Table 1.

Socio-demographic, anthropometric characteristics and life style of the participants by study groups. Results are shown as arithmetic mean and standard deviation and percentage.

	Group 1 [<59 ug/L] (n=16)	Group 2 [≥59 <256 ug/L] (n=17)	Group 3 [≥256 <664 ug/L] (n=17)
Age (years)	8.68 ± 1.74	9.29 ± 1.96	8.52 ± 1.66
Gender (%)
Female	56.25	58.82*	58.82*
Male	56.25	41.18	41.18
BMI**	17.98 ± 2.99	18.48 ± 3.61	16.73 ± 3.95
Type of water used at home (%)
Tap water	43.75	29.41	41.18
Bottled water	50.00	64.71	52.94
Both	6.25	5.88	5.88
Type of water used at school (%)
Tap water	100	94.12	88.24
Bottled water	0	5.88	5.88
Both	0	0	5.88
Type of water for cooking (%)
Tap water	62.50	88.24	88.24
Bottled water	31.25	11.74	11.76
Both	6.25	0	0
Use of folic acid during pregnancy
Yes	87.50	82.35	100
No	12.50	17.65	0
Second hand smoking
Yes	87.50	58.82	70.59
No	12.50	41.18	29.41
Living near to an industry
Yes	31.25	41.18	29.41
No	68.75	58.82	70.59

^*P<0.05: Mann–Whitney test o Chi² (Groups 2 or 3 vs Group 1)

^**BMI weight/heigh²