Table 1.

SOD concentration (mean ± SD), correlation and regression analysis among the blood SOD levels, heavy metals, age and working exposure in the exposed groups and control.

SOD level (units-g−1)	Exposed workers (134.59 ± 35.170)			Unexposed subjects (108.29 ± 6.10)
	Heavy metal conc.(µgL−1)	Corr.	r2	Heavy metal conc.(µgL−1)	Corr.	r2
Cd	8.39 ± 4.87	−0.391	0.016	5.48 ± 3.75	1.000**	0.918**
Cr	9.00 ± 2.30	0.927**	0.745**	4.05 ± 1.03	0.200	0.625**
Ni	4.18 ± 8.37	0.551*	0.562*	3.25 ± 1.13	0.800**	0.480
Fe	71.48 ± 21.68	−0.527*	−0.312	57.99 ± 21.70	−1.000**	−0.932**
Cu	5.63 ± 2.79	−0.127	−0.188	9.10 ± 0.27	0.211	0.327
Zn	22.30 ± 3.46	0.945**	0.775**	22.97 ± 1.50	0.400	0.621**
Pb	119.04 ± 59.32	0.436	0.267	113.3 ± 16.83	−0.400	−0.123
Mn	7.77 ± 11.1	0.210	0.072	2.82 ± 1.46	−0.800**	−0.877**
Age (years)	34.47 ± 14.38	−0.498	−0.322	27.75 ± 9.18	1.000**	0.997**
Time span (years)	14.00 ± 8.73	−0.056	0.412	6.00 ± 3.65	0.800**	0.775**

Corr. = Correlation matrix, r = linear regression *p ≤ 0.05, **p ≤ 0.01.