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

Zhou X, Dibley MJ, Cheng Y, Ouyang X, Yan H - BMC Public Health (2010)

Bottom Line: Subjects' area of residence, age and BMI were significant factors associated with the errors in self-reporting weight, height and relative BMI.Reported weight and height does not have an acceptable agreement with measured data.Alternatively, self-reported data could be considered for use, with caution, in surveillance systems and epidemiology studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: From the Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University College of Medicine, No,76 West Yanta Road, Xi'an, China.

ABSTRACT

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

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

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

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

Show MeSH

Related in: MedlinePlus

Bland Altman plot [39] of the difference versus the average of reported and measured resultant BMIs. Broken lines present 95% limits of agreement, where upper LOA is +1.96 SD and lower LOA is -1.96 SD from mean difference (solid line) of methods.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2864211&req=5

Figure 3: Bland Altman plot [39] of the difference versus the average of reported and measured resultant BMIs. Broken lines present 95% limits of agreement, where upper LOA is +1.96 SD and lower LOA is -1.96 SD from mean difference (solid line) of methods.

Mentions: The differences between self-reported and measured values were plotted against the means of the self-reported and measured values for weight (Figure 1), height (Figure 2) and BMI (Figure 3). The 95% limits of agreement were -11.16 and 6.46 for weight, -4.73 and 7.45 for height, and -4.93 and 2.47 for BMI. Thus, 95% of the adolescents' self-reported values fell between 11.16 kilograms below or 6.46 kilograms above the measured value for weight, 4.73 centimeters below or 7.45 centimeters above for height, and 4.93 kg/m2 below or 2.47 kg/m2 above for BMI. The LOA for weight was greater than one SD of the measured weight values (SD 10.3 kg) thus showing only fair agreement; for height the LOA was also greater than one SD of the measured height values (SD 8.7 cm) also showing only 'fair" agreement; but for BMI the LOA was more than two SD of the measured BMI values (SD 3.1 kg/m2) thus showing poor agreement. Thus the LOA for all three anthropometric measurements were sufficiently wide to be regarded as unacceptable, especially BMI.


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

Zhou X, Dibley MJ, Cheng Y, Ouyang X, Yan H - BMC Public Health (2010)

Bland Altman plot [39] of the difference versus the average of reported and measured resultant BMIs. Broken lines present 95% limits of agreement, where upper LOA is +1.96 SD and lower LOA is -1.96 SD from mean difference (solid line) of methods.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864211&req=5

Figure 3: Bland Altman plot [39] of the difference versus the average of reported and measured resultant BMIs. Broken lines present 95% limits of agreement, where upper LOA is +1.96 SD and lower LOA is -1.96 SD from mean difference (solid line) of methods.
Mentions: The differences between self-reported and measured values were plotted against the means of the self-reported and measured values for weight (Figure 1), height (Figure 2) and BMI (Figure 3). The 95% limits of agreement were -11.16 and 6.46 for weight, -4.73 and 7.45 for height, and -4.93 and 2.47 for BMI. Thus, 95% of the adolescents' self-reported values fell between 11.16 kilograms below or 6.46 kilograms above the measured value for weight, 4.73 centimeters below or 7.45 centimeters above for height, and 4.93 kg/m2 below or 2.47 kg/m2 above for BMI. The LOA for weight was greater than one SD of the measured weight values (SD 10.3 kg) thus showing only fair agreement; for height the LOA was also greater than one SD of the measured height values (SD 8.7 cm) also showing only 'fair" agreement; but for BMI the LOA was more than two SD of the measured BMI values (SD 3.1 kg/m2) thus showing poor agreement. Thus the LOA for all three anthropometric measurements were sufficiently wide to be regarded as unacceptable, especially BMI.

Bottom Line: Subjects' area of residence, age and BMI were significant factors associated with the errors in self-reporting weight, height and relative BMI.Reported weight and height does not have an acceptable agreement with measured data.Alternatively, self-reported data could be considered for use, with caution, in surveillance systems and epidemiology studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: From the Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University College of Medicine, No,76 West Yanta Road, Xi'an, China.

ABSTRACT

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

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

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

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

Show MeSH
Related in: MedlinePlus