Objectives In recent years, emphasis was placed on the determinants of chronic low back pain (LBP) in a tertiary prevention perspective. However, prevention of acute and subacute LBP should remain a goal of primary prevention in the workplace. The objective of this study was to investigate the risk factors for common acute and subacute LBP related to the individual characteristics or occupational exposure factors in a large sample of workers.

Methods This longitudinal study assessed the main biomechanical, psychological and organisational risk factors for LBP, by self-administered questionnaire, between 2002 and 2005, among a sample of 3,710 workers. A total of 2,332 of them were followed-up between 2007 and 2009 for the occupational becoming, health and working conditions. The risk modelling of different durations of LBP was performed using a multinomial logit model with a variable response into four categories: no LBP, short acute LBP (< 8 days during the preceding 12 months), prolonged acute LBP (8 to 30 days during the preceding 12 months) and subacute LBP (> 30 days during the preceding 12 months, but not daily). Individuals reporting chronic LBP were excluded. In addition, analyses were stratified by gender.

Results The prevalence of LBP was 52.4% among men and 51.2% among women and decreased according to the duration of LBP regardless of gender (24.8% of short acute LBP and 11.6% of subacute LBP). The combination of a high perceived physical exertion with frequent bending of the trunk was a risk factor for LBP for both genders. In addition, whole-body vibration and low social support were risk factors in men and high tall in women.

Conclusions The impact of biomechanical factors seems to be more important than organisational and psychosocial factors. analyses failed to identify risk factors specifically related to the duration of LBP.