As one of the first of its kind, this study found that age and low-back pain, but not body mass index and gender, introduce differential bias in self-reported time spent sedentary and in physical activity. We therefore recommend that self-reported information on these behaviors should be used with due caution in clinical practice, in research, as well as when designing health promotion programs. Key terms: age; back pain; bias; blue-collar worker; body mass index; body mass index; exposure modelling; gender; low-back pain; measurement error; musculoskeletal pain; pain; physical activity; questionnaire; sedentary; self-report; self-reported time This article in PubMed: www.ncbi.nlm.nih.gov/pubmed/29184965
Additional materialPlease note that there is additional material available belonging to this article on the Scandinavian Journal of Work, Environment & Health -website.
Scand J Work Environ Health 2018, vol 44, no 2
163Original article Scand J Work Environ Health. 2018;44(2):163-170. doi:10.5271/sjweh.3693 Is self-reported time spent sedentary and in physical activity differentially biased by age, gender, body mass index, and low-back pain?by Nidhi Gupta, PhD, 1 Marina Heiden, PhD, 2 Svend Erik Mathiassen, PhD, 2 Andreas Holtermann, PhD 1,3 Gupta N, Heiden M, Mathiassen SE, Holtermann A. Is self-reported time spent sedentary and in physical activity differentially biased by age, gender, body mass index and low-back pain? Scand J Work Environ Health. 2018;44(2):163-170. doi:10.5271/sjweh.3693 Objectives This study aimed to determine the extent to which age, gender, body mass index (BMI) and lowback pain (LBP) influence bias in self-reported sedentary behavior and moderate-to-vigorous physical activity (MVPA) among blue-collar workers.Methods For 2-4 consecutive working days, 147 workers wore an Actigraph accelerometer on the thigh. Proportional time spent sedentary and in MVPA was determined using the Acti4 software. The same variables were also self-reported in a questionnaire. The difference between self-reported and accelerometer-based sedentary time and MVPA was calculated and linearly regressed against age, gender, BMI, and self-reported LBP intensity as main effects, as well as interaction terms combining each of these factors with objectively measured exposure.Results Workers objectively spent 64% of their time sedentary and 9% in MVPA. On average, self-reports underestimated sedentary time by 1.5% and overestimated MVPA by 5.5%. Workers with mild/no LBP appeared to have the same size of self-report bias in MVPA regardless of how much MVPA they actually had, while workers with high LBP overestimated MVPA to an increasing extent with increasing exposure [interaction: B=0.29, 95% confidence interval (CI) 0.05-0.53]. Age was positively associated with self-report bias in sedentary time (B=0.31, 95% CI 0.09-0.54) regardless of actual sedentary time.Conclusions LBP and age, but not BMI and gender, introduced differential bias in self-reported information on sedentary behavior and MVPA among blue-collar w...