Effect of relative weight limit set as a body weight percentage on work-related low back pain among workers

Abstract

Introduction A quarter of work-related low back pain (LBP) cases result from handling heavy loads in Japan. The maximum weight male/female workers can handle is 40%/24% of their body weight but has set a constant load weight in ISO 11228–1 and NIOSH lifting equation. The preventive effect of the relative weight limit on LBP has not been clarified. This study aimed to identify the effect of relative weight limits set as body weight percentages on LBP prevalence. Methods Data from 21924 workers were collected via a web-based survey in 2022. The workers were categorized into three groups: group A, “no handling,” group B, “handling loads up to 40%/24% or less of body weight,” and group C, “handling loads over 40%/24% of body weight.” Moreover, they were categorized into eight groups: no handling, 1–5 kg, 5–10 kg, 10–15 kg, 15–20 kg, 20–25 kg, 25–30 kg, and ≥30 kg. Multiple logistic regression analysis was used to identify the effects of the limits set to body weight percentages and constant load weights on LBP. Results In groups A, B, and C, 25.5%, 39.2%, and 47.3% of males or 16.9%, 26.4%, and 38.0% of females had LBP, respectively. The odds ratio (OR) of LBP was significantly greater in group B than in group A and even greater in group C. The OR of LBP among workers handling loads under 10 kg was not significantly different compared to no-handling workers. Conclusions LBP prevalence was greater in group B than in group A but lesser than in group C. Weight limits based on body weight percentages could not eliminate the factor of handling loads. However, handling loads under 10 kg suppressed LBP. Relative weight limits set as body weight percentages were inappropriate and ineffective for preventing LBP.

Manual rolling load and low back pain among workers in Japan: a cross-sectional study

“…Severe LBP prevalence ranged from 12% to 22% among no-handling workers and the rolling task workers handling ≤20 kg and 20-40 kg, whereas this was significantly higher at 53% among the rolling task workers handling >40 kg. In analyses using the same dataset as this study, 39% of lifting, lowering, and carrying task workers 10 and 39% of pushing and pulling task workers 11 complained of severe LBP. Moreover, Fujii and Matsudaira 15 reported that 38% of Japanese workers, housewives, and unemployed persons aged 20-79 years experienced severe LBP that interfered with work and life.…”

“…These questionnaire items were similar to those used in our previous studies. 10 , 11 Data were extracted from the questionnaire for rolling and no-handling loads. For questioning on manual handling conditions, regularly managed load weights, and the severity of LBP, the initiation of the first LBP episode experienced by a worker in their current job was considered as the reference point for inquiry.…”

Investigating the characteristics of mild intervertebral disc degeneration at various age stages using single-cell genomics

“…Researchers have established that dysfunction in any component of the IVD leads to intervertebral disc degeneration (IVDD), with NP tissue degeneration recognized as the primary cause ( Lama et al, 2022 ). IVDD is a multifactorial process with aging being a significant risk factor ( Ngo et al, 2017 ; Iwakiri et al, 2023 ; Novais et al, 2024 ). However, disc degeneration can also manifest independently of the aging process, making it challenging to distinguish between physiological disc aging and degeneration ( Soufi et al, 2023 ).…”

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“…Researchers have established that dysfunction in any component of the IVD leads to intervertebral disc degeneration (IVDD), with NP tissue degeneration recognized as the primary cause (Lama et al, 2022). IVDD is a multifactorial process with aging being a significant risk factor (Ngo et al, 2017;Iwakiri et al, 2023;Novais et al, 2024). However, disc degeneration can also manifest independently of the aging process, making it challenging to distinguish between physiological disc aging and degeneration (Soufi et al, 2023).…”