Dietary restraint and the mis-reporting of anthropometric measures by middle-aged adults

What happens to diet quality in people newly diagnosed with type 2 diabetes? The 3D case-series study

BACKGROUND

Diet quality plays an important role in the prevention of diabetes-related complications in people with type 2 diabetes mellitus (T2DM). However, evidence is scarce on how diet quality typically changes over time after diagnosis. The present study aimed to describe how the diet quality of individuals newly diagnosed with T2DM changes over a 12-month period and to identify factors associated with diet quality changes.

METHODS

A 12-month prospective, observational case-series study was undertaken. Two-hundred and twenty-five Australian adults (56% men) newly diagnosed with T2DM were recruited from the Diabetes Australia national database. Participants completed five interviewer-administered surveys over 12 months: baseline, 3, 6, 9 and 12 months. Demographic, physical and health characteristics, and dietary intake data were collected at each timepoint. Diet quality was assessed using the Dietary Approaches to Stop Hypertension (DASH) scoring tool. To assess changes in DASH, energy, fruit and vegetable intake over time, repeated measure analyses of variance were used. Multivariate repeated measures models investigated characteristics associated with these dietary changes.

RESULTS

The mean DASH score of the sample remained stable at 24.0 across the 12 months. Very few participants (6.8%) improved diet quality consistently across the study period. No associations between DASH, energy, fruit or vegetable intake over time and characteristics were observed.

CONCLUSIONS

This observational study suggests that without dedicated interventions (the natural course), most people newly diagnosed with T2DM will not achieve meaningful diet quality change. The development of cost-effective interventions to achieve sustained diet quality change early after diagnosis are warranted.

Factors Accounting for Obesity and Its Perception among the Adult Spanish Population: Data from 1,000 Computer-Assisted Telephone Interviews

OBJECTIVE

Our aim was to go deeper in the self-perception of weight and health status among the Spanish population, together with the connections of familiar relationships, physical activity practice, nutritional habits, and sleep patterns with the presence of obesity.

METHODS

A total of 1,000 subjects were enrolled in April 2017 in a representative adult Spanish population sample. Computer-assisted telephone interviewing was used and self-reported anthropometric data was obtained.

RESULTS

The population was composed of 51.3% women, with a mean age of 48 (36-63) years and a BMI of 23.2 (20.3-26.6). Although only 17.7% of subjects with self-reported obesity exhibited the self-perception to suffer from obesity, they referred a bad (16%) or regular (47%) self-perceived health status. Subjects who considered themselves as people with overweight and obesity displayed a BMI of 30.5 (28.7-32.2) and 37.1 (34.8-41.5), respectively. The obesity group displayed the highest percentage (71.9%) of participants with some first-degree relative with overweight or obesity (p < 0.001) in comparison with the other groups. The main reason put forward of preventing healthy eating among subjects with obesity was that they dislike healthy food. The multivariable logistic regression model for presence of obesity showed that there was a significant association with older age, presence of a first-degree relative with weight excess, a positive snacking habit, and daily alcohol consumption (p ≤ 0.019).

CONCLUSION

The Spanish population has a low self-perception of obesity. Our data also reinforces the strong association between obesity and age, family interactions, usual snacking, and daily consumption of wine or beer.

Gender-specific mediators of the association between parental education and adiposity among adolescents: the HEIA study

Identifying the mechanisms behind socioeconomic inequalities in adiposity among youth is vital for efforts aimed at combating these inequalities. The study explored whether a broad range of behavioral and familial factors mediated the associations between parental education and indicators of adiposity among adolescents. Baseline data from a school-based intervention study conducted in 2007 among 11-year-old adolescents were used. Anthropometric outcomes, physical activity and sedentary time among adolescents were objectively measured. Other behavioral variables and parental waist circumference were self-reported. Mediation analyses were conducted. Among boys, maternal waist circumference (WC), paternal WC and TV viewing mediated 16%, 11.5% and 13% of the association between parental education and adolescent WC. The respective proportions when body fat percentage was used as the outcome variable were 22.5%, 16% and 21%. Among girls, maternal and paternal WC mediated 20% and 14% of the association between parental education and WC. The respective proportions when body fat percentage was used as the outcome variable were 14% and 10%. Other included variables did not play any mediating role. Parental WC was found to be a mediator of socioeconomic differences in adiposity in both genders; underlying mechanisms were however not investigated. Among boys, reducing TV time could contribute to the reduction of social inequalities in adiposity.

Relationship between Body Image and Body Weight Control in Overweight ≥55-Year-Old Adults: A Systematic Review

Objective: To assess the scientific evidence on the relationship between body image and body weight control in overweight ≥55-year-old adults. Methods: The literature search was conducted on MEDLINE database via PubMed, using terms related to body image, weight control and body composition. Inclusion criteria were scientific papers, written in English or Spanish, made on older adults. Exclusion criteria were eating and psychological disorders, low sample size, cancer, severe diseases, physiological disorders other than metabolic syndrome, and bariatric surgery. Results: Fifty-seven studies were included. Only thirteen were conducted exclusively among ≥55-year-old adults or performed analysis adjusted by age. Overweight perception was related to spontaneous weight management, which usually concerned dieting and exercising. More men than women showed over-perception of body image. Ethnics showed different satisfaction level with body weight. As age increases, conformism with body shape, as well as expectations concerning body weight decrease. Misperception and dissatisfaction with body weight are risk factors for participating in an unhealthy lifestyle and make it harder to follow a healthier lifestyle. Body image disturbance also made it more likely to underreport calorie intake. Conclusions: Aging is associated with a decrease in weight concerns and lower overweight perception, especially in women. However, when designing a program to improve body image in overweight ≥55-year-old adults, three items ought to be considered: physical activity, dietary and behavioral treatments.

Validation of Self-Reported Anthropometric Measures and Body Mass Index in a Subcohort of the DianaWeb Population Study

INTRODUCTION

DianaWeb is a community-based participatory project open to Italian breast cancer patients. The aim of the study was to assess the effectiveness of a lifestyle intervention in improving the prognosis after patients received diagnosis and surgery/chemotherapy. The DianaWeb study uses an interactive Web site (www.dianaweb.org) to monitor patients' lifestyles, and to obtain clinical and anthropometric data. Although detailed instructions for measuring height, body weight, waist circumference, and blood pressure (BP) are provided, individuals might tend to overestimate or underestimate those parameters. The aims of the present study were: (1) to compare self-recorded data with those from standardized ambulatory measurements; (2) to determine the trueness of a subject classification in the overweight/obesity or hypertensive subgroup on the basis of the patients' own measurements and estimates; and (3) to identify confounding variables.

PATIENTS AND METHODS

We compared self-reported with ambulatory measurements in a subgroup of 200 randomly selected women of approximately 1000 enrolled in the DianaWeb study (from September 2016 to March 2018).

RESULTS

Bland-Altman analysis showed a close agreement for self-reported and ambulatory-measured height, weight, and body mass index (BMI). On the contrary, women overestimated waist circumference and underestimated BP. Cohen κ statistics showed fair agreement only for hypertension. Binary logistic regression analysis showed that BMI and diastolic BP self-measurements were biased according to age.

CONCLUSION

The results suggest that self-reported height, weight, and BMI are satisfactorily accurate for patients in the DianaWeb study, such as accuracies of overweight/obese and central obesity classification, and that these data can be useful for our research.

Accuracy of self-reported height, weight, and waist circumference in a general adult Chinese population

Background

Self-reported height, weight, and waist circumference (WC) are widely used to estimate the prevalence of obesity, which has been increasing rapidly in China, but there is limited evidence for the accuracy of self-reported data and the determinants of self-report bias among the general adult Chinese population.

Methods

Using a multi-stage cluster sampling method, 8399 residents aged 18 or above were interviewed in the Jiangsu Province of China. Information on self-reported height, weight, and WC, together with information on demographic factors and lifestyle behaviors, were collected through structured face-to-face interviews. Anthropometrics were measured by trained staff according to a standard protocol.

Results

Self-reported height was overreported by a mean of 1.1 cm (95 % confidence interval [CI]: 1.0 to 1.2). Self-reported weight, body mass index (BMI), and WC were underreported by −0.1 kg (95 % CI: −0.2 to 0.0), −0.4 kg/m² (95 % CI: −0.5 to −0.3) and −1.5 cm (95 % CI: −1.7 to −1.3) respectively. Sex, age group, location, education, weight status, fruit/vegetable intake, and smoking significantly affected the extent of self-report bias. According to the self-reported data, 25.5 % of obese people were misclassified into lower BMI categories and 8.7 % of people with elevated WC were misclassified as normal. Besides the accuracy, the distribution of BMI and WC and their cut-off point standards for obesity of a population affected the proportion of obesity misclassification.

Conclusion

Amongst a general population of Chinese adults, there was rather high proportion of obesity misclassification using self-reported weight, height, and WC data. Self-reported anthropometrics are biased and misleading. Objective measurements are recommended.

Reliability and criterion validity of self-measured waist, hip, and neck circumferences

Background

Waist, hip, and neck circumference measurements are cost-effective, non-invasive, useful markers for body fat distribution and disease risk. For epidemiology and intervention studies, including body circumference measurements in self-report surveys could be informative. However, few studies have assessed the test-retest reliability and criterion validity of a self-report tool feasible for use in large scale studies.

Methods

At home, mothers of young children viewed a brief, online instructional video on how to measure their waist, hip, and neck circumferences. Afterwards, they created a homemade paper measuring tape from a downloaded file with scissors and tape, took all measurements in duplicate, and entered them into an online survey. A few weeks later, participants visited an anthropometrics lab where they measured themselves again, and trained technicians (n = 9) measured participants in duplicate using standard equipment and procedures. To assess differences between self- and technician-measured circumferences, duplicate measurements for participant home self-measurements, participant lab self-measurements, and technician measurements each were averaged and Wilcoxon signed-rank tests conducted. Agreement between all possible pairs of measurements were examined using Intraclass Correlations (ICCs) and Bland-Altman plots.

Results

Participants (n = 41; aged 38.05 ± 3.54SD years; 71 % white) were all mothers that had at least one child under the age of 12 yrs. Technical error of measurements for self- and technician- duplicate measurements varied little (0.08 to 0.76 inches) and had very high reliability (≥0.90). Intraclass Correlations (ICC) comparing self vs technician were high (0.97, 0.96, and 0.84 for waist, hip, and neck). Comparison of self-measurements at home vs lab revealed high test-retest reliability (ICC ≥ 0.87). Differences between participant self- and technician measurements were small (i.e., mean difference ranged from −0.13 to 0.06 inches) with nearly all (≥93 %) differences within Bland-Altman limits of agreement and <10 % exceeding the a priori clinically meaningful difference criterion.

Conclusions

This study has demonstrated a simple, inexpensive method for teaching novice mothers of young children to take their own body circumferences resulting in accurate, reliable data. Thus, collecting self-measured and self-reported circumference data in future studies may be a feasible approach in research protocols that has potential to expand our knowledge of body composition beyond that provided by self-reported body mass indexes.

Associations between adolescent and adult socioeconomic status and risk of obesity and overweight in Danish adults

BACKGROUND

It has been suggested that socioeconomic status (SES) may influence the risk of obesity; however it is important to consider individual changes in SES over the life-course in addition to SES at specific time-points to better understand the complex associations with obesity. We explored the relationship between lifetime-specific and life-course SES and risk of obesity and overweight in Danish adults.

METHODS

Data were used from the Danish Youth and Sports Study (DYSS) – a 20–22 year follow-up study of Danish teenagers born between 1964 and 1969. Baseline data gathered in 1983 and 1985 included self-reported BMI, SES and physical activity. The follow-up survey (2005) repeated these assessments in addition to an assessment of diet. Complete data on adolescent and adult SES and BMI were available for 623 participants.

RESULTS

Following adjustments, adolescent SES had no significant association with overweight/obesity in this sample, however females of low or medium adult SES were significantly more likely to be overweight/obese compared to those of high SES (low SES: OR: 2.7; 95% CI: (1.3–5.8); p = 0.008; medium SES: OR: 4.0, 95% CI (1.6–10.2); p = 0.003). Females who decreased in SES during adulthood were significantly more likely to be overweight/obese compared to those who remained of high SES (OR: 3.1; 95% CI (1.1–9.2); p = 0.04).

CONCLUSION

Effects of early life-factors may be conditional upon the environment in adulthood, particularly for the women. Further research should consider the timing of SES exposure and the mechanisms which may be responsible for the socioeconomic gradients in prevalence of obesity and overweight.

Eating behavior and perception of body shape in Japanese university students

PURPOSE

We investigated the relationship between eating behavior measured by the Dutch Eating Behaviour Questionnaire (DEBQ) and perception of body shape, examining the current physical status and 'ideal' physical parameters in females and males.

METHODS

The participants, 548 Japanese university students (age 19.2 ± 0.9 years, mean ± SD; 252 males, 296 females), completed a questionnaire which asked for their current physical status (e.g., weight and height), their ideal physical parameters, their perception of their current body shape, their ideal body shape, and their eating behaviors.

RESULTS

The ideal weight and ideal body mass index (BMI) were significantly higher than the current weight and BMI in the males, but significantly lower in the females. Among the females, the ideal body shape was smaller than their perception of current body shape. The DEBQ scores for restrained, emotional, and external eating were higher in the females than the males among the normal-weight participants, and among the underweight participants, the restrained eating and external eating scores were higher in the females than the males. Restrained eating was negatively associated with the discrepancy between the current and ideal weight, BMI, and body shape in both the males and females. Emotional eating was negatively associated with the discrepancy in current/ideal BMI and body shape only in the females.

CONCLUSIONS

At least in Japanese university students, the gender differences in ideal body shape are related to eating behavior.

Child-caregivers' body weight and habitual physical activity status is associated with overweight in kindergartners

Background

The aim of this study was to examine whether child-caregivers’, both parents and kindergarten teachers, health parameters (age, weight status, habitual physical activity score) are significantly associated with the risk of overweight in young children.

Methods

We assessed the individual body mass index standard deviation score in a regional cross-sectional health study and matched a representative sample of 434 kindergartners aged 3 to 6-years with their caregivers’ weight and habitual physical activity status. Furthermore, we identified factors associated with the general ability of child-caregivers to identify overweight in children, and the awareness to classify a child within the correct weight category.

Results

Our study confirmed most of the known associations between parental anthropometrics and psychosocial factors with childhood overweight and obesity. A significantly higher proportion of boys tended to be overweight or obese (p = 0.027) and parents were more likely to misclassified boys overweight as normal weight (OR: 1.86; 95% CI 1.21-2.86). Adjusted for confounders, logistic regression analysis revealed that kindergarten teachers’ weight status (OR: 1.97; 95%-CI: 1.01-3.83) and habitual physical activity scores (OR: 2.32; 95%-CI: 1.10-4.92) were associated with children’s weight status.

Conclusions

Kindergarten teachers’ weight and habitual physical activity score seem to be new independent risk factors for overweight in kindergartners 3 to 6-years of age. Our results suggest that the psychosocial, non-genetic association of non-parental child-caregivers on children’s weight is relatively high and that the association of non-parental child-caregivers warrants further investigation.

Validity of parentally reported versus measured weight, length and waist in 7- to 9-year-old children for use in follow-up studies

The aim of this prospective cohort study was to assess the validity of parentally reported anthropometric data compared to measured data in 7- to 9-year-old Flemish children especially for use in follow-up studies. The subjects were 116 Flemish children of a birth cohort recruited in the first Flemish Environment and Health Study (2002-2003). Data about anthropometric measures (waist circumference (WC), weight and length) were obtained by a postal parentally reported questionnaire and during a home visit. Our study showed that parents tend to overreport their child's WC and underreport the BMI, especially in children with large WC and high BMI. The median difference between measured and parentally reported WC was 1.6% of the median measured WC; for BMI, the median difference was 2.8% of the median measured BMI. Both for WC and BMI, we observed a good agreement between parentally reported values and measured values to classify children in the highest 10 and 20% of the study population. When classifying the children in 'overweight' and 'not overweight', there were less misclassifications when parentally reported WC was used compared to parentally reported BMI.

CONCLUSIONS

Although there is a high agreement between parentally reported and measured WC, the parentally reported data must be used with reserve. Moreover, this study is the first to suggest that WC is a better indicator compared to BMI when parentally reported values are used to classify children.

Obesity prevalence and unfavorable health risk behaviors among German kindergarten teachers: cross-sectional results of the kindergarten teacher health study

Background

The aim of the study was to investigate obesity status and associated health risk behaviors in a sample of German kindergarten teachers. At present, such data are not available, despite the fact that kindergarten teachers educate children at a formative time in their lives.

Methods

Kindergarten teachers aged 18–62 years (n = 313) were invited to participate in the Kindergarten Teacher Health Study (KTHS) by completing a self-reported questionnaire. We analyzed their obesity status, health risk behaviors (i.e., habitual physical activity, screen time activities, eating behavior patterns, smoking), and their general ability to identify overweight children and the associated health risks of overweight and obesity based on special age- and sex-specific silhouettes. After adjusting for covariates, bivariate correlations were conducted for associations between body mass index (BMI) and health risk behaviors, while analyses of variance (ANOVAs) were used to analyze differences of health risk behaviors between BMI groups. Logistic regression analyses were conducted to predict determinants of kindergarten teachers who did not correctly identify the overweight silhouettes and their associated physical and mental health risks. Additionally, data regarding kindergarten teachers’ weight status and smoking behavior were compared with nationally representative data from the 2009 Microcensus (n = 371310) using the Mann–Whitney U-test.

Results

The prevalence rates of overweight and obesity were 41.2% and 17.9%, respectively. The prevalence of obesity was significantly higher in kindergarten teachers (p < 0.001) compared to national Microcensus data. Only 44.6% of teachers were able to identify overweight children correctly. The fact that being overweight is associated with physical and mental health risks was only reported by 40.1% and 21.2% of teachers, respectively. Older kindergarten teachers were more likely to misclassify the overweight silhouettes, while younger, normal-weight, and overweight kindergarten teachers were more likely to underestimate the associated health risks. Obese kindergarten teachers reported spending more time in front of computer and television screens than their normal-weight counterparts, especially on weekends. In addition, obese kindergarten teachers reported eating less often with their families and more frequently reported watching television during meals.

Conclusions

Advanced monitoring and multifaceted interventions to improve the health behaviors of kindergarten teachers should be given high priority. Because kindergarten teachers’ behavioral modeling presumably mediates children’s health behaviors, additional research is needed about kindergarten teachers’ health and its proposed interaction with children’s health.

Validity of self-reported weight and height in Austrian adults: sociodemographic determinants and consequences for the classification of BMI categories

Objective

Epidemiological studies have shown that adults tend to underestimate their weight and overestimate their height. This may lead to a misclassification of their BMI in studies based on self-reported data. The aim of the present study was to assess the validity of self-reported weight and height in Austrian adults.

Design

Data on weight, height, health behaviour and sociodemographic characteristics of adults were collected in a standardized procedure via a self-filling questionnaire and a medical examination including measurements of weight and height.

Setting

A publicly accessible out-patient clinic in southern Austria.

Subjects

Austrian residents (n473) aged 18 years and older who attended a health check participated in the study.

Results

The mean difference between reported and measured BMI was not significant in younger adults (<35 years: mean difference −0·21 kg/m2;P< 0·08) but increased significantly with age (≥55 years: mean difference −0·68 kg/m2;P< 0·001). The prevalence of normal weight (BMI = 18·5–24·9 kg/m2) and overweight (BMI = 25·0–29·9 kg/m2) was overestimated based on the self-reported data on BMI, while that for underweight (BMI < 18·5 kg/m2) and obesity (BMI ≥ 30·0 kg/m2) was underestimated (P< 0·001). The self-reported data showed an obesity prevalence of 12·5 %, while measurement showed a prevalence of 15·4 % (P< 0·001).

Conclusions

Our results indicate that prevalence rates of obesity are probably underestimated for Austrian adults when using self-reported weight and height information. The deviations from the measured data clearly increased with age. Analyses based on self-reported data should therefore be adjusted for the age dependency of the validity.

Video instructions improve accuracy of self-measures of waist circumference compared with written instructions

OBJECTIVE

To determine whether video-based instructions improve the accuracy of self-measures of waist and hip circumference compared with written instructions.

DESIGN

Population-based, cross-sectional study. Self-measurements of waist circumference (WC) and hip circumference (HC) of fifty-seven participants randomly allocated to receive either written instruction or video instruction were compared with those of a trained technician.

SETTING

Aberdeen, Scotland, and Brussels, Belgium, between February and April 2010.

SUBJECTS

Adults aged 18-62 years with a high level of English language and no prior training in anthropometry.

RESULTS

WC was significantly overestimated by the written method (1·75 cm bias; P = 0·007) but not the video method (0·95 cm bias; P = 0·239). HC was significantly underestimated in both written (-0·35 cm bias; P = 0·009) and video methods (-0·75 cm bias; P = 0·046). Reliability was not significantly affected by age, sex, BMI or WC. Bland-Altman plots demonstrated wide limits of agreement for WC (-6·83, 6·08 cm for written method; -10·14, 6·72 cm for video method) and HC (-12·85, 1·60 cm for written method; -10·82, 2·50 cm for video method).

CONCLUSIONS

Video technology can support more accurate self-measurements of anthropometric data in epidemiological studies. Further research is warranted using larger and more heterogeneous samples in order that results can be generalised.

Self-reported and measured anthropometric data and risk of colorectal cancer in the EPIC-Norfolk study

BACKGROUND

Epidemiological studies have shown inconsistent results for the association between body size and colorectal cancer (CRC) risk. Inconsistencies may be because of the reliance on self-reported measures of body size.

OBJECTIVE

We examined the association of self-reported and directly assessed anthropometric data (body height, weight, body mass index (BMI), waist, hip, waist-to-hip ratio (WHR) and chest circumference) with CRC risk in the EPIC-Norfolk study.

DESIGN

A total of 20,608 participants with complete self-reported and measured height and weight and without any history of cancer were followed up an average of 11 years, during which 357 incident CRC cases were recorded. Hazard Ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models.

RESULTS

After adjustment for confounders, HRs among women in the highest quintile of the body size measure relative to the lowest quintile showed that measured height (HR=1.98, 95% CI=1.19-3.28, P (trend)=0.009), measured waist circumference (HR=1.65, 95% CI=0.97-2.86, P (trend)=0.009) and measured WHR (HR=2.07, 95% CI=1.17-3.67, P (trend)=0.001) were associated with increased CRC risk. Associations using corresponding self-reported measures were attenuated and not statistically significant. Conversely, the association of BMI with CRC risk in women was weaker using measured BMI (HR=1.57, 95% CI=0.91-2.73, P (trend)=0.05) compared with self-reported BMI (HR=1.97, 95% CI=1.18-3.30, P (trend)=0.02). In men no significantly increased CRC risk was observed with any of the anthropometric measures.

CONCLUSIONS

Measured height, waist circumference and WHR were associated with CRC risk in women, whereas any significant associations with those measures were attenuated when self-reported data were used.

Effects of body size and sociodemographic characteristics on differences between self-reported and measured anthropometric data in middle-aged men and women: the EPIC-Norfolk study

BACKGROUND/OBJECTIVES

To investigate the effects of body size and sociodemographic characteristics on differences between self-reported (SR) and measured anthropometric data in men and women.

SUBJECTS/METHODS

This study comprises 9933 men and 11,856 women aged 39-79 years at baseline survey (1993-1997) in the EPIC-Norfolk study (Norfolk arm of the European Investigation into Cancer and Nutrition Study). The effects of sex, measured height, weight, age group, educational level and social class on differences between SR and measured weight, height, body mass index (BMI), waist, hip and waist-to-hip ratio (WHR) were examined.

RESULTS

There were systematic differences between SR and measured anthropometric measurements by sex, measured height, weight and sociodemographic characteristics. Height was overestimated in both sexes while weight, waist, hip, and consequently, BMI and WHR were underestimated. Being male, shorter, heavier, older, and having no educational qualifications and manual occupation were independently associated with overreporting of height, and underreporting of weight was associated independently with being female, shorter, heavier, younger age, and higher education level and social class. Underreporting of waist circumference was strongly associated with being female and higher measured waist circumference, while underreporting of hip circumference was associated with being male and higher measured hip circumference. Furthermore, there was substantial degree of misclassification of BMI and waist circumference categories for both general and central obesity associated with SR data.

CONCLUSIONS

These findings suggest that errors in SR anthropometric data, especially waist and hip circumference are influenced by actual body size as well as sociodemographic characteristics. These systematic differences may influence associations between SR anthropometric measures and health outcomes in epidemiological studies.

Accuracy of self-reported body weight, height and waist circumference in a Dutch overweight working population

Background

In population studies, body mass index (BMI) is generally calculated from self-reported body weight and height. The self-report of these anthropometrics is known to be biased, resulting in a misclassification of BMI status. The aim of our study is to evaluate the accuracy of self-reported weight, height and waist circumference among a Dutch overweight (Body Mass Index [BMI] ≥ 25 kg/m²) working population, and to determine to what extent the accuracy was moderated by sex, age, BMI, socio-economic status (SES) and health-related factors.

Methods

Both measured and self-reported body weight and body height were collected in 1298 healthy overweight employees (66.6% male; mean age 43.9 ± 8.6 years; mean BMI 29.5 ± 3.4 kg/m²), taking part in the ALIFE@Work project. Measured and self-reported waist circumferences (WC) were available for a sub-group of 250 overweight subjects (70.4% male; mean age 44.1 ± 9.2 years; mean BMI 29.6 ± 3.0 kg/m²). Intra Class Correlation (ICC), Cohen's kappa and Bland Altman plots were used for reliability analyses, while linear regression analyses were performed to assess the factors that were (independently) associated with the reliability.

Results

Body weight was significantly (p < 0.001) under-reported on average by 1.4 kg and height significantly (p < 0.001) over-reported by 0.7 cm. Consequently, BMI was significantly (p < 0.001) under-reported by 0.7 kg/m². WC was significantly (p < 0.001) over-reported by 1.1 cm. Although the self-reporting of anthropometrics was biased, ICC's showed high concordance between measured and self-reported values. Also, substantial agreement existed between the prevalences of BMI status and increased WC based on measured and self-reported data. The under-reporting of BMI and body weight was significantly (p < 0.05) affected by measured weight, height, SES and smoking status, and the over-reporting of WC by age, sex and measured WC.

Conclusion

Results suggest that self-reported BMI and WC are satisfactorily accurate for the assessment of the prevalence of overweight/obesity and increased WC in a middle-aged overweight working population. As the accuracy of self-reported anthropometrics is affected by measured weight, height, WC, smoking status and/or SES, results for these subgroups should be interpreted with caution. Due to the large power of our study, the clinical significance of our statistical significant findings may be limited.

Trial Registration

ISRCTN04265725

Underreporting of BMI in adults and its effect on obesity prevalence estimations in the period 1998 to 2001

OBJECTIVE

To identify the determinants of underreporting BMI and to evaluate the possibilities of using self-reported data for valid obesity prevalence rate estimations.

RESEARCH METHODS AND PROCEDURES

A cross-sectional monitoring health survey was carried out between 1998 and 2002, and a review of published studies was performed. A total of 1809 men and 1882 women ages 20 to 59 years from The Netherlands were included. Body weight and height were reported and measured. Equations were calculated to estimate individuals' BMI from reported data. These equations and equations from published studies were applied to the present data to evaluate whether using these equations led to valid estimations of the obesity prevalence rate. Also, size of underestimation of obesity prevalence rate was compared between studies.

RESULTS

The prevalence of obesity was underestimated by 26.1% and 30.0% among men and women, respectively, when based on reported data. The most important determinant of underreporting BMI was a high BMI. When equations to calculate individuals' BMI from reported data were used, the obesity prevalence rate was still underestimated by 12.9% and 8.1% of the "true" obesity prevalence rate among men and women, respectively. The degree of underestimating the obesity prevalence was inconsistent across studies. Applying equations from published studies to the present data led to estimations of the obesity prevalence varying from a 7% overestimation to a 74% underestimation.

DISCUSSION

Valuable efforts for monitoring and evaluating prevention and treatment studies require direct measurements of body weight and height.