[1] Univ Wisconsin, Dept Ophthalmol & Visual Sci, Sch Med, Madison, WI 53705 USA
[2] NHLBI, Div Epidemiol & Clin Applicat, NIH, Bethesda, MD 20892 USA
[3] NCI, NIH, Bethesda, MD 20892 USA
[4] Univ Minnesota, Sch Publ Hlth, Div Epidemiol, Minneapolis, MN USA