Change in bias in self-reported body mass index in Australia between 1995 and 2008 and the evaluation of correction equations

<p>Abstract</p> <p>Background</p> <p>Many studies have documented the bias in body mass index (BMI) determined from self-reported data on height and weight, but few have examined the change in bias over time.</p> <p>Methods</p> <p>Using data from large, nationally-representative population health surveys, we examined change in bias in height and weight reporting among Australian adults between 1995 and 2008. Our study dataset included 9,635 men and women in 1995 and 9,141 in 2007-2008. We investigated the determinants of the bias and derived correction equations using 2007-2008 data, which can be applied when only self-reported anthropometric data are available.</p> <p>Results</p> <p>In 1995, self-reported BMI (derived from height and weight) was 1.2 units (men) and 1.4 units (women) lower than measured BMI. In 2007-2008, there was still underreporting, but the amount had declined to 0.6 units (men) and 0.7 units (women) below measured BMI. The major determinants of reporting error in 2007-2008 were age, sex, measured BMI, and education of the respondent. Correction equations for height and weight derived from 2007-2008 data and applied to self-reported data were able to adjust for the bias and were accurate across all age and sex strata.</p> <p>Conclusions</p> <p>The diminishing reporting bias in BMI in Australia means that correction equations derived from 2007-2008 data may not be transferable to earlier self-reported data. Second, predictions of future overweight and obesity in Australia based on trends in self-reported information are likely to be inaccurate, as the change in reporting bias will affect the apparent increase in self-reported obesity prevalence.</p

A Framework For Monitoring Overweight And Obesity In NSW

Monitoring of population weight status is valuable in order to track changes and identify likely causes and implications, and to adjust policy and program priorities. A monitoring framework sets out what information should be collected, when and how it should be collected, and systems for the reporting of this information. The framework covers dietary behaviours, physical activity and sedentary behaviours, food environment factors, physical activity environment factors, socio-demographic and other factors

Estimating Obesity Rates in Europe in the Presence of Self-Reporting Errors

Reliable measures of obesity are essential in order to develop effective policies to tackle the costs of obesity. We examine what, if anything, we can learn about obesity rates using self-reported BMI once we allow for possible measurement error. Existing approaches that correct for self-reporting errors often require strong assumptions. In this paper we combine self-reported data on BMI with estimated misclassification rates obtained from auxiliary data to derive upper and lower bounds for the population obesity rate for ten European countries using minimal assumptions on the error process. For men it is possible to obtain meaningful comparisons across countries even after accounting for measurement error. In particular the self-reported data identifies a set of low obesity countries consisting of Denmark, Ireland, Italy, Greece and Portugal and a set of high obesity countries consisting of Spain and Finland. However, it is more difficult to rank countries by female obesity rates. Meaningful rankings only emerge when the misclassification rate is bounded at a level that is much lower than that observed in auxiliary data. A similar limit on misclassification rates is also needed before we can begin to observe meaningful gender differences in obesity rates within countries

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

<p>Abstract</p> <p>Background</p> <p>Validity of self-reported height and weight has not been adequately evaluated in diverse adolescent populations. In fact there are no reported validity studies conducted in Asian children and adolescents. This study aims to examine the accuracy of self-reported weight, height, and resultant BMI values in Chinese adolescents, and of the adolescents' subsequent classification into overweight categories.</p> <p>Methods</p> <p>Weight and height were self-reported and measured in 1761 adolescents aged 12-16 years in a cross-sectional survey in Xi'an city, China. BMI was calculated from both reported values and measured values. Bland-Altman plots with 95% limits of agreement, Pearson's correlation and Kappa statistics were calculated to assess the agreement.</p> <p>Results</p> <p>The 95% limits of agreement were -11.16 and 6.46 kg for weight, -4.73 and 7.45 cm for height, and -4.93 and 2.47 kg/m²for BMI. Pearson correlation between measured and self-reported values was 0.912 for weight, 0.935 for height and 0.809 for BMI. Weighted Kappa was 0.859 for weight, 0.906 for height and 0.754 for BMI. Sensitivity for detecting overweight (includes obese) in adolescents was 56.1%, and specificity was 98.6%. Subjects' area of residence, age and BMI were significant factors associated with the errors in self-reporting weight, height and relative BMI.</p> <p>Conclusions</p> <p>Reported weight and height does not have an acceptable agreement with measured data. Therefore, we do not recommend the application of self-reported weight and height to screen for overweight adolescents in China. Alternatively, self-reported data could be considered for use, with caution, in surveillance systems and epidemiology studies.</p

An Investigation into the Dietary and Health Behaviours of Pregnant Women in Ireland

Maternal obesity increases the risk of metabolic complications in pregnancy such as gestational diabetes mellitus (GDM). Effective weight management following childbirth may reduce long-term metabolic risks among women of child bearing age. The aim of this study was to investigate the diet and health behaviours of pregnant and postpartum women in Ireland. Accurate dietary assessment in pregnancy is often difficult to achieve. We have shown that dietary under-reporting is more likely among pregnant women who are younger, materially deprived, obese and who have increased adiposity. These findings suggest that dietary underreporting represents a source of potential bias in obstetric obesity research. Obese pregnant women of low socioeconomic status may require more specialised dietary assessment methods. Technology increasingly dictates the way in which we collect and communicate information, highlighting the potential utility of innovative web-based dietary assessment and intervention tools. We compared dietary quality scores from a newly developed online Dietary Assessment Tool against nutrient intakes derived using the recently validated Willett Food Frequency Questionnaire. The relatively good agreement between these two dietary assessment methods suggests that our food-based dietary quality scores are reflective of important nutrient intakes in pregnancy. Nutritional manipulation based on dietary intervention does not appear to prevent GDM. Neither food group nor macronutrient intakes in the periconceptional period were associated with fasting plasma glucose (FPG) levels in our cohort of pregnant women. Obesity in early pregnancy was the main predictor of elevated FPG levels, highlighting the potential value of preconceptional weight management interventions in preventing GDM. There is a paucity of data describing maternal weight changes in the postpartum period. We found that maternal weight and body composition trajectories after pregnancy were not linear, and that they differed between women who were obese and those who were not obese in the first trimester. The role of breastfeeding in postpartum weight change is not clear. We found that postpartum changes in maternal weight and percentage body fat were not associated with infant feeding method after adjusting for important confounders such as diet and exercise. Overall, my findings commend the pre-conceptional period as an important window of opportunity in the prevention of GDM and postpartum obesity

Gender differences in the influence of food safety and health concerns on dietary and physical activity habits

MONOGRAFÍ

Secular change in stature and body mass in Korea over the last two millennia

Body size of a population is influenced by its environmental conditions and thus reflects the standards of living experienced by individuals within a population. In this research, for the purpose of investigating the standards of living in the Korean societies for the past two millennia, the pattern of secular changes in stature and body mass of the Korean populations were examined using both anthropometric and osteometric data. In addition, because of the necessity of reconstructing body sizes from the skeletal remains, new Korean-specific equations for stature and body mass estimation were developed using the hybrid method. The newly developed equations presented here provide a better performance in accuracy and precision compared to the previous equations that have been used to estimate stature and body mass in Korea. In regards to stature, a U-shaped secular change pattern was found for both females and males: the average stature decreased after the Three Kingdom period and increased again in the 20th century. The average body mass also increased in the 20th century for both sexes but its pattern of secular change did not exactly follow patterns identified with stature. Sexual difference in the pattern of secular changes were also identified in the 20th century. The pattern of secular changes in stature and body mass was discussed in terms of anthropometric history, occurrence of infectious diseases, quality of life, and cultural practices in Korea. Also, caveats to the newly provided equations are explained. This research is expected to have a positive impact not only on the Korean community but also on worldwide anthropological and anatomical research, both in regards to archaeological and forensic contexts. In archaeology, this research will provide a systematic and appropriate basis to assess standards of living of Korean societies in the past. Moreover, any anthropological research of which topic is related to human variation, anthropometry, and secular changes on a worldwide scale will benefit from the results of this research. Lastly, in forensics, the new equations in this research will produce more accurate body size estimates for Korean victims not only in Korea but also in other countries

Malnutrition Screening And Body Composition Measurements In Paediatric Patients With Complex Diagnosis: Translating Research Into Clinical Practice

BACKGROUND: Paediatric patients have a high risk for malnutrition, and there is an increasing consensus worldwide on the need to find better tools to identify the risk, diagnose, and manage this condition to avoid the long-term consequences in child health and development. OBJECTIVE: Evaluate the practical aspects of measuring body composition (BC) in paediatric patients with complex conditions, and their possible advantages over measurements of weight/height to predict clinical outcomes and as possible malnutrition diagnostic parameters; while also validating three paediatric malnutrition screening tools (MSTs). DESIGN: This prospective study recruited and measured 152 children 5-18yr with different anthropometric and BC techniques within 48hr of admission and at discharge to a tertiary level hospital. MSTs (PYMS, STAMP, STRONGkids) were completed on admission and data collected on clinical outcomes: length of stay, complications, and worsening nutritional status. RESULTS: BC measurements by different techniques are practical and acceptable overall in paediatric patients. Malnutrition was prevalent in 13-20% of patients, measured by different anthropometric/BC parameters. Patients were on average short and underweight compared to healthy children, and had abnormal BC (low lean mass, variable fat mass). The parameters were significantly associated with clinical outcomes, and there seemed to be an advantage for BC to predict increased LOS and complications. Similarly, malnutrition risk on admission varied depending on the MST used. STAMP and STRONGkids were significantly associated with baseline weight, height, lean and fat mass; while PYMS had better associations to clinical outcomes (increased LOS). CONCLUSION: Malnutrition is relatively common, and BC measurements seem to have a place in the diagnosis and possibly the nutritional management of paediatric patients. Future work with specific patient groups and outcomes should help clarify what parameters/tools are the most helpful to ultimately decrease the prevalence of hospital malnutrition