Table 2.

Blood levels (μg/L) of lead, mercury, cadmium, and arsenic levels in children with a hearing loss and healthy controls

	Study cases	No	Minimum	Maximum	Mean±standard error+	Levene’s test for equality of variances	P-value*
Lead	Hearing loss cases	70	5.69	173.92	53.23 ± 4.42	4.830	0.030
	Healthy control	30	11.27	103.78	38.43 ± 4.65
Cadmium	Hearing loss cases	70	0.07	1.65	0.50 ± 0.04	0.286	0.594
	Healthy control	30	0.17	1.98	0.45 ± 0.07
Arsenic	Hearing loss cases	70	0.25	10.00	1.90 ± 0.20	0.350	0.556
	Healthy control	30	0.88	8.31	2.06 ± 0.28
Mercury	Hearing loss cases	70	0.04	2.78	0.92 ± 0.08	0.610	0.437
	Healthy control	30	0.27	2.13	0.85 ± 0.10