1. Department of Health and Human Physiology University of Iowa Iowa City, IA USA
2. College of Nursing University of Iowa Iowa City, IA USA
3. Department of Epidemiology College of Public Health University of Iowa Iowa City, IA USA
4. Department of Family and Preventive Medicine University of Arkansas for Medical Sciences Little Rock AR USA
5. Department of Epidemiology Human Genetics Environmental Sciences The University of Texas Health Science Center at Houston Houston TX USA