Table 1.

Characteristics of the children (total n = 650)

	Total	Never exposed	10-499 µg/l	500+ µg/l
Characteristic	n (%)	n (%)	n (%)	n (%)
Sex
Boys	335 (51.5)	78 (49.1)	109 (57.1)	45 (48.9)
Girls	315 (48.5)	81 (50.9)	82 (42.9)	47 (51.1)
Age (years)
7-9	222 (34.2)	75 (47.2)	68 (35.6)	29 (31.5)
10-12	222 (34.2)	55 (34.6)	63 (33.0)	39 (42.4)
13-15	149 (22.9)	22 (13.8)	43 (22.5)	20 (21.7)
16-17	57 (8.8)	7 (4.4)	17 (8.9)	4 (4.4)
Grade (years) in school
No grade	66 (10.2)	3 (1.9)	18 (9.4)	11 (12.0)
1-3	269 (41.4)	93 (58.5)	84 (44.0)	35 (38.0)
4-6	208 (32.0)	42 (26.4)	66 (34.6)	37 (40.2)
7-9	93 (14.3)	18 (11.3)	19 (9.9)	8 (8.7)
10-11	14 (2.2)	3 (1.9)	4 (2.1)	1 (1.1)
Number of family members
2-4	193 (29.7)	52 (32.7)	59 (30.9)	29 (31.5)
5-6	312 (48.0)	79 (49.7)	93 (48.7)	43 (46.7)
7-8	103 (15.9)	21 (13.2)	29 (15.2)	15 (16.3)
9+	42 (6.5)	7 (4.4)	10 (5.2)	5 (5.4)
Mother’s education
No education	206 (31.7)	43 (27.0)	63 (33.0)	31 (33.7)
Primary	292 (44.9)	62 (39.0)	93 (48.7)	46 (50.0)
Secondary and above	152 (23.4)	54 (34.0)	35 (18.3)	15 (16.3)
Father’s education
No education	228 (35.1)	61 (38.4)	64 (33.5)	35 (38.0)
Primary	236 (36.3)	39 (24.5)	85 (44.5)	39 (42.4)
Secondary and above	186 (28.6)	59 (37.1)	42 (22.0)	18 (19.6)
Type of house
Mud	579 (89.1)	136 (85.5)	174 (91.1)	86 (93.5)
Mixed	32 (4.9)	11 (6.9)	3 (1.6)	5 (5.4)
Tin	31 (4.8)	9 (5.7)	13 (6.8)	1 (1.1)
Concrete	8 (1.2)	3 (1.9)	1 (0.5)	0 (–)
Rooms in the house
1	53 (8.2)	12 (7.5)	15 (7.8)	8 (8.7)
2	255 (39.2)	76 (47.8)	63 (33.0)	41 (44.6)
3	245 (37.7)	48 (30.2)	88 (46.1)	27 (29.3)
4+	97 (14.9)	23 (14.5)	25 (13.1)	16 (17.4)
Mother smokes
Yes	32 (4.9)	6 (3.8)	9 (4.7)	5 (5.4)
No	618 (95.1)	153 (96.2)	182 (95.3)	87 (94.6)
Father smokes
Yes	491 (75.5)	115 (72.3)	145 (75.9)	72 (78.3)
No	159 (24.5)	44 (26.7)	46 (24.1)	20 (21.7)