Table 3.

Estimated daily dietary iodine intake, estimated unfiltered tap water intake, dietary habits and serum Tg of controls v. NATD in the study population of volunteers aged 21–80 years, Ashkelon, Israel, March 2012–March 2014

	Control		NATD
Characteristic	Mean or n	sd or %	Mean or n	sd or %	P	OR	95 % CI
n	37		29
Estimated daily dietary iodine intake (μg/d)*	112·6	56·8	71·9	34·8	<0·05
Iodine intake<RDA, n and %†	28	76	28	97	<0·05	9·0	1·1, 75·8
Iodine intake<EAR, n and %†	8	27	22	73	<0·05	5·2	1·8, 15·2
Mean unfiltered tap water intake (litres/d)	0·8		0·5		NS
Unfiltered tap water consumption, n and %	25	68	21	72	NS
Iodine intake (μg/d)
From unfiltered tap water‡	21·6		14·4		NS
From saltwater fish and seafood§	21·0		10·1		<0·05
From cow’s milk*	17·8		11·8		<0·05
From cow’s yogurt	18·9		14·8		NS
From eggs	9·6		7·5		NS
Past or current seafood consumption, n and %	8	22	4	14	NS
Past or current seaweed consumption, n and %	5	13	2	7	NS
Iodized salt use, n and %||	7	19	1	3	0·07	0·15	0·02, 1·32
Intake of an iodine-containing dietary supplement, n and %	1	3	0	0	NS
Mean serum Tg (ng/ml)¶	17·0		33·0		0·08
Elevated serum Tg, n and %†	29	78	22	76	NS
Abnormal elevated serum Tg, n and %†	4	11	12	41	<0·05	5·8	1·6, 20·8
Mean serum TSH (mIU/l)	1·8	1·0	1·9	1·2	NS

NATD, non-autoimmune thyroid disease; EAR, Estimated Average Requirement; Tg, thyroglobulin; TSH, thyrotropin.

RDA=150 μg/d; EAR=95 μg/d; elevated serum =Tg≥10 ng/ml; abnormal elevated serum Tg=serum Tg>40 ng/ml.

^*Significant difference (Welch ANOVA test, α=0·05).

^†Significant difference (Fisher’s exact test, α=0·05).

^‡Iodine content in tap water was considered 27 µg/l.

^§Significant difference (Kruskal–Wallis test, α=0·05).

^||Iodized salt=3 μg iodine/100 g.

^¶Geometric mean.