1. Alaska Native Tribal Health Consortium, Anchorage, AK 99508, USA
2. Southcentral Foundation, Anchorage, AK 99508, USA
3. Center for Human Development, College of Health, University of Alaska Anchorage, Anchorage, AK 99508, USA
4. Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA