1. Center for Public Health, Department of Social and Preventive Medicine, Medical University of Vienna, 1090 Vienna, Austria
2. Neurological Rehabilitation Center Rosenhügel, 1130 Vienna, Austria
3. Department of Cancer Epidemiology and Prevention Research, Alberta Health Services, Calgary, AB T2S 3C3, Canada
4. Departments of Oncology and Community Health Sciences, University of Calgary, Calgary, AB T2S 3C3, Canada
5. Center for Public Health, Department of Epidemiology, Medical University of Vienna, 10090 Vienna, Austria