Challenging the role of social norms regarding body weight as an explanation for weight, height, and BMI misreporting biases: development and application of a new approach to examining misreporting and misclassification bias in surveys

The Epidemiology of Berry Consumption and Association of Berry Consumption with Diet Quality and Cardiometabolic Risk Factors in United States Adults: The National Health and Nutrition Examination Survey, 2003-2018

BACKGROUND

Berries are rich in important nutrients and bioactive compounds, which could potentially contribute to maintenance of normal lipid and glucose profiles.

OBJECTIVE

We reported the epidemiology of berry consumption and examined associations of berry consumption with diet quality [measured by Healthy Eating Index (HEI-2015)] and levels of cardiometabolic risk factors, including body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure, total cholesterol, high-density lipoprotein cholesterol (HDL cholesterol), glycated hemoglobin, and fasting biomarkers: triglycerides, low-density lipoprotein cholesterol (LDL cholesterol), glucose, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR).

METHODS

We evaluated 33,082 adults (aged ≥20 y) using two 24-h diet recalls from National Health and Nutrition Examination Survey (2003-2018). Multivariable linear regression models were applied to examine the associations of total and individual berry intake with diet quality and cardiometabolic risk factors using appropriate sample weights.

RESULTS

Approximately 25 % of the United States adults consumed berries (0.08 ± 0.003 cup-equivalents/d), representing ∼10 % of the daily mean total fruit intake. Among berry consumers, the mean intake of strawberries (0.31 ± 0.01 cup-equivalents) was higher than for other berries. Berry consumers had a significantly higher HEI-2015 score than nonconsumers (mean HEI-2015 score = 58.8 compared with 52.3, P < 0.0001). Berry consumers had significantly lower concentrations of cardiometabolic indices than nonconsumers, including BMI, WC, SBP, total cholesterol, LDL cholesterol, triglycerides, fasting insulin, HOMA-IR, and higher mean HDL cholesterol, after adjusting for sociodemographic, lifestyle, and dietary confounders (all P < 0.05).

CONCLUSIONS

United States adult berry consumers had a higher diet quality and lower concentrations of cardiometabolic risk factors, suggesting a favorable role for berries in diets and cardiometabolic disease prevention in United States adult population.

How tall am I again? A longitudinal analysis of the reliability of self-reported height

Self-reported height measures are increasingly being included in large-scale surveys in order to measure BMI. There have been concerns about the validity of self-reported measures but there remains little understanding of why respondents may not give accurate height reports. We examine whether a lack of knowledge could be a contributing factor, by investigating the reliability of self-reported height over time and across countries. We use longitudinal data from four large-scale longitudinal surveys conducted in Australia, United States, United Kingdom, and Europe (14 countries) where survey respondents were asked to report their height over multiple time periods to measure the extent of consistency of height reports across time. The overall level of inconsistent reporting of height is largest in Australia and Europe. Individuals with lower levels of education were significantly more likely to give two height reports that differed by 5 cm or more. Across all countries, inconsistent reporting with large height differences between waves was also more common among those in older populations. The findings point to subgroups of the population exhibiting a lack of knowledge regarding their own height.

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.

Accuracy of self-reported height, weight and BMI in a multiethnic Asian population

Introduction: The study assessed whether self-reported height, weight and derived body mass index (BMI) can provide an accurate measure of anthropometric data in a multiethnic adult population in Singapore. Methods: Standardised anthropometric measurements were compared against the self-reported values from 5,132 adult residents in a cross-sectional, epidemiological survey. Discrepancies in self-reports from measurements were examined by comparing overall mean differences. Intraclass correlations, Cohen’s kappa and Bland-Altman plots with limits of agreement, and sub-analysis by sex and ethnicity were also explored. Results: Data were obtained from 5,132 respondents. The mean age of respondents was 43.9 years. Overall, the height was overestimated (0.2cm), while there was an underestimation of weight (0.8kg) and derived BMI (0.4kg/m2). Women had a larger discrepancy in height (0.35cm, 95% confidence interval [CI] 0.22 to 0.49), weight (-0.95kg, 95% CI -1.11 to -0.79) and BMI (-0.49kg/m2, 95% CI -0.57 to -0.41) compared with men. Height reporting bias was highest among Indians (0.28cm, 95% CI 0.12 to 0.44) compared with Chinese and Malays, while weight (-1.32kg, 95% CI -1.53 to -1.11) and derived BMI (-0.57kg/m2, 95% CI -0.67 to -0.47) showed higher degrees of underreporting among Malays compared with Chinese and Indians. Substantially high self-reported versus measured values were obtained for intraclass correlations (0.96–0.99, P<0.001) and kappa (0.74). For BMI categories, good to excellent kappa agreement was observed (0.68–0.81, P<0.0001). Conclusion: Self-reported anthropometric estimates can be used, particularly in large epidemiological studies. However, sufficient care is needed when evaluating data from Indians, Malays and women as there is likely an underestimation of obesity prevalence. Keywords: Body mass index, epidemiology, public health, self-report, validity

Misreporting Weight and Height Among Mexican and Puerto Rican Men

Most obesity prevalence data rely on self-report, which typically differs when compared to objectively measured height, weight, and body mass index (BMI). Given that Latino men have high rates of obesity in the United States and demonstrate greater misreporting compared to Caucasian men, examining the factors that contribute to misreporting among Latino men is warranted. This study examined BMI, Latino ethnic background (Mexican or Puerto Rican), and social desirability in relation to misreporting of BMI, as defined as the discrepancy between self-reported and measured height and weight, in Latino men. Participants were 203 adult Mexican and Puerto Rican men, average age 39.41 years, who participated in a larger study. Participants self-reported their weight and height, had their weight and height objectively measured, and completed a measure of social desirability. Measured BMI was the strongest predictor of misreporting BMI, such that the greater the participants' BMI, the greater the discrepancy in BMI (p < .001). Misreporting of BMI did not vary based on ethnic background, and measured BMI did not moderate the relationship between social desirability and misreporting of BMI. When normative error was distinguished from misreporting in post-hoc analyses, results showed that only 34.5% of participants demonstrated misreporting. Findings highlight the importance of identifying normative error when examining misreporting in order to improve the accuracy of self-reported BMI data. Future research on misreporting for Latino men should include weight awareness, acculturation, and length of U.S. residency as these variables may be related to self-reported weight and height.

Dietary Quality Changes According to the Preceding Maximum Weight: A Longitudinal Analysis in the PREDIMED-Plus Randomized Trial

One-year dietary quality change according to the preceding maximum weight in a lifestyle intervention program (PREDIMED-Plus trial, 55–75-year-old overweight or obese adults; n = 5695) was assessed. A validated food frequency questionnaire was used to assess dietary intake. A total of 3 groups were made according to the difference between baseline measured weight and lifetime maximum reported weight: (a) participants entering the study at their maximum weight, (b) moderate weight loss maintainers (WLM), and (c) large WLM. Data were analyzed by General Linear Model. All participants improved average lifestyle. Participants entering the study at their maximum weight were the most susceptible to improve significantly their dietary quality, assessed by adherence to Mediterranean diet, DII and both healthful and unhealthful provegetarian patterns. People at maximum weight are the most benefitted in the short term by a weight management program. Long term weight loss efforts may also reduce the effect of a weight management program.

Validity assessment of self-reported weight and its correction process among Mexican adult women of reproductive age

Objective

We aimed to evaluate the agreement between self-reported weight (SRW) and measured weight (MW) in adult women of reproductive age, identify characteristics associated with the difference between SRW and MW (DW), and develop a correction procedure for SRW.

Methods

We used data from 3,452 non-pregnant or non-lactating adult women who participated in the Mexican Family Life Survey. Standardized personnel asked women about their weight before measuring weight and height. We conducted a Bland-Altman analysis for agreement and adjusted linear regression models for sociodemographic characteristics.

Results

Mean DW was -0.59±3.21 kg. Difference varied according to Body Mass Index (BMI) and region of residence (p< 0.05). Correction model for log-MW, included the log-SRW, age group (18–34 and 35–49 years), interaction term (age × SRW), log-height, Southern region, and living with a partner. Based on self-reported weight, we observed an overestimation of underweight/normal weight prevalence and an underestimation of overweight or obesity prevalence.

Conclusion

SRW has limitations to be considered as an alternative to MW among women of reproductive age with specific characteristics. Our proposed correction equation may decrease SRW imprecision improving the estimation of overweight and obesity. We suggest that studies consider and adjust the possible bias associated with weight misreporting on health outcomes.

Adherence to the Mediterranean Lifestyle and Desired Body Weight Loss in a Mediterranean Adult Population with Overweight: A PREDIMED-Plus Study

Background. Body weight dissatisfaction is a hindrance to following a healthy lifestyle and it has been associated with weight concerns. Objectives. The aim of this study was to assess the association between the adherence to the Mediterranean lifestyle (diet and exercise) and the desired body weight loss in an adult Mediterranean population with overweight. Methods. Cross-sectional analysis in 6355 participants (3268 men; 3087 women) with metabolic syndrome and BMI (Body mass index) between 27.0 and 40.0 kg/m² (55–75 years old) from the PREDIMED-Plus trial. Desired weight loss was the percentage of weight that participants wished to lose. It was categorized into four cut-offs of this percentage (Q1: <10%, n = 1495; Q2: 10–15%, n = 1804; Q3: <15–20%, n = 1470; Q4: ≥20%, n = 1589). Diet was assessed using a validated food frequency questionnaire and a 17-item Mediterranean diet questionnaire. Physical activity was assessed by the validated Minnesota-REGICOR and the validated Spanish version of the Nurses’ Health Study questionnaire. Results. Participants reporting higher percentages of desired weight loss (Q3 and Q4) were younger, had higher real and perceived BMI and were more likely to have abdominal obesity. Desired weight loss correlated inversely to physical activity (Q1: 2106 MET min/week; Q4: 1585 MET min/week. p < 0.001) and adherence to Mediterranean diet (Q1: 8.7; Q4: 8.3. p < 0.001). Conclusions. In older Mediterranean individuals with weight excess, desired weight loss was inversely associated with Mediterranean lifestyle adherence. Deeply rooted aspects of the MedDiet remained similar across groups. Longitudinal research is advised to be able to establish causality.

Use and reporting of Bland-Altman analyses in studies of self-reported versus measured weight and height

BACKGROUND/OBJECTIVES

Bland-Altman methods for assessing the agreement between two measures are highly cited. However, these methods may often not be used to assess agreement, and when used, they are not always presented or interpreted correctly. Our objective was to evaluate the use and the quality of reporting of Bland-Altman analyses in studies that compare self-reported with measured weight and height.

METHODS

We evaluated the use of Bland-Altman methods in 394 published articles that compared self-reported and measured weight and height data for adolescents or adults. Six reporting criteria were developed: assessment of the normality of the distribution of differences, a complete and correctly labeled Bland-Altman plot displaying the mean difference and limits of agreement (LOA), numerical values and confidence intervals, standard errors, or standard deviations for mean difference, numerical values of LOA, confidence intervals for LOA, and prespecified criteria for acceptable LOA.

RESULTS

Only 72/394 (18%) studies comparing self-reported with measured weight and height or BMI used some form of Bland-Altman analyses. No study using Bland-Altman analyses satisfied more than four of the six criteria. Of the 72 studies, 64 gave mean differences along with confidence intervals or standard deviations, 55 provided complete Bland-Altman plots that were appropriately labeled and described, 37 provided numerical values for LOA, 4 reported that they examined the normality of the distribution of differences, 3 provided confidence intervals for LOA, and 3 had prespecified criteria for agreement.

CONCLUSIONS

Bland-Altman methods appear to be infrequently used in studies comparing measured with self-reported weight, height, or BMI, and key information is missing in many of those that do use Bland-Altman methods. Future directions would be defining acceptable LOA values and improving the reporting and application of Bland-Altman methods in studies of self-reported anthropometry.

Body image (dis)satisfaction among low-income adult women

BACKGROUND & AIMS

A better understanding of the factors that affect self-perception of body characteristics may play an important role in weight control practices. The objective of this study was to analyze body weight perception and body image satisfaction in low-income adult women in Southern Brazil.

METHODS

This was a cross-sectional survey study in a cohort of women recruited from areas of social vulnerability in the city of Porto Alegre, RS. A random sample (n = 218) of women was interviewed, and socioeconomic and lifestyle factors, body image perception using the Stunkard Scale, body weight estimation, weight concern and duplicate anthropometric measurements were obtained.

RESULTS

The average age of the low-income women was 56.3 ± 9.5 years. The prevalences of overweight and obese individuals were 34.1% and 52.5%, respectively. Among all women, 83.0% were dissatisfied with their body image, and 68.9% of the women estimated their body weight correctly. In addition to BMI (body mass index), the proportions of women with a higher income (p = 0.05), smoking history (p < 0.01) and history of hypertension (p = 0.04) were significantly different between groups according to body image satisfaction. Multivariate analyses using Poisson regression showed that black/mixed race, higher income, and underweight and obese women were more likely to be dissatisfied with their body image.

CONCLUSIONS

The majority of women know their body weight and have body image dissatisfaction. Skin color, higher income and BMI were significantly associated with dissatisfaction. In addition, these women consider the "healthiest" body image to be thinner than the "ideal" body image, and the "ideal" image is one of normal weight and not too thin.

Extreme under-reporting of body weight by young adults with obesity: relation to social desirability

Objective

The objective of this study was to determine whether there is an association between under‐reporting of body weight and social desirability as is found with self‐reports of energy intake.

Methods

Twenty‐seven lean individuals (mean body mass index ± standard deviation = 21.6 ± 2.0 kg m⁻²) and 26 individuals with obesity (mean body mass index = 35.4 ± 4.8 kg m⁻²) were e‐mailed a questionnaire on which they had to state their body weight and conduct a home food inventory. The next day, research team members went to their homes to weigh the participants, conduct their own food inventory and administer the Marlowe–Crowne scale for social desirability.

Results

Among individuals with obesity, lower social desirability scores were associated with a greater degree of under‐reporting body weight (r = +0.48, p < 0.02). Among lean individuals, the correlation was negative but statistically non‐significant (p = −0.22, p > 0.10). Nine individuals with obesity were extreme under‐reporters (2.27 kg or more), and eight of these had social desirability scores in the bottom half of the Marlowe–Crowne scale (p < 0.01). Six under‐reported on the home food inventory by three or more items.

Conclusions

Individuals with obesity and low social desirability scores are more likely than others to be extreme under‐reporters of body weight, possibly due to a lack of awareness of their own weight.

Validity of self-reported weight, height, and BMI in mothers of the research Birth in Brazil

OBJECTIVE

To evaluate the accuracy of information on pre-gestational weight, height, pre-gestational body mass index, and weight at the last prenatal appointment, according to maternal characteristics and sociodemographic and prenatal variables.

METHODS

The study was developed using data from the face-to-face questionnaire and prenatal card (gold standard) of the study "Birth in Brazil, 2011-2012". To evaluate the differences between the measured and self-reported anthropometric variables, we used the the Kruskal-Wallis test for the variables divided into quartiles. For the continuous variables, we used the Wilcoxon test, Bland-Altman plot, and average difference between the information measured and reported by the women. We estimated sensitivity and the intraclass correlation coefficient.

RESULTS

In the study, 17,093 women had the prenatal card. There was an underestimation of pre-gestational weight of 1.51 kg (SD = 3.44) and body mass index of 0.79 kg/m2 (SD = 1.72) and overestimation of height of 0.75 cm (SD = 3.03) and weight at the last appointment of 0.22 kg (SD = 2.09). The intraclass correlation coefficients (ICC) obtained for the anthropometric variables were: height (ICC = 0.89), pre-gestational weight (ICC = 0.96), pre-gestational body mass index (ICC = 0.92), and weight at the last appointment (ICC = 0.98).

CONCLUSIONS

The results suggest that the mentioned anthropometric variables were valid for the study population, and they may be used in studies of populations with similar characteristics.

You can be too thin (but not too tall): Social desirability bias in self-reports of weight and height

Previous studies of survey data from the U.S. and other countries find that women tend to understate their body weight on average, while both men and women overstate their height on average. Social norms have been posited as one potential explanation for misreporting of weight and height, but lack of awareness of body weight has been suggested as an alternative explanation, and the evidence presented to date is inconclusive. This paper is the first to offer a theoretical model of self-reporting behavior for weight and height, in which individuals face a tradeoff between reporting an accurate weight (or height) and reporting a socially desirable weight (or height). The model generates testable implications that help us to determine whether self-reporting errors arise because of social desirability bias or instead reflect lack of awareness of body weight and/or other factors. Using data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010, we find that self-reports of weight offer robust evidence of social desirability bias. However, lack of awareness of weight may also contribute to self-reporting biases, and this factor appears to be more important within some demographic groups than others. Among both women and men, self-reports of height exhibit significant social desirability bias only among those of below-average height, and very few individuals underreport their height. Implied self-reports of BMI exhibit gender-specific patterns similar to those observed for self-reporting of weight, and the inferred social norms for BMI (20.8 for women and 24.8 for men) are within the "normal" range established by public health institutions. Determining why individuals misreport their weight has important implications for survey design as well as for clinical practice. For example, our findings suggest that health care providers might take additional steps to increase self-awareness of body weight. The framework also helps to explain previous findings that the degree of self-reporting bias in weight is stronger in telephone surveys than it is in in-person surveys.

Validity of self-reported anthropometry in adult Mexican women

OBJECTIVE:

To compare direct and self-reported anthropometry in Mexican women.

MATERIALS AND METHODS:

Women aged 30-72 years, participating in the Mexican Teachers' Cohort, completed a questionnaire with their anthropometric data in 2006-2008. After eleven months (median time), technicians performed anthropometry in 3756 participants. We calculated correlations and multivariable-adjusted mean differences between direct and self-reported anthropometric measures.

RESULTS:

Correlations between direct and self-reported anthropometric measures ranged from 0.78 (waist circumference) to 0.93 (weight). On average, women over-reported their height by 2.2 cm and underreported their weight, body mass index (BMI) and waist and hip circumferences by 1.3 kg, 1.3 kg/m2, 1.8 cm and 1.9 cm, respectively. Errors in self-reported anthropometry increased with rising measured BMI and were also independently associated with age, education and socioeconomic status.

CONCLUSION:

Self-reported anthropometry is sufficiently valid for epidemiological purposes in adult Mexican women. Errors in self-reported anthropometry might result in underestimation of the prevalence of overweight and obesity.

Body image satisfaction and weight concerns among a Mediterranean adult population

Background

People tend to underestimate their current weight and overestimate their height minimizing health risk factors. The aim of this study was to assess body weight satisfaction, acceptance of body image, weight concern and dieting habits among a Mediterranean adult population.

Methods

Cross-sectional survey was carried out (2009–2010) in the Balearic Islands, Spain. A random sample (n = 1081) of young (18–35 y.o.) and middle-aged adults (36–55 y.o.) was interviewed and anthropometrically measured.

Results

Women were more dissatisfied being overweight, less dissatisfied being underweight, and more worried about weight gain than men. Middle-aged participants were more dissatisfied with body shape and underestimated body weight than young’s. Employed women defined better current weight than unemployed, but unemployed were more worried about body weight gain. Overweight adults were more likely to underestimate their body weight but were also very worried about weight gain and more likely to report current dieting than their leaner counterparts. Active participants self-reported better body weight and were more satisfied with body image than sedentary.

Conclusions

Most of studied population reported body image dissatisfaction, but half of them are not worried about it. Women were more concerned about their body weight status. Practice of physical activity is a positive factor in self-perception. Holistic strategies are needed to avoid promoting unreal bodies, as well as the acceptance of the real body image.

A feasibility study to assess the validity of administrative data sources and self-reported information of breast cancer survivors

BACKGROUND

Cancer survivorship has increasingly become the focus of research due to progress in early detection and advancements in the therapeutic approach, but high-quality information sources for outcomes, potential confounders and personal characteristics present a challenge. Few studies have collected breast cancer care data from mixed data sources and validated them, and to the best of our knowledge, none so far have been conducted in Israel, where National Health Insurance Law assures universal health care, delivered through four health care funds with computerized administrative, pharmaceutical and medical databases. This validation study is aimed to assess the accuracy and completeness of information on cancer care and health outcomes using several research tools, before embarking on a full-scale study aimed to evaluate the long-term treatment-related health adverse outcomes in a cohort of breast cancer survivors.

METHODS

One hundred twenty randomly sampled female patients diagnosed with primary breast cancer in years 2000-2010 in northern Israel, who are members of the "Leumit" healthcare fund, were included. Data sources included "Leumit" medical records, the National Cancer Registry and a self-report questionnaire. The questionnaire was completed by 99 % of the women contacted. The accuracy of the information regarding cancer care was assessed with the reference standard set as one of the research tools, varying per the characteristic being under investigation. For example: health outcomes and medical history were validated against "Leumit" medical records, while construct validity of the self-reported questionnaire served to assess the prevalence of chronic pain. Agreement, predictive values, correlations, and internal consistency were calculated. Logistic regression models were constructed to assess potential predictors of correct responses.

RESULTS

The overall level of agreement (Kappa) was almost perfect for demographics and outcomes, above 0.8 for treatments and chronic pain, while only fair to moderate for most of the self-reported medical history. Correct responses of medical history were associated with Jewish ethnicity, recency of breast cancer diagnosis, and family history of cardiovascular disease. The internal consistency of the quality-of-life scale was above 0.9.

CONCLUSION

In the absence of a national registry for cancer care, a mixed methodology for data collection is the most complete source.

TRIAL REGISTRATION

Trial registration number Not available. This is an observational study with prospective data collection and no intervention; therefore, trial registration number is not required.

Speaker height estimation from speech: Fusing spectral regression and statistical acoustic models

Estimating speaker height can assist in voice forensic analysis and provide additional side knowledge to benefit automatic speaker identification or acoustic model selection for automatic speech recognition. In this study, a statistical approach to height estimation that incorporates acoustic models within a non-uniform height bin width Gaussian mixture model structure as well as a formant analysis approach that employs linear regression on selected phones are presented. The accuracy and trade-offs of these systems are explored by examining the consistency of the results, location, and causes of error as well a combined fusion of the two systems using data from the TIMIT corpus. Open set testing is also presented using the Multi-session Audio Research Project corpus and publicly available YouTube audio to examine the effect of channel mismatch between training and testing data and provide a realistic open domain testing scenario. The proposed algorithms achieve a highly competitive performance to previously published literature. Although the different data partitioning in the literature and this study may prevent performance comparisons in absolute terms, the mean average error of 4.89 cm for males and 4.55 cm for females provided by the proposed algorithm on TIMIT utterances containing selected phones suggest a considerable estimation error decrease compared to past efforts.

The role of answering behaviours on weight misreporting

BACKGROUND

Biases in self-reported weight are very common among young adults and adults. Although social norms are the most commonly accepted explanation for these misreports, corresponding evidence is scarce and conflict-ridden. An alternative explanation for biases in weight self-reports comes from answering behaviours; non-random rounding, formally an answering behaviour, has been found to play a significant role in several studies of weight misreporting. However, the presumably rich role of answering behaviours has seldom been explored. This study brings a second answering behaviour into the analysis: inconsistency.

METHODS

An inconsistency index was computed as an individual-level score from several questions across waves in the National Health and Nutrition Examination Survey. By regression analysis (N=3480 men and 1856 women) the simultaneous role of inconsistency and of non-random rounding on weight misreporting was explored.

RESULTS

Inconsistency was found to be associated with higher self-reported weights. Inconsistent individuals provided significantly different misreports, with women under-reporting 0.23[kg] (0.01-0.45) less and men over-reporting 0.42[kg] (0.02-0.82) more than their consistent counterparts. Inconsistency was found to play a simultaneous and substantially larger role than non-random rounding. This result was clearer among men than it was among women.

DISCUSSION

Although social norms are usually thought to be the central explanation of weight-biased misreports, there are other factors, such as answering behaviours, that might play a more influential role.

Gender comparisons of physical fitness indexes in Inner Mongolia medical students in China

Introduction:

The aim of present study was to investigate gender differences in physical fitness indexes in regard to BMI (body mass index) levels among Inner Mongolia medical students in China.

Methods:

Data on participant characteristics came from basic information contained in the school database. Physical fitness indexes including BMI, vital capacity index, sidestep test, and standing long jump, were conducted.

Results:

Female students had a higher rate of normal weight than those of males. The obesity rate of males was 5 times higher compared to females. Compared with male students, female students had a higher pass rate in vital capacity index, sidestep and standing long jump. Females were higher 17% than males in the pass rate of the sidestep test. Males performed better than females in the standing long jump. In both the malnutrition and normal weight group, the pass rate of the 3 physical fitness indexes for both male and female students was higher than obese group. The not pass rate was higher than pass rate both male and female students in the vital capacity index in the obese group.

Discussion:

Males had a poor physical fitness level compared with females. Male students may be more likely to spend more time using computers and it will cut down the time of participating in physical activities. So, in our university, more attention should pay on physical education, especially for males.

Self-reported anthropometric information cannot vouch for the accurate assessment of obesity prevalence in populations of middle-aged and older Korean individuals

While there are strong correlations between self-reported and directly measured anthropometric data, the discrepancy and systematic errors associated with these, particularly among middle-aged and older persons residing in South Korea, remain a contentious issue. All participants were selected from the Korean Longitudinal Study of Aging (KLoSA), a panel study conducted by the Korea Labor Institute; data from 510 participants (290 females; 56.9%) were analyzed. We considered general characteristics, including sex, age, education, marital status, employment, income, and residential region, and used self-rated health (SRH) as a generic indicator of health status. One-way ANOVA, t-test, and Scheffé's test (α=0.1) were employed to explore the difference between directly measured and self-reported values. Sensitivity and specificity values were used to assess the validity of obesity diagnoses based on self-reported body mass index (BMI: body weight in kilograms divided by the square of height in meters). The means of BMI differences were 1.3 (±1.2)kg/m(2) among men and 1.8 (±1.5)kg/m(2) among women. In men, the difference could be attributed to measured BMI and residential region; among women, age and education level influenced the discrepancy in BMI. Scheffé's test (α=0.1) for multiple comparisons of group means revealed that women over the age of 65 years, with lower than middle-school education, who lived in rural areas, and had a measured BMI of 25kg/m(2) or more, were more likely to have significant BMI discrepancies. In contrast, for men, significant predictors were living in rural areas and being obese. Although adequate correlations were seen in self-reported BMI, they indicated low sensitivity, with 46.5% and 60.1% among males and females, respectively. However, specificities were very high, at 97.8% and 98.0% for males and females, respectively. The diagnostic performance of self-reported BMI is insufficient for assessing obesity prevalence among middle-aged or older Koreans.

How accurate is web-based self-reported height, weight, and body mass index in young adults?

BACKGROUND

Web-based approaches are an effective and convenient medium to deliver eHealth interventions. However, few studies have attempted to evaluate the accuracy of online self-reported weight, and only one has assessed the accuracy of online self-reported height and body mass index (BMI).

OBJECTIVE

This study aimed to validate online self-reported height, weight, and calculated BMI against objectively measured data in young Australian adults.

METHODS

Participants aged 18-35 years were recruited via advertisements on social media sites and reported their current height and weight as part of an online survey. They then subsequently had the same measures objectively assessed by a trained researcher.

RESULTS

Self-reported height was significantly overestimated by a mean of 1.36 cm (SD 1.93; P<.001), while self-reported weight was significantly underestimated by -0.55 kg (SD 2.03; P<.001). Calculated BMI was also underestimated by -0.56 kg/m(2) (SD 0.08; P<.001). The discrepancy in reporting resulted in the misclassification of the BMI category of three participants. Measured and self-reported data were strongly positively correlated (height: r=.98, weight: r=.99, BMI: r=.99; P<.001). When accuracy was evaluated by BMI category and gender, weight remained significantly underreported by females (P=.002) and overweight/obese participants (P=.02).

CONCLUSIONS

There was moderate to high agreement between self-reported and measured anthropometric data. Findings suggest that online self-reported height and weight can be a valid method of collecting anthropometric data.

Self-reporting and measurement of body mass index in adolescents: refusals and validity, and the possible role of socioeconomic and health-related factors

Background

Body mass index assessment using self-reported height and weight (BMIsr) can encounter refusals and under/over-reporting while for assessment with measured data (BMIm) refusals can be more frequent. This could relate to socioeconomic and health-related factors. We explored these issues by investigating numerous potential factors: gender, age, family structure, father’s occupation, income, physical/sports activity, subjective weight perception, school performance, unhealthy behaviours, physical/psychological health, social relationships, living environment, having sustained violence, sexual abuse, and involvement in violence.

Methods

The sample included 1559 adolescents from middle schools in north-eastern France. They completed a questionnaire including socioeconomic and health-related data, self-reported height/weight, measured height/weight, and weight perception (participation rate 94%). Data were analysed using logistic regression models.

Results

BMIsr encountered under-reporting (with change in BMI category, 11.8%), over-reporting (6.0%), and reporting refusals (3.6%). BMIm encountered more numerous refusals (7.9%). Reporting refusal was related to living with a single parent, low school performance, lack of physical/sports activity, sustained violence, poor psychological health, and poor social relationships (gender/age-adjusted odds ratios 1.95 to 2.91). Further to these factors, measurement refusal was related to older age, having divorced/separated parents, a father being a manual worker/inactive, insufficient family income, tobacco/cannabis use, involvement in violence, poor physical health, and poor living environment (1.30 to 3.68). Under-reporting was related to male gender, involvement in violence, poor psychological health, and overweight/obesity (as assessed with BMIm) (1.52 to 11). Over-reporting was related to male gender, younger age, alcohol consumption, and underweight (1.30 to 5.35). Weight perception was linked to reporting refusals and under/over-reporting, but slightly linked to measurement refusal. The contributions of socioeconomic and health-related factors to the associations of weight perception with reporting refusal and under/over-reporting ranged from −82% to 44%. There were substantial discrepancies in the associations between socioeconomic/health-related factors and overweight/obesity assessed with BMIsr and BMIm.

Conclusions

BMIsr and BMIm were affected by numerous biases related to vulnerability which were also obesity risk factors. BMIsr encountered under/over-reporting which were related to some socioeconomic and health-related factors, weight perception, and BMIm. BMIm was more affected by refusals than BMIsr due to socioeconomic and health-related factors. Further research is needed.

Use of data from the Health Survey for England in obesity policy making and monitoring

Health data and statistics are the foundation of health policy. Over the last 20 years, numerous government documents have been commissioned and published to inform obesity strategies in the UK. The Health Survey for England, an annual cross-sectional survey of a nationally representative random general population sample in England, collects information on health, lifestyle and socioeconomic factors, physical measurements and biological samples. Heights and weights measured by the Health Survey for England are believed to have played a major part in promoting, shaping and evaluating obesity strategies. A formal review of how these data have been used has not been conducted previously. This paper reviews government documents demonstrating the contribution of Health Survey for England examination data to every stage of the policy making process: quantifying the obesity problem in England (e.g. Chief Medical Officer's reports); identifying inequalities in the burden of obesity (Acheson report); modelling potential future scenarios (Foresight); setting and monitoring specific, measurable, attainable targets (calorie reduction challenge in manufacturers' Responsibility Deal); developing and informing strategies and clinical guidance; and evaluating the success of obesity strategies (Healthy Weights, Healthy Lives progress report). Measurement data are needed and used by governments to produce evidence-based strategies to combat obesity.

Validade de peso, altura e índice de massa corporal autorreferidos na população adulta de Brasília

OBJETIVO: Avaliar a validade do peso, altura e índice de massa corporal (IMC) autorreferidos em adultos de Brasília e identificar os fatores associados às diferenças entre os valores medidos e autorreferidos. MÉTODOS: Em amostra por conglomerados de 250 domicílios foram aferidos peso e altura de todos os adultos residentes, após entrevista. A concordância entre os parâmetros medidos e autorreferidos foi feita por Bland & Altman (B&A). Utilizou-se análise de variância múltipla e estimou-se a sensibilidade e especificidade para o excesso de peso (IMC ? 25 kg/m2), estratificado por anos de estudo e faixa etária. RESULTADOS: As entrevistas e mensurações foram feitas em 469 indivíduos. Os resultados de B&A mostram viés (diferença dos valores medidos e autorreferidos) não significativo para o peso (-0,17 kg, p = 0,1) e significativo para a altura (-1 cm, p < 0,001). Os limites de concordância (LC) foram amplos: de ±4 kg e de -6 cm a 4 cm. O viés do IMC foi de - 0,06 kg/m2 e não significativo (p = 0,08) e os LC de - 1,5 a +1,4 kg/m2. Observou-se que homens com IMC < 25 kg/m2 superestimam o peso, enquanto aqueles com sobrepeso e obesos o subestimam (p < 0,01). Homens com + 60a de idade (p = 0,037) e mulheres com < 12a de estudo (p < 0,01) superestimam a altura. A sensibilidade e a especificidade para o excesso de peso foram para homens e mulheres, respectivamente: 94% e 88%; 90% e 98%. A sensibilidade foi de 77% para mulheres acima de 60 anos, de 75% para mulheres com 9 a 11 anos de estudo, e a especificidade de 78% para homens entre 30 e 39 anos. CONCLUSÃO: Em Brasília, a altura autorreferida pode ser utilizada para subgrupos de homens < 60anos de idade e mulheres com + 12 anos de estudo. Homens com IMC adequado superestimam o peso corporal quando comparados com aqueles com sobrepeso ou obesos. As medidas autorreferidas prestam-se para acompanhamento populacional do excesso de peso.

Measuring the accuracy of self-reported height and weight in a community-based sample of young people

BACKGROUND

Self-reported anthropometric data are commonly used to estimate prevalence of obesity in population and community-based studies. We aim to: 1) Determine whether survey participants are able and willing to self-report height and weight; 2) Assess the accuracy of self-reported compared to measured anthropometric data in a community-based sample of young people.

METHODS

Participants (16-29 years) of a behaviour survey, recruited at a Melbourne music festival (January 2011), were asked to self-report height and weight; researchers independently weighed and measured a sub-sample. Body Mass Index was calculated and overweight/obesity classified as ≥25 kg/m². Differences between measured and self-reported values were assessed using paired t-test/Wilcoxon signed ranks test. Accurate report of height and weight were defined as <2 cm and <2 kg difference between self-report and measured values, respectively. Agreement between classification of overweight/obesity by self-report and measured values was assessed using McNemar's test.

RESULTS

Of 1405 survey participants, 82% of males and 72% of females self-reported their height and weight. Among 67 participants who were also independently measured, self-reported height and weight were significantly less than measured height (p=0.01) and weight (p<0.01) among females, but no differences were detected among males. Overall, 52% accurately self-reported height, 30% under-reported, and 18% over-reported; 34% accurately self-reported weight, 52% under-reported and 13% over-reported. More females (70%) than males (35%) under-reported weight (p=0.01). Prevalence of overweight/obesity was 33% based on self-report data and 39% based on measured data (p=0.16).

CONCLUSIONS

Self-reported measurements may underestimate weight but accurately identified overweight/obesity in the majority of this sample of young people.

Temporal changes in bias of body mass index scores based on self-reported height and weight

Objectives:

To investigate temporal changes in the bias associated with self-reported (as opposed to measured) body mass index (BMI) and explore the relationship of such bias to changing social attitudes towards obesity.

Methods:

Using data from the National Health and Nutrition Examination Survey covering two time periods, 1988–1994 and 2005–2008, discrepancy scores between self-reported vs measured BMI were generated. Changes in the sensitivity of BMI categories based on self-reports were examined for six weight groups, both for the US adult population as a whole and major demographic groups. Linear regression models were used to examine temporal changes in average bias, as well as attitudes about weight within each weight category and by demographic group.

Results:

Between 2005–2008 and 1988–1994, the bias towards underestimation of a person's BMI based on interview responses has declined among obese individuals, a trend evident in virtually all demographic subgroups explored. Conversely, most demographic groups showed little change in the extent of bias among underweight and normal-weight individuals. Although the 2005–2008 survey respondents underestimated their measured BMI more than the 1988–1994 respondents, this shift can be entirely explained by the increased prevalence of obesity in more recent years. In fact, obese individuals in 2005–2008 were less likely to overreport their height and underreport their weight than their counterparts in the 1988–1994. Evidence from responses to questions about ideal weight and desire to lose weight point in the direction of a shift in social attitudes, which may make it easier to ‘admit' to greater weight in surveys.

Conclusion:

Over the past 20 years, the bias in self-reported height and weight has declined leading to more accurate BMI categorizations based on self-report. This change is likely to affect efforts to find correction factors to adjust BMI scores based on self-reported height and weight.