Table 1.

Baseline characteristics of pregnant women and school-aged children in Zinder, rural Niger

	Mean or n	sd or %
Pregnant women (n 662)
Age (years), mean and sd	27·7	6·2
Height (cm), mean and sd	158·3	5·9
Weight (kg), mean and sd	56·0	8·7
Mid-upper arm circumference (cm), mean and sd	24·8	2·8
Trimester, n and %
First	1	0·2
Second	182	27·5
Third	408	61·6
Parity, n and %
1	60	9·1
2	52	7·6
≥3	550	83·1
School-aged children (n 373)
Male, n and %	186	50·0
Age (years), mean and sd	7·7	2·2
Height (cm), mean and sd	114·8	13·8
Weight (kg), mean and sd	19·6	5·4
Mid-upper arm circumference (cm), mean and sd	15·8	1·7
Child currently attending school, n and %	186	50·4
Household level
Iodine content of salt in household*, n and %
0 ppm	235	40·7
>0–15 ppm	258	44·7
>15 ppm	61	10·6
No salt available	22	3·8
Iodine content of salt assessed by titration (ppm)†, n and %
<5 ppm	47	43·5
5–15 ppm	56	51·8
15–<20 ppm	3	2·8
≥20 ppm	2	1·9
Median (min–max), ppm	5·5	0–41·3
Household food security (HFIAS), n and %
Food secure	276	41·7
Mildly food insecure	55	8·3
Moderately food insecure	140	21·2
Severely food insecure	191	28·8
Primary water source during dry season, n and %
Non-covered well	272	41·1
Manual borehole well	122	18·4
Public fountain	111	16·8
Faucet (interior or exterior)	93	14·0
Surface water (river, etc.)	30	4·5
Covered well	17	2·6
Motor borehole well	17	2·6

Min–max, minimum–maximum; HFIAS, Household Food Insecurity Access Scale.

^*Iodine content of salt samples was assessed by rapid test (MBI, Madras, India) in 554 households.

^†Iodine content was assessed by iodometric titration in a randomly selected subset of 108 households.