Background: Reporting errors have been quantified in epidemiologic studies by comparing reported intakes with predicted energy requirements (pERs). Several studies lacking measures of physical activity level (PAL) assigned low active levels to obtain pERs.
Objective: We applied objective physical activity measures to current methods to quantify dietary reporting errors and compared associations with anthropometric and dietary variables among plausible and implausible reporters.
Design: This study included 2868 adolescents with an average age of 13 y. Three day dietary records accelerometers and dual energy X ray absorptiometry were used to assess diet activity and body composition respectively. Three variations of physical activity coefficients were used l) assigning low physical activity coefficients (PA(low)) 2) calculating PAL values (PA(PAL)) and 3) applying minutes of moderate to vigorous physical activity (PA(MVPA)).
Results: Of the total participants 51.5% 51.8% and 37.1% of the PA(low), PA(PAL) and PA(MVPA) groups respectively were classified as underreporters and 40.8% 37.9% and 42.4% of the respective groups were classified as plausible reporters. Underreporters had a higher body mass index body fat and waist circumference than did plausible reporters (P < 0.001 for all). Overreporters had a lower weight and body fat than did plausible reporters (P < 0.001 for all). Underreporters reported lower dairy and calcium intakes than did plausible reporters the results were attenuated with adjustment for total energy.
Conclusion: Accounting for objective physical activity measures to quantify reporting errors resulted in different and potentially more reasonable proportions of Implausible reporters.