Validity of Web-Based Self-Reported Weight and Height: Results of the Nutrinet-Sante Study

Camille Lassale (1) , Sandrine Péneau (2) , Mathilde Touvier (2) , Chantal Julia (2, 3) , Pilar Galan (2) , Serge Hercberg (2, 3) , Emmanuelle Kesse-Guyot (2)

1 Université Paris Nord (Paris 13)
2 UREN - Unité de Recherche en Epidémiologie Nutritionnelle
3 Hôpital Avicenne [AP-HP]

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-Sante 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/m(2) (SD 0.66) and -0.34 kg/m(2) (SD 1.67), respectively. Mean BMI underreporting was -0.16, -0.36, and -0.63 kg/m(2) 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-Sante 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.

Mots clés: anthropometry; body weight; obesity; self-report; weights and measures; validation studies; BODY-MASS INDEX; NUTRITION EXAMINATION SURVEY; SOCIAL DESIRABILITY; NATIONAL-HEALTH; US ADULTS; OBESITY; RELIABILITY

Mots clés: ACTIVITY QUESTIONNAIRE IPAQ; POPULATION; EPIDEMIOLOGY

Domaines: Sciences du Vivant [q-bio]

Camille Lassale, Sandrine Péneau, Mathilde Touvier, Chantal Julia, Pilar Galan, et al.. Validity of Web-Based Self-Reported Weight and Height: Results of the Nutrinet-Sante Study. Journal of Medical Internet Research, 2013, 15 (8), ⟨10.2196/jmir.2575⟩. ⟨hal-02651732⟩