Baseline characteristics of participants
| Characteristic | Missing n (%) | UC (n = 174) | UC+MI (n = 170) | UC+SVAI (n = 170) |
| Age (years), median (IQR) | 49 (40–55) | 49 (41–56) | 49 (41–56) | |
| Women, n (%) | 94 (54) | 99 (58) | 100 (59) | |
| Married/living with partner, n (%) | 1 (0.2) | 120 (69) | 119 (70) | 119 (70) |
| Norwegian as first language, n (%) | 2 (0.4) | 151 (87) | 154 (91) | 145 (86) |
| Education, n (%) | ||||
| Compulsory education | 21 (12) | 14 (8) | 20 (12) | |
| High school | 92 (53) | 95 (56) | 84 (49) | |
| College or university <4 years | 40 (23) | 46 (27) | 49 (29) | |
| College or university ≥4 years | 21 (12) | 15 (9) | 17 (10) | |
| Health literacy* (12–72), median (IQR) | 49 (10) | 51 (44–60) | 53 (45–59) | 52 (44–59) |
| Smokers, n (%) | 39 (22) | 35 (21) | 36 (21) | |
| Body mass index (kg/m2), median (IQR) | 13 (3) | 28 (24–31) | 27 (24–31) | 27 (24–31) |
| Days of physical activity previous week, n (%) | 1 (0.2) | |||
| 0 days | 65 (37) | 54 (32) | 64 (38) | |
| 1-2 days | 46 (26) | 43 (25) | 39 (23) | |
| 3-4 days | 38 (22) | 45 (27) | 41 (24) | |
| 5-7 days | 25 (14) | 27 (16) | 26 (15) | |
| Musculoskeletal health† (0–56), mean (SD) | 21 (4) | 27 (9) | 27 (8) | 27 (8) |
| Work ability‡ (0–10), median (IQR) | 3 (0.6) | 2 (0–5) | 3 (1–5) | 3 (0–5) |
| ÖMPSQ-SF§ (≥60), n (%) | 65 (37) | 55 (32) | 59 (35) | |
| Keele STarT MSK tool (0–12) | ||||
| High risk (≥9), n (%) | 61 (35) | 49 (29) | 48 (28) | |
| Medium risk (5–8), n (%) | 85 (49) | 86 (51) | 98 (58) | |
| Low risk (<5), n (%) | 28 (16) | 35 (21) | 24 (14) | |
| High-risk for long-term sick leave¶, n (%) | 38 (22) | 36 (21) | 35 (21) | |
| Work satisfaction** (0–10), median (IQR) | 1 (0.2) | 8 (6–9) | 8 (7–9) | 8 (6–9) |
| In conflict with employer, yes n (%) | 4 (0.8) | 6 (3.5) | 5 (3.0) | 14 (8.3) |
| Followed-up by employer, n (%) | 7 (1) | |||
| No follow-up | 65 (38) | 72 (44) | 72 (43) | |
| Dialogue meeting or follow-up plan | 64 (37) | 53 (32) | 65 (38) | |
| Dialogue meeting and follow-up plan | 44 (25) | 40 (24) | 32 (19) | |
| White-collar workers, n (%) | 58 (33) | 56 (33) | 61 (36) | |
| Blue-collar workers, n (%) | 116 (67) | 114 (67) | 109 (64) | |
| Work, n (%) | ||||
| Full-time | 120 (69) | 110 (65) | 111 (65) | |
| Part-time 50–99% of full work hours per week | 39 (22) | 53 (31) | 48 (28) | |
| Part-time <50% of full work hours per week | 15 (9) | 7 (4) | 11 (6) | |
| Graded disability pension††, yes n (%) | 5 (1) | 15 (9) | 12 (7) | 9 (5) |
| Sickness absence days previous year (work days‡‡), median (IQR) | 5 (1) | 38 (30–50) | 35 (31–50) | 36 (26–50) |
| Duration of consecutive sick leave at baseline (calendar days), median (IQR) | 5 (1) | 51 (50–55) | 51 (50–55) | 51 (49–56) |
| Sick leave at baseline, n (%) | 5 (1) | |||
| Full-time sick leave | 103 (60) | 109 (65) | 103 (61) | |
| Sick leave 50–99% of contracted work hours | 65 (38) | 54 (32) | 63 (37) | |
| Sick leave <50% of contracted work hours | 3 (2) | 6 (4) | 3 (2) | |
| Area of body pain, n (%) | 14 (3) | |||
| Lower limb | 6 (4) | 18 (11) | 15 (9) | |
| Upper limb | 30 (18) | 30 (18) | 30 (18) | |
| Neck | 12 (7) | 12 (7) | 10 (6) | |
| Back | 34 (20) | 42 (25) | 43 (26) | |
| Multisite pain | 12 (7) | 8 (5) | 10 (6) | |
| Joint disorders | 20 (12) | 13 (8) | 10 (6) | |
| Fractures | 14 (8) | 16 (10) | 11 (7) | |
| Other | 40 (24) | 26 (16) | 38 (23) |
The distribution was skewed for all continuous variables, except for the MSK-HQ.
*Measured with the Health Literacy Scale Questionnaire.
†Measured with the Musculoskeletal Health Questionnaire (MSK-HQ).
‡Measured with a single question from the Work Ability Index.
§ÖMPSQ-SF: The Örebro MSK Pain Screening Questionnaire Short Form (0–100).
¶High-risk group in the MI-NAV trial: ≥60 on the ÖMPSQ-SF and ≥9 on the Keele STarT MSK Tool.
**Work satisfaction: 0=not satisfied at all, 10=totally satisfied.
††Individuals who work part-time and receive a graded disability pension.
‡‡Lost workdays due to sick leave, adjusted for work hours per week and amount of sick leave.
MI, motivational interviewing; n, number of participants; SVAI, stratified vocational advice intervention; UC, usual case management.