Table 2.

Odds ratio (OR) and 95% confidence intervals (CI) for prevalence of hyperthyroidism: effects of potential risk factors.

Characteristic	Case (76)	Noncase (11,777)	Rate per 103	ORa	95% CI	Test for Heterogeneity, Pb
Place of residency						0.60
Zhytomyr	20	3221	6.17	1
Kyiv	17	2375	7.11	1.27	0.64,2.50
Chernihiv	39	6181	6.27	1.38	0.74,2.64
Period of examination						0.11
Dec-Feb	12	2092	5.7	1
Mar-May	15	3412	4.38	0.67	0.30,1.56
Jun-Aug	22	2850	7.66	1.44	0.70,3.07
Sep-Nov	27	3423	7.83	1.33	0.67,2.79
ATPO level, U/mL						<0.01
< 60	56	10369	5.37	1
≥ 60	20	1408	14.01	2.63	1.51,4.40
Thyroid volume, ml						0.07
< 20	67	11063	6.02	1
≥ 20	9	714	12.45	2.07	0.93,4.10
Ultrasound-detected nodules						0.05
No	70	11523	6.04	1
Yes	6	254	23.08	2.63	0.99,5.82
Year of examination						0.50
1998	16	2805	5.67	1
1999	11	1296	8.42	1.68	0.67,4.08
2000	49	7676	6.34	1.05	0.59,1.97
Urinary iodine, μg/L						0.29
< 20	5	1524	3.27	1
20–49	31	4574	6.73	2.16	0.91,6.38
50–99	21	3263	6.39	2.06	0.83,6.23
≥100	11	1324	8.24	2.55	0.91,8.21
Missing/Unknown	8	1092	7.27	1.85	0.61,6.21
Current smoking						0.84
No	56	7823	7.11	1
Yes	20	3954	5.03	1.06	0.57,1.92
Vitamin consumption						0.64
No	71	11096	6.36	1
Yes	5	681	7.29	1.26	0.43,2.89
Thyroid disease history in relatives						0.96
No	52	7956	6.49	1
Yes	7	875	7.94	1.02	0.42,2.13
Unknown	17	2946	5.74	0.92	0.51,1.57

^aAll analyses performed with adjustment for factors gender, age at examination by gender, place of residency, period of examination, ATPO level, thyroid volume, ultrasound-detected nodules and I-131 dose with the 3-category non-parametric response.

^bBased on the LRT for the categorical effects vs no effect.