[1] Univ Washington, Sch Nursing, Dept Family & Child Nursing, Seattle, WA 98195 USA
[2] Univ Washington, Sch Publ Hlth & Community Med, Dept Hlth Serv, Seattle, WA 98195 USA
[3] Univ Washington, Sch Publ Hlth & Community Med, Dept Epidemiol, Seattle, WA 98195 USA