Zhangye Residents Jinchang Residents Ni Refinery Workers P value** N Age (years) Smokers [n (%)] Urinary Ni µg/L µg/g creatinine 29 43.4 ± 4.9 25 (86.2) 6.83 ± 3.53 4.15 ± 1.52 30 41.6 ± 6.3 25 (83.3) 6.55 ± 3.51 4.13 ± 2.05 30 43.3 ± 4.9 25 (83.3) 8.43 ± 3.22 5.79 ± 2.08 > 0.05 > 0.05 0.0246 0.0002 *: all participating subjects were male **: comparison between Ni refinery workers and control subjects (residents in Zhangye and Jinchang)

Table 1: Demographic Characteristics of Participating Subjects*.