Questionnaire-Based Scoring System for Screening Moderate-to-Vigorous Physical Activity in Middle-Aged Japanese Workers

Objectives: Currently available questionnaires have limited ability to measure physical activity (PA) using accelerometers as a gold standard. This study aimed to develop a PA questionnaire for middle-aged Japanese workers and propose a PA scoring system for predicting low moderate-to-vigorous PA (MVPA). Methods: A total of 428 participants (median age, 49 years; percentage of men, 75.8%) participated in a 7-day PA measurement using an accelerometer and a questionnaire. The association between questionnaire responses and low MVPA (<150 min/week) was assessed by logistic regression analysis. A score was assigned to each response based on the correlation coefficients of the multivariate model. The ability of the sum score to predict low MVPA was assessed using the area under the receiver operating characteristic curve (AUC). Results: Five questionnaire items were used for measuring PA scores (range: 0–50; higher scores indicated a higher probability of low MVPA). The AUC was 0.741 (95% confidence interval, 0.689–0.792), and the sensitivity and specificity at the optimal cut-off value were 66.7% and 68.2%, respectively. This predictive ability was slightly increased by body mass index (AUC, 0.745 [0.693–0.796]; sensitivity, 69.9%; specificity, 66.9%). These predictive values were greater than those of conventional questionnaires used in health checkups in Japan (P<0.05). Conclusions: This questionnaire-based PA scoring system showed moderate accuracy in predicting low MVPA. It is useful for screening physically inactive workers and promoting PA.