Are forward bending of the trunk and low back pain associated among Danish blue-collar workers? A cross-sectional field study based on objective measures

Abstract

The aim of this cross-sectional study was to investigate the association between the duration of objectively measured forward bending of the trunk and low back pain (LBP) intensity among 198 Danish blue-collar workers (male = 115; female = 83). The duration of forward bending of ≥ 30°, ≥ 60° and ≥ 90° was divided into high (the highest tertile) and low-moderate (the remaining tertiles) categories. High (>5) and low ( ≤ 5) pain intensities were categorised from a self-reported 0-9 scale. Results of multi-adjusted logistic regressions indicated no significant positive associations between forward bending and LBP intensity. On the contrary, higher duration of forward bending of ≥ 30° was associated with lower LBP intensity during all day (OR = 0.40; 95% CI, 0.15-1.02; p = 0.05) and work (OR = 0.44; 95% CI, 0.17-1.15; p = 0.09). This indication of a negative association may be explained by fear-avoidance behaviour of the blue-collar worker, job crafting or healthy worker effect.

Does objectively measured daily duration of forward bending predict development and aggravation of low-back pain? A prospective study

“…Some studies report a positive association (8,10) but comparison with our study is highly challenged by the aforementioned different exposure measurements between studies (11,16). A few studies support our finding of lack of association between forward bending and LBP (12,37). The Villumsen et al study (12) also used objective measurements of forward bending but in a cross-sectional design, while Harkness et al (37) reported lack of association between self-reported forward bending and new onset of LBP among newly hired workers.…”

“…A few studies support our finding of lack of association between forward bending and LBP (12,37). The Villumsen et al study (12) also used objective measurements of forward bending but in a cross-sectional design, while Harkness et al (37) reported lack of association between self-reported forward bending and new onset of LBP among newly hired workers. Therefore, to our knowledge, this is the first prospective study of the association between objective exposure measurements of forward bending and prospectively registered LBP.…”

“…A recent cross-sectional study from the DPhacto study, found that high duration of forward bending increased the odds of LBP among workers experiencing low but not high social support at work (12). It could therefore be suggested that social support at work acts as a modifier also on the prospective association between forward bending and LBP.…”

“…Therefore, we generated a population including only workers with ≥4 hours of measurements or measured for ≥75% of the working time registered in the diary (N=644). The choice of criteria is based on previous studies among similar populations and with identical measurements (12,35,36).…”

“…Forward bending of the trunk is a relatively frequently occurring activity, particularly among blue-collar workers (12). Accordingly, LBP is shown to be more prevalent among blue-than white-collar workers (13).…”