摘要：Objectives. We sought to gain a better understanding of the relationship between learning disabilities, attention-deficit/hyperactivity disorder (ADHD), and risk of occupational injury among young workers. Methods. We assessed 15- to 24-year-old workers (n = 14 379) from cycle 2.1 of the Canadian Community Health Survey (CCHS). We gathered data on demographic characteristics, work-related factors, and presence of learning disabilities or ADHD. We conducted a multivariate logistic regression analysis to assess occurrences of medically attended work injuries. Results. There was an 89% adjusted increase in work injury risk among workers with self-reported dyslexia (a type of learning disability) relative to workers reporting no learning disabilities, although this result did not meet traditional statistical significance criteria. Being out of school, either with or without a high school diploma, was associated with a significantly increased risk of work injury, even after control for a number of demographic and work-related variables. Conclusions. Our findings underscore the notion that individual differences salient in the education system (e.g., learning disabilities, school dropout) need to be integrated into conceptual models of injury risk among young workers. Paid employment is a common part of young people's lives in the United States and Canada. 1 , 2 Canadian employment figures show robust levels of youth employment, with 44.7% of adolescents (15–19 years old) and 70.9% of young adults (20–24 years old) holding jobs in any given month in 2004. 2 Canadian adolescents frequently juggle work and school, with 82% being involved in both activities in 2004. According to data from Statistics Canada, Canadian adolescents are most likely to hold sales and service jobs (75.5%), and they are relatively well represented in manual and goods-producing jobs (e.g., construction, agriculture; 15.5%). 3 By young adulthood, Canadians are still largely concentrated in sales and service jobs (50.4%), but with an increased percentage holding manual and goods-producing jobs (22.4%). Many of the work injuries sustained by young people have health and economic consequences. One study of work-related injuries among adolescents reported to a state department of labor showed that 15% of these young people sustained permanent impairments such as chronic pain, scarring, sensory loss, and loss of range of motion. 4 Another study revealed that annual earnings were significantly lower among young adults aged 16 to 24 years who suffered a work injury causing a 1-week work absence than among their uninjured counterparts, and this was true even more than a year after the occurrence of the injury. 5 Work-related injury rates are 1.6 times higher among young Canadian workers than among adults older than 25 years (5.8 and 3.5 per 100 full-time equivalents [FTEs], respectively), and thus such injuries are a public health concern. 6 With regard to factors associated with work injuries among young people, reviews of studies in the literature indicate that work setting (e.g., restaurants, construction), frequency of hazard exposure, and perceived work overload are consistently associated with the likelihood of such injuries. 1 , 7 , 8 In terms of demographic characteristics and individual factors, descriptive epidemiological studies of young workers indicate that injury rates are elevated among male workers and those in late adolescence and young adulthood. 1 , 8 Furthermore, according to a systematic review of the multivariate studies published in the literature about young workers, visible minority status shows consistent associations with risk even after control for job and workplace factors. 7 In addition, educational status (i.e., educational level and school attendance) has been shown to be associated with work injuries. In one study of Canadian workers aged 15 to 24 years, unadjusted work injury rates were higher among those who had left school early (8.2 per 100 FTEs) than among those attending high school (3.1 per 100 FTEs); they were also higher among those who had completed high school but had not pursued postsecondary education (5.1 per 100 FTEs) than among those attending a postsecondary institution (2.7 per 100 FTEs). 9 These elevated risks persisted even when demographic and work covariates (e.g., occupation, work hours) were controlled. Similarly, a longitudinal study of Canadian workers aged 16 to 24 years revealed that those with less than a high school education were almost 3 times more likely to have a work disability absence than were those with at least a high school diploma, even after control for type of job and number of hours worked. 10 Relationships between educational status and work injuries highlight the heterogeneity of background characteristics even among young workers and raise questions about the factors that may underlie these associations. Given that young people with learning disabilities and attention-deficit/hyperactivity disorder (ADHD) are at higher risk than those without such conditions of not completing high school and not attending a postsecondary institution, 11 , 12 we sought to examine the association between these 2 mental health conditions, types of jobs held, and the occupational injury experiences of Canadians aged 15 to 24 years. The primary features of ADHD are inattention, impulsivity, and excessive energy (e.g., restlessness, fidgeting). Two Canadian studies in which a standardized diagnostic interview (i.e., the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition [ DSM-III-R ] 13 ) and parental reports were used to assess symptoms and impairment among community samples of children and adolescents revealed ADHD prevalence rates of 3% to 4%. 14 , 15 These rates were comparable to the rates reported in US studies in which the DSM-III-R criteria have been used (3.8% average prevalence across 7 studies). 16 A similar ADHD prevalence rate (4.4%) has been reported in young adults (those aged 18–24 years). 17 “Learning disabilities” is an umbrella term for a heterogeneous group of information-processing problems that manifest as significant language or math difficulties in the context of overall average cognitive ability. Dyslexia is a type of learning disability characterized by particular problems with reading, spelling, and writing. Depending on the information-processing issue, problems can also emerge in cognitive functions such as memory, abstract reasoning, and spatial orientation. 18 From the 1960s to the 1990s, as a result of a combination of changes in assessment methods and the availability of special education, the prevalence of learning disabilities in the United States tripled. 19 US Department of Education data from 1998–1999 indicate a rate of 4.49% among students aged 6 to 21 years, 20 and a 1998 survey of students enrolled in a postsecondary institution revealed prevalence rates ranging from 0.5% to 10%. 21 In the 1992 US National Adult Literacy Survey, which was representative of the general population, the rate of learning disabilities among respondents older than 16 years was 3%, and 15% to 20% of adults with less than an 8th-grade education reported that they had a learning disability. 22 We hypothesized that learning disabilities and ADHD may influence occupational injury risk in 2 ways. First, when these conditions limit educational attainment, young people have fewer job-relevant skills and less of the technical knowledge valued in a labor market, and as a result they are more likely to hold low-skill, manual jobs that increase their exposure to hazards. Although some studies examining employment patterns show that, 3 to 5 years after high school, young people with learning disabilities have employment rates similar to those of young people in the general population, 11 other investigations indicate that young people with learning disabilities have lower occupational status and make more frequent job changes. 23 , 24 People with ADHD also appear to change jobs more frequently and have lower occupational status than those without ADHD. 25 Thus, we predicted that a greater proportion of young people with learning disabilities or ADHD than those without either condition will hold physically demanding and hazardous jobs and that these job differences may contribute to their work injury risk. Second, even when young people with and without learning disabilities or ADHD hold comparable jobs, the cognitive and behavioral consequences of their learning or behavioral difficulties place those in the former group at increased risk for work injury. For example, both learning disabilities and ADHD can make it difficult to efficiently read instructions and remember previously taught information. 26 Additional areas of difficulty can include executive functions such as task prioritization and flexibility in changing behavior while learning new tasks. Young people with these conditions may also have particular difficulty in completing multiple concurrent tasks, dealing with time pressure, and having to complete tasks in a required sequence. 18 Consistent with the notion that learning disabilities and ADHD may influence work injury risk, a recent longitudinal study showed that children or teenagers who met the criteria for ADHD had a 40% increased risk of any kind of injury (not only work-related injuries). 27 Evidence (albeit preliminary and indirect) for this learning/behavioral consequences hypothesis would be indicated if learning disabilities or ADHD remained an independent predictor of work injury risk even after control for demographic and work-related variables.
