Objective: Measurement errors in dietary data lead to attenuated estimates of associations between dietary exposures and health outcomes. The present study aimed to compare and evaluate different approaches of handling implausible reports by exemplary analysis of the association between dietary intakes (total energy, soft drinks, fruits/vegetables) and overweight/obesity in children.
Design: Cross-sectional multicentre study.
Setting: Kindergartens/schools from eight European countries participating in the IDEFICS Study.
Subjects: Children (n 5357) aged 2-9 years who provided one 24 h dietary recall and complete covariate information.
Results: The 24 h recalls were classified into three reporting groups according to adapted Goldberg cut-offs: under-report, plausible report or over-report. In the basic logistic multilevel model (adjusted for age and sex, including study centre as random effect), the dietary exposures showed no significant association with overweight/obesity (energy intake: OR=0·996 (95 % CI 0·983, 1·010); soft drinks: OR = 0·999 (95 % CI 0·986, 1·013)) and revealed even a positive association for fruits/vegetables (OR = 1·009 (95 % CI 1·001, 1·018)). When adding the reporting group (dummy variables) and a propensity score for misreporting as adjustment terms, associations became significant for energy intake as well as soft drinks (energy: OR = 1·074 (95 % CI 1·053, 1·096); soft drinks: OR = 1·015 (95 % CI 1·000, 1·031)) and the association between fruits/vegetables and overweight/obesity pointed to the reverse direction compared with the basic model (OR = 0·993 (95 % CI 0·984, 1·002)).
Conclusions: Associations between dietary exposures and health outcomes are strongly affected or even masked by measurement errors. In the present analysis consideration of the reporting group and inclusion of a propensity score for misreporting turned out to be useful tools to counteract attenuation of effect estimates.