An assessment of adolescent overweight and obesity in Xi'an City, China.

OBJECTIVES: To assess the magnitude of overweight and obesity, and its associated socio-demographic factors in adolescents in Xi'an city, China. METHODS: A total of 1804 adolescents attending junior high schools in Xi'an City (age: 11-17 years) were included in this cross-sectional study. Body mass index using IOTF cut-offs defined overweight and obesity. Socio-demographic information was collected from the parents of the survey participants using self-administered, structured and pre-coded questionnaires. RESULTS: Overall, 16.3% of adolescents were overweight or obese, but there was a marked gender difference in the prevalence with 19.4% (95% CI: 15.6% - 23.7%) of boys versus 13.2% (95% CI: 10.0% - 16.4%) ofthe girls being overweight or obese. In a multivariate model, age, residence, household wealth, and parents' body mass index were significantly associated with being overweight/obese (p < 0.05). After adjusting for age and gender, the odds of an adolescent being overweight or obese was 2.7 times (95% CI: 1.8 - 4.0) higher in urban areas compared to rural areas; and 1.6 times (95% CI: 1.04 - 2.5) higher for adolescents from rich compared to poor families. An adolescent with one or both parents being overweight was 1.8 times (95% CI: 1.3 - 2.5) more likely to be overweight themselves compared to those with normal weight parents. CONCLUSIONS: 1) Overweight and obesity is a major public health problem in adolescents in Xi'an City and is likely to increase rapidly in the near future; 2) Overweight and obesity is more prevalent in younger boys from richer families living in urban districts and whose parents were either overweight or obese.     

Body mass index and the risk of acute injury in adolescents

OBJECTIVE:

To evaluate the relationship between body mass index (BMI) and acute injury in adolescents.

METHODS:

An analysis of cross-sectional data from the Canadian Community Health Survey (CCHS) Cycle 3.1 collected by Statistics Canada in 2005 was conducted. The CCHS is a population-based survey that collects information pertaining to the Canadian population health status, health care use and health determinants. The CCHS Cycle 3.1 included 132,221 respondents, of whom 12,317 were 12 to 17 years of age. Multivariate logistic regression was used to estimate the odds of injury occurrence by BMI categories (obese, overweight and neither).

RESULTS:

The association between overweight and obese BMI levels and injury occurrence in the bivariate model was not significant after adjusting for sex, health status, activity levels and socioeconomic status (OR=1.10 [95% CI 0.97 to 1.24] for overweight and OR=1.12 [95% CI 0.92 to 1.37] for obesity). A subanalysis of those with an injury in the past 12 months found an elevated odds of experiencing multiple injuries in the overweight group, after adjusting for age, health status and physical activity level (OR=1.43 [95% CI 1.16 to 1.77]).

CONCLUSION:

An increased risk of acute injury in obese and overweight adolescents was not observed. However, the subgroup analysis suggested that multiple injuries are relatively frequent in the overweight BMI group.     

Physician weight counseling for adolescents

Adolescent obesity prevalence is increasing, with minimal study of physician weight counseling with youth. This study examines adolescents' (n=110) perceptions of physicians' weight counseling. Overweight adolescents (> or =85th percentile for body mass index, BMI) report receiving counseling more than nonoverweight adolescents. Physicians more often have counseled obese (> or =95th BMI percentile) than overweight but not obese adolescents (85th-94th BMI percentile). Prior counseling and adolescents' ethnicity were related to greater perceived physician concern and adolescent receptivity to future counseling. Overweight adolescents report attempting weight loss strategies at rates similar to recommendations, but recommendations for specific weight control behaviors do not increase the likelihood of adolescent attempts. Clin Pediatr. 2002;41:575-585     

Social marginalization of overweight children

BACKGROUND: Overweight is the most common health problem that faces children and adolescents. Although the correlation among overweight, low self-esteem, and depression is well known, social isolation among overweight children and adolescents has not been studied. OBJECTIVE: To investigate social networks of overweight and normal-weight adolescents in a large, nationally representative sample. DESIGN: Cross-sectional, nationally representative cohort study.Population A total of 90 118 adolescents aged 13 to 18 years who were enrolled in the National Longitudinal Study of Adolescent Health, of which a 1:5 subsample was selected for detailed in-home assessment, including height and weight measurements (n = 17 557). Overweight was defined according to body mass index (>95th percentile for age and sex). MAIN OUTCOME MEASURES: This analysis focuses on the number of friendship nominations each adolescent received from other adolescents. The number of friendship nominations and other social network measures were calculated using statistical software. RESULTS: Overweight adolescents were more likely to be socially isolated and to be peripheral to social networks than were normal-weight adolescents. Although overweight adolescents listed similar numbers of friends as normal-weight adolescents, overweight adolescents received significantly fewer friendship nominations from others than were received by normal-weight adolescents (mean [SE] number of friendship nominations, 3.39 [0.08] vs 4.79 [0.04]; P<.001). Overweight adolescents were also more likely to receive no friendship nominations than were normal-weight adolescents (odds ratio, 1.71; 95% confidence interval, 1.39-2.20). Decreased television viewing (P<.001), increased levels of sports participation (P<.001), and increased participation in school clubs (P<.001) were associated with significantly more friendship nominations and higher network centrality scores among both overweight and normal-weight adolescents. CONCLUSIONS: Many overweight adolescents are socially marginalized. Such isolation may aggravate the social and emotional consequences of overweight in this age group.     

Overweight and obesity prevalence in children and adolescents from a private school in Recife

OBJECTIVES: To determine the prevalence of overweight and obesity in students from a private school in Recife; compare the prevalence rates of overweight and obesity in boys and girls and in different age groups (children and adolescents) and verify the correlation between body mass index and triceps skinfold thickness in this population. METHODS: Cross-sectional study with 762 students (332 children and 430 adolescents) from a middle/upper class school in Recife, in 1999. Overweight was defined as body mass index equal or above the 85th percentile for age and gender. Obesity was defined as body mass index and triceps skinfold thickness equal or above the 85th percentile. RESULTS: The prevalence rates were 26.2% (95%CI = 23 to 29%) for overweight, and 8.5% (CI95% = 6.5 to 10.5%) for obesity. Overweight was more prevalent among children (34.3%) than among adolescents (20.0%) (P<0.001). Obesity was more frequent among children (14.2%) than among adolescents (4.2%) (P<0.001). The prevalence of overweight in boys (34.6%) was higher than in girls (20.6%) (P<0.001). The prevalence of obesity was also higher in boys (14.7%) than in girls (4.4%) (P<0.001). The correlation coefficient between body mass index and triceps skinfold thickness was equal to 0.64 (95%CI = 0.60 to 0.68). CONCLUSIONS: The prevalence of overweight in our study population was as high as that found in industrialized countries; obesity, however, was less frequent.     

Accuracy of weight perception, life-style behaviours and psychological distress among overweight and obese adolescents

Aim: To compare overweight and obese adolescents with accurate and inaccurate self‐reported weight perception across a range of behaviours and measures of psychological well‐being. Methods: This study uses a cross‐sectional survey of grade 7–12 high school students in New South Wales, Australia, conducted in 2008 (n= 7553). Overweight and obese students based on body mass index were classified as accurate perceivers (weight perception was ‘too fat’) or inaccurate perceivers (weight perception was ‘about right’). Results: Nearly a third of adolescents had incongruity between self‐perceived body weight status and body mass index‐determined weight category. Compared with boys, girls were less likely to underestimate their body weight (odds ratio: 0.26; 95% confidence interval: 0.25, 0.27) and more likely to overestimate their body weight (odds ratio: 3.4; 95% confidence interval: 3.3, 3.5). Accurate body weight perception was higher in obese adolescents compared with overweight adolescents (69.5% vs. 44.0%). Compared with mis‐perceivers, accurate overweight and obese perceivers had significantly higher odds of trying to lose weight and being more physically active; however, they showed a combination of unhealthy and healthy behaviours (i.e. dietary patterns and sedentary activities). Accurate weight perception among overweight and obese adolescents was associated with increased odds of feeling sad or depressed in the past 6 months. Conclusions: Further research on social, familial and psychological factors that predict or mediate healthy and unhealthy weight‐related behaviours among adolescents by accuracy of weight perception is needed. Accurate weight perception should be considered in counselling and behavioural interventions.     

Gender-specific prevalence and associated risk factors of prehypertension among rural children and adolescents in Northeast China: a cross-sectional study

Little is known about the prevalence and risk profile of prehypertension among Chinese children and adolescents. The aim of the present study was to investigate the prehypertensive status and its associated risk factors among rural Chinese children and adolescents. We conducted a cross-sectional study including 5,245 children and adolescents (2,732 boys and 2,513 girls) aged 5–18 years in Northeast China. Main anthropometric data and related information were collected. The overall prevalence of prehypertension and hypertension was 15 % and 20.2 %, respectively. The prevalence of prehypertension among boys was 15.7 %, compared to that of 14.2 % among girls (P?=?0.256). After adjusting for age, race, weight status, waist circumference, triceps skinfold, family income, smoking and drinking status, boys aged 12–14 and 15–18 years had a 2.86- and 5.97-fold risk of prehypertension, respectively, compared to those aged 5–8 years. Overweight and obese boys had an increased risk of prehypertension in comparison to those with normal weight (overweight: odds ratio [OR]?=?1.837, 95 % confidence interval [CI] 1.321–2.556; obese: OR?=?2.941, 95 % CI 1.783–4.851). A larger triceps skinfold (≥90th percentile) was significantly related to increased odds of prehypertension (OR?=?2.32; 95 % CI, 1.516–3.55) among boys. For girls, only older age was found to be a risk factor for prehypertension. Conclusion: Pediatric prehypertension is highly prevalent in rural Northeast China. The risk factors for prehypertension differed among boys and girls. A more comprehensive risk profile of prehypertension among children and adolescents needs to be established for early prevention.     

不同营养状况下儿童青少年骨龄发育提前或落后的风险分析

目的 分析不同营养状况下儿童青少年的骨龄发育特点,探讨超重、肥胖及消瘦与骨龄发育提前或落后的相关性。方法 运用CHN法对2012年1月至2019年2月期间在首都儿科研究所附属儿童医院就诊的4~18岁7 062例（男3 310例,女3 752例）儿童的左手腕部骨龄进行评价,利用“儿童生长发育与营养评估系统”计算体质指数Z值（BMIZ）,BMIZ＜-2为消瘦组,BMIZ＞+1和BMIZ＞+2分别为超重组和肥胖组,比较不同性别和营养状况下骨龄年龄差（BAD）的差异,并对超重、肥胖儿童骨龄提前的发生风险进行分析。结果 消瘦和正常儿童平均骨龄与年龄相符,超重、肥胖儿童骨龄提前,且女童提前幅度大于男童,超重男、女童分别提前1.10岁和1.36岁（P=0.000）;肥胖男、女童分别提前1.60岁和1.78岁（P=0.000）。与正常体重相比,超重男、女童骨龄提前的风险分别增加2.358倍（95% CI：2.759~4.086）和2.483倍（95% CI：2.928~4.144）;肥胖男、女童骨龄提前的风险分别增加5.820倍（95% CI：5.066~9.181）和7.537倍（95% CI：6.319~11.534）;消瘦男、女童骨龄落后的风险分别增加1.540倍（95% CI：1.481~4.355）和3.790倍（95% CI：2.245~10.221）（P均＜0.05）。结论 超重肥胖增加骨龄提前的风险,超重男、女童骨龄提前风险接近,肥胖女童骨龄提前风险大于男童。消瘦增加骨龄落后的风险。     

Overweight and obesity in 6- to 14-year-old Czech children in 1991: protective effect of breast-feeding

OBJECTIVE: To assess the impact of breast-feeding on childhood overweight/obesity in an Eastern European socialist society with relatively homogeneous lifestyles. STUDY DESIGN: Cross-sectional survey data collected in 1991 on 33,768 school-children aged 6 to 14 years in the Czech Republic were analyzed by using multiple logistic regression analyses (main outcome body mass index [BMI] >90th percentile [overweight] and BMI >97th percentile [obesity]). RESULTS: Overall prevalence of overweight (obesity) was lower in breast-fed children: ever breast-fed (9.3%; 95% CI, 8.9-9.6 [3.2%; 95% CI, 3.0-3.4]) compared with never breast-fed (12.4%; 95% CI, 11.3-13.6 [4.4%; 95% CI, 3.7-5.2]). The effect of breast-feeding on overweight/obesity did not diminish with age in children 6 to 14 years old and could not be explained by parental education, parental obesity, maternal smoking, high birth weight, watching television, number of siblings, and physical activity. Adjusted odds ratios for breast-feeding were for overweight 0.80 (95% CI, 0.71-0.90) and for obesity 0.80 (95% CI, 0.66-0.96). CONCLUSIONS: A reduced prevalence of overweight/obesity was associated with breast-feeding in a setting where socioeconomic status was homogeneous. This suggests that the effect of breast-feeding on the prevalence of obesity is not confounded by socioeconomic status.     

Gender, type of education, family background and overweight in adolescents.

OBJECTIVE: To examine gender-specific socio-educational correlations of overweight in adolescents enrolled in post-mandatory education. SUBJECTS AND METHODS: Data were drawn from the Swiss Multicenter Adolescent Survey on Health, a cross-sectional study conducted on a representative sample of 3439 females and 4109 males aged 16 to 20 and enrolled in either vocational education (apprentices) or full time school (students). Adolescents reporting a body mass index (BMI) > 85th percentile for age and gender were compared with those reporting a BMI around the median (25th-75th percentile). RESULTS: Multivariate logistic regression showed that apprentices of both genders were more likely to report a BMI > or = 85th percentile than students: odds ratio (OR) in females 1.49 (95% confidence interval [CI] 1.11, 1.99), OR in males 1.61 (95%CI 1.19, 2.19). In females, but not in males, reported BMI was associated with parental education level (father with baccalaureate or university degree, OR = 1.00; father with vocational proficiency certificate, OR = 1.48 [95% CI 1.06, 2.07] and father without post-mandatory education, OR =3.44 [95% CI 2.20, 5.38]). CONCLUSIONS: The observed differences in the correlation of parents' and adolescents' own educational status with overweight suggest that parental and adolescents' own education represent distinct risk factors for overweight. Apprentices' higher risk of being overweight might be of particular interest for prevention, as they represent a large number of adolescents, who enter the adult workforce at a young age. Overall, socio-educational characteristics explained only a small fraction of the variance in overweight, particularly in males.     

Decreased quality of life associated with obesity in school-aged children

OBJECTIVES: To examine the association between health-related quality of life and body mass index (BMI) in preadolescent school-aged children and to provide the possible risk factors among participant characteristics, BMI status, and health-related quality of life.Design, Setting, and PARTICIPANTS: Cross-sectional analysis of 371 (50% female; 32% minority) children from a community-based sample of 8- to 11-year-olds participating in an ongoing cohort study, excluding those who had sleep apnea or who were born prematurely. Using BMI percentiles for age and sex, 17.5% of the children were considered overweight (BMI > or =95th percentile), 12.4% were at risk for overweight (BMI 85th-94th percentile), 8.1% were relatively underweight (BMI <20th percentile), and the remaining 62.0% were of normal weight (BMI 20th-84th percentile). MAIN OUTCOME MEASURES: Health-related quality-of-life scores as determined by the Child Health Questionnaire-Parent Form 50, dichotomized into the bottom quartile or decile. RESULTS: After adjustment for covariates (host factors and health status measurements), overweight children compared with normal weight children scored lower on the Psychosocial Health Summary (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1-3.6) and on subscales measuring self-esteem (OR, 3.5; 95% CI, 1.9-6.3), physical functioning (OR, 2.8; 95% CI, 1.7-6.8), and effect on the parent's emotional well-being (OR, 2.0; 95% CI, 1.1-3.6). Compared with the normal weight group, children who are at risk for overweight scored significantly lower for physical functioning. CONCLUSION: Overweight children have an increased odds of low scores for several health-related quality-of-life domains, suggesting the importance in considering such dimensions in programs aimed at further understanding obesity in children.     

Impact of overweight and obesity in carotid intima-media thickness of portuguese adolescents

Aim: To measure carotid intima‐media thickness (cIMT) in obese, overweight and normal‐weight Portuguese adolescents, to evaluate the association between body weight early signs of atherosclerosis. Methods: Cross‐sectional study, enrolling 150 adolescents (50 normal weight, 50 overweight and 50 obese) with mean age of 12.9 years. All underwent clinical, analytical and carotid common artery ultrasonographic evaluation. Results: After adjusting for systolic blood pressure and plasma High‐density lipoprotein, Low‐density lipoprotein and Triglycerides levels, higher mean cIMT values were observed in both overweight and obese patients, when compared to normal‐weight group. Moreover, adolescents with metabolic syndrome (MS) had greater cIMT [normal‐weight: cIMT mean 0.418 mm (95% confidence intervals (95% CI) 0.399–0.437); overweight: 0.461 mm (95% CI: 0.444–0.477); obese: 0.472 mm (95% CI: 0.455–0.488); MS: 0.482 mm (95% CI: 0.444–0.520) p = 0.001]. When normal‐weight and overweight adolescents were exclusively compared, differences in cIMT remained significant (p < 0.001). cIMT was positively correlated with body mass index (BMI) (r = 0.439, p < 0.001), waist circumference (r = 0.301, p = 0.018) and diastolic blood pressure (r = 0.266, p = 0.001). Conclusions: We have shown that cIMT is positively associated with BMI increase in adolescents, even in moderate overweight ranges, independent of age, gender, systolic blood pressure and plasma lipid concentrations.     

High incidence of obesity co-morbidities in young children: a cross-sectional study

Aim: The prevalence of overweight and obesity in children is a public health problem because of future morbidity. However, the prevalence of medical complications in overweight and obese primary school children in Australia is not well documented. As part of the larger, prospective cohort Growth and Development Study, this report aimed to identify the medical complications of obesity in a population‐based community sample of primary school‐aged children. Methods: Two groups of primary school children were studied: a random community sample of overweight/obese children (not seeking treatment) and a matched community sample of normal weight children. Demographics, medical history, family history and symptoms of complications of overweight were collected. Children had a physical examination, oral glucose tolerance tests with insulins, fasting lipid profiles and liver function tests. Results: Data from 283 children are presented (6.1–13.4 years, mean 9.8 years). There were no differences in birth data, family composition, parental age or socio‐economic status between groups. Overweight and obese children were more likely to complain of musculoskeletal pain, depression, anxiety and bullying, and had more adverse examination findings than control children. They also had more abnormal investigations: overweight children: impaired glucose tolerance (IGT) 1.3%, hyperinsulinism 19.5%, dyslipidaemia 63.8%, raised alanine transaminase (ALT) 9.0%; obese children: IGT 5.3%, hyperinsulinism 38.9%, dyslipidaemia 73.7%, raised ALT 31.6%. Conclusion: Overweight and obese primary school‐aged children have significant medical complications of their weight status. Overweight children, in addition to obese children, should be screened for complications. A secondary finding is a high proportion of normal weight children with lipid levels outside desirable healthy ranges.     

Obesity class does not further stratify outcome in overweight and obese pediatric patients after heart transplantation

The effect of obesity stratification on pediatric heart transplant outcomes is unknown. The UNOS database was queried for patients ≥2‐<18 years listed for heart transplant and stratified by BMI: normal (BMI>5%‐≤85 percentile), overweight (BMI=86%‐95 percentile), class 1 (BMI=100%‐120% of 95 percentile), class 2 (BMI=121%‐140% of 95 percentile), and class 3 obesity (BMI>140% of 95 percentile). A total of 5056 individuals were listed for transplant, with 71% normal, 13% overweight, 10% class 1, 4% class 2, and 2% class 3 obesity. Waitlist survival was not different between groups. Post‐transplant survival was decreased in overweight and combined obese groups vs normal, with no further difference between overweight and obese classes. Overweight and obese patients had higher listing status and were more likely to have ventilator, inotrope, and mechanical circulatory support at listing. After transplant, there was an association of overweight‐obese patients with diabetes and rejection requiring hospitalization. Stricter definition of normal weight reveals overweight‐obese status was an independent risk factor for poorer post‐transplant survival, without further effect by stratification of weight class. However, because there is no difference in waitlist survival, this study does not allow the selection of absolute weight‐based criteria regarding transplant listing and suggests the need to look further for modifiable risk factors post‐transplant.     

Ethnic group differences in overweight and obese children and young people in England: cross sectional survey.

AIMS: To determine the percentage of children and young adults who are obese or overweight within different ethnic and socioeconomic groups. METHODS: Secondary analysis of data on 5689 children and young adults aged 2-20 years from the 1999 Health Survey for England. RESULTS: Twenty three per cent of children (n = 1311) were overweight, of whom 6% (n = 358) were obese. More girls than boys were overweight (24% v 22%). Afro-Caribbean girls were more likely to be overweight (odds ratio 1.73, 95% CI 1.29 to 2.33), and Afro-Caribbean and Pakistani girls were more likely to be obese than girls in the general population (odds ratios 2.74 (95% CI 1.74 to 4.31) and 1.71 (95% CI 1.06 to 2.76), respectively). Indian and Pakistani boys were more likely to be overweight (odds ratios 1.55 (95% CI 1.12 to 2.17) and 1.36 (95% CI 1.01 to 1.83), respectively). There were no significant differences in the prevalence of obese and overweight children from different social classes. CONCLUSION: The percentage of children and young adults who are obese and overweight differs by ethnic group and sex, but not by social class. British Afro-Caribbean and Pakistani girls have an increased risk of being obese and Indian and Pakistani boys have an increased risk of being overweight than the general population. These individuals may be at greater combined cumulative risk of morbidity and mortality from cardiovascular disease and so may be a priority for initiatives to target groups of children at particular risk of obesity.     

Prevalence of Overweight and Obesity in a Large Clinical Sample of Children With Autism

BackgroundOverweight and obesity are major pediatric public health problems in the United States; however, limited data exist on the prevalence and correlates of overnutrition in children with autism.MethodsThrough a large integrated health care system's patient database, we identified 6672 children ages 2 to 20 years with an assigned ICD-9 code of autism (299.0), Asperger syndrome (299.8), and control subjects from 2008 to 2011 who had at least 1 weight and height recorded in the same visit. We calculated age-adjusted, sex-adjusted body mass index and classified children as overweight (body mass index 85th to 95th percentile) or obese (≥95th percentile). We used multinomial logistic regression to compare the odds of overweight and obesity between groups. We then used logistic regression to evaluate factors associated with overweight and obesity in children with autism, including demographic and clinical characteristics.ResultsCompared to control subjects, children with autism and Asperger syndrome had significantly higher odds of overweight (odds ratio, 95% confidence interval: autism 2.24, 1.74–2.88; Asperger syndrome 1.49, 1.12–1.97) and obesity (autism 4.83, 3.85–6.06; Asperger syndrome 5.69, 4.50–7.21). Among children with autism, we found a higher odds of obesity in older children (aged 12–15 years 1.87, 1.33–2.63; aged 16–20 years 1.94, 1.39–2.71) compared to children aged 6 to 11 years. We also found higher odds of overweight and obesity in those with public insurance (overweight 1.54, 1.25–1.89; obese 1.16, 1.02–1.40) and with co-occurring sleep disorder (obese 1.23, 1.00–1.53).ConclusionsChildren with autism and Asperger syndrome had significantly higher odds of overweight and obesity than control subjects. Older age, public insurance, and co-occurring sleep disorder were associated with overweight or obesity in this population.     

Lower relative bone mineral content in obese adolescents: role of non-weight bearing exercise

We assessed relative bone mineral content (BMC) in normal-weight (BMI < 85th percentile), overweight (BMI ≥ 85th---< 95th percentile), and obese (BMI ≥ 95th percentile) adolescents and evaluated the impact of nonweight bearing stationary cycle exercise training in a subset of obese participants. Obese and overweight adolescents had higher (p = .001) BMC than normal-weight counterparts, but after adjusting for total body mass the overweight and obese adolescents had a significantly lower (p < .001) BMC than normal-weight subjects. Although aerobic training such as cycling would seem optimal for caloric expenditure in obese adolescents, this study showed that eight weeks of cycle training did not improve BMC in obese adolescents. Weight-bearing aerobic exercise would be a better option for optimizing bone health in this population.     

Ethnic group differences in overweight and obese children and young people in England: cross sectional survey

Aims: To determine the percentage of children and young adults who are obese or overweight within different ethnic and socioeconomic groups. Methods: Secondary analysis of data on 5689 children and young adults aged 2–20 years from the 1999 Health Survey for England. Results: Twenty three per cent of children (n = 1311) were overweight, of whom 6% (n = 358) were obese. More girls than boys were overweight (24% v 22%). Afro-Caribbean girls were more likely to be overweight (odds ratio 1.73, 95% CI 1.29 to 2.33), and Afro-Caribbean and Pakistani girls were more likely to be obese than girls in the general population (odds ratios 2.74 (95% CI 1.74 to 4.31) and 1.71 (95% CI 1.06 to 2.76), respectively). Indian and Pakistani boys were more likely to be overweight (odds ratios 1.55 (95% CI 1.12 to 2.17) and 1.36 (95% CI 1.01 to 1.83), respectively). There were no significant differences in the prevalence of obese and overweight children from different social classes. Conclusion: The percentage of children and young adults who are obese and overweight differs by ethnic group and sex, but not by social class. British Afro-Caribbean and Pakistani girls have an increased risk of being obese and Indian and Pakistani boys have an increased risk of being overweight than the general population. These individuals may be at greater combined cumulative risk of morbidity and mortality from cardiovascular disease and so may be a priority for initiatives to target groups of children at particular risk of obesity.     

Decreased prevalence of nonalcoholic fatty liver disease in black obese children

OBJECTIVES: Nonalcoholic fatty liver disease (NAFLD) is a common cause of pediatric liver disease. Studies suggest decreased prevalence in blacks, females, and younger children. However, the proportion of black subjects in these studies was small, and children under 12 were not included. We propose that abnormal alanine aminotransferase (ALT) is more common in whites than blacks, males than females, and children over 12 compared with younger children in a prospective study. METHODS: We enrolled 181 consecutive asymptomatic obese children attending general pediatric clinics who denied recent fever or known liver disease. Obesity was defined as body mass index (BMI) z score of greater than 1.64 (95th percentile for age and sex). Elevated ALT was defined as greater than 40 U/L. BMI z score, race, sex, age, and parental obesity were compared using the chi-square test and Fisher's exact test. RESULTS: The population included 81 males and 100 females, 147 non-Hispanic black, 33 non-Hispanic white, and 1 Hispanic white. Elevated ALT occurred in 14 (8%) subjects. White children were significantly more likely to have abnormal ALT (odds ratio [OR] = 4.0, P < .02). Very obese children (BMI z score >2.3) were more likely to have abnormal ALT compared with mildly obese children (OR = 4.0, P < 0.05). Sex, age, hepatomegaly, acanthosis nigricans, and parental obesity did not significantly predict elevated ALT. CONCLUSION: Eight percent of asymptomatic, obese children had an elevated ALT suggestive of NAFLD. White and very obese children are more likely to be affected. Sex and age are not good clinical predictors of NAFLD. We suggest that all obese children be screened for NAFLD.     

Sex differences in the association between sleep and body mass index in adolescents

OBJECTIVE: To determine whether an association between short sleep duration and increased body mass index (BMI) exists in a sample of U.S. adolescents. STUDY DESIGN: Public-use dataset of the National Longitudinal Study of Adolescent Health. Final sample included 4486 adolescents (51% female). Main outcome was BMI transformed into z-scores for age and sex using reference values from the Centers for Disease Control/National Center for Health Statistics. Overweight was defined as > or =95th percentile. Linear and logistic regression models were calculated. Sleep duration was self-reported in hours. A quadratic term for sleep was added to test curvilinear association. Covariates included age, race, parental education, activity and inactivity scores. RESULTS: Among males, linear regression indicated that sleep duration significantly predicted BMI z-score (Beta = -0.08, 95% CI: -0.12, -0.03). Logistic regression indicated that sleep duration predicted risk of overweight among males (OR = 0.90, 95% CI: 0.82, 1.00). Sleep duration was not a significant predictor among females in either regression model. Quadratic term for sleep was not significant for either sex. CONCLUSIONS: Longer sleep duration was weakly associated with lower BMI and risk of overweight among male adolescents only. This sex-related difference may be due to differences in the physiology of puberty or in sleep characteristics.