Table 2.

Relationships between characteristics of study subjects and PSHI by injury risk level

Variables	PSHI (Low-risk group)				PSHI (High-risk group)
	Total	Yes		p-valuec	Total	Yes		p-valuec
	Na	Na	%b		Na	Na	%b
General characteristics
Age (years)
15–29	2746	1541	57.6	< 0.001	708	459	67.5	< 0.001
30–39	4811	3053	63.7	0.168d	1340	973	72.8	0.039d
40–49	5284	3369	63.9		1808	1280	71.6
50–59	3349	2087	62.3		1571	1084	69.8
≥ 60	1987	1177	60.2		923	600	65.6
Sex
Male	8640	5757	66.2	< 0.001	3999	2976	74.4	< 0.001
Female	9537	5470	58.7		2351	1420	62.5
Education level
Middle school or below	1887	1064	58.5	< 0.001	1109	708	65.3	< 0.001
High school	6266	3512	56.7	< 0.001d	3189	2179	69.1	< 0.001d
College or above	10,024	6651	66.0		2052	1509	74.1
Monthly income (KRW 10,000)
< 150	5501	2872	53.8	< 0.001	1934	1148	61.1	< 0.001
150–249	6198	3816	61.6	< 0.001d	2312	1555	67.8	< 0.001d
250–399	4773	3261	67.2		1694	1345	78.9
≥ 400	1705	1278	73.4		410	348	84.2
Occupational characteristics
Occupational type
White-collar	8943	6050	67.4	< 0.001	1285	1024	79.8	< 0.001
Pink-collar	4865	2465	51.6		1576	905	59.9
Blue-collar	4369	2712	61.9		3489	2467	70.5
Number of employees
1–4	4047	1887	48.5	< 0.001	1448	776	56.3	< 0.001
5–49	9302	5723	61.8	< 0.001d	3212	2181	68.5	< 0.001d
50–299	3317	2398	71.3		1142	935	80.9
≥ 300	1511	1219	77.9		548	504	91.4
Working hours per a week (hours)
< 40	10,350	6479	63.0	< 0.001	2951	2072	71.7	< 0.001
41–52	4955	3117	63.1	< 0.001d	1841	1326	72.1	< 0.001d
53–60	2011	1152	58.2		1076	697	66.4
≥ 61	861	479	57.1		482	301	61.9
Tenure (years)
< 1	2203	1132	52.2	< 0.001	815	518	67.2	< 0.001
1–5	6713	3956	59.5	< 0.001d	2133	1379	65.0	< 0.001d
≥ 5	9261	6139	66.6		3402	2499	74.1
Shift work
Yes	1643	1117	67.0	< 0.001	908	745	80.9	< 0.001
No	16,534	10,110	61.8		5442	3651	68.3
Type of employment
Regular	13,841	8997	64.6	< 0.001	4347	3185	73.3	< 0.001
Temporary	4336	2230	53.8		2003	1211	62.7
Labor unions
Presence	2506	1978	77.4	< 0.001	935	813	86.1	< 0.001
Absence	15,671	9249	59.8		5415	3583	67.3
Job-related factors
Physical risk factors
Yes	5243	3452	65.8	< 0.001	4224	3035	72.3	< 0.001
No	12,934	7775	60.9		2126	1361	65.8
Biochemical risk factors
Yes	3017	2012	65.7	< 0.001	3080	2255	73.2	< 0.001
No	15,160	9215	61.6		3270	2141	67.1
Ergonomic risk factors
Yes	14,438	8794	61.5	< 0.001	6057	4171	69.7	0.004
No	3739	2433	65.1		293	225	77.1
Usage of personal protective equipment
No need	15,468	8866	58.3	< 0.001	3042	1612	54.4	< 0.001
Need/wear	2440	2179	89.4		3038	2621	86.5
Need/no wear	269	182	66.3		270	163	62.1

^aUnweighted case numbers of workers

^bPercentages based on weighted analysis

^cP-value of the weighted chi-squared test results

^dP-value for trend in the weighted analysis