Table 1.

Basic characteristics (age, education level, medical history and use of iodine-containing supplements) of participants in the two groups, mothers and adult family members, Tehran, Iran

	Mothers		Adult family members
	(n 290)		(n 290)
Characteristic	n	%	n	%	P value
Age (years)					<0·001
19–24	10	3·4	51	17·6
25–34	46	15·9	53	18·3
35–49	131	45·2	98	33·8
≥50	103	35·5	88	30·3
Education					<0·001
Illiterate	24	8·3	9	3·1
Primary	127	43·8	86	29·7
Secondary	114	39·3	112	38·6
University	25	8·6	83	28·6
Goitre	11	3·8	2	0·7	0·005
Hypothyroidism	24	8·3	3	1·0	<0·001
Hyperthyroidism	3	1·0	2	0·7	0·749
Hypertension	40	13·8	28	9·3	0·044
Use of iodine-containing supplements	8	2·8	1	0·3	0·011