Response to “Ergonomic Intervention For Musculoskeletal Disorders in Construction Workers”

We read with great interest the recently published article entitled “Use of Ergonomic Measures Related to Musculoskeletal Complaints among Construction Workers: A 2-year Follow-up Study” by Frings-Dresen et al [1]. Ergonomic intervention prevents work-related musculoskeletal injuries in workers. We compliment the authors for their initiative to implement ergonomic measures through a national campaign “Lighter Work(s),” which aimed to reduce musculoskeletal injuries among construction workers [1]. With regard to this interesting study, we would like to request the opinions of the study authors on some of our following queries and comments concerning the methodologies adopted in their study. In the study being discussed, the authors implemented a huge campaign by recruiting 4,500 workers from nine different subsets of occupations within the construction industry. Although the current study was a national-level campaign, the authors did not provide details on how they determined the sample size for each of the nine substudy populations. Unfortunately, the selection criteria for the study participants were also not specified. Past evidence has suggested that both inclusion and exclusion criteria are essential for maximizing uniformity among study participants to ensure reliable study results [2,3]. We would like to request further information from the authors about the selection criteria applied to the participants in their study. Were any dropout rates considered for sample size calculation and for reporting the results? Such information may help to estimate the dropout prediction rate to design large-scale ergonomic intervention trials. Is it likely that the study results may differ if the aforementioned factors were controlled and addressed adequately? We would appreciate the response of the authors on these methodological issues, as such information may help future researchers design a rigorous methodology in large-scale ergonomic trials. We appreciate the effort of authors to design separate questionnaires for each subset of occupations within the construction industry. Standardization of the questionnaire within a study population is a necessary requirement to obtain reliable information [4]. We would like to know how the authors handled issues pertaining to reliability of the tool, especially when it involves several subsets of population within an occupation. In addition, availability of the contents of such uniquely designed questionnaires would be of great help to researchers and practitioners in