- Title
- How is online self-reported weight compared with image-captured weight? A comparative study using data from an online longitudinal study of young adults
- Creator
- Whatnall, Megan C.; Kolokotroni, Katerina Z.; Fozard, Therese E.; Evans, Tamla S.; Marwood, Jordan R.; Ells, Louisa J.; Burrows, Tracy L.
- Relation
- American Journal of Clinical Nutrition Vol. 118, Issue 2, p. 452-458
- Publisher Link
- http://dx.doi.org/10.1016/j.ajcnut.2023.05.029
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2023
- Description
- Background: Accurate anthropometric measurement is important within epidemiological studies and clinical practice. Traditionally, self-reported weight is validated against in-person weight measurement. Objectives: This study aimed to 1) determine the comparisonof online self-reported weight against images of weight captured on scales in a young adult sample, 2) compare this across body mass index (BMI), gender, country and age groups, and 3) explore demographics of those who did/did not provide a weight image. Methods: Cross-sectional analysis of baseline data from a 12-month longitudinal study of young adults in Australia and the UK was conducted. Data was collected by online survey via Prolific research recruitment platform. Self-reported weight and socio-demographics (e.g. age, gender) were collected for the whole sample (n=512), and images of weight for a sub-set (n=311). ests included Wilcoxon signed-rank test to evaluate differences between measures, Pearson correlation to explore the strength of the linear relationship, and Bland-Altman plots to evaluate agreement. Results: Self-reported weight (median (IQR), 92.5kg (76.7-112.0)) and image-captured weight (93.8kg (78.8-112.8)) were significantly different (z=-6.76, p<0.001), but strongly correlated (r=0.983, p<0.001). In the Bland-Altman plot ((mean difference -0.99kg (-10.83, 8.84), most values were within limits of agreement (2 SD). Correlations remained high across BMI, gender, country and age groups (r>0.870, p<0.002). Participants with BMI in ranges 30-34.9 and 35-39.9kg/m2 ranges were less likely to provide an image. Conclusions: This study demonstrates the method concordance of image-based collection methods with self-reported weight in online research.
- Subject
- validation; weight; self-report; online; young adults
- Identifier
- http://hdl.handle.net/1959.13/1484026
- Identifier
- uon:51258
- Identifier
- ISSN:0002-9165
- Language
- eng
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