1. Department of Social and Behavioral Sciences, School of Public HealthWest Virginia University Morgantown WV USA
2. Icelandic Center for Social Research and AnalysisReykjavik University Reykjavik Iceland
3. Department of PsychologyReykjavik University Reykjavik Iceland
4. Department of Health and Behavior Studies, Teachers CollegeColumbia University New York NY USA
5. Faculty of Social SciencesUniversity of Iceland Reykjavik Iceland
6. Mailman School of Public HealthColumbia University New York NY USA