Abstract
Objective: To explore factors associated with long-term outcomes of work and marital status in individuals who had experienced a mild head injury (MHI), as well as those who had not.
Design: Population-based study using logistical regression analyses to investigate the impact of preinjury characteristics on work and marital status.
Participants: Two groups of Vietnam-era Army veterans: 626 who had experienced a MHI an average of 8 years before examination, and 3,896 who had not.
Main outcome measures: Demographic characteristics, concurrent medical conditions, early life psychiatric problems, loss of consciousness (LOC), and interactions among these variables were used to predict current work and marital status.
Results: Multiple variables were associated with work and marital status in the sample with MHI, accounting for approximately 23% and 17% of the variance in these two outcome variables, respectively. In contrast, the same factors accounted for significantly less variance in outcome in the sample without a head injury-13.3% and 9.4% for work and marital status, respectively.
Conclusions: These findings suggest a more potent role for and increased vulnerability to the influence of demographic, medical, and psychiatric factors on outcomes after a MHI. That is, MHI itself moderates the influence of preinjury characteristics on work and marital status. In addition, in those who had a MHI, moderator relationships were found between education and LOC for both work and marital status. Similarly, complex moderator relationships among race, region of residence, and LOC were found for both work and marital status outcomes.
ONE OF THE most devastating consequences of traumatic brain injury (TBI) is difficulty in adequately performing social roles held before the injury, an important contributor to subjective quality of life. 1 The ability to return to work or to maintain a marital relationship, two major social roles, frequently are disrupted after TBI. 1-10 These outcomes can be affected by a variety of factors.
Novack et al 11 found that the preinjury characteristics of age, education, employment status, and a variety of mental health problems were significantly related to postinjury functioning, including productive activity, in a sample of patients with severe TBI. Age, education, employment status, substance use, and social history directly accounted for 8% of the variance in 12-month postinjury outcome, and additional variance was accounted for by indirect effects through other variables. In other studies, younger age at time of injury, lower degree of disability during rehabilitation, and less severe original injury were associated with better vocational outcomes or community reintegration in samples of patients with moderate to severe brain injuries. 12-13 However, not all studies have found that age affects postinjury outcomes. 3
Rosenthal et al 14 also found ethnicity to be related to postinjury outcome. Although at 1 year postinjury, no differences were found between majority and minority ethnic groups on measures of cognition or functional abilities, minorities performed worse on social integration and productivity measures of community integration, even after controlling for severity of injury, age, gender, functional status, and etiology of injury. In addition, competitive employment declined to a greater extent among minorities post-injury (from 46% to 13%) than among nonminorities (from 60% to 30%).
Not surprisingly, higher levels of postinjury cognitive functioning also have been associated with better vocational outcomes at 6 and 12 months post-injury. 11,15-16 Approximately 4 years postinjury, performance IQ at time of acute rehabilitation was the most significant predictor of return to work or school, more so than sociodemographic variables, injury severity, or physical impairment. 17 Compared with emotional and functional status 6 months postinjury, cognitive status was the most powerful predictor of 12-month outcome in the study by Novack and colleagues. 11 To our knowledge, no studies have examined preinjury cognitive functioning on postinjury outcome.
Premorbid psychiatric or psychosocial problems have been linked to lingering post-TBI disability, particularly after mild head injury (MHI). These preexisting problems are often found in individuals who had a MHI and who remain symptomatic 18-20 and often complicate recovery. 21 Luis et al 22 found that early life psychiatric difficulties were more predictive of persisting postconcussive symptoms than was loss of consciousness (LOC). However, the relationship between premorbid mental health characteristics and postinjury work and marital status in MHI is an unexplored area.
The presence of chronic medical problems may negatively impact quality of life and limit an individual's ability to return to work. Comorbid chronic medical conditions have been associated with failure to return to work in other patient populations. 23 Diseases such as hypertension, chronic obstructive pulmonary disease, diabetes, and alcoholism can result in neuropsychologic impairments similar to those found after brain injury. 24 Comorbid medical conditions, therefore, might be expected to compound the effects of brain injury by either further reducing already weakened cognitive abilities or by adding to physical limitations. Within a population of individuals with head injuries, the relationship between comorbid medical conditions and postinjury work and marital status remains unexplored.
Considerably fewer studies exist regarding employment and marital status outcomes after MHI. Typically, MHI is defined by a brief loss or alteration of consciousness after some blow to the head, an emergency room Glasgow Coma Scale 25 score of 13 to 15, and no abnormal findings on neuroimaging studies. 26 Virtually no studies have examined outcomes in nonclinic, nonreferred samples with MHI. However, in the studies that do exist using referred symptomatic patients, unresolved symptoms after MHI can result in limitations in return to work, recreation, and social interactions, although psychologic and litigation factors may contribute to these outcomes. 24,27-28
The objective of the present study was to examine preinjury factors associated with or moderating long-term outcomes in individuals who sustained a MHI. Specifically, the outcomes of work and marital status were examined an average of 8 years after a MHI. A secondary objective was to determine whether relationships among factors associated with work and marital status are unique to the MHI population or similar to the general population; that is, might a MHI itself be a factor moderating the impact of other predictors of work and marital status? In contrast to virtually all studies to date, the current study used a nonclinic, nonreferred, population-based randomly selected sample.