Table 1

Prevalence of covariates in different levels of PWL measured by the JEM index score

	Male workers with occasional MSP										Female workers with occasional MSP
	Low n=661		Medium–low n=671		Medium–high n=634		High n=607		Total n=2573		Low n=930		Medium–low n=780		Medium–high n=749		High n=683		Total n=3142
	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%
Age (years)
18–29	35	5.3	60	8.9	86	13.6	95	15.7	276	10.7	66	7.1	86	11.0	138	18.4	157	23.0	447	14.2
30–39	227	34.3	214	31.9	158	24.9	161	26.5	760	29.5	287	30.9	236	30.3	202	27.0	179	26.2	904	28.8
40–49	213	32.2	208	31.0	200	31.5	184	30.3	805	31.3	352	37.8	223	28.6	205	27.4	172	25.2	952	30.3
50–59	186	28.1	189	28.2	190	30.0	167	27.5	732	28.4	225	24.2	235	30.1	204	27.2	175	25.6	839	26.7
Completed education
Primary (1–9 years)	12	1.8	36	5.4	83	13.1	133	21.9	264	10.3	18	1.9	52	6.7	48	6.4	117	17.1	235	7.5
Secondary (12 years)	136	20.6	272	40.5	327	51.6	390	64.3	1125	43.7	218	23.4	332	42.6	278	37.1	438	64.1	1266	40.3
Tertiary (12+ years)	513	77.6	363	54.1	224	35.3	84	13.8	1184	46.0	694	74.6	396	50.8	423	56.5	128	18.7	1641	52.2
Long-term health condition
No	559	84.6	541	80.6	504	79.5	487	80.2	2091	81.3	759	81.6	650	83.3	605	80.8	565	82.7	2579	82.1
Yes	102	15.4	130	19.4	130	20.5	120	19.8	482	18.7	171	18.4	130	16.7	144	19.2	118	17.3	563	17.9
Psychological distress (GHQ12 score>3)
No	564	85.3	579	86.3	534	84.2	544	89.6	2221	86.3	736	79.1	635	81.4	601	80.2	548	80.2	2520	80.2
Yes	97	14.7	92	13.7	100	15.8	63	10.4	352	13.7	194	20.9	145	18.6	148	19.8	135	19.8	622	19.8
Smoking
No	633	95.8	625	93.1	559	88.2	516	85.0	2333	90.7	848	91.2	695	89.1	644	86.0	538	78.8	2725	86.7
Yes	28	4.2	46	6.9	75	11.8	91	15.0	240	9.3	82	8.8	85	10.9	105	14.0	145	21.2	417	13.3
Leisure-time physical activity
Sedentary	46	7.0	59	8.8	73	11.5	92	15.2	270	10.5	68	7.3	63	8.1	50	6.7	81	11.9	262	8.3
Moderate	468	70.8	477	71.1	420	66.2	413	68.0	1778	69.1	692	74.4	561	71.9	563	75.2	499	73.1	2315	73.7
Regular	147	22.2	135	20.1	141	22.2	102	16.8	525	20.4	170	18.3	156	20.0	136	18.2	103	15.1	565	18.0
BMI
Underweight/ normal	236	35.7	237	35.3	208	32.8	186	30.6	867	33.7	605	65.1	473	60.6	429	57.3	374	54.8	1881	59.9
Overweight	372	56.3	372	55.4	359	56.6	346	57.0	1449	56.3	263	28.3	243	31.2	260	34.7	241	35.3	1007	32.0
Obese	53	8.0	62	9.2	67	10.6	75	12.4	257	10.0	62	6.7	64	8.2	60	8.0	68	10.0	254	8.1
Decision authority
High	635	96.1	526	78.4	154	24.3	47	7.7	1362	52.9	894	96.1	506	64.9	163	21.8	87	12.7	1650	52.5
Low	26	3.9	145	21.6	480	75.7	560	92.3	1211	47.1	36	3.9	274	35.1	586	78.2	596	87.3	1492	47.5

BMI, body mass index; GHQ-12, 12-Item General Health Questionnaire.JEM, job-exposure matrix; MSP, musculoskeletal pain; PWL, physical workload.