1. Department of Medicine, Nursing Area, School of Medicine and Health Sciences, University of Oviedo, Oviedo, Spain
2. Basic Health Zone Pisueña-Cayon, Primary Health Care of Cantabria, Santander, Spain
3. Primary Health Care of Cantabria, Mortera, Spain
4. Public Health Observatory of Cantabria, Marqués de Valdecilla Fundation, Cantabria, Spain