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. Author manuscript; available in PMC: 2014 Apr 11.

Published in final edited form as: Neurotoxicology. 2006 Aug 22;28(1):126–135. doi: 10.1016/j.neuro.2006.08.005

Table 1.

Summary of demographic data among Mn-exposed and control workers

Parameters	Control	Mn exposed
Parameters	Control	Low	High	Combine
Number of cases	9	5	13	18
Mean age (years) (95% CI)	40.3 ± 9.2 (33.3–47.4)	42.8 ± 9.6 (30.8–54.8)	33.2 ± 8.8 (27.9–38.4)	35.8 ± 9.8
Years in employment (95% CI)	17.6 ± 8.0 (12.0–27.5)	21.6 ± 11.1 (7.9–35.4)	11.3 ± 9.1 (5.8–16.8)	14.1 ± 10.5^*
Initial working age (years) (95% CI)	21.0 ± 2.9 (18.9–23.2)	21.4 ± 2.5 (18.3–24.5)	22.2 ± 3.9 (19.9–24.6)	22.0 ± 3.5
Smoking (%)	33.3	40.0	46.2	44.4
Alcohol (%)	33.3	40.0	30.1	33.3
Airborne MnO₂ (mg/m³) (95% CI)	0.01 (0–0.03)	0.66^* (0.36–0.96)	1.26^**^▲ (1.05–1.48)	0.60^**
MnB (μg/mL) (95% CI)	0.04 ± 0.02 (0.02–0.05)	0.05 ± 0.01 (0.04–0.06)	0.05 ± 0.03 (0.03–0.07)	0.05 ± 0.03
MnP (μg/mL) (95% CI)	0.05 ± 0.03 (0.04–0.08)	0.04 ± 0.01^* (0.03–0.05)	0.05 ± 0.02 (0.04–0.07)	0.05 ± 0.02
MnRBC (μg/mL) (95% CI)	0.14 ± 0.01 (0.14–0.16)	0.15 ± 0.02 (0.12–0.18)	0.16 ± 0.05 (0.12–0.18)	0.15 ± 0.04

Data represent mean ± S.D.

^*

p < 0.05,

^**

p < 0.01 compared with the control workers;

^▲

p < 0.01 compared with low-exposed workers.

Note. The statistical significance among groups was further analyzed by ANCOVA (see Table 4).