Gaber 1999.

Methods	RCT
Participants	Subjects: 209 male workers whose jobs included manual material handling at an airport. The majority of the workers (77%) had no or only mild LBP at the start of the study.
Interventions	Preventive intervention: 1) Synthetic lumbar support (n=118), lumbar support use at work for 12 months. Control intervention: 2) No intervention (n=91)
Outcomes	Pain score, sick leave due to LBP and medicine intake due to LBP. No differences in pain and sick leave; less medication intake in lumbar support group.
Notes	Of the 267 workers included at the start of the study only 209 have finished the study. Only data of these subjects is presented in the study. No data on compliance.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Unclear from text
Allocation concealment?	Unclear risk	B ‐ Unclear
Blinding? All outcomes ‐ patients?	High risk
Blinding? All outcomes ‐ outcome assessor?	High risk
Incomplete outcome data addressed? All outcomes ‐ drop‐outs?	High risk
Incomplete outcome data addressed? All outcomes ‐ ITT analysis?	High risk
Similarity of baseline characteristics?	Low risk
Co‐interventions avoided or similar?	Low risk
Compliance acceptable?	High risk
Timing outcome assessments similar?	Low risk