Table 1. Comparisons of two subject groups (Daiichi vs. Daini).

			Subject groups
			Total		Daiichi		Daini		Daiichi vs. Daini
			n	%	n	%	n	%	?2	p
Total			1,411	100	831	100	580	100
Sociodemographic factors	Age, years	20–29	381	25.6	227	25.7	154	25.4
		30–39	347	23.3	202	22.9	145	23.9
		40–49	395	26.5	235	26.6	160	26.4
		50–59	348	23.4	211	23.9	137	22.6
		60–69	18	1.2	8	0.9	10	1.7	2.09	0.72
	Sex	Male	1,337	94.8	804	96.8	533	91.9	15.5	<0.001***
	Supervisory work status	Yes	147	10.4	86	10.3	61	10.5	0.07	0.79
	Preexisting illness(es)	Yes	203	14.4	126	15.2	77	13.3	0.96	0.33
Disaster-related experiences	Discrimination/slurs	Yes	179	12.7	115	13.8	64	11	2.97	0.085
	Near-death experience	Yes	593	42	446	53.7	147	25.3	117	<0.001***
	Escape from tsunami	Yes	175	12.4	82	9.9	93	16	12.9	<0.001***
	Witnessing of plant explosion(s)	Yes	372	26.4	303	36.5	69	11.9	112	<0.001***
	Family member death(s)	Yes	81	5.7	50	6	31	5.3	0.11	0.74
	Colleague death(s)	Yes	249	17.6	166	20	83	14.3	7.49	0.006**
	Major property loss	Yes	408	28.9	269	32.4	139	24	11.1	0.001**
	Home evacuation	Yes	945	67	582	70	363	62.6	8.2	0.004**

**p<0.01.

***p<0.001.