Table 2.

Univariate Analysis of Post-Traumatic Stress Reaction for House Flooding Strata Among Resident Survivors of the Tsunami That Followed the Great East Japan Earthquake on March 11, 2011 (n=4706)

	Post-Traumatic Stress Reaction
	No Flooding a (n=888)					Below the Ground Floor a (n=631)					Above the Ground Floor a (n= 187)
	Yes		No			Yes		No			Yes		No
	No.	%	No.	%	P -value b	No.	%	No.	%	P -value b	No.	%	No.	%	P -value b
Sex
Male	9	3.0	296	97.0	0.273	6	2.9	203	97.1	0.019	55	5.1	1020	94.9	0.031
Female	26	4.5	557	95.5		32	7.6	390	92.4		150	7.1	1962	92.9
Age
15 to 39 years	4	2.2	176	97.8	0.274	5	5.5	86	94.5	0.564	19	3.6	508	96.4	0.011
40 to 64 years	16	5.1	296	94.9		13	5.0	247	95.0		107	7.3	1353	92.7
≥65 years	15	3.8	381	96.2		20	7.1	260	92.9		79	6.6	1121	93.4
Direct exposure to seawater
Yes	0	0	30	100	0.627	0	0	45	100	0.101	42	9.1	422	90.9	0.018
No	35	4.1	812	95.9		38	6.6	540	93.4		159	5.9	2515	94.1
Regular intake of psychotropic medicine(s)
Yes	3	11.1	24	88.9	0.086	3	18.8	13	81.3	0.065	16	14.4	95	85.6	<0.001
No	32	3.7	829	96.3		35	5.7	580	94.3		189	6.1	2887	93.9
Number of cohabitants
More than 6 persons	3	5.4	53	94.6	0.770	1	2.9	33	97.1	0.482	8	5.4	140	94.6	0.059
1 to 6 person(s)	28	3.7	720	96.3		35	6.5	504	93.5		166	6.1	2545	93.9
None	4	4.8	80	95.2		2	3.4	56	96.6		31	9.5	297	90.5
Water supply
Yes	31	3.8	782	96.2	0.289	36	5.9	572	94.1	0.299	197	6.5	2851	93.5	0.521
No	4	6.8	55	93.2		2	11.1	16	88.9		4	4.3	90	95.7
Electricity supply
Yes	35	4.1	823	95.9	0.635	35	5.8	571	94.2	0.555	194	6.4	2850	93.6	0.463
No	0	0	11	100		0	0	10	100		6	7.1	79	92.9
Gas supply
Yes	35	4.1	814	95.9	0.535	36	6.1	558	93.9	0.397	178	6.3	2644	93.7	0.274
No	0	0	15	100		0	0	15	100		17	7.5	209	92.5

^a Number may not be add up to 888, 631, or 3187 because not all the respondents answered all the questions.

^b Chi-square test or Fisher exact test.