1. Introduction
Worldwide the construction industry is characterized by a high prevalence of musculoskeletal complaints [
1]. This review of Umer et al. showed that in the construction industry, musculoskeletal complaints with the highest one-year prevalence concern the low back with 51%, followed by the knee with 37%, and in third place is the shoulder with 32% [
1]. The prevalences of the other body regions are 30% for the wrist, 24% for the neck and ankle/foot, 20% for the elbow and upper back, and 15% for the hip/thigh [
1]. These prevalences of low back and knee complaints are also high when looking at clinically assessed diagnoses of musculoskeletal diseases and disorders among construction workers. Dale et al. reported annual prevalences of claims for acute musculoskeletal injuries (ICD10:S00-T14) and chronic musculoskeletal disorders (ICD10:M.x [x = any number] over the period of January 2015 to June 2018 [
2]. The percentage for the back/torso was 30% and runners-up were both the lower and upper extremity with 15%, respectively. Similar results are reported by Van der Molen et al. in their study on incidence rates of occupational diseases in the Dutch construction sector for 2010–2014 [
3]. These incidence rates were based on a dynamic prospective cohort of occupational physicians reporting to the Netherlands Center for Occupational Diseases. An occupational disease is defined as a clinically assessed diagnosis that is predominantly caused by work-related factors according to the reporting occupational physician [
3]. The annual incidence of low back pain (ICD-10 code M545) was the highest with 750 per 100,000 construction workers. For osteoarthritis including the knee (ICD-10 codes M159, M169, M179, M189, M199 and excluding the spine) this was 688 per 100,000 construction workers. Not only self-reported complaints of the low back and knee, physician-diagnosed (occupational) diseases or disorders of the low back and knee, but also surgically treated musculoskeletal diseases and disorders regarding the low back and knee appear high among construction workers, like lumbar disc herniation [
4,
5] and hip and knee osteoarthritis [
6]. Construction workers with these musculoskeletal diseases or disorders are at increased risk of sick leave [
7] and paid labor force exit due to work disability [
8]. An occupation within the construction industry where workers run an increased risk of low back pain, lumbosacral radicular syndrome and knee osteoarthritis are sand-cement bound screed floor layers [9-11]
To get insight in the efficacy of a preventive measures to reduce the number of floor layers with such a disease or disorder, insight in the proportional reduction of the number of these diseases or disorders is needed if floor layers are not or less exposed to the physical demands of this type of work [
12,
13]. In recent years, several systematic reviews have assessed to what extent physical demands at work contributed to these multifactorial musculoskeletal diseases and disorders, like low back pain [
14], lumbosacral radiculopathy syndrome [
15] and knee osteoarthritis [
16]. Insight in the attributable fraction does not only provide insight in the number of work-related diseases or disorders that potentially might be prevented, but can also be used to estimate the potential health benefit of a specific preventive measure. Especially lumbosacral radicular syndrome and knee osteoarthritis have a long latency period before symptom onset. Therefore, a controlled prevention study to assess the incidence these musculoskeletal diseases is not only time consuming but probably requires a great number of participants to secure enough new cases and statistical power.
An alternative might be to perform a health impact assessment. The World Health Organisation [
17] defines a health impact assessment as ‘… a practical approach used to judge the potential health effects of a policy, program or project on a population, particularly on vulnerable or disadvantaged groups. Recommendations are produced for decision-makers and stakeholders, with the aim of maximizing the proposal’s positive health effects and minimizing its negative health effects.’
In the Netherlands, the Dutch Labor Inspectorate wanted to reduce the exposure to bending of the trunk and kneeling among sand-cement bound screed floor layers and thereby reduce the risk of low back pain, lumbosacral radicular syndrome and knee osteoarthritis by stimulating the use of a manually moved screed levelling machine (
Figure 1). Compared to the traditional working technique (
Figure 1a), the work can be performed in a more upright standing and walking position (
Figure 1b). This recommendation of the Dutch Labor Inspectorate was based on two studies of Visser et al. [11, 18]. The first study [
11] assessed the physical work demands of the traditional working technique of sand-cement bound screed floor layers and of anhydrite-bound screed floor layer [
11]. The second study [
18] assessed the physical work demands only among sand–cement bound screed floor layers using two electrical screed levelling machines namely a manually moved screed levelling machine (
Figure 1b) and a self-propelled machine.. Based on these two studies, Visser et al [11, 18] concluded that the manually moved screed levelling machine may help to reduce the high physical work demands on floor layers while working with the traditional working technique. However, the studies by Visser et al [
11,
18] did not answer the question how much the health benefit is for floor layers regarding the reduction of the risk on low back pain, lumbosacral radicular syndrome and knee osteoarthritis. To overcome this research gap, this paper aims to assess what the potential health benefit is for low back pain, lumbosacral radicular syndrome and knee osteoarthritis using a health impact assessment. Given that the exposure to bending of the trunk and kneeling among sand-cement bound screed floor layers using the manually moved screed levelling machine is lower than using the traditional working technique, we hypothesize that the manually moved screed levelling machine results in a reduction of the risk of low back pain, lumbosacral radicular syndrome and knee osteoarthritis. However, the real world potential effects size has to be established yet.
In summary, therefore the research question is: How much health gain can be expected by working with the manually moved screed levelling machine compared to the traditional working technique in preventing low back pain, lumbosacral radicular syndrome and knee osteoarthritis among sand-cement bound screed floor layers in the Netherlands?
Author Contributions
“Conceptualization, P.K., S.V. and H.F.M.; methodology, P.K., S.V. and H.F.M.; validation, P.K., S.V. and H.F.M; data curation and software, S.V.; investigation, P.K. and S.V.; formal analysis, P.K. and S.V.; writing—original draft preparation, P.K..; writing—review and editing, S.V. and H.F.M.; visualization, S.V..; supervision, P.K.; All authors have read and agreed to the published version of the manuscript.”