Epidemiological and ergonomic study of occupational factors associated with syndromes of upper limb disorders in keyboard operators

Two linked studies were undertaken to examine a wide variety of factors which may be associated with symptoms of upper limb disorders in keyboard operators, including characteristics of the work, workplace, posture, and psychological stresses.In Phase 1, almost 4,500 questionnaires were given to keyboard users working for a number of public and private organisations. Almost 80% of these were returned completed. Of the respondents, 55% had experienced symptoms of upper limb disorders at some time, and 49% reported experiencing symptoms in the last three months. Fourteen percent had asked for advice about their symptoms from a health professional (e.g. a doctor or physiotherapist).In Phase 2, a sample of 295 of these cases with symptoms were compared with 154 controls without symptoms. For each of these, a detailed examination of the workplace was conducted by an ergonomist, who applied a standard interview, administered questionnaires, and observed work practices. Although there were differences between the upper limb syndrome groups, female gender and increased age were often significantly associated with risk of being a case. Analyses of almost 100 variables showed a number of work-related factors also to be significant. Both the number of hours per week spent using a keyboard and the length of time spent at the keyboard without a break were particularly strongly associated with case status. Large numbers of the factors that were associated with symptoms of ULDs could be related to psychosocial stresses in the work environment.A number of the associations identified are supportive of the provisions of the Health and Safety (Display Screen Equipment) Regulations 1992, which came into force during the course of this research.