Work Injury Risk Among Young People With Learning Disabilities and Attention-Deficit/Hyperactivity Disorder in Canada

Abstract

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.

METHODS

We used data from cycle 2.1 of the Canadian Community Health Survey (CCHS), a large, population-based survey conducted by Statistics Canada between January and September 2003. The CCHS, which involved a multistage, stratified cluster sampling design in which households were the final sampling unit, covered about 98% of Canadian residents older than 12 years. Selection of respondents was designed to oversample young people aged 12 to 19 years. At the national level, the CCHS response rate was 80.7% (n = 134 072). Survey weights developed by Statistics Canada for each respondent were used, and thus the data represent the entire Canadian population at the beginning of the observation period. The weights accounted for sampling probabilities and nonresponse. Further details of the sampling and weighting strategy can be found in the user guide published by Statistics Canada.²⁸

We included in our study CCHS respondents who were between the ages of 15 and 24 years and reported having been employed at some point during the 12-month observation period. Respondents were asked about injuries they had sustained in the preceding 12 months and that were serious enough to have limited their normal activities (e.g., broken bones, bad cuts or burns, sprains, or poisonings; respondents were specifically asked to exclude repetitive strains). Respondents were then asked to indicate the most serious of these injuries, after which they were further probed to determine whether this injury took place while they were working (excluding travel to or from work). Injuries identified as taking place during work were considered to be work-related injuries for the purposes of this study. It should also be noted that, because a respondent could report details on only 1 injury, the number of work injury events included in our analyses may have been a slight underestimate.

Measures

Respondents indicated whether they had been diagnosed with dyslexia, another type of learning disability, attention-deficit disorder (ADD; i.e., inattention but not hyperactivity), or ADHD. We created a summary variable in which ADD and ADHD were collapsed into a single category. When respondents were identified as experiencing more than 1 of these disorders, dyslexia was considered first, followed by other learning disorders and, finally, ADD or ADHD.

We used a 4-category variable to assess school status that considered whether each respondent had completed high school and was currently enrolled in a postsecondary institution, had completed high school but was not currently enrolled in a postsecondary institution, had not completed high school but was currently in school, or had not completed high school and was not currently enrolled in a secondary or postsecondary institution. We calculated a measure of working hours by taking reported average number of hours worked per week and multiplying by the number of weeks worked in the preceding 12 months. This total number of working hours was expressed as a proportion of an FTE, considered to be 2000 hours per year.

We used an occupational coding system²⁹ to group Standard Occupational Classification codes and create a job type variable. In this coding system, the physical demands of work tasks are assessed and, on the basis of standard occupational codes, each job is classified into 1 of 3 physical demand categories: manual (e.g., bricklayers, chefs, carpenters), mixed (e.g., veterinarians, nurses, typesetters), or nonmanual (e.g., architects, dentists, teachers). The system was developed through behavioral observations of work tasks performed by employees and through agreement among occupational health and safety experts on the typical frequency of handling loads and the weights of those loads.

Multiple job holders were defined as those who held at least 2 jobs simultaneously at any point in the 12-month observation period. In the analyses involving these respondents, the job characteristics used were those associated with the job at which they worked the most hours.

Other covariates considered were the respondent's age, gender, and province of residence. Province of residence was considered as a covariate given that education legislation and subsequent resources for the diagnosis and management of respondents with learning disabilities differ by province. Variables related to socioeconomic status were not considered given their relationship to educational status and job type.

Analysis

We generated a logistic regression model to assess the relationship between learning disabilities, ADD or ADHD, school status, demographic characteristics, work variables, and work-related injuries. A listwise deletion was employed in which observations that did not involve complete responses to all covariates were eliminated. As a result of the complex nature of the survey, we used a weighted bootstrap method with 500 replicates to adjust variance estimates.³⁰

RESULTS

Of the CCHS respondents, 14 379 were aged 15 to 24 years and had been employed at some point in the previous 12 months. Table 1 provides descriptive information, by learning disability status, for all of the variables considered in our analyses. Overall, 4.4% of the 14 379 CCHS respondents used were classified as having some type of learning disability or ADHD. Respondents with learning disabilities or ADHD were more likely than respondents without these conditions to be male (61.3% vs 50.9%). Related to our hypothesis regarding jobs held, respondents with learning disabilities or ADHD were more likely than those without either condition to hold a manual job (56.5% vs 40.7%).

TABLE 1.

Percentages of and Odds Ratios for Learning Disabilities or ADHD and ADD, by Respondent Characteristics: Canadian Community Health Survey, 2003

		Any Learning Disability or ADHD/ADD
	Total, No. (%) or Mean (SD)	Yes, No. (%) or Mean (SD)	No, No. (%) or Mean (SD)	Crude Odds Ratio
Total	14 379 (100.00)	637 (4.43)	13 742 (95.57)
Dyslexia	116 (18.06)
Other learning disability	197 (30.63)
ADHD/ADD	330 (51.31)
School status
Not completed high school but currently enrolled in school	3 331 (23.36)	172 (27.51)	3 159 (23.17)	2.33
Completed high school but not currently enrolled in a postsecondary institution	4 785 (33.56)	213 (33.91)	4 573 (33.54)	1.98
Not completed high school and not currently enrolled in a secondary or postsecondary institution	1 052 (7.38)	125 (19.99)	927 (6.80)	5.77
Completed high school and currently in a postsecondary institution	5 091 (35.70)	117 (18.60)	4 975 (36.49)	(Ref)
Age, y
15	859 (5.98)	52 (8.23)	807 (5.87)	1.41
16	1 137 (7.91)	50 (7.80)	1 087 (7.91)	0.99
17	1 407 (9.79)	60 (9.44)	1 347 (9.80)	0.97
18	1 500 (10.43)	80 (12.53)	1 420 (10.34)	1.22
19	1 403 (9.76)	64 (10.05)	1 339 (9.75)	1.04
20	1 652 (11.49)	68 (10.65)	1 584 (11.53)	0.93
21	1 695 (11.79)	86 (13.54)	1 608 (11.70)	1.16
22	1 641 (11.41)	63 (9.97)	1 578 (11.48)	0.87
23	1 577 (10.96)	47 (7.36)	1 530 (11.13)	0.66
24	1 507 (10.48)	66 (10.44)	1 441 (10.49)	(Ref)
Gender
Male	7 382 (51.34)	390 (61.29)	6 992 (50.88)	1.53
Female	6 997 (48.66)	246 (38.71)	6 750 (49.12)	(Ref)
Province of residence
Newfoundland and Labrador	243 (1.69)	6 (1.01)	237 (1.72)	0.49
Prince Edward Island	71 (0.50)	1 (0.22)	70 (0.51)	0.36
Nova Scotia	443 (3.08)	14 (2.27)	428 (3.12)	0.61
New Brunswick	352 (2.45)	14 (2.19)	338 (2.46)	0.74
Quebec	3 170 (22.05)	112 (17.55)	3 059 (22.26)	0.66
Manitoba	510 (3.55)	27 (4.22)	483 (3.52)	1.00
Saskatchewan	481 (3.35)	18 (2.85)	463 (3.37)	0.71
Alberta	1 633 (11.36)	78 (12.19)	1 555 (11.32)	0.90
British Columbia	1 744 (12.13)	66 (10.31)	1 679 (12.21)	0.70
Territories	52 (0.36)	2 (0.27)	50 (0.36)	0.62
Ontario	5 680 (39.50)	299 (46.94)	5 382 (39.16)	(Ref)
Work-related injury
Yes	517 (3.60)	37 (5.89)	480 (3.49)	1.73
No	13 859 (96.40)	599 (94.11)	13 260 (96.51)	(Ref)
Job type
Manual	5 907 (41.44)	358 (56.47)	5 549 (40.74)	2.55
Mixed	4 116 (28.87)	171 (27.03)	3 944 (28.96)	1.71
Nonmanual	4 233 (29.69)	105 (16.50)	4 128 (30.31)	(Ref)
Multiple job holder
Yes	1 896 (13.21)	87 (13.68)	1 809 (13.19)	1.04
No	12 457 (86.79)	549 (86.32)	11 907 (86.81)	(Ref)
Mean FTE	0.56 (0.42)	0.60 (0.49)	0.56 (0.42)	1.30

Note. ADHD = attention-deficit/hyperactivity disorder; ADD = attention-deficit disorder; FTE = full-time equivalent.

In addition, respondents with learning disabilities or ADHD were more likely than were respondents without either condition to have not completed high school and not currently be enrolled in a secondary or postsecondary institution (20.0% vs 6.8%). Similarly, those with learning disabilities or ADHD were less likely than those without either condition to have completed high school and currently be enrolled in a postsecondary institution (18.6% vs 36.5%).

Table 2 presents data on the relationships between work-related injuries and all of the variables considered. Respondents with dyslexia were more likely than respondents without learning disabilities or ADHD to have sustained a work-related injury (crude odds ratio [OR] = 2.7). Likewise, respondents who had not completed high school and were not currently enrolled in a secondary or postsecondary institution were more likely than those who had completed high school and were currently enrolled in a postsecondary institution to have suffered such an injury (crude OR = 3.2). As expected, work-related injury rates were higher among male respondents than among female respondents (crude OR = 2.4), and those with manual jobs had nearly a 3-fold increased risk of work-related injury relative to those with nonmanual jobs (crude OR = 2.9).

TABLE 2.

Percentages of and Odds Ratios for Work-Related Injuries, by Respondent Characteristics: Canadian Community Health Survey, 2003

	Work-Related Injury
	Yes, No. (%)	No, No. (%)	Crude Odds Ratio
Learning disability status
Dyslexia	10 (2.02)	106 (0.76)	2.72
Other learning disability	5 (1.02)	187 (1.35)	0.78
ADHD/ADD	21 (4.07)	279 (2.01)	2.08
No learning disabilities	480 (92.89)	13 260 (95.87)	(Ref)
School status
Not completed high school but currently in school	80 (15.66)	3251 (23.65)	0.91
Completed high school but not currently enrolled in a postsecondary institution	212 (41.58)	4570 (33.25)	1.72
Not completed high school and not currently enrolled in a secondary or postsecondary institution	85 (16.55)	968 (7.04)	3.24
Completed high school and currently in a postsecondary institution	134 (26.20)	4957 (36.06)	(Ref)
Age, y
15	10 (1.94)	849 (6.13)	0.31
16	22 (4.34)	1115 (8.04)	0.52
17	25 (4.76)	1383 (9.97)	0.46
18	77 (14.84)	1423 (10.27)	1.40
19	65 (12.49)	1338 (9.65)	1.25
20	53 (10.34)	1598 (11.53)	0.87
21	79 (15.27)	1616 (11.66)	1.27
22	60 (11.66)	1581 (11.40)	0.99
23	70 (13.56)	1509 (10.89)	1.21
24	56 (10.80)	1450 (10.46)	(Ref)
Gender
Male	367 (71.00)	7014 (50.61)	2.39
Female	150 (29.00)	6845 (49.39)	(Ref)
Province of residence
Newfoundland and Labrador	8 (1.62)	235 (1.69)	1.08
Prince Edward Island	3 (0.53)	69 (0.50)	1.20
Nova Scotia	25 (4.81)	417 (3.01)	1.80
New Brunswick	16 (3.06)	336 (2.42)	1.42
Quebec	126 (24.38)	3044 (21.97)	1.25
Manitoba	22 (4.22)	488 (3.52)	1.35
Saskatchewan	18 (3.55)	463 (3.34)	1.20
Alberta	64 (12.34)	1567 (11.31)	1.23
British Columbia	52 (10.15)	1692 (12.21)	0.94
Territories	1 (0.17)	51 (0.37)	0.52
Ontario	182 (35.18)	5498 (39.67)	(Ref)
Job type
Manual	327 (63.17)	5579 (40.62)	2.90
Mixed	107 (20.63)	4008 (29.18)	1.32
Nonmanual	84 (16.20)	4149 (30.20)	(Ref)
Multiple job holder
Yes	451 (87.27)	12 003 (86.77)	1.05
No	549 (86.32)	11 907 (86.81)	(Ref)
Mean FTE	0.78 (0.42)	0.55 (0.42)	3.13

Note. ADHD = attention-deficit/hyperactivity disorder; ADD = attention-deficit disorder; FTE = full-time equivalent.

Table 3 shows the results from the full model predicting work-related injuries. Because of the listwise deletion employed, approximately 4% of the sample was not eligible for the final modeling stage. Most of the deleted cases were due to missing data on school status or number of work hours, information required to calculate FTEs.

TABLE 3.

Odds Ratios From Fully Adjusted Logistic Model Examining Work-Related Injuries and Learning Disabilities: Canadian Community Health Survey, 2003

	Work-Related Injury, OR (95% CI)
Learning disability status
Dyslexia	1.89 (0.60, 5.97)
Other learning disability	0.63 (0.22, 1.77)
ADHD/ADD	1.06 (0.48, 2.31)
No learning disabilities	1.00
School status (Ref)
Not completed high school but currently in school	1.09 (0.74, 1.60)
Completed high school but not currently enrolled in a postsecondary institution	1.80 (1.01, 3.19)
Not completed high school and not currently enrolled in a secondary or postsecondary institution	1.86 (1.03, 3.35)
Completed high school and currently in a postsecondary institution (Ref)	1.00
Age, y
15	0.38 (0.14, 1.07)
16	0.58 (0.23, 1.46)
17	0.46 (0.21, 1.16)
18	1.76 (0.99, 3.15)
19	1.42 (0.79, 2.54)
20	0.99 (0.51, 1.93)
21	1.55 (0.80, 3.00)
22	1.17 (0.62, 2.21)
23	1.20 (0.60, 2.40)
24 (Ref)	1.00
Gender
Male	1.65 (1.21, 2.24)
Female (Ref)	1.00
Province of residence
Newfoundland and Labrador	1.26 (0.56, 2.84)
Prince Edward Island	1.09 (0.37, 3.20)
Nova Scotia	1.78 (0.78, 4.05)
New Brunswick	1.19 (0.57, 2.47)
Quebec	1.27 (0.82, 1.96)
Manitoba	0.91 (0.48, 1.72)
Saskatchewan	1.14 (0.70, 1.96)
Alberta	1.06 (0.70, 1.61)
British Columbia	0.97 (0.61, 1.56)
Territories	0.48 (0.02, 12.65)
Ontario (Ref)	1.00
No. of working hours (FTE)	2.54 (1.67, 3.85)
Job type
Manual	2.29 (1.51, 3.48)
Mixed	1.31 (0.80, 2.16)
Nonmanual (Ref)	1.00
Multiple job holder
Yes	1.03 (0.69, 1.52)
No	1.00

Note. ADHD = attention-deficit/hyperactivity disorder; ADD = attention-deficit disorder; OR = odds ratio; CI = confidence interval; FTE = full-time equivalent.

After full adjustment for demographic and work variables, work-related injury risk was higher among respondents with dyslexia than among respondents without learning disabilities, ADHD, or ADD (OR = 1.9; 95% confidence interval [CI] = 0.6, 6.0). Although dyslexia almost doubled the likelihood of work injury in the fully adjusted model, this result did not meet traditional statistical significance criteria. The adjusted odds ratio for dyslexia was somewhat reduced relative to the crude odds ratio of 2.7 (Table 2), suggesting that demographic and work-related variables accounted for a portion of the elevated risk.

Risk of work-related injury did not appear to differ between respondents with ADHD or ADD (or both) and those without either condition (OR = 1.1; 95% CI = 0.5, 2.3). The adjusted odds ratio for ADHD or ADD was notably reduced in comparison with the crude odds ratio of 2.1. Independent predictors of work injury risk in the fully adjusted model included male gender (OR = 1.7; 95% CI = 1.2, 2.2), completion of high school but no current enrollment in a postsecondary institution (OR = 1.8; 95% CI = 1.0, 3.2), failure to complete high school and no current enrollment in a secondary or postsecondary institution (OR = 1.9; 95% CI = 1.0, 3.4), hours of work (OR = 2.5; 95% CI = 1.7, 3.9), and holding a manual job (OR = 2.3; 95% CI = 1.5, 3.5).

DISCUSSION

We sought to better understand the relationships between learning disabilities, ADHD, and risk of work injury among young workers. Our descriptive findings are consistent with the results of previous studies suggesting that young people with learning disabilities or ADHD (or both) are more likely to leave school early.

In addition, our results showed that respondents with learning disabilities or ADHD were more likely than those without these conditions to hold a manual job (Table 1). We hypothesized that the types of jobs held by people with learning disabilities or ADHD would account for their work injury risk. Consistent with this hypothesis, the unadjusted likelihood of a work injury was twice as high among young people with ADHD as among those without ADHD or learning disabilities, but this elevated risk was eliminated after control for demographic and job characteristics. This hypothesis was also partially supported among young people with dyslexia. These respondents had an unadjusted likelihood of work injury that was 2.7 times that of respondents without learning disabilities or ADHD; in the fully adjusted model, this likelihood was reduced to 1.9 times that of young people without these conditions.

We also hypothesized that even when young people with and without learning disabilities or ADHD hold the same jobs, the learning or behavioral difficulties (e.g., difficulties in cognitive–behavioral functioning) faced by those in the former group might place them at increased risk of injury. Control for demographic and work-related variables appeared to account for the unadjusted elevated risk associated with ADHD, and control for demographic and work variables reduced the association between dyslexia and injury somewhat. However, the finding in the multivariate model that dyslexia was still associated with almost double the likelihood of work injury serves as preliminary and indirect support for this second hypothesis.

Although the dyslexia–injury relationship we observed did not meet traditional statistical significance criteria, and the degree of precision was limited by the number of respondents with dyslexia and by the number of injury events in our study, we believe that this association is meaningful. Such a finding may indicate that the fit between those with dyslexia and their work environment is poorer than the fit among their counterparts. Sources of these poor fits could include learning difficulties related to training and poor supervisor–worker communication secondary to difficulties in memory or comprehension. Identifying possible cognitive or behavioral mechanisms underlying relationships between dyslexia and injury is an important avenue for future research.

As in our previous study,⁹ young workers who were not in school (whether they had obtained their high school diploma or not) showed an elevated risk of work injury. School status continued to be an independent predictor of injury risk even with learning disabilities, ADHD, and demographic and work variables controlled. Although it is not immediately clear what additional individual or work factors could account for this excess risk associated with school status, the finding does point to the importance of the relationship between educational trajectories in the school-to-work transition and work injury risk.

Limitations

Certain limitations of the analysis are noteworthy. First, identification of learning disabilities and ADHD was based on self-report; respondents were not asked about specific symptoms related to criteria of the fourth edition of the DSM.³¹ Childhood ADHD, for example, is largely diagnosed in clinical and school settings on the basis of parent and teacher reports, because young people with ADHD often underreport their symptoms.³² This suggests that the prevalence estimates reported here may be conservative, and thus associations with predictors may be reduced. It should be noted, however, that this self-reported measure showed concurrent validity in that it was associated in expected ways with demographic variables such as gender and school status.

Second, our ability to correctly classify which respondents had dyslexia and ADHD could also have been adversely affected by the fact that the respondents may have had symptoms of these conditions in childhood (which could have affected their educational achievement) but few or no symptoms when they were surveyed. This potential misclassification may have attenuated associations with other predictors such as school status and job type, as well as the dependent variable. Taken together, the developmental pathways linking learning disability and school to occupation and working injury can be complex and unfold over time,³³ thereby requiring a longitudinal study design.

Conclusions

Given the preliminary nature of our findings on dyslexia and work injuries among young people, it is premature to recommend a specific injury prevention approach. An important issue for future research would be a replication of our results regarding a dyslexia–injury relationship in a larger sample, ideally in a longitudinal survey. Furthermore, there is a need for a better understanding of the potential mechanisms—specifically, types of hazards encountered, comprehension of safety training, and use of safety practices—underlying the elevated risk observed among those with dyslexia. Work environments should also be assessed given the possibility that young workers are particularly vulnerable in disorganized and chaotic workplaces.^34,35

A conclusive finding of this study is that school status is related to work injury. An implication would be that more effort is required to improve the fit between young workers' experiences and capabilities and their physical and social work environments, and this is particularly the case among young people not in school. Clearly, standard injury prevention principles such as eliminating hazards through engineering when possible, providing education and training, and enforcing occupational health and safety regulations relevant to young workers apply in this situation.³⁶ If safety knowledge deficits and lack of training comprehension are found to contribute to injury risk among young workers who are not in school, practitioners could consider occupational health and safety (OHS) training and procedures that incorporate principles of universal design, an approach in which materials and environments are designed so that they are usable by all people (i.e., regardless of their age, ability, or situation) to the greatest extent possible.³⁷

Our results underscore the notion that young workers are a heterogeneous group and that individual differences salient in the education system (e.g., learning disabilities, school dropout) need to be integrated into conceptual models of work-related injury risk in this population. This may suggest that not only should more effort be made in schools to help educate young people about occupational health and safety, but the occupational health and safety system should be sensitive to and advocate for broader issues such as increased literacy levels, which may underlie some of the results reported here.