Restrictive spirometry pattern is associated with low physical activity levels. A population based international study - Carsin, AE; Fuertes, E; Schaffner, E; Jarvis, D; Antó, JM; Heinrich, J; Bellisario, V; Svanes, C; Keidel, D; Imboden, M; Weyler, J; Nowak, D; et al. (Respiratory Medicine, 2019)