Quantitative Genetic Epidemiology, Fred Hutchinson Cancer Research Center, Seattle 98109-1024, USA.|Quantitative Genetic Epidemiology, Fred Hutchinson Cancer Research Center, Seattle 98109-1024, USA.|Quantitative Genetic Epidemiology, Fred Hutchinson Cancer Research Center, Seattle 98109-1024, USA.|Quantitative Genetic Epidemiology, Fred Hutchinson Cancer Research Center, Seattle 98109-1024, USA.