Accuracy of different body mass index reference values to predict body fat in adolescents

This study evaluates the accuracy of cutoff points in the body mass index (BMI) for identifying adolescents with overweight, compared to the percentage of body fat, estimated by electric bioimpediance, in a probabilistic sample of 610 adolescents from 12 to 19 years of age (222 boys and 388 girls) enrolled in public schools in Niterói, Rio de Janeiro, Brazil. ROC was used to evaluate the sensitivity and specificity of BMI cutoffs from one Brazilian, two North American, and one international reference. The cutoff points in the study sample were lower than the other references, with 76% to 95% sensitivity and 75% to 95% specificity. The Brazilian cutoff points were also more sensitive (53% to 100%) as compared to the other references (40% to 86%). The international parameter showed better sensitivity for older adolescents, and the Northern American references for younger adolescents. BMI was a good proxy for adiposity, but cutoff points from other population references should be used with caution, since they can lead to classification errors in adolescents with overweight.     

上海市2000-2014年中小学生体质量指数变化趋势

了解2000-2014年上海市学龄儿童青少年体质量指数(BMI)的变化趋势,为儿童青少年超重、肥胖判别标准研制及预防干预提供参考.方法 选取2000,2005,2010,2014年4次全国学生体质与健康调研中7~18岁儿童青少年作为研究对象.应用最小均方(Least Mean Square,LMS)法探讨不同性别、年龄组儿童青少年BMI的变化趋势.结果 14年间学生BMI P85低年龄组差异比较小,随年龄增加差异逐渐增大,青春期后有减小的趋势,男生平均增加2.1百分点,女生平均增加1.3百分点.学生BMI增长主要集中在中等和高百分位数,尤其是P90后,差值逐渐增大.7~11,12~15岁男生在P5o后差值均逐渐增大,P95分别达2.0,3.2百分点,其中12岁男生从23.4 kg/m2增加到26.8 kg/m2,14岁女生从24.0 kg/m2增加到25.9 kg/m2.与WGOC标准相比,2014年男生BMI P85,P95均较高,而女生BMI P85 10岁之前高于WGOC标准,从11岁开始与WGOC标准基本相一致.2014年上海市7~18岁儿童青少年超重、肥胖检出率分别为15.4%,9.1%,较2000年总体均呈上升趋势,分别上升6.4,5.2百分点.结论 BMI分布高百分位的个体比低百分位个体的变化更大.在肥胖防治工作中,加强对群体BMI曲线的监测分析,对适时调整宏观调控战略意义重大.     

Trends in overweight among adolescents living in the poorest and richest regions of Brazil

OBJECTIVES: We assessed changes in body mass index (BMI) among Brazilian adolescents. METHODS: In 1975, 1989, and 1997, we conducted household surveys of the weights and statures of a probabilistic sample of about 50,000 Brazilian adolescents aged 10 to 19 years. Weighted prevalences were calculated and an analysis was performed with the sample design taken into account. RESULTS: Adolescents of rich (southeast) and poor (northeast) regions showed a substantial increase in BMI. In the southeast, the prevalence of overweight, defined by international age- and gender-specific BMI cutoffs, for both genders reached 17% in 1997, whereas in the northeast, the prevalence tripled, reaching 5% among boys and 12% among girls. Older girls living in urban areas in the southeast showed a decrease in prevalence from 16% to 13% in the latter 2 surveys. For all boys and for young girls, the BMI values for the 85th percentile in 1997 were much higher than the 95th percentile values in 1975. CONCLUSIONS: BMI increased dramatically in Brazilian adolescents, mainly among boys; among older girls from the richest region, the prevalence of overweight is decreasing.     

Central adiposity in Brazilian schoolchildren aged 7-10 years

Waist circumference (WC) is a measure of central adiposity related to elevated risk factor levels in children and adolescents. The aim of the present study was to describe WC percentiles in 7- to 10-year-old Brazilian children and to compare frequencies of obesity and overweight as defined by BMI and frequencies of excess and at risk of abdominal adiposity as defined by WC to the corresponding age and sex data from British references. A representative sample of 2919 schoolchildren of the city of Florianopolis (southern Brazil) was examined. Smoothed WC percentiles were derived using the least mean square method. Frequencies of overweight and obesity and of excess and at risk of abdominal adiposity were assessed using the 91st and 98th centiles of the British references as cut-off points. WC increased with age in both boys and girls, with higher values for boys at every age and percentile level. Nutritional status categories of children assessed by the 91st and 98th British BMI and WC centiles showed moderate agreement (weighted kappa = 0.58). Overweight was more frequent in Brazilian than British children: 15.1 % of girls and 20.1 % of boys were above the 91st percentile of the 1990 BMI for age British references. About one-quarter (22.0 % of girls and 26.9 % of boys) exceeded the 91st percentile of WC British references. The present data could be used to compare WC in children in other populations and may serve as a baseline for future studies of temporal trends in WC in Brazil.     

Reference growth curves for cypriot children 6 to 17 years of age.

OBJECTIVE: The purpose of the study was to present smoothed percentiles for body weight and height, waist circumference, and body mass index (BMI) in Cypriot children and to compare their BMI 85th and 95th percentiles with those of children in other countries. RESEARCH METHODS AND PROCEDURES: The study was a cross-sectional study, including a representative sample of 2472 healthy children (49.1% boys) in Cyprus ages 6 to 17 years, who were evaluated during the 1999-2000 school year. Body weight and height and waist circumference were measured using standard procedures. BMI was calculated as weight in kilograms per height in square meters. Smoothed, sex-specific percentiles for these variables were calculated using polynomial regression models. Crude weight, height, waist, and BMI percentile values are presented in sex-specific tables and smoothed percentile curves are presented in charts. The 85th and 95th percentiles for BMI were compared with measurements from other countries, because of the concern of the upper limits of BMI in respect to the evaluation of obesity. RESULTS: The 85th and 95th BMI percentile values are higher in Cypriot boys than in Swedish and Iranian boys through all ages and in girls ages 6 to 15 years, whereas after the age of 15 years, both Swedish and Iranian girls' percentiles are equalized with their Cypriot peers. DISCUSSION: Weight, height, waist circumference, and BMI values and charts are presented for the first time for Cypriot children and adolescents. Much concern should be addressed to the observation that for the majority of the Cypriot sample, the upper BMI limits are higher than the peers of developing and developed countries.     

Obesity and socioeconomic status in children of Tijuana

BACKGROUND: Although obesity has been associated with socioeconomic status among Hispanics living in the United States, little is known about whether a similar association exists among Hispanics living in Mexico, particularly among those living along the U.S.-Mexico border. OBJECTIVE: To determine the prevalence of obesity and its association with socioeconomic status in Mexican schoolchildren attending public and private schools in Tijuana, Baja California. METHODS: Anthropometric measurements and socioeconomic status were assessed in a cross-sectional study of 1172 school children, aged 6 to 13 years from 55 schools in Tijuana in 2001-2002. Underweight (body mass index [BMI] for age 5th percentile or lower), risk of overweight (BMI at 85th percentile or higher), and overweight (BMI greater than 95th percentile) were assessed using charts published by the Centers for Disease Control and Prevention. RESULTS: Abnormalities in weight were found in 46.3% of 587 boys and 43.7% of 585 girls in the study. Undernutrition was found in 3.7% of the boys and 3.8% of the girls. The general prevalence of overweight was 23.2% for boys and 21.7% for girls. Children living in low-income neighborhoods had the thickest biceps skinfolds (p<0.01), while children living in moderate-income neighborhoods and attending public schools had the thickest triceps skinfolds (p<0.001). Although boys living in high socioeconomic status neighborhoods were at decreased risk for being overweight, boys and girls attending private schools had a 75% increased risk (odds ratio, 1.75; confidence interval, 1.22-2.52) of being overweight than children attending public schools. CONCLUSIONS: Adiposity varies by type of school and neighborhood socioeconomic status. The biphasic curve in risk for being overweight associated with neighborhood socioeconomic status suggests that Mexican children living along the U.S. border may be experiencing a nutrition transition with respect to an increased risk of obesity and related chronic disease.     

Weight status in childhood as a predictor of becoming overweight or hypertensive in early adulthood

OBJECTIVE: To assess the extent to which weight status in childhood or adolescence predicts becoming overweight or hypertensive by young adulthood. RESEARCH METHODS AND PROCEDURES: We conducted a prospective study of 314 children, who were 8 to 15 years old at baseline, and were followed up 8 to 12 years later. Weight, height, and blood pressure were measured by trained research staff. Incident overweight was defined as BMI>or=25 kg/m2 among participants who had not been overweight as children. RESULTS: More male subjects (48.3%) than female subjects (23.5%) became overweight or obese between their first childhood visit and the young adult follow-up (p<0.001). Being in the upper one half of the normal weight range (i.e., BMI between the 50th and 84th percentiles for age and gender in childhood) was a good predictor of becoming overweight as a young adult. Compared with children with a BMI<50th percentile, girls and boys between the 50th and 74th percentiles of BMI were approximately 5 times more likely [boys, odds ratio (OR)=5.3, p=0.002; girls, OR=4.8, p=0.07] and those with a BMI between the 75th and 84th percentiles were up to 20 times more likely (boys, OR=4.3, p=0.02; girls, OR=20.2, p=0.001) to become overweight. The incidence of high blood pressure was greater among the male subjects (12.3% vs. 1.9%). Compared with boys who had childhood BMI below the 75th percentile, boys between the 75th and 85th percentiles of BMI as children were four times more likely (OR=3.6) and those at above the 85th percentile were five times more likely (OR=5.1) to become hypertensive. DISCUSSION: High normal weight status in childhood predicted becoming overweight or obese as an adult. Also, among the boys, elevated BMI in childhood predicted risk of hypertension in young adulthood.     

Mexican anthropometric percentiles for ages 10-18

OBJECTIVE: To elaborate Mexican growth charts based on international methodology. DESIGN: Data were obtained from the Mexican National Health Survey. The survey was stratified and probabilistic representative of all the country. SETTING: Nationwide open population living in urban and rural areas. SUBJECTS: Boys (8545) and girls (9983) from 10 to 18 years participating in the survey. METHODS: Age, weight and height were recorded. Empirical percentiles were calculated and smoothed. Smoothed curves were approximated using least-mean square estimation. RESULTS: Tables and figures for percentile values of weight, height and body mass index (BMI) for age, as well as percentile values of weight and BMI for height for both genders are presented. Regarding 50th BMI for age percentiles, Mexicans had higher levels than the Americans in the Centers for Disease Control and Prevention growth charts; Mexicans were lower but had similar weights than the Americans. Owing to the high BMI, the percentile corresponding to an overweight level (25 kg/m(2)) at 18 years was 74.5 in boys and 72.5 in girls, whereas obesity level (30 kg/m(2)) at 18 years was 97.3 and 97.4 in boys and girls, respectively. CONCLUSIONS: The present growth charts are snapshots of a Mexican population. Because of the high median BMI compared to US and World Health Organization standards, we must be cautious in establishing an upper normal cutoff for clinical normality, not merely selecting the 85th and 95th percentiles as equivalents of overweight and obesity, respectively. Therefore, we proposed percentiles 74.5 in boys and 72.5 in girls as the action points of overweight as they are the percentiles corresponding to BMI 25 kg/m(2) at 18 years. SPONSORSHIP: The survey was supported by the Mexican Minister of Health. Statistical analyses were sponsored by Dr Del-Rio-Navarro.     

Overweight and aerobic fitness in children in the United States/Mexico border region.

OBJECTIVE: To study overweight and aerobic fitness among children in the third and fourth grades of elementary schools in a city in the United States of America (El Paso, Texas) and a city in Mexico (Chihuahua, Chihuahua) that are on or near the border between those two countries, and to compare the results from those two cities with earlier findings for other children in the United States. METHODS: We followed the El Paso children (427 boys and 385 girls, 93% of them of Mexican descent) from third to fourth grade and assessed the change in their body mass index (BMI). In the city of Chihuahua we cross-sectionally measured the BMI of a sample of third grade children (221 boys and 237 girls) and a sample of fourth grade children (268 boys and 215 girls). BMI and triceps skinfolds were measured for all the children studied in the two cities. BMI was used to assess risk for overweight (at least the 85th percentile BMI for age and gender) and overweight (at least the 95th percentile BMI for age and gender) in all the children. The distance that El Paso children ran in nine minutes was used to assess their aerobic fitness (aerobic fitness was not measured in the Chihuahua children). The data from El Paso were collected in 1999, 2000, and 2001, and the Chihuahua data were collected in 2000 and 2001. RESULTS: In the El Paso boys, overweight significantly increased in the one year from third grade to fourth grade, from 22% to 28%, while risk for overweight significantly increased, from 37% to 44%. In the El Paso girls, risk for overweight significantly increased over the same one-year period, from 29% to 37%. The El Paso boys and girls were significantly less fit when compared to samples of children from throughout the United States. Third and fourth grade children from Chihuahua had similar rates of risk for overweight and of overweight when compared to the children from the same grades in El Paso. CONCLUSIONS: Children in both El Paso and Chihuahua were more overweight than were non-Hispanic white children throughout the United States. In addition, the children in El Paso were less aerobically fit than were non-Hispanic white children and than were other Mexican-American children in the United States. These results clearly show that efforts should be made in the border regions of both Mexico and the United States to develop physical activity and nutrition programs to help stem rising rates of overweight.     

Prevalence of the metabolic syndrome in Chinese adolescents

Since national figures on the occurrence of metabolic syndrome among Chinese adolescents are lacking, this study aims to estimate its prevalence and distribution among Chinese youngsters. The 2002 China National Nutrition and Health Survey is a nationally representative cross-sectional study. Applying the criteria for US adolescents, we estimated the prevalence of metabolic syndrome among 2761 adolescents aged 15 to 19 years. The prevalence of metabolic syndrome among Chinese adolescents overall was 3.7 % (10 % in US adolescents). It was 35.2 %, 23.4 % and 2.3 % among adolescents who were overweight (BMI > or = 95th percentile), at risk of overweight (BMI between 85th and 95th percentile) and normal weight (BMI below the 85th percentile), respectively. Urban boys had the highest rate (5.8 %) compared with girls and rural youngsters. Among adolescents who had a BMI > or = 85th percentile and one or two parent(s) with metabolic syndrome, the prevalence was 46.4 %. A total of 96 % of overweight adolescents had at least one and 74.1 % overweight adolescents had at least two abnormalities of metabolic syndrome. Based on these figures, it is estimated that more than three million Chinese adolescents have metabolic syndrome. Both overweight and metabolic syndrome prevalence among adolescents are still relatively low in China, but the prevalence of metabolic syndrome among Chinese overweight adolescents is similar to those living in the USA.     

Prevalence of overweight and associated factors in southern Brazilian adolescents

OBJECTIVE: The aim of this study was to determine the prevalence of overweight in adolescents in a southern Brazilian city, and ascertain gender differences and association with socio-economic and demographic conditions, family factors and individual behaviours. METHODS: Cross-sectional population-based study with random cluster sampling of households, including 722 adolescents (10-19 years), from a city in southern Brazil. Body mass index (BMI) was calculated based on the National Center for Health and Statistics reference curve, defining overweight as BMI 85th percentile. RESULTS: Prevalence of overweight was 17% in girls and 19% in boys. In multivariate Poisson regression, chronic illness in parent(s) and household of up to four people were associated with overweight in boys, whereas low fibre intake, more hours spent watching television and regular exercise were associated with overweight in girls. CONCLUSION: The prevalence of overweight in Brazilian adolescents is high, with gender differences in associated factors. Health workers in schools and public health services should be aware of these differences in order to improve preventive and therapeutic strategies in this age group.     

Prevalence of overweight and obesity among Costa Rican elementary school children.

OBJECTIVE: Given that excessive body weight during childhood influences the development of several chronic diseases in adulthood, this study was conducted to determine the prevalence of overweight and obesity in urban and rural Costa Rican elementary school children. METHODS: The study was carried out from July 2000 to April 2001. A total of 1 718 students ages 7-12 were selected from 34 schools in the capital city of San José and in other nearby urban and rural areas. Both younger children (ones aged 7 through 9 years) and older children (ones aged 10 through 12 years) with a body mass index (BMI) at or above the sex-specific 85th percentile were considered overweight. The younger children were classified as being obese if their triceps skinfold was greater than or equal to the 85th percentile for age and sex using the percentiles by age for children in the United States of America as normative standards. The older children were considered obese if they had a BMI at or above the sex-specific 85th percentile and both the triceps and subscapular skinfold thickness at or above the 90th percentile. RESULTS: The prevalence of overweight was 34.5%. Children aged 7-9, boys, children from urban areas, and children of a higher socioeconomic status had a higher prevalence of overweight. The prevalence of obesity was 26.2%. A higher prevalence of obesity was found among children aged 7-9, boys, children from urban areas, and children of middle socioeconomic status. CONCLUSIONS: Given the high prevalence of obesity that we found in the Costa Rican children, primary and secondary prevention measures are needed in order to reduce the proportion of deaths due to chronic nontransmissible diseases among Costa Rican adults in the coming decades.     

Die Verbreitung von Übergewicht und Adipositas bei Kindern und Jugendlichen in Deutschland

Overweight and obesity are an increasing problem: worldwide, for Germany and for children and adolescents. Until now there have been no representative and age-specific assessments of the prevalence of obesity among children and adolescents in Germany. Thus, the standardised height and weight measurements gathered in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) have, for the first time, provided national, representative data about overweight and obesity in young people. The terms 'overweight' and 'obese' are defined based on percentiles of the body mass index (BMI) of the Kromeyer-Hauschild reference system. Of children and adolescents between the ages of 3 and 17, 15% exceed the 90th BMI percentile of the reference data and are thus overweight, 6.3% exceed the 97th BMI percentile and thus suffer from obesity by this definition. The proportion of overweight rises from 9% of 3-6-year-olds to 15% of 7-10-year-olds and 17% of 14-17-year-olds. The prevalence of obesity is 2.9%, 6.4% and 8.5% for the same age groups respectively. No clear differences between boys and girls or between East and West Germany are detected. Children are at a higher risk of being overweight or obese if they have a lower socioeconomic status, have a migration background, or have mothers who are also overweight.     

A comparison of international references for the assessment of child and adolescent overweight and obesity in different populations

OBJECTIVE: To compare different references assessing child and adolescent overweight and obesity in different populations. DESIGN: Comparison cross-sectional study. SETTING: The United States, Russia, China. SUBJECTS: A total of 6108 American, 6883 Russian and 3014 Chinese children aged 6-18 y. INVESTIGATION: Using nationwide survey data from the USA (NHANES III, 1988-1994), Russia (1992), and China (1991), we compared three references: (1) the International Obesity Task Force (IOTF) reference, sex-age-specific body mass index (BMI) cut-offs that correspond to BMIs of 25 for overweight and 30 for obesity at age 18; (2) the World Health Organization (WHO) reference--BMI 85th percentiles for overweight in adolescents (10-19 y) and weight-for-height Z-scores for obesity in children under 10; (3) a USA reference--BMI 85th and 95th percentiles to classify overweight and obesity, respectively. RESULTS: Using the IOTF reference and 85th BMI percentiles, overweight prevalence was 6.4 and 6.5% in China, 15.7 and 15.0% in Russia, and 25.5 and 24.4% in the USA, respectively. Notable differences existed for several ages. Kappa (=0.84-0.98) indicated an excellent agreement between the two references in general, although they varied by sex-age groupings and countries. Overweight prevalence was twice as high in children (6-9 y) than in adolescents (10-18 y) in China and Russia, but was similar in the USA. Estimates of obesity prevalence using these three references varied substantially. CONCLUSIONS: The references examined produce similar estimates of overall overweight prevalence but different estimates for obesity. One should be cautious when comparing results based on different references. SPONSORSHIP: University of Illinois and University of North Carolina.     

Prevalence of overweight and obesity in urban and semi-urban Jordanian children aged 3-6 years

Objectives   To show the prevalence of overweight and obesity among the Jordanian urban and semi-urban children; to compare their body mass index (BMI) with the international standards of BMI.
Methods   We measured 1695 healthy children (842 boys and 853 girls) between 3 and 6 years for height, weight and mid upper arm circumference. BMI was calculated and transformed into percentiles. Children were divided into boys and girls.
Results   The mean and SD values of BMI observed in our study were 16.69 ± 4.9 kg/m² for boys and 16.82 ± 4.77 kg/m² for girls aged 3–6 years. The prevalence of obesity and overweight among boys was 20.8% and 3.8% respectively and among girls was 19.1% and 7.2% respectively. In total, 48.0% of boys and 38.1% of girls were of healthy weight.
Conclusions   The mean BMI observed in our study's children aged 3–6 years was higher than the expected 50th percentile of the (World Health Organization/Centers for Disease Control and Prevention) reference values for a similar age range but, it was equivalent to the 75th percentile values. Obesity was more frequent than overweight among boys and girls aged 3–6 years.     

Childhood Asthma and Extreme Values of Body Mass Index: The Harlem Children’s Zone Asthma Initiative

To examine the association between body mass index (BMI) percentile and asthma in children 2-11 years of age, we performed a cross-sectional analysis of 853 Black and Hispanic children from a community-based sample of 2- to 11-year olds with measured heights and weights screened for asthma by the Harlem Children's Zone Asthma Initiative. Current asthma was defined as parent/guardian-reported diagnosis of asthma and asthma-related symptoms or emergency care in the previous 12 months. Among girls, asthma prevalence increased approximately linearly with increasing body mass index (BMI) percentile, from a low of 12.0% among underweight girls (BMI 95th percentile). After adjusting for age, race/ethnicity, and household smoking, among girls, having asthma was associated with being at risk for overweight (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.4-5.0) and being overweight (OR, 2.1; 95% CI, 1.2-3.8) compared to normal weight; among boys, having asthma was associated both with overweight (OR, 2.4; 95% CI, 1.4-4.3) and with underweight (OR, 2.9; 95% CI, 1.1-7.7). Large, prospective studies that include very young children are needed to further explore the observed association between underweight and asthma among boys. Early interventions that concomitantly address asthma and weight gain are needed among pre-school and school-aged children.     

Factors associated with obesity among adolescents]

INTRODUCTION: Obesity during adolescence is considered a strong predictor of adult obesity. The present study assessed the overweight/obesity prevalence and associated factors in middle class adolescents of a school in the city of Niteroi, Rio de Janeiro, Brazil, and evaluated the correlation between body mass index with anthropometric measures of fatness. METHOD: The analysis covered 391 students aged from 15 to 17 years. Adolescents had their weight, height, skinfold thickness and upper arm circumference measured at school. A food frequency questionnaire (list of 79 items) and a questionnaire including food habits, parents anthropometric characteristics, physical activity and other factors associated with obesity were filled out by the adolescents at school. RESULTS: The proportion of overweight individuals among boys (Body Mass Index (BMI) greater than the 90th percentile of the Brazilian population) was 23.9%, whereas the prevalence among girls was 7.2%. The fact of being on a slimming diet was a relevant factor for the prediction of BMI and was 7 times more frequent among girls than among boys. Among boys, being on a diet, absence of breakfast, and family body appearance were positively associated with BMI. Among girls these variables were also significantly associated, whereas age at menarche was negatively associated with BMI. Hours of watching TV/video/video-game was associated with BMI only among boys. The correlation coefficient between BMI and measures of fatness varied from 0.7 to 0.9 for boys, and from 0.8 to 0.90 for girls. CONCLUSIONS: BMI appears to be a good indicator of obesity among adolescents and showed that girls demonstrated an exaggerated preoccupation with body image and stereotyped slim body patterns.     

Diagnosis of overweight in adolescents: comparative study of the performance different criteria for body mass index

OBJECTIVE: In an attempt to simplify the screening process for detecting obesity in adolescence, the performance of different cutoff values for body mass index (BMI) was assessed in a population-based cohort in Southern Brazil. METHODS: A total of 493 adolescents aged 15-16 years who lived in the city of Pelotas, Brazil, were studied. Obesity was defined according to the WHO criteria taking into account age and sex (a BMI equal to or greater than the 85th percentile of the NHANES I reference, plus subscapular and triceps skinfold equal to or greater than the 90th percentile of the same reference). Different BMI cutoff values were used to assess their specificity and sensitivity. RESULTS: For boys, BMI>/=25 kg/m(2) showed the best performance for detecting obesity, with a sensitivity of 90% and only 5% of false positives. The Brazilian proposed criteria that was used had 100% sensitivity but up to 23% of false positives. Higher cutoff values were also tested, but there was a slight increase in specificity, accompanied by a marked reduction in sensitivity. CONCLUSIONS: The BMI cutoff of 25 kg/m(2) presented the best performance for screening obesity in the studied sample, and it is recommended for adolescents aged 15 and more in populations with similar characteristics. It provides a single cutoff value to be used in primary health services, eliminating the need for age and sex-specific values and skinfold measurements, and it is also consistent with the cutoff value proposed to identifying overweight adults.     

Body mass index in adolescence in relation to total mortality: 32-year follow-up of 227,000 Norwegian boys and girls

A large number of studies have explored the relation between body mass index (BMI) and mortality in adults. The relation between BMI in adolescence and mortality has been investigated to a lesser extent. It has been suggested that all-cause mortality is elevated among those who were overweight during adolescence, but the limitation of previous studies has been study size. The present study explored this relation in a Norwegian cohort of 227,003 boys and girls, aged 14-19 years, whose height and weight were measured during tuberculosis screening in 1963-1975. These persons were followed for an average of 31.5 years (about 7.2 million person-years). A total of 7,516 deaths were registered. Multivariate Cox proportional hazards regression models were used in the analyses. An increasing risk of death by increasing BMI in adolescence was observed. Mortality among males whose baseline BMI was between the 85th and 95th percentiles and above the 95th percentile in the US reference population was 30% and 80% higher, respectively, than that among those whose baseline BMI was between the 25th and 75th percentiles. The corresponding rates among females were 30% and 100%. The excess mortality among adolescents whose BMI was high was not clearly manifested before they reached their thirties. Hence, BMI in adolescence is predictive of adult mortality.     

Overweight and obesity in Portuguese children and adolescents

The objective of this study is to obtain reliable data from recent studies concerned with obesity and its determinants in Portuguese children and adolescents. We searched in Medline/PubMed published data on overweight and obesity in Portuguese children and adolescents; search terms included “Portugal”, “overweight”, “obesity”, “children” and “adolescents”. We also conducted limited hand-searching of additional studies from PhD theses and other academic theses that addressed overweight or obesity in children and adolescents. Studies that considered body mass index based on self-reported weight and height were excluded. We identified 15 studies that reported overweight and obesity in children and adolescents in Portugal, but 1 study was excluded because it included self-reported weight and height. The International Task Force Recommendation (IOTF) using Cole cut-offs was the most used criterion to estimate overweight and obesity, followed by the age- and sex-specific BMI reference percentiles developed by the United States Centers for Disease Control and Prevention (CDC). The range of ages in these studies was between 2 and 15 years. There were some variations in the prevalence of overweight and obesity among studies and different regions. In children between 3 and 5 years of age, one study reported that overweight reached 13.6% in boys and 20.4% in girls, and obesity varied between 6.5% and 6.9%, respectively, in boys and girls. Between 6 and 10 years of age (using the IOTF definition), in boys, the prevalence of overweight varied from 14.7 to 30.5% and obesity from 5.3 to 13.2%; in girls, overweight values ranged from 16.5 to 29.1% and obesity from 6.4 to 12.6%. One study evaluated only adolescents that were born in 1990 (ages varied between 13 and 14 years) and reported both prevalences of overweight and obesity; the applied method was CDC criteria; in boys, the percentage of overweight was 16.9%, and obesity prevalence was 11.3%; in girls, overweight was 16.0% and the percentage of obese was 9.2%. The prevalence of overweight and obesity in Portuguese children and adolescents may be considered as alarming, and early intervention to prevent obesity is needed.