1. Department of Medicine, University of Otago, Christchurch, New Zealand
2. Department of Biochemistry, University of Otago, Dunedin, New Zealand
3. Medicine Service, VA Medical Center, Birmingham, AL, USA
4. Department of Medicine at the School of Medicine, University of Alabama at Birmingham, Birmingham, AL
5. Division of Epidemiology at the School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA