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

Validity of self-reported weight and height among female young adults in the United Arab Emirates

Self-reported weight and height serve as important metrics in estimating overweight and obesity prevalence within epidemiological studies, primarily due to their cost and time efficiency. However, the accuracy and reliability of these self-reported measures remain controversial, with conflicting reports emerging from different regions. This study aims to compare self-reported weight and height with measured values among young female adults in the United Arab Emirates. A cross-sectional study of 131 female university students aged 17-27 reported their weight and height on a self-administered questionnaire and on the same day had their height and weight measured. Body Mass Index (BMI) values of both self-reported and measured weight and height were calculated and categorized according to the World Health Organization's cut-off points. Overall, 87% of students had a resultant self-reported BMI value within their actual BMI category. The mean differences between self-reported and measured weight and height in the present study were -0.92 kg and 0.38 cm, respectively. Results indicated strong agreement between self-reported and direct measurements, as demonstrated by weighted Kappa statistics (kappa = 0.87). Bland & Altman plots illustrated that the majority of values fell within the limits of agreement (2 SD), with no systemic bias detected. BMI calculated from self-reported data demonstrates high sensitivity and specificity. Linear regression analyses revealed that self-reported weight (r2 = 0.973; p<0.001), height (r2 = 0.902; p<0.001), and BMI (r2 = 0.964; p<0.001) accurately predicted measured weight, height, and BMI. The study's results highlight the ability of female university students in the UAE to accurately provide self-reports of their weight and height. This finding provides further support for the utilization of self-reported data on height and weight as a valid method for collecting anthropometric information.

Effect of High BMI on Human Bone Marrow-Derived Mesenchymal Stromal Cells

Bone marrow-derived mesenchymal stromal cells (BMSCs) are attractive candidates in tissue engineering and regenerative medicine. Growing evidence has suggested that a high body mass index (BMI) can affect the properties of BMSCs, resulting in a reduced quality of the cells. However, the results are not consistent. Therefore, this study aimed to investigate the influences of high BMI on human BMSCs (hBMSCs). To avoid gender bias, BMSCs from females and males were studied independently. Finally, hBMSCs from 89 females and 152 males were separately divided into the normal BMI group (18.5 kg/m2 ≤ BMI < 25 kg/m2) and the high BMI group (BMI > 25 kg/m2). The cells were analyzed for the colony-forming potential; proliferation capacity; in vitro adipogenic, osteogenic, and chondrogenic differentiation potentials; and the expression of 32 common surface antigens. The results showed that high BMI did not change the number of colonies at passage 1 in females and males. In contrast, significantly reduced colony numbers at passage 4 (P4) were found in both female and male donors with high BMI. The doubling time of hBMSCs was comparable between the normal and the high BMI groups of females and males. Furthermore, the results of trilineage differentiation did not differ between the different BMI groups of males. In females, the high and the normal BMI groups also showed similar adipogenic and chondrogenic differentiation, while osteogenic differentiation was significantly enhanced in the high-BMI group. Regarding the expression of surface antigens, the expressions of CD200 and SSEA4 on hBMSCs were reduced in the high-BMI group of females and males, respectively. In conclusion, high BMI suppressed the clonogenicity of female and male hBMSCs at P4, improved the in vitro osteogenesis of female hBMSCs, and decreased the expressions of CD200 on hBMSCs in females and SSEA4 in males.

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.

Underweight among adolescents in Denmark: prevalence, trends (1998-2018), and association of underweight with socioeconomic status

BACKGROUND

Underweight among adolescents is an important clinical and public health issue. It is associated with adverse health outcomes throughout the life-span and may reflect food poverty, unhealthy eating habits, or some underlying health conditions.

OBJECTIVE

To study prevalence and trends in underweight among adolescents 1998-2018, to examine social inequality in underweight, and whether social inequality changed over time.

METHODS

Data were derived from 6 cross-sectional school surveys from The Health Behaviour in School-aged Children study in Denmark. The study included 11-, 13-, and 15-year-old schoolchildren in random samples of schools in 1998, 2002, 2006, 2010, 2014, and 2018 (n = 22,177). Underweight was determined by body mass index-for-age thinness grade 2-3 (the Cole and Lobstein method). Socioeconomic status was determined using occupational social class (the Danish OSC Measurement).

RESULTS

The overall prevalence of underweight was 3.1% among boys and 5.3% among girls (P < 0.0001) and decreased by age (P < 0.0001) among both boys and girls. The prevalence of underweight was almost stable from 1998 to 2018. There was no observed absolute or relative social inequality in the prevalence of underweight among boys or girls.

CONCLUSION

The prevalence of underweight in 11- to 15-year-olds was significantly higher among girls than boys. The prevalence remained stable from 1998 to 2018. There was no significant association between SES and prevalence of underweight. It is important to elucidate the underlying causes of underweight such as malnutrition, eating disorders, eating problems, loss of appetite, chronic diseases, insufficient knowledge of nutrients effects on bodily functions, and persistent pain.

The Accuracy of Self-Reported Body Weight Is High but Dependent on Recent Weight Change and Negative Affect in Teenage Girls

BACKGROUND

Research studies often rely on self-reported weight to calculate body mass index. The present study investigated how the accuracy of self-reported body weight in adolescent girls is affected by overweight/obesity, race/ethnicity, and mental health factors.

METHODS

In a cohort of girls who participated in the Trial of Activity for Adolescent Girls at ages 11 and 17 (n = 588), self-reported and measured weight were compared, and linear regression models were fitted to model the over- or underreporting. The Center for Epidemiological Studies-Depression Scale (CES-D) was used to calculate depressive symptom subscales for negative affect, anhedonia and somatic symptoms.

RESULTS

Allowing 3% difference between self-reported and measured weight for the correct reporting of body weight, 59.2% of girls reported their weight correctly, 30.3% underreported (-5.8 ± 4.8 kg), and 10.5% overreported (4.3 ± 3.5 kg). The average difference between self-reported and measured body weight was -1.5 ± 4.3 kg (p < 0.001). Factors for misreporting body weight were overweight (β ± SE - 2.60 ± 0.66%), obesity (β ± SE - 2.41 ± 0.71%), weight change between ages 11 and 17 (β ± SE - 0.35 ± 0.04% for each kg), height change between ages 11 and 17 (β ± SE 0.29 ± 0.10% for each cm), and negative affect (β ± SE - 0.18 ± 0.08% for each score unit).

CONCLUSIONS

The difference between self-reported and measured body weight in adolescent girls is relatively small. However, the accuracy of self-reported body weight may be lower in girls with overweight or obesity, recent weight and height change, and higher negative affect.

Accuracy of self-reported BMI using objective measurement in high school students

Self-reported measures for body mass index (BMI) are considered a limitation in research design, especially when they are a primary outcome. Studies have found some populations to be quite accurate when self-reporting BMI; however, there is mixed research on the accuracy of self-reported measurements in adolescents. The aim of this study is to examine the accuracy of self-reported BMI by comparing it with measured BMI in a sample of U.S. adolescents and to understand gender differences. This cross-sectional study collected self-reported height and weight measurements of students from five high schools in four states (Tennessee, South Dakota, Kansas and Florida). Trained researchers took height and weight of students for an objective measurement. BMI was calculated from both sources and categorized (underweight, normal, overweight and obese) using the Centers for Disease Control and Prevention's BMI-for-age percentiles. Participants (n 425; 51⋅0 % female) had a mean age of 16⋅3 years old, and the majority were White (47⋅5 %). Limits of agreement (LOA) analysis revealed that BMI and weight were underreported, and height was overreported in the overall sample, in females, and in males. LOA analysis was fair for BMI in all three groups. Overall agreement in BMI categorisation was considered substantial (Κ 0⋅71, P < 0⋅001). As BMI increased, more height and weight inaccuracies led to decreased accuracy in BMI categorisation, and the specificity of obese participants was low (50⋅0 %). This study's findings suggest that using self-reported values to categorize BMI is more accurate than using continuous BMI values when self-reported measures are used in health-related interventions.

Trends in social inequality in overweight and obesity among adolescents in Denmark 1998-2018

OBJECTIVES

The aim was to analyze trends in overweight and obesity in relation to socioeconomic position among Danish adolescents in the 20-year period 1998-2018.

METHODS

The study used data on self-reported height and weight and parents' occupational social class (OSC) from 11-, 13- and 15-year-old schoolchildren in 1998, 2002, 2006, 2010, 2014 and 2018, n = 22,177. The analyses included absolute social inequality in overweight/obesity (prevalence difference between low and high OSC) and relative social inequality (OR for overweight/obesity).

RESULTS

In the total sample, the prevalence of overweight and obesity was 9.7% and 1.4%, respectively, with significantly higher prevalence in low than high OSC. There were significantly increasing trends in both overweight and obesity 1998-2018 in low OSC and no significant increase in high OSC. The OR for overweight was 1.59 (1.42-1.74) in middle and 2.16 (1.89-2.46) in low OSC, OR for obesity 1.74 (1.29-2.34) in middle and 2.97 (2.15-4.11) in low OSC. Associations were not modified by survey year.

CONCLUSIONS

There was a persistent absolute and relative social inequality in overweight and obesity 1998-2018 among Danish adolescents.

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.

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.

Validity of self-reported weight and height: a cross-sectional study among Malaysian adolescents

Background

Self-reported weight and height are commonly used in lieu of direct measurements of weight and height in large epidemiological surveys due to inevitable constraints such as budget and human resource. However, the validity of self-reported weight and height, particularly among adolescents, needs to be verified as misreporting could lead to misclassification of body mass index and therefore overestimation or underestimation of the burden of BMI-related diseases. The objective of this study was to determine the validity of self-reported weight and height among Malaysian secondary school children.

Methods

Both self-reported and directly measured weight and height of a subgroup of 663 apparently healthy schoolchildren from the Malaysian Adolescent Health Risk Behaviour (MyAHRB) survey 2013/2014 were analysed. Respondents were required to report their current body weight and height via a self-administrative questionnaire before they were measured by investigators. The validity of self-reported against directly measured weight and height was examined using intraclass correlation coefficient (ICC), the Bland-Altman plot and weighted Kappa statistics.

Results

There was very good intraclass correlation between self-reported and directly measured weight [r = 0.96, 95% confidence interval (CI): 0.93, 0.97] and height (r = 0.94, 95% CI: 0.90, 0.96). In addition the Bland-Altman plots indicated that the mean difference between self-reported and direct measurement was relatively small. The mean difference (self-reported minus direct measurements) was, for boys: weight, −2.1 kg; height, −1.6 cm; BMI, −0.44 kg/m² and girls: weight, −1.2 kg; height, −0.9 cm; BMI, −0.3 kg/m². However, 95% limits of agreement were wide which indicated substantial discrepancies between self-reported and direct measurements method at the individual level. Nonetheless, the weighted Kappa statistics demonstrated a substantial agreement between BMI status categorised based on self-reported weight and height and the direct measurements (kappa = 0.76, 95% CI: 0.67, 0.84).

Conclusion

Our results show that the self-reported weight and height were consistent with direct measurements and therefore can be used in assessing the nutritional status of Malaysian school children from the age of 13 to 17 years old in epidemiological studies and for surveillance purposes when direct measurements are not feasible, but not for assessing nutritional status at the individual level.

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.

The association between misperceptions around weight status and quality of life in adults in Australia

Background

Limited evidence supports a possible association between a person’s perception of their weight status and their quality of life (QoL). This study evaluates whether misperception around weight status is associated with QoL and the impact of gender on this association.

Methods

A cross-sectional survey of Australian adults (n = 1,905 analysed) collected self-reported height and weight (used to estimate BMI), gender and QoL (described using the AQoL-8D). Participants reported whether they perceived their weight status to be ‘underweight’, ‘healthy weight’, ‘overweight’ or ‘obese’. Misperception around weight status was categorised based on perceived weight status and self-reported BMI. Ordinary least squares regression was used to test associations between self-reported overall, physical and psychosocial QoL, misperception of weight status, and gender, across different BMI categories, after controlling for income, education, relationship status and health conditions.

Results

Compared to accurate perception, underestimation of weight status was associated with higher overall QoL for obese males and females and for overweight males. Overestimation of weight status was associated with higher overall QoL for underweight females and lower overall QoL for healthy weight males and females. The same pattern was seen for psychosocial QoL. Physical QoL was less sensitive to misperception than psychosocial QoL.

Conclusions

Self-reported misperception around weight status is associated with overall, psychosocial and to a lesser extent physical QoL in Australian adults, although its role depends on BMI category and gender. Generally misperception in the direction of “healthy weight” is associated with higher QoL and overestimation of weight status by those who are of healthy weight is associated with lower QoL. Findings should be confirmed in datasets that contain measured as opposed to self-report height and weight.

Electronic supplementary material

The online version of this article (doi:10.1186/s12955-017-0627-7) contains supplementary material, which is available to authorized users.

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.

Physical activity among adolescents: The role of various kinds of parental support

The objectives of this study were (a) to examine the association between various kinds of parental social support and adolescents' physical activity (PA) and (b) to examine whether various kinds of social support from mothers and fathers were differently associated with boys' and girls' PA. Data came from the Aarhus School Survey that included 2100 schoolchildren at 11, 13, and 15 years of age. Parental social support for PA was measured by items about encouragement to do PA, doing joint PA, parents watching PA, and talking about PA. PA was measured as at least 4 h of vigorous PA per week during leisure time. We used logistic regression analyses to estimate the associations for girls and boys separately, adjusted by age group, parents' occupational social class, family structure, and migration status. There were significant and graded associations between adolescents' PA and all four dimensions of parental support for PA. The association patterns were similar for mothers' and fathers' social support and similar for girls and boys. Social processes in the family are important for adolescents' participation in PA. It is important to continue to explore these social processes in order to understand why some adolescents are physically active and others are not.

Body Mass Index Accuracy in Preadolescents: Can We Trust Self-Report or Should We Seek Parent Report?

OBJECTIVES

To assess the accuracy of self- and parent-report of weight, height, and body mass index (BMI) in children between 8 and 12 years of age and to determine whether self- or parent-report should be preferred for preadolescents' subjective measures.

STUDY DESIGN

Through at-home questionnaires, 875 preadolescent children (44% boys; 56% girls) and their parents (N = 821) were asked to report the children's weight and height. Objective weight and height were measured at school by trained interviewers.

RESULTS

Correlations between objective, self-reported, and parent-reported measures were strong for weight, height, and BMI, but children and parents generally underestimated the children's weight by about 1 kg, their height by less than 1 cm, and their BMI by less than 0.25 kg/m(2). The magnitude of the underestimation varied by age, sex, and BMI category, with older children, girls, and children in the overweight and obese BMI categories underestimating their weight to a greater extent. Weight estimates provided by girls' parents tended to be lower than the real values more often than those of boys' parents.

CONCLUSIONS

Children and parents are likely to misreport children's weight, height, and BMI. For most youths aged 8 years of age and older, self-report appears as accurate as parent-report and could, therefore, be used interchangeably.

Are associations between electronic media use and BMI different across levels of physical activity?

Background

The use of electronic media has been found to be a risk factor for higher BMI and for being overweight. Physical activity has been found to be associated with lower BMI and lower risk for being overweight. Little is known about whether the associations between physical activity and electronic media use are additive or interactive in predicting BMI and risk for overweight among adolescents.

Methods

The data used in this study stem from the 2009/2010 survey of “Health Behaviour in School-aged Children (HBSC) study: A WHO Cross-National Survey. The sample consisted of 107184 13 and 15 year students from 30 different countries. Multilevel regression models were used to produce the presented estimates.

Results

Overall, 18% of boys and 11% of girls were classified as overweight. EM use was found to be associated with increased BMI z-scores and odds for overweight among both boys and girls who did not comply with physical activity guidelines. Among physically active adolescents, EM was found to be significantly associated with BMI or odds for overweight among girls, but not among boys.

Conclusion

While the usage of EM appear to be inconsequential for BMI and the risk of overweight among physically active boys, we find evidence indicating that EM use is associated with BMI and risk for overweight among girls, including those who report complying with MVPA guidelines.

Web-based self-reported height, weight, and body mass index among Swedish adolescents: a validation study

Background

Web-collected height and weight are increasingly used in epidemiological studies; however, the validity has rarely been evaluated.

Objective

The aim of the study was to validate self-reported height, weight, and corresponding body mass index (BMI) among Swedish adolescents aged approximately 16 years. A secondary aim was to investigate possible prediction factors for validity of self-reported BMI.

Methods

The study included 1698 adolescents from the population-based cohort BAMSE. Height and weight were collected through a Web-based questionnaire and subsequently measured using standard procedures. Differences between reported and measured height, weight, and corresponding BMI were compared by t tests and agreement was evaluated by Pearson correlation and Bland-Altman plots. Multivariable linear regression analysis was used to investigate whether lifestyle and demographic factors predicted validity of self-reported BMI.

Results

On average, weight was underestimated by 1.1 kg and height was overestimated by 0.5 cm, leading to an underestimation of BMI by 0.5 kg/m2. Correlation coefficients were .98 for height, .97 for weight, and .94 for BMI, and highly significant. Females underestimated weight to a higher extent than males and overweight and obese participants underestimated weight to a higher extent than normal-weight participants, which resulted in higher underestimation of BMI. Underweight participants, on the contrary, overestimated weight and correspondingly BMI. Overall, a high proportion of participants were classified into the correct BMI category; however, among overweight and obese participants, only 60.2% (139/231) and 46% (20/44) were correctly classified, respectively. In the multivariable prediction model, only gender and BMI status significantly predicted discrepancy between reported and measured BMI.

Conclusions

Web-collected BMI may be used as a valid, quick, and cost-effective alternative to measured BMI among Swedish adolescents. The accuracy of self-reported BMI declines with increasing BMI and self-reported BMI should not be used to estimate the prevalence of overweight or obesity.

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.