Dealing with missings in predicting determinants for musculoskeletal pain among Danish fishermen via conditional imputation and missing categories

摘要

BackgroundThe aim of the analysis is to estimate the determinants of musculoskeletalpain among Danish fishermen after several positivestructural changes for the physical work environment have been initiated.The present analysis focuses on considering missings viadifferent methods such as conditional imputation and a ‘‘missing’’-category in multiple regression analyses.Health—exploring complexity: an interdisciplinary systems approach HEC2016 S23123MethodsA cross sectional survey in a random sample of Danish fishermen wasdone in 2015 with application of the Nordic questionnaire for musculoskeletalpain in nine different body regions (neck, shoulder,elbow, hand, upper back, lower back, hip, knee, and foot). In total,270 fishermen participated in the study (response rate 27 %). Determinantsfor musculoskeletal pain were tested using a multiple linearregression analysis with an overall pain score summing up all ninepain locations. Missing answers were calculated out of the mean valueof the remaining answers of the relevant person (conditional imputation).Cronbach alpha of 0.91 indicates a very good internalconsistency of the scale. Additionally, multinomial logistic regressionanalyses considering relevant confounders were used to look at eachsingle pain site with missing as an additional outcome. In all analyses,sideline occupations, work position, vessel type, education, andduration at sea were considered as further predictors.ResultsThe prevalence of pain was high for all musculoskeletal locations. Inthe multiple linear regression analysis, workload was positivelyassociated with musculoskeletal pain (Beta: 0.05 (95 % CI 0.04;0.05). Having a sideline occupation was negatively associated withmusculoskeletal pain (Beta: -0.15; 95 % CI -0.24; -0.03). A linearregression model excluding all missing’s revealed similar results.Multinomial regression models showed that workload was the onlyconsistent predictor for musculoskeletal pain, in particular regardingupper and lower limb pain. Two additional predictors were found forthe nine different pain locations models; sideline occupation wasassociated with less shoulder pain, and work duration of more than30 days per year was a predictor for hip pain. An additional categoryfor missing values was considered in the multinomial regressionanalysis to see if missing by itself had an effect on the outcome.Overall, the odds ratios for missing categories were small and farfrom being significant which suggest that missing values do not biasthe overall results. Both methods considering missings, the multiplelinear regression model with conditional imputation and the multinomiallogistic regression using missing categories in categoricaloutcomes revealed similar results.ConclusionThe work as a fisherman remains physically demanding, although thisis much less than previously. Fishermen still have a high prevalenceof musculoskeletal pain. Workload is the only and consistent predictorof pain. Different forms of missing imputation revealed similarresults suggesting missings to occur unsystematically.