%0 Journal Article
%@ 14388871
%I JMIR Publications Inc.
%V 15
%N 8
%P e152
%T Validity of Web-Based Self-Reported Weight and Height: Results of the Nutrinet-Santé Study
%A Lassale,Camille
%A Péneau,Sandrine
%A Touvier,Mathilde
%A Julia,Chantal
%A Galan,Pilar
%A Hercberg,Serge
%A Kesse-Guyot,Emmanuelle
%+ Université Paris 13, Sorbonne Paris Cité, UREN (Nutritional Epidemiology Research Unit), Inserm (U557), Inra (U1125), Cnam, 74 rue Marcel Cachin, Bobigny, 93017, France, 33 148388974, c.lassale@uren.smbh.univ-paris13.fr
%K anthropometry
%K body weight
%K obesity
%K self-report
%K weights and measures
%K validation studies
%D 2013
%7 08.08.2013
%9 Original Paper
%J J Med Internet Res
%G English
%X Background: With the growing scientific appeal of e-epidemiology, concerns arise regarding validity and reliability of Web-based self-reported data. Objective: The objectives of the present study were to assess the validity of Web-based self-reported weight, height, and resulting body mass index (BMI) compared with standardized clinical measurements and to evaluate the concordance between Web-based self-reported anthropometrics and face-to-face declarations. Methods: A total of 2513 participants of the NutriNet-Santé study in France completed a Web-based anthropometric questionnaire 3 days before a clinical examination (validation sample) of whom 815 participants also responded to a face-to-face anthropometric interview (concordance sample). Several indicators were computed to compare data: paired t test of the difference, intraclass correlation coefficient (ICC), and Bland–Altman limits of agreement for weight, height, and BMI as continuous variables; and kappa statistics and percent agreement for validity, sensitivity, and specificity of BMI categories (normal, overweight, obese). Results: Compared with clinical data, validity was high with ICC ranging from 0.94 for height to 0.99 for weight. BMI classification was correct in 93% of cases; kappa was 0.89. Of 2513 participants, 23.5% were classified overweight (BMI≥25) with Web-based self-report vs 25.7% with measured data, leading to a sensitivity of 88% and a specificity of 99%. For obesity, 9.1% vs 10.7% were classified obese (BMI≥30), respectively, leading to sensitivity and specificity of 83% and 100%. However, the Web-based self-report exhibited slight underreporting of weight and overreporting of height leading to significant underreporting of BMI (P<.05) for both men and women: –0.32 kg/m2 (SD 0.66) and –0.34 kg/m2 (SD 1.67), respectively. Mean BMI underreporting was –0.16, –0.36, and –0.63 kg/m2 in the normal, overweight, and obese categories, respectively. Almost perfect agreement (ie, concordance) was observed between Web-based and face-to-face report (ICC ranged from 0.96 to 1.00, classification agreement was 98.5%, and kappa 0.97). Conclusions: Web-based self-reported weight and height data from the NutriNet-Santé study can be considered as valid enough to be used when studying associations of nutritional factors with anthropometrics and health outcomes. Although self-reported anthropometrics are inherently prone to biases, the magnitude of such biases can be considered comparable to face-to-face interview. Web-based self-reported data appear to be an accurate and useful tool to assess anthropometric data. 
%M 23928492
%R 10.2196/jmir.2575
%U http://www.jmir.org/2013/8/e152/
%U https://doi.org/10.2196/jmir.2575
%U http://www.ncbi.nlm.nih.gov/pubmed/23928492