to our IV approach, several sensitivity analyses confirm the robustness of our findings.     

Zinc nutritional status in obese children and adolescents

Studies in animals and humans have corroborated that zinc (Zn) metabolism is altered in obesity. The present work intends to evaluate the Zn nutritional status in obese children and adolescents by the determination of some biochemical parameters and analyses of the diets. The investigation was carried out in a group of obese children and adolescents (n=23) and compared to a control group (n=21), both between 7 and 14 yr of age. A software analyzed diet information from 3-d food records. Body composition was evaluated by body mass index, bioelectrical impedance, and skinfold measurements. Zinc nutritional status was evaluated by Zn determination in plasma, erythrocyte, and 24-h urine, by atomic absorption spectrophotometry (γ=213.9 nm). Diets consumed by both groups had marginal concentrations of zinc. Zinc concentrations in plasma and erythrocytes were significantly lower in the obese group. Urinary zinc excretion was significantly higher in the same group. The results allowed one to conclude that zinc nutritional status in obese individuals is altered.     

Prevalence and risk factors of overweight and obesity in China

Objective: To examine the prevalence and risk factors of overweight and obesity in China. Research Methods and Procedures: A cross‐sectional survey was conducted in a nationally representative sample of 15,540 Chinese adults in 2000–2001. Body weight, height, and waist circumference were measured by trained observers. Overweight and obesity were defined according to the World Health Organization classification. Central obesity was defined according to guidelines of the International Diabetes Federation. Results: Mean BMI and waist circumference were 23.1 kg/m² and 79.6 cm, respectively, for men and 23.5 kg/m² and 77.2 cm, respectively, for women. The prevalences of overweight and obesity were 24.1% and 2.8% in men and 26.1% and 5.0% in women, respectively. The prevalence of central obesity was 16.1% in men and 37.6% in women. The prevalences of overweight, obesity, and central obesity were higher among residents in northern China compared with their counterparts in southern China and among those in urban areas compared with those in rural areas. Lifestyle factors were the most important risk factors to explain the differences in overweight and central obesity between northern and southern residents. Among women, lifestyle and diet were the most important risk factors to explain the differences between urban and rural residents, whereas socioeconomic status, lifestyle, and diet were all important among men. Discussion: Our study indicates that overweight and obesity have become important public health problems in China. Environmental risk factors may be the main reason for regional differences in the prevalence of overweight and obesity in China.     

Vitamin E supplementation and plasma 8-isoprostane and adiponectin in overweight subjects

Objective: Isoprostanes are a marker of oxidant stress and atherosclerotic risk, and plasma concentrations are elevated in obesity. Adiponectin is a regulator of insulin sensitivity, and low circulating levels are associated with oxidant stress and obesity. The aim of this study was to determine the effect of vitamin E supplementation on plasma concentrations of 8‐isoprostane and adiponectin in overweight/obese subjects. Research Methods and Procedures: The study was a 6‐month, randomized, double‐blind, placebo‐controlled trial in 80 overweight subjects (60 women and 20 men, BMI >27 kg/m²). Exclusion criteria were serious illness, smoking, or taking antioxidant supplements. Participants were randomized to receive 800 IU/d natural vitamin E (n = 39) or placebo (n = 41) for 3 months with an increase in the dose to 1200 IU/d for a further 3 months. Plasma 8‐isoprostane and adiponectin concentrations were measured at baseline and 3 and 6 months. Results: During 6 months of supplementation with vitamin E, plasma vitamin E concentration increased significantly (p < 0.001) by 76%, and plasma 8‐isoprostane concentrations decreased significantly (?11%, p = 0.03), whereas plasma adiponectin concentrations did not change significantly. Discussion: These findings suggest that supplementation with high‐dose vitamin E decreases systemic oxidative stress and 8‐isoprostane concentrations in overweight/obese individuals. A decrease in plasma 8‐isoprostane has the potential to reduce risk of cardiovascular disease in obesity.     

Food consumption, activity, and overweight among elementary school children in an Appalachian Kentucky community

In the U.S., child overweight is on the rise and is implicated in later adult chronic illness. Given that overweight is hardly tractable, prevention as compared to treatment is seen as a better alternative for lowering the risk of long-term health consequences. To increase the success of prevention efforts, many argue that programs must be "culturally sensitive and targeted toward specific populations at greater risk. However, there exists a limited understanding of how overweight is distributed across the landscape, among and within populations and groups. This paper reports the prevalence of overweight among 54 school children in a rural, Appalachian community with a high rate of poverty, and it compares boys to girls. Thirty-seven percent of boys and 10.3% of girls are overweight, based on the 90th percentile body mass index (BMI). Analysis of food intake indicates a pattern of food consumption that is high in fatty and sugary foods and low in fruit and vegetable consumption. Analysis of activity indicates that children report more low-intensity activity than high; that overweight children report more episodes of video/computer play compared to nonoverweight children; and that boys spend more time than girls in front of the computer/television screen.