[1] Wroclaw Med Univ, Fac Hlth Sci, Dept Clin Nursing, 5 Bartla St, PL-51618 Wroclaw, Poland
[2] Wroclaw Med Univ, Dept & Clin Internal & Occupat Dis & Hypertens, Wroclaw, Poland
[3] Univ Calif San Francisco, Sch Nursing, Dept Physiol Nursing, San Francisco, CA 94143 USA
[4] Univ Calif San Francisco, Sch Med, Dept Epidemiol & Biostat, San Francisco, CA USA