Table 1.

Serum micromineral levels in drug dependent subjects (n = 253) and non-drug dependent controls (n = 100).

Micromineral (μmol/L)	Drug addict			Non-addict control			P-value*
	N	%	Mean ± SD	N	%	Mean ± SD
Copper
9.0–10.9	7	2.8	21.6 ± 5.8	20	20.0	15.2 ± 4.1	t = 10.001
11.0–21.9	132	52.1		74	74.0		p = 0.002
22.0–45.0	114	45.1		6	6.0
Zinc
5.0–11.5	80	31.6	13.8 ± 4.5	53	53.0	12.3 ± 4.1	t = 3.00
11.6–18.5	137	54.2		39	39.0		p = 0.001
18.6–40.0	36	14.2		8	8.0
Iron
8.5–14.5	34	13.4	20.5 ± 6.5	0		32.4 ± 8.9	t = 13.94
14.6–32.2	206	81.4		48	48.0		p = 0.001
32.3–42.0	13	5.2		52	52.0

*Significant (p < 0.05).

Legend: Replicate analyses were carried out for every sample.

Descriptive statistics: Frequencies, descriptive, crosstabs.

Compare means: Independent-sample t-test.