Differences in measured and self-reported height and weight in Dutch adolescents

Agreement between parent-report and EMR height, weight, and BMI among rural children

Introduction

Remote anthropometric surveillance has emerged as a strategy to accommodate lapses in growth monitoring for pediatricians during coronavirus disease 2019 (COVID-19). The purpose of this investigation was to validate parent-reported anthropometry and inform acceptable remote measurement practices among rural, preschool-aged children.

Methods

Parent-reported height, weight, body mass index (BMI), BMI z-score, and BMI percentile for their child were collected through surveys with the assessment of their source of home measure. Objective measures were collected by clinic staff at the child's well-child visit (WCV). Agreement was assessed using correlations, alongside an exploration of the time gap (TG) between parent-report and WCV to moderate agreement. Using parent- and objectively reported BMI z-scores, weight classification agreement was evaluated. Correction equations were applied to parent-reported anthropometrics.

Results

A total of 55 subjects were included in this study. Significant differences were observed between parent- and objectively reported weight in the overall group (-0.24 kg; p = 0.05), as well as height (-1.8 cm; p = 0.01) and BMI (0.4 kg/m2; p = 0.02) in the ≤7d TG + Direct group. Parental reporting of child anthropometry ≤7d from their WCV with direct measurements yielded the strongest correlations [r = 0.99 (weight), r = 0.95 (height), r = 0.82 (BMI), r = 0.71 (BMIz), and r = 0.68 (BMI percentile)] and greatest classification agreement among all metrics [91.67% (weight), 54.17% (height), 83.33% (BMI), 91.67% (BMIz), and 33.33% (BMI percentile)]. Corrections did not remarkably improve correlations.

Discussion

Remote pediatric anthropometry is a valid supplement for clinical assessment, conditional on direct measurement within 7 days. In rural populations where socioenvironmental barriers exist to care and surveillance, we highlight the utility of telemedicine for providers and researchers.

Self-reported and measured anthropometric variables in association with cardiometabolic markers: A Danish cohort study

General obesity is a recognized risk factor for various metabolically related diseases, including hypertension, dyslipidemia, and pre-diabetes. In epidemiological studies, anthropometric variables such as height and weight are often self-reported. However, misreporting of self-reported data may bias estimates of associations between anthropometry and health outcomes. Further, few validation studies have compared self-reported and measured waist circumference (WC). This study aimed to quantify the agreement between self-reported and measured height, weight, body mass index (BMI), WC, and waist-to-height ratio (WHtR), and to investigate associations of these anthropometric measures with cardiometabolic biomarkers. A total of 39,514 participants aged above 18 years were included into the Diet, Cancer, and Health-Next Generation Cohort in 2015-19. Self-reported and measured anthropometric variables, blood pressure, and cardiometabolic biomarkers (HbA1c, lipid profiles, C-reactive protein and creatinine) were collected by standard procedures. Pearson correlations (r) and Lin's concordance correlations were applied to evaluate misreporting. Misreporting by age, sex and smoking status was investigated in linear regression models. Multivariable regression models and Receiver Operating Characteristic analyses assessed associations of self-reported and measured anthropometry with cardiometabolic biomarkers. Self-reported height was overreported by 1.07 cm, and weight was underreported by 0.32 kg on average. Self-reported BMI and WC were 0.42 kg/m2 and 0.2 cm lower than measured, respectively. Self-reported and measured height, weight, BMI, WC and WtHR were strongly correlated (r = 0.98, 0.99, 0.98, 0.88, 0.86, respectively). Age, sex, smoking, and BMI contributed to misreporting of all anthropometric measures. Associations between self-reported or measured anthropometric measures and cardiometabolic biomarkers were similar in direction and strength. Concordance between self-reported and measured anthropometric measures, including WC, was very high. Self-reported anthropometric measures were reliable when estimating associations with cardiometabolic biomarkers.

Reliability of Self-Reported Height and Weight in Children: A School-Based Cross-Sectional Study and a Review

Since anthropometric measurements are not always feasible in large surveys, self-reported values are an alternative. Our objective was to assess the reliability of self-reported weight and height values compared to measured values in children with (1) a cross-sectional study in Switzerland and (2) a comprehensive review with a meta-analysis. We conducted a secondary analysis of data from a school-based study in Switzerland of 2616 children and a review of 63 published studies including 122,629 children. In the cross-sectional study, self-reported and measured values were highly correlated (weight: r = 0.96; height: r = 0.92; body mass index (BMI) r = 0.88), although self-reported values tended to underestimate measured values (weight: -1.4 kg; height: -0.9 cm; BMI: -0.4 kg/m²). Prevalence of underweight was overestimated and prevalence of overweight was underestimated using self-reported values. In the meta-analysis, high correlations were found between self-reported and measured values (weight: r = 0.94; height: r = 0.87; BMI: r = 0.88). Weight (-1.4 kg) and BMI (-0.7 kg/m²) were underestimated, and height was slightly overestimated (+0.1 cm) with self-reported values. Self-reported values tended to be more reliable in children above 11 years old. Self-reported weight and height in children can be a reliable alternative to measurements, but should be used with caution to estimate over- or underweight prevalence.

Maternal Body Dissatisfaction and Accuracy of Infant Weight Perception in Families From Low-Income Backgrounds

OBJECTIVE

To examine the association between maternal body dissatisfaction and mother's (mis)perception of their infant's weight classification among families from low-income households.

METHODS

Mother-infant dyads were recruited during well-child visits from 2 urban primary care clinics. Maternal body dissatisfaction was measured using the Stunkard Figure Rating Scale. Perception of infant weight was assessed using a 5-point Likert scale. Infant weight-for-length percentiles were calculated using World Health Organization growth charts. Associations between maternal body dissatisfaction score and mother's (mis)perception of their infant's weight classification were examined using logistic regression allowing for nonlinear associations via restricted cubic splines.

RESULTS

Mothers (n = 180) were 26.6 ± 5.1 years old and 72% Black; infants were 8.8 ± 2.1 months old. Mean infant weight-for-length percentile was 64 ± 26. On average, mothers wanted to be one body figure smaller than their perceived current body size. Most mothers (82%) accurately perceived their infant's weight classification while few overestimated (7%) or underestimated (11%) their child's weight category. The probability of mothers misperceiving their infant's weight classification increased as maternal body dissatisfaction increased in either extreme in unadjusted (P < .05) and adjusted analysis (P = .06).

CONCLUSIONS

Increased maternal body dissatisfaction may be associated with mother's misperception of infant weight classification. Future studies should examine this relationship in a heterogeneous population.

National and Local Strategies in the Netherlands for Obesity Prevention and Management in Children and Adolescents

BACKGROUND

As in many other countries around the world, the Netherlands has a high prevalence of overweight and obesity in children. About 1 in 7 of children aged 2-19 years has either overweight or obesity.

SUMMARY

In this paper the national and local activities aimed at the prevention and management of obesity in children and adolescents in the Netherlands are reviewed. It is recommended to, nationally as well as locally, take an integrated-systems approach that tackles the obesogenic food environment as well as upstream and downstream determinants of obesity. Efforts should take a life course approach and be focused on promoting obesity prevention as well as improving the management of children who already have obesity. The national policies in the Netherlands rely heavily on self-regulation by stakeholders such as supermarkets, restaurants, and the food industry. Local policies and actions such as the whole-systems approach in Amsterdam are promising. Future directions include development of tools for the operationalization and evaluation of local systems approaches. Regulation by national and local governments is necessary to ensure a healthy food environment for children and their families, but health policies require intersectoral action. Key Messages: In the Netherlands many policies are in place or under development, especially at the municipal level (e.g., in Amsterdam), but more substantial action is urgently required.

The validity of parental-reported body height and weight: a comparison with objective measurements of 7-8-year-old Czech children

The values of body weight and height can be recorded in various ways. Self-reports and parentalreport methods are amongst the most typical ways to collect data. These methods have advantages, but also limits. Anthropometric measures are recommended to improve measurement precision. The aim of this study was to investigate whether the parental-reported body weight and height of 7-8-year-old Czech children corresponded with the measured body weight and height. Data concerning children’s body weight and body height were collected via parental informed consent and anthropometric measurements. The research sample consisted of 388 children from 7 to 8 years-old (boys, n = 176; girls, n = 162). Only children with parental informed consent were included. Correlations between parental-reported and measured data were analysed with the Pearson correlation coefficient to examine the strength of linear dependence between the two methods. The differences between parental-reported and measured data were tested using the Wilcoxon signed-rank test. P-values below α = 0.05 were considered statistically significant. Parents manifested a tendency to underestimate body weight and especially the body height of their children. This trend was seen in boys and girls in both age groups. Out of the 338 children with parent-reported height, parents under-reported their child’s height by 1 cm or more in 37.1% of the children, 39.6% of the parents reported a height within 0.99 cm of the measured height, and 23.3% of parents over-reported their child’s height by 1 cm or more. The same number of children had parentreported weights, parents under-reported their child’s weight by 1 kg and more in 25.2% of the children, 57.7% of the parents reported a weight within 0.99 kg of the measured weight, and 17.1% of the parents over-reported their child’s weight by 1 kg or more. The Pearson correlation coefficient between the measured and parental-reported height and weight revealed a statistically significant strong positive linear relationship in both genders (rheight = 0.912, rweight = 0.943; all p< 0.001). The differences between the measured and parental-reported height and weight were not significantly different (all p< 0.05). The high agreement and correlation between measured and parental-reported body height and weight suggest that parental-report methods can be an appropriate alternative to objective measurement and can be used as a valid tool to classify body height and weight for large population studies of Czech children in school-based research when anthropometric measures are not available.

Trends and correlates of unhealthy dieting behaviours among adolescents in the United States, 1999-2013

Background

The increase in adiposity problems among United States adolescents has been accompanied by persistently high prevalence of unhealthy dieting behaviours (UDBs) such as fasting, taking diet pills/powders/liquids, and vomiting/taking laxatives. This study aimed to examine the associations of self-perceptions of weight status, weight change intentions (WCIs) and UDBs with sex, age and race, as well as trends of UDBs in American adolescents across the weight spectrum.

Methods

Data come from the biennial cross-sectional, school-based surveys, the Youth Risk Behaviour Surveillance System (1999–2013, n = 113,542). The outcome measures were the self-reported UDBs: fasting for 24 h or more; taking diet pills/powders/liquids; and vomiting/taking laxatives. Sex-stratified logistic regressions assessed relationships between weight status misperceptions across all weight statuses, race and WCIs with UDBs. Differential trends between races were assessed using race*year interaction terms.

Results

In males, all non-White races had higher odds of fasting and vomiting/taking laxatives than Whites (except fasting in Hispanic/Latinos), with Adjusted Odds Ratios (AORs) between 1.44 and 2.07. In females, Black/African Americans and Hispanic/Latinos had lower odds of taking diet pills/powders/liquids compared to Whites (AORs 0.50 and 0.78 respectively). Racial disparities persisted throughout the study period. Prevalence of fasting and vomiting/taking laxatives did not change between 1999 and 2013 for all races, while taking diet pills/powders/liquids decreased. Compared to individuals of normal weight who were accurate weight status perceivers, individuals of almost all other combinations of weight status and weight status perception had significantly higher odds of displaying any UDB outcome. Overestimation of weight status was found to be the strongest determinant of UDBs. Compared to individuals endorsing "not wanting to do anything" about their weight, individuals endorsing all other WCIs (including wanting to gain weight) also showed significantly higher odds for every UDB outcome, with wanting to lose weight having AORs of the greatest magnitudes.

Conclusions

Prevalence of UDBs is persistently high, and highest among females across all racial groups. UDBs may elevate undesired weight gain and weight loss in individuals who are obese/overweight and underweight respectively. Further research into weight status perceptions among adolescents may inform efforts to reduce UDBs.

How accurate is the prevalence of overweight and obesity in children and adolescents derived from self-reported data? A meta-analysis

OBJECTIVE

The aim of the current meta-analysis was to evaluate the accuracy of using BMI based on self-reported height and weight (BMIsr) to estimate the prevalence of overweight and obesity among children and adolescents.

DESIGN

A systematic literature search was conducted to select studies that compared the prevalence rates of overweight and obesity based on BMIsr and BMIm (BMI based on measured height and weight). A random-effect model was assumed to estimate summary prevalence rates and prevalence ratio (PR).

RESULTS

Thirty-seven studies were included. The aggregated prevalence of overweight and obesity based on BMIsr (0·190, 95 % CI 0·163, 0·221) was significantly lower than that based on BMIm (0·233, 95 % CI 0·203, 0·265). The pooled mean PR was 0·823 (95 % CI 0·775, 0·875). Moderator analyses showed that the underestimation was related to gender, age, weight status screened (overweight v. obesity) and weight status screening tool.

CONCLUSIONS

BMIsr may produce less biased results under some conditions than others. Future researchers using BMIsr may consider these findings and avoid the conditions that could lead to more severe underestimation of the prevalence of overweight and obesity among children and adolescents.

The impact of childhood overweight and obesity on healthcare utilisation

Rising levels of childhood overweight and obesity represent a major global public health challenge. A number of studies have explored the association between childhood overweight and obesity and healthcare utilisation and costs. This paper adds to the literature by estimating the causal effect of child overweight and obesity status on use of general practitioner (GP) and hospital inpatient stays at two time points using instrumental variable (IV) methods The paper uses data from two waves of the Growing Up in Ireland survey of children when they are 9 and 13 years respectively and uses the biological mother's body mass index (BMI) as an instrument for the child's BMI. Our results demonstrate that child overweight and obesity status do not have a significant effect on healthcare utilisation for children when they are 9 years, but do have a large and significant effect at 13 years. Across all our models, the effects on both GP and hospital inpatient stays are found to be larger when endogeneity in childhood BMI status is addressed. Previous studies that did not address endogeneity concerns are likely to have significantly underestimated the impact of child overweight and obesity status on healthcare utilisation.

Self-Reported Height and Weight in Oceanian School-Going Adolescents and Factors Associated With Errors

We examined the accuracy of self-reported weight and height in New Caledonian school-going adolescents. Self-reported and measured height and weight data were collected from 665 adolescents of New Caledonia and were then compared. Multivariable logistic regressions identified the factors associated with inaccurate self-reports. Sensitivity and specificity of self-reported body mass index values to detect overweight or obesity were evaluated. Self-reported weight was significantly lower than measured weight (boys, -3.56 kg; girls, -3.13 kg). Similar results were found for height (boys, -2.51 cm; girls, -3.23 cm). Multiple regression analyses indicated that the difference between self-reported and measured height was significantly associated with ethnicity and pubertal status. Inaccurate self-reported weight was associated with socioeconomic status, place of residence, body-size perception and weight status. Screening accuracy of self-reported body mass index was low, particularly in the Melanesian subgroup. These findings should be considered when overweight is estimated in the Melanesian adolescent population at individual scale.

Health profiles of overweight and obese youth attending general practice

BACKGROUND

Literature suggests that overweight and obese young people use healthcare services more often, but this awaits confirmation in primary care.

OBJECTIVE

To identify health profiles of underweight, overweight and obese young people attending general practice and compare them to normal-weight youth and also to explore the weight-related health risks of eating and exercise behaviour in the four different weight categories.

METHODS

This study used a cross-sectional design with baseline data from a trial including 683 young people (14-24 years of age) presenting to general practice. Through computer-assisted telephone interviews data were obtained on number and type of health complaints and consultations, emotional distress, health-related quality of life (HRQoL) and eating and exercise behaviour.

RESULTS

General practitioners (GPs) were consulted more often by overweight (incidence rate ratio (IRR): 1.28, 95% CI (1.04 to 1.57)) and obese youth (IRR: 1.54, 95% CI (1.21 to 1.97), but not for different health problems compared with normal-weight youth. The reason for presentation was seldom a weight issue. Obese youth reported lower physical HRQoL. Obese and underweight youth were less likely to be satisfied with their eating behaviour than their normal-weight peers. Exercise levels were low in the entire cohort.

CONCLUSIONS

Our study highlights the need for effective weight management given that overweight and obese youth consult their GP more often. Since young people do not present with weight issues, it becomes important for GPs to find ways to initiate the discussion about weight, healthy eating and exercise with youth.

TRIAL REGISTRATION NUMBER

ISRCTN16059206.

Accuracy of using self-reported data to screen children and adolescents for overweight and obesity status: A diagnostic meta-analysis

OBJECTIVE

To estimate the accuracy of using the self-reported body mass index (BMIsr) for screening children and adolescents for overweight and obesity status by quantitatively synthesizing individual studies in the research literature.

METHOD

Three databases, namely PubMed, Web of Science, and EBSCOhost were searched up to September 2016. Studies were included that collected both the self-reported data (BMIsr) and direct measurement data (i.e., BMI based on measured height and weight, BMIm) to screen children and adolescents for overweight and obesity status, and provided sufficient data on sensitivity and specificity. Sensitivity, specificity, likelihood ratios, and diagnostic odds ratios from each of the included studies were pooled by using a random-effects meta-analytic model, and summary receiver operating characteristic curve (ROC) was also constructed.

RESULTS

Twenty-three studies were identified. For screening children and adolescents with overweight and obesity, the use of BMIsr presented a pooled sensitivity of 0.76 (95% CI, 0.76-0.77), a pooled specificity of 0.96 (95% CI, 0.96-0.97) and a pooled DOR of 92.4 (95% CI: 74.3-114.8). Moderator analyses showed that the sample regions (America vs. Europe vs. Asia), weight status screening references (IOTF vs. CDC vs. Nation-specific standard) and weight status screened (overweight vs. obesity) had contributed to the inconsistent findings concerning the screening accuracy across the studies.

CONCLUSIONS

Based on the results of current meta-analysis, the use of BMIsr has good overall performance with moderate sensitivity and high specificity, and it is a viable alternative when direct measurement of BMI is not available.

Actual and perceived weight status and its association with slimming and energy-balance related behaviours in 10- to 12-year-old European children: the ENERGY-project

BACKGROUND

Both parents' and children's perception of children's weight status may be important predictors of slimming and energy-balance related behaviours, independent of children's actual weight status.

OBJECTIVES

We examined the cross-sectional association of children's self-reported slimming and energy-balance related behaviours with children's (i) actual, (ii) self-perceived and (iii) parent-perceived weight status.

METHODS

Data of 10- to 12-year-old European children and their parents were used. Multilevel logistic and linear regression analyses were performed, adjusting for age, gender, parental weight controlling behaviours, education, marital status and ethnicity.

RESULTS

Independent of their actual weight status, a higher proportion of children reported slimming when they or their parents perceived them as too fat. Children's self-perceived weight status was more strongly associated with slimming than their parents' perception or their actual weight status. Moreover, children who perceive themselves as overweight reported less physical activity and more screen time. Children whose parents perceive them as overweight reported less physical activity.

CONCLUSIONS

Children's own perception of their weight status appears to be more important for their self-reported slimming than their actual or their parent's perceptions of their weight status. Additionally, children's self-perceived weight status seems important in engaging more physical activity and reduces screen time.

Adolescent Weight Status: Associations With Structural and Functional Dimensions of Social Relations

PURPOSE

To examine the associations between weight status and structural and functional dimensions of social relations among 11- to 15-year-old girls and boys.

METHODS

Analyses were based on cross-sectional data from the Danish contribution to the international Health Behavior in School-aged Children study 2010. The study population (n = 4,922) included students in the fifth, seventh, and ninth grade from a representative sample of Danish schools. Multinomial logistic regression analyses were used to study the associations between weight status and social relations, supported by a conceptual framework for the study of social relations.

RESULTS

Among girls, overweight/obese weight status was associated with spending less time with friends after school compared to normal-weight status (0 days/week: odds ratio: 6.25, 95% confidence interval: 2.18-17.95, 1 day/week: 2.81, 1.02-7.77, 2 days/week: 3.27, 1.25-8.56, 3 days/week: 3.32, 1.28-8.61, and 4 days/week: 3.23, 1.17-8.92, respectively vs. 5 days/week). Among girls, overweight/obese weight status was associated with being bullied (2.62, 1.55-4.43). Among boys, overweight/obese weight status was associated with infrequent (1 to 2 days vs. every day) communication with friends through cellphones, SMS messages, or Internet (1.66, 1.03-2.67). In the full population, overweight/obese weight status was associated with not perceiving best friend as a confidant (1.59, 1.11-2.28). No associations were found between weight status and number of close same-sex and opposite-sex friends, mother/father as confidant, and perceived classmate acceptance.

CONCLUSIONS

This study shows that overweight/obese adolescents have higher odds of numerous poor social relations than their normal-weight peers both in terms of structural and functional dimensions of social relations.

Accuracy of BMI correction using multiple reports in children

Background

Errors in reported height and weight raise concerns about body mass index (BMI) and obesity estimates obtained from self or proxy reports. Researchers have corrected BMI using linear statistical models, primarily with adult samples. We compared the accuracy of BMI correction in children for models that included child or parent reports versus both reports, and models that separately predicted height and weight compared to a single model for BMI.

Methods

Height and weight from child reports, parent reports, and objective measurements for 475 children participating in the Military Teenagers’ Environment, Exercise and Nutrition Study were analyzed. Two approaches were evaluated: (1) separate linear correction models for height and weight versus (2) a single linear correction model for BMI. Each approach considered models for height, weight, or BMI with child reports, parent reports, or both reports, respectively, as predictors, stratified by gender. Prediction accuracy was computed using leave-one-out validation. Models were compared using root mean squared error for BMI, and sensitivity and specificity for overweight and obesity indicators.

Results

Models that included both reports provided the best fit relative to a model using either set of reports, with adjusted R² of height, weight, and BMI models ranging from 67.1 to 87.6 % in males, and 69.2 to 88.3 % in females. Estimates of BMI from separate models for height and weight had the least prediction error, relative to those derived from a single model for BMI or from uncorrected (child or parent) reports. Cross-validated Root Mean Squared Error (RMSEs) preferred a model that included only parent reports among males and females, compared to models with only child reports or both reports. When assessing sensitivity (true positive) for obesity and overweight/obesity, the results varied by gender and outcomes. Specificity (true negative) was similarly high for all models.

Conclusion

Objective measurements are more accurate than self- or proxy-reports of BMI. In situations where objective measurement is infeasible, an approach that combines collecting a validation sub-sample including multiple reports of children’s height and weight, with estimation of BMI correction models maybe a cost-effective and practical solution. Correction models generate BMI estimates that are closer to objective measurements than reports.

Validity of home-measured height, weight and waist circumference among adolescents

This study assesses the validity of home-measured height, weight and waist circumference among Finnish adolescents from the Fin-HIT cohort. The adolescents were measured by fieldworkers, and were instructed to measure themselves at home with an adult's assistance. Paired t-test was used for statistical analyses. Home-measured mean height, weight and waist circumference were slightly higher, but BMI lower than measured by the fieldworker. The difference in means was statistically significant for weight (0.51 kg) and waist circumference (1.6 cm), but not for height and BMI. Home-measured height, weight, waist circumference and BMI are sufficiently accurate to be used in epidemiologic studies.

The association of dairy intake of children and adolescents with different food and nutrient intakes in the Netherlands

Background

Dairy products are nutrient-rich foods that may contribute to adequate nutrient intakes. However, dairy intake might also be associated with other food sources that influence nutrient intakes. Therefore, we studied the association of dairy, milk and cheese intake with intake of foods and nutrients from (non)dairy sources.

Methods

Dietary intake was assessed from 2007 to 2010 through two non-consecutive 24-h dietary recalls in 1007 children (7–13 years) and 706 adolescents (14–18 years). Participants were divided into non-consumers of a particular dairy product and tertiles according to their dairy intake (lowest, medium and highest intake). P for trend was calculated by linear regression over the median intakes of non-consumers and the tertiles for dairy, milk and cheese.

Results

In children, higher dairy consumption was associated with higher intakes of fruits (54.8 g ± 22.3; p < 0.0001), vegetables (25.0 g ± 14.6; p = 0.001) and cereals (18.5 g ± 20.7; p = 0.01) and with lower consumption of non-alcoholic beverages (−281 g ± 101; p = 0.01): soft drinks (−159 g ± 28.2; p < 0.0001) and fruit juices (−40.5 ± 14.8; p = 0.01). Results were comparable for milk consumption. In adolescents, similar results were found for milk and dairy consumption, except for the associations with higher fruits and vegetable intake.

In children and adolescents, higher cheese consumption was associated with higher vegetable and non-alcoholic beverages consumption; and lower meat consumption (−7.8 g ± 4.8; p = 0.05) in children. Higher cheese consumption was also associated with higher intakes of saturated fat (8.5 g ± 0.9), trans-fatty acids (0.48 g ± 0.06), sodium (614 mg ± 59.3) and several vitamins and minerals .

Conclusions

Higher milk and dairy consumption were associated with lower non-alcoholic beverages consumption, and higher cereal, fruit and vegetable consumption in children, which was also reflected in the nutrient intakes. These findings confirm that the consumption of milk and dairy products might be a marker for healthier eating habits.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0524-3) contains supplementary material, which is available to authorized users.

Updated prevalence rates of overweight and obesity in 11- to 17-year-old adolescents in Germany. Results from the telephone-based KiGGS Wave 1 after correction for bias in self-reports

Background

The nationwide “German Health Interview and Examination Survey for Children and Adolescents” (KiGGS), conducted in 2003–2006, showed an increase in the prevalence rates of overweight and obesity compared to the early 1990s, indicating the need for regularly monitoring. Recently, a follow-up—KiGGS Wave 1 (2009–2012)—was carried out as a telephone-based survey, providing self-reported height and weight. Since self-reports lead to a bias in prevalence rates of weight status, a correction is needed. The aim of the present study is to obtain updated prevalence rates for overweight and obesity for 11- to 17-year olds living in Germany after correction for bias in self-reports.

Methods

In KiGGS Wave 1, self-reported height and weight were collected from 4948 adolescents during a telephone interview. Participants were also asked about their body perception. From a subsample of KiGGS Wave 1 participants, measurements for height and weight were collected in a physical examination. In order to correct prevalence rates derived from self-reports, weight status categories based on self-reported and measured height and weight were used to estimate a correction formula according to an established procedure under consideration of body perception. The correction procedure was applied and corrected rates were estimated.

Results

The corrected prevalence of overweight, including obesity, derived from KiGGS Wave 1, showed that the rate has not further increased compared to the KiGGS baseline survey (18.9 % vs. 18.8 % based on the German reference).

Conclusion

The rates of overweight still remain at a high level. The results of KiGGS Wave 1 emphasise the significance of this health issue and the need for prevention of overweight and obesity in children and adolescents.

Validity of self-reported height and weight for estimating prevalence of overweight among Estonian adolescents: the Health Behaviour in School-aged Children study

Background

Low to moderate agreement between self-reported and directly measured anthropometry is shown in studies for adults and children. However, this issue needs further evaluation during puberty, a period marked by several transitions. We examined the correspondence of BMI status based on self-reported versus measured anthropometric data among Estonian adolescents with a specific focus on gender and age differences.

Methods

Self-reported height and weight were determined in a national representative sample of Estonian schoolchildren collected within the framework of the HBSC (health behaviour of school-aged children) survey. Self-reported and directly measured height and weight were collected from 3379 students (1071 aged 11, 1133 aged 13 and 1175 aged 15 years). The standardized HBSC questionnaire was used for collecting self-reported data; direct anthropometric measures were taken after the HBSC questionnaires were completed. The accuracy of the self-reported values by age and gender groups were determined by comparing mean differences, Bland–Altman plots with limits of agreement, Kappa statistics, and by estimation of the sensitivity and positive predictive value for detecting overweight.

Results

Mean self-reported weight, height and body mass index (BMI) values were significantly lower than corresponding values obtained using direct measurements. Mean differences between self-reported and directly measured weight, height and BMI were largest among 11-year-olds and smallest among students aged 15 years. Underestimation of overweight prevalence (includes obese) showed a graded trend which decreased in older age groups; the difference was greater among girls than boys in all age groups. The mean underestimation of overweight prevalence based on self-reported anthropometry was 3.6 percentage points. The positive predictive value was 72.3 % for boys and 63.4 % for girls.

Conclusion

A distinct age-related pattern in underestimation of weight, height and prevalence of overweight was found; the bias decreased with increasing age. The mean underestimation of overweight prevalence based on self-reports was small, 3.6 %. Self-reported height and weight remain the method of choice in large surveys for practical and logistical reasons.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1587-9) contains supplementary material, which is available to authorized users.

Weight development from age 13 to 30 years and adolescent socioeconomic status: The Norwegian Longitudinal Health Behaviour study

Objectives

To describe the weight development and model change in body mass index (BMI), and to examine the association of adolescent socioeconomic status (SES) with change in BMI distribution in a cohort followed from adolescence through adulthood.

Methods

Participants (n = 924) from western Norway were surveyed seven times from age 13 to 30 (1990–2007). BMI was based on self-reported height and weight. Quantile regression analyses were used to model change in weight development and to investigate associations between SES (measured by parental education) and change in BMI distribution. The analyses were adjusted for curvilinearity in BMI development, gender and relevant health behaviours.

Results

Body mass index increased over time with the greatest increase in the 90th percentile. No significant associations between change in BMI and SES were observed at any of the percentiles (10th, 25th, 50th, 75th or 90th).

Conclusions

Those in the upper BMI percentile gained more weight than those in the lower percentiles indicating that these might need targeted interventions. Further investigation of the association of change in BMI and SES with better quality data might be warranted.

Measuring the bias, precision, accuracy, and validity of self-reported height and weight in assessing overweight and obesity status among adolescents using a surveillance system

BACKGROUND

Evidence regarding bias, precision, and accuracy in adolescent self-reported height and weight across demographic subpopulations is lacking. The bias, precision, and accuracy of adolescent self-reported height and weight across subpopulations were examined using a large, diverse and representative sample of adolescents. A second objective was to develop correction equations for self-reported height and weight to provide more accurate estimates of body mass index (BMI) and weight status.

METHODS

A total of 24,221 students from 8th and 11th grade in Texas participated in the School Physical Activity and Nutrition (SPAN) surveillance system in years 2000-2002 and 2004-2005. To assess bias, the differences between the self-reported and objective measures, for height and weight were estimated. To assess precision and accuracy, the Lin's concordance correlation coefficient was used. BMI was estimated for self-reported and objective measures. The prevalence of students' weight status was estimated using self-reported and objective measures; absolute (bias) and relative error (relative bias) were assessed subsequently. Correction equations for sex and race/ethnicity subpopulations were developed to estimate objective measures of height, weight and BMI from self-reported measures using weighted linear regression. Sensitivity, specificity and positive predictive values of weight status classification using self-reported measures and correction equations are assessed by sex and grade.

RESULTS

Students in 8th- and 11th-grade overestimated their height from 0.68cm (White girls) to 2.02 cm (African-American boys), and underestimated their weight from 0.4 kg (Hispanic girls) to 0.98 kg (African-American girls). The differences in self-reported versus objectively-measured height and weight resulted in underestimation of BMI ranging from -0.23 kg/m2 (White boys) to -0.7 kg/m2 (African-American girls). The sensitivity of self-reported measures to classify weight status as obese was 70.8% and 81.9% for 8th- and 11th-graders, respectively. These estimates increased when using the correction equations to 77.4% and 84.4% for 8th- and 11th-graders, respectively.

CONCLUSIONS

When direct measurement is not practical, self-reported measurements provide a reliable proxy measure across grade, sex and race/ethnicity subpopulations of adolescents. Correction equations increase the sensitivity of self-report measures to identify prevalence of overall overweight/obesity status.

Systematic review to identify and appraise outcome measures used to evaluate childhood obesity treatment interventions (CoOR): evidence of purpose, application, validity, reliability and sensitivity

BACKGROUND

Lack of uniformity in outcome measures used in evaluations of childhood obesity treatment interventions can impede the ability to assess effectiveness and limits comparisons across trials.

OBJECTIVE

To identify and appraise outcome measures to produce a framework of recommended measures for use in evaluations of childhood obesity treatment interventions.

DATA SOURCES

Eleven electronic databases were searched between August and December 2011, including MEDLINE; MEDLINE In-Process and Other Non-Indexed Citations; EMBASE; PsycINFO; Health Management Information Consortium (HMIC); Allied and Complementary Medicine Database (AMED); Global Health, Maternity and Infant Care (all Ovid); Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCOhost); Science Citation Index (SCI) [Web of Science (WoS)]; and The Cochrane Library (Wiley) - from the date of inception, with no language restrictions. This was supported by review of relevant grey literature and trial databases.

REVIEW METHODS

Two searches were conducted to identify (1) outcome measures and corresponding citations used in published childhood obesity treatment evaluations and (2) manuscripts describing the development and/or evaluation of the outcome measures used in the childhood intervention obesity evaluations. Search 1 search strategy (review of trials) was modelled on elements of a review by Luttikhuis et al. (Oude Luttikhuis H, Baur L, Jansen H, Shrewsbury VA, O'Malley C, Stolk RP, et al. Interventions for treating obesity in children. Cochrane Database Syst Rev 2009;1:CD001872). Search 2 strategy (methodology papers) was built on Terwee et al.'s search filter (Terwee CB, Jansma EP, Riphagen II, de Vet HCW. Development of a methodological PubMed search filter for finding studies on measurement properties of measurement instruments. Qual Life Res 2009;18:1115-23). Eligible papers were appraised for quality initially by the internal project team. This was followed by an external appraisal by expert collaborators in order to agree which outcome measures should be recommended for the Childhood obesity Outcomes Review (CoOR) outcome measures framework.

RESULTS

Three hundred and seventy-nine manuscripts describing 180 outcome measures met eligibility criteria. Appraisal of these resulted in the recommendation of 36 measures for the CoOR outcome measures framework. Recommended primary outcome measures were body mass index (BMI) and dual-energy X-ray absorptiometry (DXA). Experts did not advocate any self-reported measures where objective measurement was possible (e.g. physical activity). Physiological outcomes hold potential to be primary outcomes, as they are indicators of cardiovascular health, but without evidence of what constitutes a minimally importance difference they have remained as secondary outcomes (although the corresponding lack of evidence for BMI and DXA is acknowledged). No preference-based quality-of-life measures were identified that would enable economic evaluation via calculation of quality-adjusted life-years. Few measures reported evaluating responsiveness.

LIMITATIONS

Proposed recommended measures are fit for use as outcome measures within studies that evaluate childhood obesity treatment evaluations specifically. These may or may not be suitable for other study designs, and some excluded measures may be more suitable in other study designs.

CONCLUSIONS

The CoOR outcome measures framework provides clear guidance of recommended primary and secondary outcome measures. This will enhance comparability between treatment evaluations and ensure that appropriate measures are being used. Where possible, future work should focus on modification and evaluation of existing measures rather than development of tools de nova. In addition, it is recommended that a similar outcome measures framework is produced to support evaluation of adult obesity programmes.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Large proportions of overweight and obese children, as well as their parents, underestimate children’s weight status across Europe. The ENERGY (EuropeaN Energy balance Research to prevent excessive weight Gain among Youth) project

Objective

To investigate the magnitude and country-specific differences in underestimation of children’s weight status by children and their parents in Europe and to further explore its associations with family characteristics and sociodemographic factors.

Design

Children’s weight and height were objectively measured. Parental anthropometric and sociodemographic data were self-reported. Children and their parents were asked to comment on children’s weight status based on five-point Likert-type scales, ranging from ‘I am much too thin’ to ‘I am much too fat’ (children) and ‘My child’s weight is way too little’ to ‘My child’s weight is way too much’ (parents). These data were combined with children’s actual weight status, in order to assess underestimation of children’s weight status by children themselves and by their parents, respectively. Chi-square tests and multilevel logistic regression analyses were conducted to examine the aims of the current study.

Setting

Eight European countries participating in the ENERGY (EuropeaN Energy balance Research to prevent excessive weight Gain among Youth) project.

Subjects

A school-based survey among 6113 children aged 10–12 years and their parents.

Results

In the total sample, 42·9 % of overweight/obese children and 27·6 % of parents of overweight/obese children underestimated their and their children’s weight status, respectively. A higher likelihood for this underestimation of weight status by children and their parents was observed in Eastern and Southern compared with Central/Northern countries. Overweight or obese parents (OR=1·81; 95 % CI 1·39, 2·35 and OR=1·78, 95 % CI 1·22, 2·60), parents of boys (OR=1·32; 95 % CI 1·05, 1·67) and children from overweight/obese (OR=1·60; 95 % CI 1·29, 1·98 and OR=1·76; 95 % CI 1·29, 2·41) or unemployed parents (OR=1·53; 95 % CI 1·22, 1·92) were more likely to underestimate children’s weight status.

Conclusions

Children of overweight or obese parents, those from Eastern and Southern Europe, boys, younger children and children with unemployed parents were more likely to underestimate their actual weight status. Overweight or obese parents and parents of boys were more likely to underestimate the actual weight status of their children. In obesity prevention such underestimation may be a barrier for behavioural change.

Development and validation of correction formulas for self-reported height and weight to estimate BMI in adolescents. Results from the KiGGS study

OBJECTIVE

The use of reported instead of measured height and weight induces a bias in prevalence rates for overweight and obesity. Therefore, correction formulas are necessary.

METHODS

Self-reported and measured height and weight were available from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) baseline study (2003-2006) from 3,468 adolescents aged 11-17 years. With regression analyses, correction formulas for height and weight were developed. Cross-validation was conducted in order to validate and compare the formulas. Corrected BMI was calculated, and corrected prevalence rates were estimated. Sensitivity, specificity, and predictive values for overweight and obesity were calculated.

RESULTS

Through the correction procedure, the mean differences between reported and measured height and weight become remarkably smaller and thus the estimated prevalence rates more accurate. The corrected proportions for overweight and obesity are less under-reported, while the corrected proportions for underweight are less over-reported. Sensitivity for overweight and obesity increased after correction. Specificity remained high.

CONCLUSION

The validation process showed that the correction formulas are an appropriate tool to correct self-reports on an individual level in order to estimate corrected prevalence rates of overweight and obesity in adolescents for studies which have collected self-reports only.

Are weight-related attitudes and behaviours associated with the accuracy of BMI derived from self-reported weight and height among 13-year-olds?

AIMS

The aim was to explore the association between weight-related attitudes and behaviours and the accuracy of body mass index (BMI) derived from self-reported weight and height.

METHODS

A total of 828 adolescents from the Health In Adolescents study were included. Self-reported and objective weight and height data were collected, and BMI was computed. Information about weight-related attitudes and behaviours was obtained. The association between weight-related attitudes and behaviours and the difference between BMI computed from self-reported and objective measures was assessed using generalized linear mixed model analyses.

RESULTS

BMI was under-reported by overweight girls (p<0.001) and boys (p<0.001) compared to their normal weight counterparts. Underweight girls on the other hand over-reported their BMI (p=0.002). Girls who reported trying to lose weight under-reported their BMI compared to girls who had not tried to do anything about their weight (p=0.02). Girls who perceived their weight as being too much under-reported their BMI compared to girls who thought their weight was ok, the association was however borderline significant (p=0.06); this association was also found among boys (p=0.03). Self-weighing and the reported importance of weight for how adolescents perceive themselves were not associated with the accuracy of BMI.

CONCLUSIONS

weight perception and weight control behaviour among girls only were related to the accuracy of self-reported BMI; no association was found with self-weighing behaviour and the perceived importance of weight for how adolescents perceive themselves. Knowledge of such factors will allow for a better interpretation and possibly adjustment/correction of results of surveys based on self-reported weight and height data.

Comparisons of measured and self-reported anthropometric variables and blood pressure in a sample of Hong Kong female nurses

Objectives

To assess the validity of self-reported weight, height, body mass index (BMI), waist circumference and blood pressure compared with standardized clinical measurements and to determine the classification accuracy in overweight/obesity and central adiposity.

Methods

This pilot study was integrated into a life-course study entitled “Hong Kong Women's Health Study” among 1,253 female nurses in Hong Kong who were aged 35 years to 65 years. Data were collected from self-administered questionnaires that were mailed to the respondents. Of these participants, we obtained the standard body measurements of 144 (11.5%) at our research center. We then compared the self-reported anthropometric variables and blood pressure with the measured data to assess validity based on the level of misreporting, percentage of agreement, consistency, sensitivity and specificity.

Results

The self-reported and measured values were highly correlated in terms of anthropometry and blood pressure (correlation coefficients ranged from 0.72 to 0.96). Height was overestimated at an average of 0.42 cm, and waist circumference was underestimated at 2.33 cm (both P<0.05), while no significant differences were observed from weight, blood pressure and BMI (all P>0.05). The proportions of overweight, obesity, and central adiposity by self-reported data did not vary greatly from the measured data (all P>0.05). The self-reporting resulted in correct classifications of BMI, waist circumference, and systolic blood pressure in 85%, 78%, and 87% of women, with corresponding Kappa index values of 0.79, 0.55, and 0.82, respectively. Sensitivity and specificity were 84.6% and 95.7%, respectively, with respect to overweight/obesity detection, whereas those for central adiposity detection were 70.6% and 83.8%, respectively.

Conclusion

In a sample of female Hong Kong nurses, the self-reported measures of height, weight, BMI, waist circumference and blood pressure were generally valid. Furthermore, the classification accuracies of overweight/obesity and central adiposity were acceptable.

High frequency body mass measurement, feedback, and health behaviors

We analyze weight and fat percentage measurements of respondents in an online general population panel in the Netherlands, collected using wireless scales, with an average frequency of 1.6 measurements per week. First, we document the existence of a weekly cycle; body mass is lowest on Fridays and highest on Mondays, showing significant (p<0.01) differences of, on average, 0.2 kilogram in weight, 0.06 in BMI value, and 0.03 in fat percentage. Second, we find that in the general population fat-based measures of obesity point at a three times larger prevalence of obesity (53%) than BMI-based measures (17%). Third, we find that feedback that includes a recommended weight range increases the temporal variation in individual body mass by almost ten percent (sd for weight increases from 1.13 to 1.22; sd for BMI increases from 0.37 to 0.41; sd for fat percentage increases from 0.55 to 0.61.

Applying a correction procedure to the prevalence estimates of overweight and obesity in the German part of the HBSC study

Background

Prevalence rates for overweight and obesity based on self-reported height and weight are underestimated, whereas the prevalence rate for underweight is slightly overestimated. Therefore a correction is needed. Aim of this study is to apply correction procedures to the prevalence rates developed on basis of (self-reported and measured) data from the representative German National Health Interview and Examination Survey for Children and Adolescents (KiGGS) to (self-reported) data from the German Health Behaviour in School Aged Children (HBSC) study to determine whether correction leads to higher prevalence estimates of overweight and obesity as well as lower prevalence rates for underweight.

Methods

BMI classifications based on self-reported and measured height and weight from a subsample of the KiGGS study (2,565 adolescents aged 11–15) were used to estimate two different correction formulas. The first and the second correction function are described. Furthermore, the both formulas were applied to the prevalence rates from the HBSC study (7,274 adolescents aged 11–15) which are based on self-reports collected via self-administered questionnaires.

Results

After applying the first correction function to self-reported data of the HBSC study, the prevalence rates of overweight and obesity increased from 5.5% to 7.8% (compared to 10.4% in the KiGGS study) and 2.7% to 3.8% (compared to 7.8% in the KiGGS study), respectively, whereas the corrected prevalence rates of underweight and severe underweight decreased from 8.0% to 6.7% (compared to 5.7% in the KiGGS study) and from 5.5% to 3.3% (compared to 2.4% in the KiGGS study), respectively. Application of the second correction function, which additionally considers body image, led to further slight corrections with an increase of the prevalence rates for overweight to 7.9% and for obese to 3.9%.

Conclusion

Subjective BMI can be used to determine the prevalence of overweight and obesity among children and adolescents. Where there is evidence of bias, the prevalence estimates should be corrected using conditional probabilities that link measured and subjectively assessed BMI from a representative validation study. These corrections may be improved further by considering body image as an additional influential factor.

Validity of self-reported height and weight among adolescents: the importance of reporting capability

Background

This study proposes a new approach for investigating bias in self-reported data on height and weight among adolescents by studying the relevance of participants’ self-reported response capability. The objectives were 1) to estimate the prevalence of students with high and low self-reported response capability for weight and height in a self-administrated questionnaire survey among 11–15 year old Danish adolescents, 2) to estimate the proportion of missing values on self-reported height and weight in relation to capability for reporting height and weight, and 3) to investigate the extent to which adolescents’ response capability is of importance for the accuracy and precision of self-reported height and weight. Also, the study investigated the impact of students’ response capability on estimating prevalence rates of overweight.

Methods

Data was collected by a school-based cross-sectional questionnaire survey among students aged 11–15 years in 13 schools in Aarhus, Denmark, response rate =89%, n = 2100. Response capability was based on students’ reports of perceived ability to report weight/height and weighing/height measuring history. Direct measures of height and weight were collected by school health nurses.

Results

One third of the students had low response capability for weight and height, respectively, and every second student had low response capability for BMI. The proportion of missing values on self-reported weight and height was significantly higher among students who were not weighed and height measured recently and among students who reported low recall ability. Among both boys and girls the precision of self-reported height and weight tended to be lower than among students with low response capability. Low response capability was related to BMI (z-score) and overweight prevalence among girls. These findings were due to a larger systematic underestimation of weight among girls who were not weighed recently (−1.02 kg, p < 0.0001) and among girls with low recall ability for weight (−0.99 kg, p = 0.0024).

Conclusion

This study indicates that response capability may be relevant for the accuracy of girls’ self-reported measurements of weight and height. Consequently, by integrating items on response capability in survey instruments, participants with low capability can be identified. Similar analyses based on other and less selected populations are recommended.

Underestimation of adolescent obesity

BACKGROUND

Previous studies assessing the validity of adolescent self-reported height and weight for estimating obesity prevalence have not accounted for, potential bias due to nonresponse in self-reports.

OBJECTIVES

The aim of this study was to assess the implications of selective nonresponse in self-reports of height and weight for estimates of adolescent obesity.

METHODS

The authors analyzed 613 adolescents ages 12-17 years from the 2006-2008 Los Angeles Family and Neighborhood Survey, a longitudinal study of Los Angeles County households with an oversample of poor neighborhoods. Obesity prevalence estimates were compared based on (a) self-report, (b) measured height and weight for those who did report, and (c) measured height and weight for those who did report.

RESULTS

Among younger teens, measured obesity prevalence was higher for those who did not report height and weight compared with those who did (40% vs. 30%). Consequently, obesity prevalence based on self-reported height and weight underestimated measured prevalence by 12 percentage points (when accounting for nonresponse) versus 9 percentage points (when nonresponse was not accounted for). Results were robust to the choice of difference child growth references.

DISCUSSION

Adolescent obesity surveillance and prevention efforts must take into account selective nonresponse for self-reported height and weight, particularly for younger teens. Results should be replicated in a nationally representative sample.

Nutritional and pubertal status influences accuracy of self-reported weight and height in adolescents: the HELENA Study

BACKGROUND AND AIMS

The aim of this study was to assess factors that have an effect on the accuracy of self-reported weight and height in adolescents.

METHODS

Weight and height of 3,865 European adolescents aged 12.5 to 17.5 years were self-reported via specific questionnaire. Then real weight and height were measured using accurate equipment and standardized protocols. Differences (D) between self-reported and measured weight and height were calculated, and factors that could have influenced the accuracy of self-reported weight and height were assessed. Data were analyzed using ANOVA, Student's t test and multivariate regression.

RESULTS

Adolescents underestimated their weight (D = -0.81 kg; n = 2,968) and overestimated their height (D = +0.74 cm; n = 3,308). Obese girls underestimated their weight (D = -4.70 kg) and overestimated their height (D = +0.22 cm) to a greater extent (p < 0.05) than obese boys (D = -3.13 kg and +0.14 cm for weight and height, respectively). Underestimation of weight (D = -1.25 kg) and overestimation of height (D = +0.15 cm) were only significant for girls who had finished puberty (Tanner stage 5). Socioeconomic status, nutritional knowledge, physical fitness, physical activity level, food choice and preference, and healthy eating behaviour had no significant influence on the accuracy of self-reported weight and height.

CONCLUSION

Our data confirms that self-reports of weight and height made by adolescents are inaccurate and demonstrate that inaccuracy is strongly influenced by nutritional status, pubertal status and gender.

Multi-ethnic reference values for spirometry for the 3-95-yr age range: the global lung function 2012 equations

The aim of the Task Force was to derive continuous prediction equations and their lower limits of normal for spirometric indices, which are applicable globally. Over 160,000 data points from 72 centres in 33 countries were shared with the European Respiratory Society Global Lung Function Initiative. Eliminating data that could not be used (mostly missing ethnic group, some outliers) left 97,759 records of healthy nonsmokers (55.3% females) aged 2.5-95 yrs. Lung function data were collated and prediction equations derived using the LMS method, which allows simultaneous modelling of the mean (mu), the coefficient of variation (sigma) and skewness (lambda) of a distribution family. After discarding 23,572 records, mostly because they could not be combined with other ethnic or geographic groups, reference equations were derived for healthy individuals aged 3-95 yrs for Caucasians (n=57,395), African-Americans (n=3,545), and North (n=4,992) and South East Asians (n=8,255). Forced expiratory value in 1 s (FEV(1)) and forced vital capacity (FVC) between ethnic groups differed proportionally from that in Caucasians, such that FEV(1)/FVC remained virtually independent of ethnic group. For individuals not represented by these four groups, or of mixed ethnic origins, a composite equation taken as the average of the above equations is provided to facilitate interpretation until a more appropriate solution is developed. Spirometric prediction equations for the 3-95-age range are now available that include appropriate age-dependent lower limits of normal. They can be applied globally to different ethnic groups. Additional data from the Indian subcontinent and Arabic, Polynesian and Latin American countries, as well as Africa will further improve these equations in the future.

Differences in weight status and energy-balance related behaviours according to ethnic background among adolescents in seven countries in Europe: the ENERGY-project

OBJECTIVE

The aim of this study was to explore differences in weight status and energy balance behaviours according to ethnic background among adolescents across Europe.

METHODS

A school-based survey among 10-12-year-old adolescents was conducted in seven European countries. Weight, height and waist circumference were measured; engagement in physical activity, sedentary and dietary behaviour, and sleep duration was assessed by child and parent-report. A distinction between native and non-native ethnic background was based on language spoken at home, and the parents' country of birth. Analyses were conducted with and without adjustment for parental education.

RESULTS

With valid data on both indicators of ethnic background for 5149 adolescents, 7307 adolescents (52% girls; 11.6 ± 0.7 years) participated. Significantly higher prevalence of overweight, obesity, body mass index and waist circumference were observed among non-native compared with native adolescents. Non-native adolescents had less favourable behavioural patterns (sugary drinks, breakfast skipping, sport, TV and computer time, hours of sleep) with the exception of active transport to school. Similar patterns were observed for both indicators of ethnicity, and in most of the separate countries; however, in Greece, weight status indicators were better among non-native adolescents. After adjustment for parental education, most differences remained significant according to country of origin of the parents, but not according to language spoken at home.

CONCLUSION

Adolescents of native ethnicity of the country of residence have, in general, more favourable weight status indicators and energy balance-related behaviours than adolescents of non-native ethnicity across Europe.

Accuracy of self-reported weight and height and resulting body mass index among obese binge eaters in primary care: relationship with eating disorder and associated psychopathology

OBJECTIVE

This study assessed the accuracy of self-reported weight, height, and body mass index in obese patients with binge-eating disorder (DSM-IV-TR criteria) presenting at primary care clinics and tested whether the degree of inaccuracy was associated with demographic factors or eating disorder and depressive features.

METHOD

Sixty-six participants were interviewed using the Eating Disorder Examination interview, completed the Eating Disorder Examination Questionnaire and the Beck Depression Inventory, and had their height and weight measured between November 2007 and May 2009.

RESULTS

Self-reported and measured weight did not differ significantly, but participants significantly overestimated their height (P < .01), and this discrepancy resulted in a significantly lower self-reported than measured body mass index (P < .05). Discrepancy scores did not differ by eating disorder or depressive symptoms, sex, or ethnicity, although increasing age was associated with overestimation of height and underestimation of body mass index.

CONCLUSIONS

The findings suggest that obese patients with binge-eating disorder in primary care settings are reasonably accurate reporters of weight and height and that the degree of inaccuracy does not appear to be systematically related to eating disorder psychopathology or depressive features.

Is obesity at individual and national level associated with lower age at menarche? Evidence from 34 countries in the Health Behaviour in School-aged Children Study

PURPOSE

A unique standardized international data set from adolescent girls in 34 countries in Europe and North America participating in the Health Behaviour in School-aged Children Study (HBSC) is used to investigate the contribution of body mass index (BMI) at individual and country level to cross-national differences in age at menarche.

METHODS

Two independent nationally representative survey data sets from 15-year-olds (n = 27,878, in 34 countries, year = 2005/2006) and 11-year-olds (n = 18,101, in 29 countries, year = 2001/2002) were analyzed. The survey instrument is a self-report questionnaire. Median age at menarche and 95% confidence intervals (CIs) were estimated using Kaplan-Meier analysis. Hierarchical models were used to assess the relationship between BMI and age at menarche (months). "Country-level obesity" was measured by prevalence of overweight/obesity (%) in each country.

RESULTS

Country-level median age at menarche ranged between 12 years and 5 months and 13 years and 5 months. Country-level prevalence of overweight among 15-year-old girls ranged from 4% to 28%. Age at menarche was inversely associated with individual BMI (unstandardized regression coefficient beta = -1.01; 95% CI, -1.09 to -.94) and country-level aggregate overweight at age 11 (unstandardized regression coefficient beta = -.25; 95% CI, -.43 to -.08). Individual- and country-level measures of BMI account for 40% of the country-level variance in age at menarche.

CONCLUSIONS

The findings add to the evidence that obesity in childhood is a risk factor for early puberty in girls and accounts for much of the cross-national variation in age at menarche. Future HBSC surveys can track this relationship in the wake of the obesity "epidemic."

Validity and predictors of BMI derived from self-reported height and weight among 11- to 17-year-old German adolescents from the KiGGS study

Background

For practical and financial reasons, self-reported instead of measured height and weight are often used. The aim of this study is to evaluate the validity of self-reports and to identify potential predictors of the validity of body mass index (BMI) derived from self-reported height and weight.

Findings

Self-reported and measured data were collected from a sub-sample (3,468 adolescents aged 11-17) from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). BMI was calculated from both reported and measured values, and these were compared in descriptive analyses. Linear regression models with BMI difference (self-reported minus measured) and logistic regression models with weight status misclassifications as dependent variables were calculated.

Height was overestimated by 14- to 17-year-olds. Overall, boys and girls under-reported their weight. On average, BMI values calculated from self-reports were lower than those calculated from measured values. This underestimation of BMI led to a bias in the prevalence rates of under- and overweight which was stronger in girls than in boys. Based on self-reports, the prevalence was 9.7% for underweight and 15.1% for overweight. However, according to measured data the corresponding rates were 7.5% and 17.7%, respectively. Linear regression for BMI difference showed significant differences according to measured weight status: BMI was overestimated by underweight adolescents and underestimated by overweight adolescents. When weight status was excluded from the model, body perception was statistically significant: Adolescents who regarded themselves as 'too fat' underestimated their BMI to a greater extent. Symptoms of a potential eating disorder, sexual maturation, socio-economic status (SES), school type, migration background and parental overweight showed no association with the BMI difference, but parental overweight was a consistent predictor of the misclassification of weight status defined by self-reports.

Conclusions

The present findings demonstrate that the observed discrepancy between self-reported and measured height and weight leads to inaccurate estimates of the prevalence of under- and overweight when based on self-reports. The collection of body perception data and parents' height and weight is therefore recommended in addition to self-reports. Use of a correction formula seems reasonable in order to correct for differences between self-reported and measured data.

What can parents do to reduce youth obesity? An initial study with a diverse sample

The body mass index (BMI) of diverse, low-income fifth grade students (n = 36) was regressed on physical activity (Child Adolescent Activity Log), percentage dietary fat (Food Habits Questionnaire), and the Food/Activity Parenting Practices Questionnaire. The model explained 50% of the variance in student BMI, adjusted R(2) = .50, F (4, 19) = 6.84, p = .001. Students accurately perceived their weight status. Students' perception of parenting strategies, along with dietary fat, was significantly associated with their BMI. Parent's (n = 14) BMI, not the child's, was associated with the strategies they used. Three parents tested an online authoritative parenting program. Further research is needed.

Ethnic variation in validity of the estimated obesity prevalence using self-reported weight and height measurements

Background

We examined ethnic differences between levels of body mass index (BMI) based on self-reported and measured body height and weight and the validity of self-reports used to estimate the prevalence of obesity (BMI≥30 kg/m²) in Turkish, Moroccan, and Dutch people in the Netherlands. Furthermore, we investigated whether BMI levels and the prevalence of obesity in Turkish and Moroccan people with incomplete self-reports (missing height or weight) differ from those with complete self-reports.

Methods

Data on self-reported and measured height and weight were collected in a population-based survey among 441 Dutch, 414 Turks and 344 Moroccans aged 18 to 69 years in Amsterdam, the Netherlands in 2004. BMI and obesity were calculated from self-reported and measured height and weight.

Results

The difference between measured and estimated BMI was larger in Turkish and Moroccan women than in Dutch women, which was explained by the higher BMI of the Turkish and Moroccan women. In men we found no ethnic differences between measured and estimated BMI. Sensitivity to detect obesity was low and specificity was high. In participants with available self-reported and measured height and weight, self-reports produced a similar underestimation of the obesity prevalence in all ethnic groups. However, many obese Turkish and Moroccan women had incomplete self-reports, missing height or weight, resulting in an additional underestimation of the prevalence of obesity. Among men (all ethnicities) and Dutch women, the availability of height or weight by self-report did not differ between obese and non obese participants.

Conclusions

BMI based on self-reports is underestimated more by Turkish and Moroccan women than Dutch women, which is explained by the higher BMI of Turkish and Moroccan women. Further, in women, ethnic differences in the estimation of obesity prevalence based on self-reports do exist and are due to incomplete self-reports in obese Turkish and Moroccan women. In men, ethnicity is not associated with discrepancies between levels of BMI and obesity prevalence based on measurements and self-reports. Hence, our results indicate that using measurements to accurately determine levels of BMI and obesity prevalence in public health research seems even more important in Turkish and Moroccan migrant women than in other populations.

Bias in self-reported height and weight in preadolescents

OBJECTIVES

To examine the validity of self-reported height and weight and factors related to misreporting in preadolescents. The accuracy of screening for underweight (thinness), overweight, and obesity using self-reported data was also tested.

STUDY DESIGN

Self-reported height and weight was administered and then measured in 798 fourth graders age 8 to 11 years. Body mass index (BMI) was calculated from self-reported and measured data and BMI categories were determined using international age- and sex-specific BMI criteria.

RESULTS

Preadolescents overestimated their height by 0.54 ± 5.17 cm and underreported their weight by 0.80 ± 3.09 kg. BMI derived from self-reported data was underestimated by 0.47 ± 1.79 kg/m². Measured BMI category was an important independent predictor of bias in self-reported weight and BMI. Children who were overweight or obese underestimated their weight and BMI to a greater degree compared with normal weight/underweight children. The influence of sociodemographic factors on bias in self-reported values was relatively small. Approximately 15% of children were misclassified in BMI categories when self-reported data were used, especially in the underweight (thinness) and obese category.

CONCLUSIONS

Children age 8 to 11 years were not able to accurately estimate their actual height and weight, leading to erroneous estimating rates of their weight status.

Parental socioeconomic position and development of overweight in adolescence: longitudinal study of Danish adolescents

BACKGROUND

An inverse social gradient in overweight among adolescents has been shown in developed countries, but few studies have examined whether weight gain and the development of overweight differs among adolescents from different socioeconomic groups in a longitudinal study. The objective was to identify the possible association between parental socioeconomic position, weight change and the risk of developing overweight among adolescents between the ages 15 to 21.

METHODS

Prospective cohort study conducted in Denmark with baseline examination in 1996 and follow-up questionnaire in 2003 with a mean follow-up time of 6.4 years. A sample of 1,656 adolescents participated in both baseline (mean age 14.8) and follow-up (mean age 21.3). Of these, 1,402 had a body mass index (BMI = weight/height2kg/m2) corresponding to a value below 25 at baseline when adjusted for age and gender according to guidelines from International Obesity Taskforce, and were at risk of developing overweight during the study period. The exposure was parental occupational status. The main outcome measures were change in BMI and development of overweight (from BMI < 25 to BMI > = 25).

RESULTS

Average BMI increased from 21.3 to 22.7 for girls and from 20.6 to 23.6 in boys during follow-up. An inverse social gradient in overweight was seen for girls at baseline and follow-up and for boys at follow-up. In the full population there was a tendency to an inverse social gradient in the overall increase in BMI for girls, but not for boys. A total of 13.4% developed overweight during the follow-up period. Girls of lower parental socioeconomic position had a higher risk of developing overweight (OR's between 4.72; CI 1.31 to 17.04 and 2.03; CI 1.10-3.74) when compared to girls of high parental socioeconomic position. A tendency for an inverse social gradient in the development of overweight for boys was seen, but it did not meet the significance criteria

CONCLUSIONS

The levels of overweight and obesity among adolescents are high and continue to rise. Results from this study suggest that the inverse social gradient in overweight becomes steeper for girls and emerges for boys in late adolescence (age span 15 to 21 years). Late adolescence seems to be an important window of opportunity in reducing the social inequality in overweight among Danish adolescents.

Estimated and measured BMI and self-perceived body image of adolescents in Germany: part 1 - general implications for correcting prevalence estimations of overweight and obesity

OBJECTIVE

This study examines the degree of divergence between BMI calculated from subjective assessments and BMI calculated from measured height and weight as a function of gender and body image.

METHODS

In the German National Health Interview and Examination Survey for Children and Adolescents (KiGGS) the height and weight of 17,641 children and adolescents aged 0-18 years were measured. Participants were also questioned about their subjective body image (whether they considered themselves much too thin, a bit too thin, exactly the right weight, too fat or much too fat). A representative subsample of adolescents between 11 and 17 years old (N = 3,436: 1,663 boys and 1,773 girls) was asked additionally to self-report their body weight and height before being measured.

RESULTS

The bias in the self-reported BMI yielded an underestimation of overweight and obesity prevalence. Girls who considered themselves much too fat or too fat and boys who considered themselves as much too fat underestimated their BMI. This was taken into account using a correction procedure for prevalence estimates of overweight and obesity based on the concept of conditional probabilities.

CONCLUSION

The proposed correction formula using data from the KiGGS study can be applied to other German studies of adolescents in which weight, height and body image are only determined by self-report. Furthermore the correction procedure in principle can be transferred to other studies in other countries as long as a parallel validation study has been conducted to assess both subjective and objective BMI and body image.

The role of weight status, gender and self-esteem in following a diet among middle-school children in Sicily (Italy)

BACKGROUND

Weight-related issues such as obesity, dieting and eating disorders in adolescents are major public health problems. Moreover, undertaking a diet tends to be common among school children and the reasons for doing so are not always related to weight status. The objectives of the study were to evaluate the role of body mass index (BMI), gender and self-esteem in the adoption of a diet in middle-school Sicilian children.

METHODS

The survey included middle-school children in some Sicilian provinces. Weight status was determined by sex-specific body mass index for age according to the international BMI cut-off proposed by Cole. Classic chi-square test and linear trend chi-square were used to compare percentages. Univariate and multivariate logistic regressions were computed to study the risk of dieting according to weight status (with the underweight group as the reference group), gender, self-esteem adjusted for province. Adjusted odds ratios (ORs) and 95% confidence intervals (CI) along with associated p-values were furnished.

RESULTS

The survey showed that 45.2% of the children were of average-weight, 6.6% were underweight, 12.6% were overweight and 2.9% were clinically obese. The missing data were up to 32.8%. Regarding dieting, 26.3% of the children stated that they had been on a diet during the last three months, 56.4% claimed they had not, and 17.2% did not answer. Age was not associated with dieting (p = 0.76). More girls than boys had undertaken a diet (31.4% versus 21.4%, p < 0.0001). Self-esteem had an influence on the choice of following a diet; in fact, 40.8%, 28.5% and 20.9% of the children with negative, normal and positive self-esteem were following a diet (trend p < 0.0001). The multivariate analysis showed that self-esteem seemed to influence more girls than boys (p = 0.06), and stratified analysis by gender indicated that it seemed more influent in girls (p = 0.0008) than in boys (p = 0.01).

CONCLUSIONS

In addition to the relation between dieting and BMI, our results highlight the link between dieting, gender and self-esteem. We underline the importance of interventions within the context of health education in order to improve global self-esteem and to encourage proper eating habits to prevent weight-related health problems.

Weight status, psychological health, suicidal thoughts, and suicide attempts in Dutch adolescents: results from the 2003 E-MOVO project

This study describes the association between weight status and psychological health, suicidal thoughts and suicide attempts in adolescents from a population-based study of 21,730 adolescents who responded to a classroom-based internet questionnaire. It demonstrated clear associations between weight status in adolescents and poor psychological health, suicidal thoughts and suicide attempts, especially in obese individuals. Obese boys and girls were more likely to be classified as "psychologically unhealthy" than were normal weight subjects. They also reported more suicidal thoughts and suicide attempts.

Validity of self-reported weight, height and resultant body mass index in Chinese adolescents and factors associated with errors in self-reports

Background

Validity of self-reported height and weight has not been adequately evaluated in diverse adolescent populations. In fact there are no reported validity studies conducted in Asian children and adolescents. This study aims to examine the accuracy of self-reported weight, height, and resultant BMI values in Chinese adolescents, and of the adolescents' subsequent classification into overweight categories.

Methods

Weight and height were self-reported and measured in 1761 adolescents aged 12-16 years in a cross-sectional survey in Xi'an city, China. BMI was calculated from both reported values and measured values. Bland-Altman plots with 95% limits of agreement, Pearson's correlation and Kappa statistics were calculated to assess the agreement.

Results

The 95% limits of agreement were -11.16 and 6.46 kg for weight, -4.73 and 7.45 cm for height, and -4.93 and 2.47 kg/m² for BMI. Pearson correlation between measured and self-reported values was 0.912 for weight, 0.935 for height and 0.809 for BMI. Weighted Kappa was 0.859 for weight, 0.906 for height and 0.754 for BMI. Sensitivity for detecting overweight (includes obese) in adolescents was 56.1%, and specificity was 98.6%. Subjects' area of residence, age and BMI were significant factors associated with the errors in self-reporting weight, height and relative BMI.

Conclusions

Reported weight and height does not have an acceptable agreement with measured data. Therefore, we do not recommend the application of self-reported weight and height to screen for overweight adolescents in China. Alternatively, self-reported data could be considered for use, with caution, in surveillance systems and epidemiology studies.

Taller - Healthier - more equal? The biological standard of living in Switzerland in the second half of the 20th century

This paper analyzes the trends in physical stature and body mass of the Swiss population born between 1955 and 1985, based on data collected in the "Living in Switzerland Survey" (Swiss Household Panel) of 2004. Aside from the time trend, we investigate the impact of educational and marital status as well as spatial effects on height and BMI. The results corroborate previous studies: average height increased during the second half of the 20th century for both women and men, better educated individuals are tallest, divorced men are shorter than married men and urban populations enjoy a height advantage over rural ones. We also compare the level and the trend in height to other postindustrial populations to identify key causes of physical growth and conclude that the quality of the health care systems and equal access to it seem to have a greater impact than other redistributive aspects of the welfare state. The relatively low level of inequality in health led to average height in Switzerland that are similar to those obtained in the Scandinavian social-democratic welfare states. Other measures such as income inequality do not have a high explanatory power for the average stature of the Swiss population.

Self-reported and measured weight, height and body mass index (BMI) in Italy, the Netherlands and North America

BACKGROUND

Self-reported values of height and weight are used increasingly despite warnings that these data-and derived body mass index (BMI) values-might be biased. The present study investigates whether differences between self-reported and measured values are the same for populations from different regions, and the influences of gender and age.

METHODS

Differences between self-reported and measured weights, heights and resulting BMIs are compared for representative samples of the adult population of Italy, the Netherlands and North America.

RESULTS

We observed that weight is under-reported (1.1 ± 2.6 kg for females and 0.4 ± 3.1 kg for males) and height over-reported (1.1 ± 2.2 cm for females and 1.7 ± 2.1 cm for males), in accordance with the literature. This leads to an overall underestimation of BMI values (0.7 ± 1.2 kg/m(2) or 2.8% for females and 0.6 ± 1.1 kg/m(2) or 2.3% for males). When BMI values are assigned to four categories (from 'underweight' to 'obesity'), 11.2% of the females and 12.0% of the males are categorized too low when self-reported weights and heights are used, with an extreme of 17.2% for Italian females. Older people tend to relatively over-report height and under-report weight, but the magnitude differs between countries and gender.

CONCLUSION

We conclude that, apart from a general overestimation of height and underestimation of weight resulting in an underestimation of BMI, substantial differences are observed between countries, between females and males and between age groups.

Challenges of accurately measuring and using BMI and other indicators of obesity in children

BMI is an important indicator of overweight and obesity in childhood and adolescence. When measurements are taken carefully and compared with appropriate growth charts and recommended cutoffs, BMI provides an excellent indicator of overweight and obesity that is sufficient for most clinical, screening, and surveillance purposes. Accurate measurements of height and weight require that adequate attention be given to data collection and management. Choosing appropriate equipment and measurement protocols and providing regular training and standardization of data collectors are critical aspects that apply to all settings in which BMI will be measured and used. Proxy measures for directly measured BMI, such as self-reports or parental reports of height and weight, are much less preferred and should only be used with caution and cognizance of the limitations, biases, and uncertainties attending these measures. There is little evidence that other measures of body fat such as skinfolds, waist circumference, or bioelectrical impedance are sufficiently practicable or provide appreciable added information to be used in the identification of children and adolescents who are overweight or obese. Consequently, for most clinical, school, or community settings these measures are not recommended for routine practice. These alternative measures of fatness remain important for research and perhaps in some specialized screening situations that include a specific focus on risk factors for cardiovascular or diabetic disease.

Socioeconomic position, macroeconomic environment and overweight among adolescents in 35 countries

OBJECTIVE

It is important to understand levels and social inequalities in childhood overweight within and between countries. This study examined prevalence and social inequality in adolescent overweight in 35 countries, and associations with macroeconomic factors.

DESIGN

International cross-sectional survey in national samples of schools.

SUBJECTS

A total of 11-, 13- and 15-year-olds from 35 countries in Europe and North America in 2001-2002 (N=162 305).

MEASUREMENTS

The main outcome measure was overweight based on self-reported height and weight (body mass index cut-points corresponding to body mass index of 25 kg/m(2) at the age of 18 years). Measures included family and school affluence (within countries), and average country income and economic inequality (between countries).

RESULTS

There were large variations in adolescent overweight, from 3.5% in Lithuanian girls to 31.7% in boys from Malta. Prevalence of overweight was higher among children from less affluent families in 21 of 24 Western and 5 of 10 Central European countries. However, children from more affluent families were at higher risk of overweight in Croatia, Estonia and Latvia. In Poland, Lithuania, Macedonia and Finland, girls from less affluent families were more overweight whereas the opposite was found for boys. Average country income was associated with prevalence and inequality in overweight when considering all countries together. However, economic inequality as measured by the Gini coefficient was differentially associated with prevalence and socioeconomic inequality in overweight among the 23-high income and 10-middle income countries, with a positive relationship among the high income countries and a negative association among the middle income countries.

CONCLUSION

The direction and magnitude of social inequality in adolescent overweight shows large international variation, with negative social gradients in most countries, but positive social gradients, especially for boys, in some Central European countries. Macroeconomic factors are associated with the heterogeneity in prevalence and social inequality of adolescent overweight.