http://informahealthcare.com/bij ISSN: 0269-9052 (print), 1362-301X (electronic) Brain Inj, 2015; 29(5): 639–643 ! 2014 Informa UK Ltd. DOI: 10.3109/02699052.2014.989406
ORIGINAL ARTICLE
Interpersonal violence and traumatic brain injuries among Native Americans and women Kristen Faye Linton School of Social Work, University of Hawaii at Manoa, Honolulu, HI, USA
Abstract
Keywords
Objectives: This study aimed to assess the odds of experiencing a traumatic brain injury (TBI) as a result of interpersonal violence (IPV) among Native Americans compared to other races controlling for gender, age, socioeconomic status, rurality and intoxication at the time of the injury. Methods: A secondary data analysis of the Arizona Trauma Database consisting of 18 944 cases of TBI between 2008–2010 throughout the state of Arizona was conducted. There were 312 patients who experienced injuries caused by IPV in the sample. Descriptive statistics, crosstabulations, bivariate analyses and a logistic regression model were used for analyses. Results: The logistic regression model found that Native Americans (OR ¼ 1.15), patients from the other race category (OR ¼ 1.18), females (OR ¼ 1.35) and those who were insured (OR ¼ 1.26) had higher odds of experiencing a TBI as a result of IPV. Rurality and intoxication were mediators of the correlation between Native American race and TBI as a result of IPV. Conclusions: Native Americans are more likely than Whites and females are more likely than males to experience TBIs as a result of IPV.
Brain injury, interpersonal violence, Native American, rural
Introduction Interpersonal violence (IPV), including child abuse and intimate partner violence, among children and adults is a significant public health problem [1]. Not only is this violence associated with physical and emotional challenges, but also traumatic brain injuries (TBI). Over 25% of TBIs are caused by violence [2]. The outcomes of people who experience violence-related TBIs are complex. The Centers for Disease Control and Prevention [2] have identified violence-related TBIs as the leading cause of TBI-related death, especially those caused by firearms. However, other research on survivors of TBI found that those who survive violence-related TBIs typically experience milder physical, cognitive and emotional impairments than those who experience TBIs due to motor vehicle accidents or falls. These mild symptoms leave them difficult to detect, thus they are often left undiagnosed [1]. With a population that is already vulnerable due to their violent victimization, identification of all consequences of the IPV is essential to their full recovery. A growing body of literature recognized the association between IPV and TBI [3, 4]. In addition, research has also illustrated specific IPV challenges among Native American communities with unique associations to brain injuries in rural communities [5–7]. Yet, no studies have assessed TBIs as a consequence of IPV among Correspondence: Kristen Faye Linton, MA, PhD, Assistant Professor, School of Social Work, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA. Tel: 702-895-2903. E-mail: [email protected]
History Received 7 July 2014 Revised 15 September 2014 Accepted 15 November 2014 Published online 17 December 2014
Native Americans compared to other races controlling for location and other demographic variables. A majority of child and adult IPV victims are treated for facial or other physical injuries, often leaving TBIs undetected and untreated [3]. A literature review found that six articles have documented an association between IPV and TBI demonstrating the existence of this commonly missed phenomenon. The prevalence of TBI among patients seeking emergency care or shelter for intimate partner violence ranged from 30–74% in the peer-reviewed articles [4]. The combination between IPV, possible mild cognitive or executive functioning impairments as a result of a TBI and more isolation post-injury may exacerbate recidivism in IPV by adding additional challenges for the victim to leave the abusive situation. Identification and treatment of TBIs among victims of IPV represents an opportunity to break the cycle of violence [3]. The National Institute of Justice reported that Native American women experience the highest rate of violence of any racial or ethnic group in the US National Institute of Justice [7]. Native Americans also have over 3-times the odds of experiencing a violent TBI than Whites and have been more likely than others to experience blunt-force traumas [9]. While 40% of 112 urban Native Americans reported experiencing domestic violence, 60% of rural Native American women (n ¼ 312) reported physical violence. This suggests overall higher reports of violence in the rural sample [5, 6]. Among the rural women, 31.1% reported a resulting head injury [5]. Brain injuries were not assessed with the urban sample.
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Other demographic characteristics have been associated with IPV. For example, those with lower socioeconomic status in the rural sample of women had higher odds of experiencing IPV (OR ¼ 5, CI ¼ 95%) [5]. Focus groups and surveys with three different rural Native American tribes also found that historical trauma, poverty, intoxication by the victim or perpetrator and rural isolation were associated with a higher likelihood of experiencing childhood and adult interpersonal violence [8, 10, 11]. Previous research has demonstrated associations between IPV and TBI among the general population, with limited evidence among Native Americans [4, 5]. Research has also shown that sociodemographic variables, such as gender and location, contribute to one’s likelihood of experiencing a TBI due to IPV, especially among Native Americans [10, 11]. Given scant research, this study aimed to assess the odds of experiencing a TBI as a result of IPV among Native Americans compared to other races controlling for gender, age, socioeconomic status, rurality and intoxication at the time of the injury.
Methods A secondary data analysis of the Arizona Trauma Database consisting of 18 944 cases of TBI between 2008–2010 was conducted. Data included information collected in emergency rooms at hospitals throughout the state of Arizona. The sample consisted of patients who ranged in age from 0–105 (M ¼ 38.21, SD ¼ 23.73) and were males (n ¼ 12 704), females (n ¼ 6240), White non-Hispanics (n ¼ 13 508), Black (n ¼ 713), Native American (n ¼ 1763), Asian/Pacific Islander (n ¼ 189) or other race (n ¼ 2695). Seventy-six patients’ race was missing. Black patients refers to those of African descent. There were 312 patients who experienced injuries caused by IPV in the sample. While all races were included in descriptive analyses, Black, Asian/Pacific Islander and missing race patients were not included in further analyses due to their small sub-sample sizes. Measures Demographic statistics, such as race, gender, age and insurance (proxy for socioeconomic status) were selfreported by patients. The aetiology of the TBIs was reported by medical professionals in emergency rooms. IPV aetiology was separated into various sub-categories by medical professionals. There were two sub-categories for abuse by parents, step-parents, boyfriends or girlfriends (n ¼ 50), seven sub-categories for battering by child, caregiver, relative, sibling, spouse or other person (n ¼ 118) and four sub-categories for domestic violence including the use of furniture as a weapon (n ¼ 144). These sub-categories were collapsed into one IPV category. Intoxication and rurality were also determined by medical professionals. Intoxication was determined by blood–alcohol (BAC) levels. Those with BAC levels above the legal limit (BAC ¼ 0.08) were considered to be intoxicated at the time of injury. Helicopter transportation to the emergency room was used as a proxy for rurality. Typically, only those who live far from a hospital are transported via air [12].
Brain Inj, 2015; 29(5): 639–643
Analyses Descriptive statistics and cross-tabulations for the study variables were examined initially. A logistic regression model was developed for the data with experiencing a TBI due to IPV as the dependent variable and race as the independent variables with gender, age, insurance, rurality and intoxication as covariates. Standardized independent variables and covariates (indicated with a Z) were used in the logistic regression. Standardized variables were calculated by subtracting by the mean and dividing by the standard deviation. This process improves the interpretation of analyses and can be used on both continuous and dichotomous variables [13]. Whites were chosen as the reference group for race, because reference groups typically include the group with the largest sample size so that the regression coefficients represent deviations of smaller groups from the largest group [14]. Stepwise logistic regression with backward elimination was used for model development to identify mediators. All analyses were performed with PASW Statistics 18.
Results Descriptive statistics showed that patients who experienced a TBI as a result of IPV were younger on average than those who experienced a TBI due to other aetiologies (Table I). The percentage of Native Americans was also higher among those who experienced a TBI as a result of IPV than other aetiologies, yet it was not a statistically significant difference ( 2(1, n ¼ 18 868) ¼ 1.80, p ¼ 0.18). For patients with BAC levels above the legal limit, their levels ranged from 0.081– 0.381. There were White (n ¼ 13), Native American (n ¼ 13), Black (n ¼ 2) and other race (n ¼ 3) patients who experienced BAC levels above the legal limit in the sub-sample of those who experienced IPV. The cross-tabulation shows that Native Americans were more likely than patients of other races to experience rurality and intoxication (Table II). A t-test of the differences between Native Americans’ (M ¼ 0.159, SD ¼ 0.118) and other race patients’ (M ¼ 0.064, SD ¼ 0.111) BAC levels found that Native Americans had statistically significantly higher mean BAC levels than others (t ¼ 3.16, p ¼ 0.002, df ¼ 84). The cross-tabulation also showed that a higher percentage of Native Americans (66.67%) lived in rural areas than other races (0–17.53%). In addition, while patients in the other race category were not the focus of this study, it should be noted that they had a significantly lower average age. Fifty-nine (60.8%) of the other race victims were infants under 1 year old. Table III represents the logistic regression analysis on the odds of experiencing a TBI as a result of IPV. Native Americans (OR ¼ 1.15), patients from the other race category (OR ¼ 1.18), females (OR ¼ 1.35) and those who were insured (OR ¼ 1.26) had higher odds of experiencing a TBI as a result of IPV. Although rurality and intoxication were not significant, when rurality and intoxication variables were removed from the model, there was no longer a significant association between Native Americans and TBI as a result of IPV. Rurality and intoxication had a mediation effect on the relationship between Native American race and TBI as a result of IPV. Due to previous literature expressing the importance of rurality and intoxication among Native
Interpersonal violence and traumatic brain injury
DOI: 10.3109/02699052.2014.989406
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Table I. Descriptive statistics (n ¼ 18 944). TBI due to other aetiology (n ¼ 18 632)
Age (range ¼ 0–88) Gender Male Female Race White Black Native American Other Asian Race Missing Insurance Uninsured Insured Insurance Missing Alcohol None Intoxicated Location Urban Rural
TBI due to interpersonal violence (n ¼ 312)
M
SD
M
SD
38.64 Frequency
23.53 Percentage
12.38 Frequency
21.34 Percentage
12 547 6085
67.3 32.7
157 155
50.3 49.7
13 341 704 1727 2598 186 76
71.3 3.8 9.3 14.2 1.0 0.4
167 9 36 97 3
53.5 2.9 11.5 31.3 1.0
2389 15 804 440
12.61 83.42 2.32
21 290
6.8 93.2
14 413 4219
77.4 22.6
281 31
90.1 9.9
12 740 5892
68.4 31.6
229 83
73.4 26.6
Table II. Cross-tabulation analyses of independent variable among sub-sample that experienced a TBI due to interpersonal violence by race. White Age, Mean (SD) 15.24 Gender, frequency (%) Male 76 Female 91 Insurance, frequency (%) Uninsured 10 Insured 156 Alcohol, frequency (%) None 154 Intoxicated 13 Location, frequency (%) Urban 126 Rural 41
(24.15)
Black
Native American
Other
Asian
18.22 (22.46)
22.25 (23.56)
3.39 (9.09)
7.33 (12.7)
(45.5) (54.5)
5 (55.6) 4 (44.4)
19 (52.8) 17 (47.2)
56 (57.7) 41 (42.3)
1 (33.3) 2 (66.7)
(6.0) (94.0)
1 (11.1) 8 (88.9)
2 (5.6) 34 (94.4)
8 (8.2) 89 (91.8)
0 (0) 3 (100)
(92.21) (7.78)
7 (77.78) 2 (22.22)
23 (63.89) 13 (36.11)
95 (97.93) 2 (2.06)
2 (66.7) 1 (33.3)
(75.45) (24.55)
8 (88.89) 1 (11.11)
12 (33.33) 24 (66.67)
80 (82.47) 17 (17.53)
3 (100) 0 (0)
Table III. Odds of experiencing a TBI as a result of interpersonal violence logistic regression model. Variable
OR
95% CI
Wald test
df
p
White (ref) Z_American Indian Z_Other Z_Age Z_Female Z_Insured Z_Rural Z_Intoxicated
1.15 1.18 0.17 1.35 1.26 0.94 0.86
1.03–1.28 1.08–1.29 0.14–0.22 1.22–1.51 1.09–1.48 0.83–1.06 0.74–1.01
6.05 12.36 240.26 29.86 9.33 1.12 3.19
1 1 1 1 1 1 1
0.014* 50.000** 50.000** 50.000** 0.002* 0.290 0.074
Ref, reference group; *p50.05, **p50.01.
Americans and IPV in addition to the cross-tabulation and bivariate analysis showing higher prevalence of rurality and intoxication among Native Americans, the variables were kept in the model as mediators.
Discussion This study provides one of the first data that makes a connection between Native Americans, women, IPV and TBI. The proportion of Native Americans who experienced TBI as a result of IPV was lower than previously reported. Malcoe et al. [6] found that 31.3% of rural Native American women reported TBI as a result of IPV, while this study found that 11% of Native Americans reported TBI as a result of IPV. The Malcoe et al. statistic was also a self-report among rural patients, while this study included emergency room data among rural and urban patients. This difference could have also been due to including males and females in the sample; however, after consulting the data, it showed that Native Americans males (n ¼ 19) were just as likely as females (n ¼ 17) to experience TBI due to IPV. Additionally, the definitions of TBI and IPV could differ between this study and others. This study found that Native Americans experienced a higher likelihood of experiencing a TBI due to IPV than
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Whites. This study also found that females were almost 2times more likely than males to experience a TBI due to IPV controlling for race, age, insurance, rurality and intoxication, which confirmed previous knowledge [7]. The mediating effect of rurality and intoxication on the association between Native Americans and their odds of experiencing a TBI due to IPV is a new, yet not surprising finding of this study. Previous research has suggested that rural Native Americans experience more domestic violence than urban and qualitative studies have also found that intoxication is associated with increases in IPV [5, 6, 10, 11]. This study makes an additional step to bring attention to the importance of including rural location and alcohol use in studies of odds of experiencing TBI as a result of IPV. While previous research has shown a negative association between socioeconomic status and IPV, this study found a positive association between health insurance and TBI due to IPV [6]. However, this study’s sample consisted of patients with very high rates of insurance (90.5%). Many of the patients may have been low income and still insured on the state’s Medicaid program. The State of Arizona offered one of the loosest eligibility requirements compared to other states. While it has since changed eligibility requirements, Medicaid was offered to childless adults in Arizona between 2001– 2010. Childless adult coverage under Medicaid is unique [15]. This may skew results on the association between insurance status and TBI as a result of IPV. Implications While some literature has discussed the potentially unrecognized association between TBI and IPV, this study assessed this phenomenon specifically among Native Americans, finding that they are more likely to be victims of TBI as a result of IPV. Since a majority of IPV victims are primarily treated for facial and other physical injuries leaving TBIs undiagnosed, these findings suggest the importance of assessing IPV victims for TBI, especially Native Americans who are rural and have BAC above the legal limit at the time of their injury [3]. The cycle of IPV, according to previous research, is common among Native Americans [5, 6]. Identification of TBIs is essential to reducing the violence experienced in Native American communities. Untreated impairments associated with TBI may leave victims unable to have the physical and cognitive capacity to advocate and go away from the violent situation, leaving them vulnerable to more IPV and possibly future brain injuries. Preventive efforts should be made by educators, elders and leaders in Native American communities to prevent IPV in general and educate families about the possible effects of IPV on TBI. Intervention efforts should be conducted by medical professionals, law enforcement and social workers to assess for TBI among patients after IPV has been identified. Study limitations and future research While this study is one of the first to assess the odds of experiencing a TBI as a result of IPV, it should be noted that cases of violence or abuse are often under-reported, thus the sub-sample most likely does not represent all victims of violence in the sample. In particular, there was a small sub-
Brain Inj, 2015; 29(5): 639–643
sample of Native Americans in this study. The medical professionals report the aetiology of TBI with information given to them by patients and family members or friends of patients. If IPV information is not given to the medical professionals, then the aetiology will be defined differently. Future research on IPV and TBI should be conducted in collaboration with hospitals to collect primary data with special attention to IPV cases and suspected IPV cases by medical professionals that were possibly not reported by patients or others to gather more data on IPV and TBI. Additionally, future research should assess the association between Native Americans, IPV and TBI using national TBI data with larger samples of Native Americans. A surprising finding was the significant number of infant IPV experienced by patients in the other race category. Unfortunately, one of the limitations of using secondary data is that no further information is known about patients in the ‘other race’ category, such as ethnicities included in this category, to help to understand this occurrence. Future research in Arizona should attempt to understand the high proportions of infant TBI victims as a result of IPV in the other race category.
Acknowledgements The de-identified data used in this analysis were provided by the Arizona Department of Health Services, Bureau of Emergency Medical Systems and Trauma System.
Declaration of interest The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.
References 1. U.S. Department of Health and Human Services [Internet]. Native Americans with Traumatic Brain Injury and the First National Native American Summit on TBI. Bismarck, North Dakota; 2012. Available online at: https://tbitac.hrsa.gov/download/ NativeAmericanSummit508.pdf, accessed 14 November 2013. 2. Centers for Disease Control and Prevention. [Internet]. Traumatic brain injury in the United States: A report to congress. Atlanta, GA; 2010. Available online at: http://www.cdc.gov/traumaticbraininjury/tbi_report_to_congress.html, accessed 14 November 2014. 3. Banks ME. Overlooked but critical: Traumatic brain injury as a consequence of interpersonal violence. Trauma, Violence, & Abuse 2007;8:290–298. 4. Kwako LE, Glass N, Campbell J, Melvin KC, Barr T, Gill JM. Traumatic brain injury in intimate partner violence: A critical review of outcomes and mechanisms. Trauma, Violence, & Abuse 2011;12:115–126. 5. Evans-Campbell T, Lindhorst T, Huang B, Walters KL. Interpersonal violence in the lives of urban American Indian and Alaska Native women: Implications for health, mental health, and help-seeking. American Journal of Public Health 2006;96: 1416–1422. 6. Malcoe L, Duran B, Montgomery J. Socioeconomic disparities in intimate partner violence against Native American women: A crosssectional study. BMC Medicine 2004;2:1–14. 7. National Institute of Justice. [Internet]. Impact evaluation of STOP grant program for reducing violence against women among Indian Tribes: Final report (NIJ 195174). Washington, DC; 2002. Available online at: www.ncjrs.org/pdffiles1/nij/ grants/195174.pdf, accessed 15 November 2013. 8. Kim H, Colantonio A, Dawson DR, Bayley MT. Community integration outcomes after traumatic brain injury due to physical assault. Canadian Journal of Occupational Therapy 2013;80:49–58.
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9. Linton KF, Kim BJ. Traumatic brain injury as a result of violence in Native American and black communities spanning from childhood to older adulthood. Brain Injury 2014;28:1076–1081. 10. Jones L. The distinctive characteristics and needs of domestic violence victims in a Native American community. Journal of Family Violence 2008;23:113–118. 11. Yuan NP, Koss MP, Polacca M, Goldman D. Risk factors for physical assault and rape among six Native American tribes. Journal of Interpersonal Violence 2006;21:1566–1590. 12. Saler M, Switzer JA, Hess DC. Use of telemedicine and helicopter transport to improve stroke care in remote locations.
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Current Treatment Options in Cardiovascular Medicine 2011;13: 215–224. 13. Gelman A. Scaling regression inputs dividing by two standard deviations. Statistics in Medicine 2007;27:2865–2873. 14. Polissar L, Diehr P. Regression analysis in health services research: The use of dummy variables. Medical Care 1982;20:959–966. 15. Somers SA, Hamblin A, Verdier JM, Byrd VLH. Covering lowincome childless adults in Medicaid: Experiences from selected states. Hamilton, NJ: Center for Health Care Strategies Inc.; 2010. Available online at: www.chcs.org/media/Medicaid_Expansion_ Policy_Brief.pdf, accessed November 2013.
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ORIGINAL ARTICLE
Interpersonal violence and traumatic brain injuries among Native Americans and women Kristen Faye Linton School of Social Work, University of Hawaii at Manoa, Honolulu, HI, USA
Abstract
Keywords
Objectives: This study aimed to assess the odds of experiencing a traumatic brain injury (TBI) as a result of interpersonal violence (IPV) among Native Americans compared to other races controlling for gender, age, socioeconomic status, rurality and intoxication at the time of the injury. Methods: A secondary data analysis of the Arizona Trauma Database consisting of 18 944 cases of TBI between 2008–2010 throughout the state of Arizona was conducted. There were 312 patients who experienced injuries caused by IPV in the sample. Descriptive statistics, crosstabulations, bivariate analyses and a logistic regression model were used for analyses. Results: The logistic regression model found that Native Americans (OR ¼ 1.15), patients from the other race category (OR ¼ 1.18), females (OR ¼ 1.35) and those who were insured (OR ¼ 1.26) had higher odds of experiencing a TBI as a result of IPV. Rurality and intoxication were mediators of the correlation between Native American race and TBI as a result of IPV. Conclusions: Native Americans are more likely than Whites and females are more likely than males to experience TBIs as a result of IPV.
Brain injury, interpersonal violence, Native American, rural
Introduction Interpersonal violence (IPV), including child abuse and intimate partner violence, among children and adults is a significant public health problem [1]. Not only is this violence associated with physical and emotional challenges, but also traumatic brain injuries (TBI). Over 25% of TBIs are caused by violence [2]. The outcomes of people who experience violence-related TBIs are complex. The Centers for Disease Control and Prevention [2] have identified violence-related TBIs as the leading cause of TBI-related death, especially those caused by firearms. However, other research on survivors of TBI found that those who survive violence-related TBIs typically experience milder physical, cognitive and emotional impairments than those who experience TBIs due to motor vehicle accidents or falls. These mild symptoms leave them difficult to detect, thus they are often left undiagnosed [1]. With a population that is already vulnerable due to their violent victimization, identification of all consequences of the IPV is essential to their full recovery. A growing body of literature recognized the association between IPV and TBI [3, 4]. In addition, research has also illustrated specific IPV challenges among Native American communities with unique associations to brain injuries in rural communities [5–7]. Yet, no studies have assessed TBIs as a consequence of IPV among Correspondence: Kristen Faye Linton, MA, PhD, Assistant Professor, School of Social Work, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA. Tel: 702-895-2903. E-mail: [email protected]
History Received 7 July 2014 Revised 15 September 2014 Accepted 15 November 2014 Published online 17 December 2014
Native Americans compared to other races controlling for location and other demographic variables. A majority of child and adult IPV victims are treated for facial or other physical injuries, often leaving TBIs undetected and untreated [3]. A literature review found that six articles have documented an association between IPV and TBI demonstrating the existence of this commonly missed phenomenon. The prevalence of TBI among patients seeking emergency care or shelter for intimate partner violence ranged from 30–74% in the peer-reviewed articles [4]. The combination between IPV, possible mild cognitive or executive functioning impairments as a result of a TBI and more isolation post-injury may exacerbate recidivism in IPV by adding additional challenges for the victim to leave the abusive situation. Identification and treatment of TBIs among victims of IPV represents an opportunity to break the cycle of violence [3]. The National Institute of Justice reported that Native American women experience the highest rate of violence of any racial or ethnic group in the US National Institute of Justice [7]. Native Americans also have over 3-times the odds of experiencing a violent TBI than Whites and have been more likely than others to experience blunt-force traumas [9]. While 40% of 112 urban Native Americans reported experiencing domestic violence, 60% of rural Native American women (n ¼ 312) reported physical violence. This suggests overall higher reports of violence in the rural sample [5, 6]. Among the rural women, 31.1% reported a resulting head injury [5]. Brain injuries were not assessed with the urban sample.
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K. F. Linton
Other demographic characteristics have been associated with IPV. For example, those with lower socioeconomic status in the rural sample of women had higher odds of experiencing IPV (OR ¼ 5, CI ¼ 95%) [5]. Focus groups and surveys with three different rural Native American tribes also found that historical trauma, poverty, intoxication by the victim or perpetrator and rural isolation were associated with a higher likelihood of experiencing childhood and adult interpersonal violence [8, 10, 11]. Previous research has demonstrated associations between IPV and TBI among the general population, with limited evidence among Native Americans [4, 5]. Research has also shown that sociodemographic variables, such as gender and location, contribute to one’s likelihood of experiencing a TBI due to IPV, especially among Native Americans [10, 11]. Given scant research, this study aimed to assess the odds of experiencing a TBI as a result of IPV among Native Americans compared to other races controlling for gender, age, socioeconomic status, rurality and intoxication at the time of the injury.
Methods A secondary data analysis of the Arizona Trauma Database consisting of 18 944 cases of TBI between 2008–2010 was conducted. Data included information collected in emergency rooms at hospitals throughout the state of Arizona. The sample consisted of patients who ranged in age from 0–105 (M ¼ 38.21, SD ¼ 23.73) and were males (n ¼ 12 704), females (n ¼ 6240), White non-Hispanics (n ¼ 13 508), Black (n ¼ 713), Native American (n ¼ 1763), Asian/Pacific Islander (n ¼ 189) or other race (n ¼ 2695). Seventy-six patients’ race was missing. Black patients refers to those of African descent. There were 312 patients who experienced injuries caused by IPV in the sample. While all races were included in descriptive analyses, Black, Asian/Pacific Islander and missing race patients were not included in further analyses due to their small sub-sample sizes. Measures Demographic statistics, such as race, gender, age and insurance (proxy for socioeconomic status) were selfreported by patients. The aetiology of the TBIs was reported by medical professionals in emergency rooms. IPV aetiology was separated into various sub-categories by medical professionals. There were two sub-categories for abuse by parents, step-parents, boyfriends or girlfriends (n ¼ 50), seven sub-categories for battering by child, caregiver, relative, sibling, spouse or other person (n ¼ 118) and four sub-categories for domestic violence including the use of furniture as a weapon (n ¼ 144). These sub-categories were collapsed into one IPV category. Intoxication and rurality were also determined by medical professionals. Intoxication was determined by blood–alcohol (BAC) levels. Those with BAC levels above the legal limit (BAC ¼ 0.08) were considered to be intoxicated at the time of injury. Helicopter transportation to the emergency room was used as a proxy for rurality. Typically, only those who live far from a hospital are transported via air [12].
Brain Inj, 2015; 29(5): 639–643
Analyses Descriptive statistics and cross-tabulations for the study variables were examined initially. A logistic regression model was developed for the data with experiencing a TBI due to IPV as the dependent variable and race as the independent variables with gender, age, insurance, rurality and intoxication as covariates. Standardized independent variables and covariates (indicated with a Z) were used in the logistic regression. Standardized variables were calculated by subtracting by the mean and dividing by the standard deviation. This process improves the interpretation of analyses and can be used on both continuous and dichotomous variables [13]. Whites were chosen as the reference group for race, because reference groups typically include the group with the largest sample size so that the regression coefficients represent deviations of smaller groups from the largest group [14]. Stepwise logistic regression with backward elimination was used for model development to identify mediators. All analyses were performed with PASW Statistics 18.
Results Descriptive statistics showed that patients who experienced a TBI as a result of IPV were younger on average than those who experienced a TBI due to other aetiologies (Table I). The percentage of Native Americans was also higher among those who experienced a TBI as a result of IPV than other aetiologies, yet it was not a statistically significant difference ( 2(1, n ¼ 18 868) ¼ 1.80, p ¼ 0.18). For patients with BAC levels above the legal limit, their levels ranged from 0.081– 0.381. There were White (n ¼ 13), Native American (n ¼ 13), Black (n ¼ 2) and other race (n ¼ 3) patients who experienced BAC levels above the legal limit in the sub-sample of those who experienced IPV. The cross-tabulation shows that Native Americans were more likely than patients of other races to experience rurality and intoxication (Table II). A t-test of the differences between Native Americans’ (M ¼ 0.159, SD ¼ 0.118) and other race patients’ (M ¼ 0.064, SD ¼ 0.111) BAC levels found that Native Americans had statistically significantly higher mean BAC levels than others (t ¼ 3.16, p ¼ 0.002, df ¼ 84). The cross-tabulation also showed that a higher percentage of Native Americans (66.67%) lived in rural areas than other races (0–17.53%). In addition, while patients in the other race category were not the focus of this study, it should be noted that they had a significantly lower average age. Fifty-nine (60.8%) of the other race victims were infants under 1 year old. Table III represents the logistic regression analysis on the odds of experiencing a TBI as a result of IPV. Native Americans (OR ¼ 1.15), patients from the other race category (OR ¼ 1.18), females (OR ¼ 1.35) and those who were insured (OR ¼ 1.26) had higher odds of experiencing a TBI as a result of IPV. Although rurality and intoxication were not significant, when rurality and intoxication variables were removed from the model, there was no longer a significant association between Native Americans and TBI as a result of IPV. Rurality and intoxication had a mediation effect on the relationship between Native American race and TBI as a result of IPV. Due to previous literature expressing the importance of rurality and intoxication among Native
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Table I. Descriptive statistics (n ¼ 18 944). TBI due to other aetiology (n ¼ 18 632)
Age (range ¼ 0–88) Gender Male Female Race White Black Native American Other Asian Race Missing Insurance Uninsured Insured Insurance Missing Alcohol None Intoxicated Location Urban Rural
TBI due to interpersonal violence (n ¼ 312)
M
SD
M
SD
38.64 Frequency
23.53 Percentage
12.38 Frequency
21.34 Percentage
12 547 6085
67.3 32.7
157 155
50.3 49.7
13 341 704 1727 2598 186 76
71.3 3.8 9.3 14.2 1.0 0.4
167 9 36 97 3
53.5 2.9 11.5 31.3 1.0
2389 15 804 440
12.61 83.42 2.32
21 290
6.8 93.2
14 413 4219
77.4 22.6
281 31
90.1 9.9
12 740 5892
68.4 31.6
229 83
73.4 26.6
Table II. Cross-tabulation analyses of independent variable among sub-sample that experienced a TBI due to interpersonal violence by race. White Age, Mean (SD) 15.24 Gender, frequency (%) Male 76 Female 91 Insurance, frequency (%) Uninsured 10 Insured 156 Alcohol, frequency (%) None 154 Intoxicated 13 Location, frequency (%) Urban 126 Rural 41
(24.15)
Black
Native American
Other
Asian
18.22 (22.46)
22.25 (23.56)
3.39 (9.09)
7.33 (12.7)
(45.5) (54.5)
5 (55.6) 4 (44.4)
19 (52.8) 17 (47.2)
56 (57.7) 41 (42.3)
1 (33.3) 2 (66.7)
(6.0) (94.0)
1 (11.1) 8 (88.9)
2 (5.6) 34 (94.4)
8 (8.2) 89 (91.8)
0 (0) 3 (100)
(92.21) (7.78)
7 (77.78) 2 (22.22)
23 (63.89) 13 (36.11)
95 (97.93) 2 (2.06)
2 (66.7) 1 (33.3)
(75.45) (24.55)
8 (88.89) 1 (11.11)
12 (33.33) 24 (66.67)
80 (82.47) 17 (17.53)
3 (100) 0 (0)
Table III. Odds of experiencing a TBI as a result of interpersonal violence logistic regression model. Variable
OR
95% CI
Wald test
df
p
White (ref) Z_American Indian Z_Other Z_Age Z_Female Z_Insured Z_Rural Z_Intoxicated
1.15 1.18 0.17 1.35 1.26 0.94 0.86
1.03–1.28 1.08–1.29 0.14–0.22 1.22–1.51 1.09–1.48 0.83–1.06 0.74–1.01
6.05 12.36 240.26 29.86 9.33 1.12 3.19
1 1 1 1 1 1 1
0.014* 50.000** 50.000** 50.000** 0.002* 0.290 0.074
Ref, reference group; *p50.05, **p50.01.
Americans and IPV in addition to the cross-tabulation and bivariate analysis showing higher prevalence of rurality and intoxication among Native Americans, the variables were kept in the model as mediators.
Discussion This study provides one of the first data that makes a connection between Native Americans, women, IPV and TBI. The proportion of Native Americans who experienced TBI as a result of IPV was lower than previously reported. Malcoe et al. [6] found that 31.3% of rural Native American women reported TBI as a result of IPV, while this study found that 11% of Native Americans reported TBI as a result of IPV. The Malcoe et al. statistic was also a self-report among rural patients, while this study included emergency room data among rural and urban patients. This difference could have also been due to including males and females in the sample; however, after consulting the data, it showed that Native Americans males (n ¼ 19) were just as likely as females (n ¼ 17) to experience TBI due to IPV. Additionally, the definitions of TBI and IPV could differ between this study and others. This study found that Native Americans experienced a higher likelihood of experiencing a TBI due to IPV than
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Whites. This study also found that females were almost 2times more likely than males to experience a TBI due to IPV controlling for race, age, insurance, rurality and intoxication, which confirmed previous knowledge [7]. The mediating effect of rurality and intoxication on the association between Native Americans and their odds of experiencing a TBI due to IPV is a new, yet not surprising finding of this study. Previous research has suggested that rural Native Americans experience more domestic violence than urban and qualitative studies have also found that intoxication is associated with increases in IPV [5, 6, 10, 11]. This study makes an additional step to bring attention to the importance of including rural location and alcohol use in studies of odds of experiencing TBI as a result of IPV. While previous research has shown a negative association between socioeconomic status and IPV, this study found a positive association between health insurance and TBI due to IPV [6]. However, this study’s sample consisted of patients with very high rates of insurance (90.5%). Many of the patients may have been low income and still insured on the state’s Medicaid program. The State of Arizona offered one of the loosest eligibility requirements compared to other states. While it has since changed eligibility requirements, Medicaid was offered to childless adults in Arizona between 2001– 2010. Childless adult coverage under Medicaid is unique [15]. This may skew results on the association between insurance status and TBI as a result of IPV. Implications While some literature has discussed the potentially unrecognized association between TBI and IPV, this study assessed this phenomenon specifically among Native Americans, finding that they are more likely to be victims of TBI as a result of IPV. Since a majority of IPV victims are primarily treated for facial and other physical injuries leaving TBIs undiagnosed, these findings suggest the importance of assessing IPV victims for TBI, especially Native Americans who are rural and have BAC above the legal limit at the time of their injury [3]. The cycle of IPV, according to previous research, is common among Native Americans [5, 6]. Identification of TBIs is essential to reducing the violence experienced in Native American communities. Untreated impairments associated with TBI may leave victims unable to have the physical and cognitive capacity to advocate and go away from the violent situation, leaving them vulnerable to more IPV and possibly future brain injuries. Preventive efforts should be made by educators, elders and leaders in Native American communities to prevent IPV in general and educate families about the possible effects of IPV on TBI. Intervention efforts should be conducted by medical professionals, law enforcement and social workers to assess for TBI among patients after IPV has been identified. Study limitations and future research While this study is one of the first to assess the odds of experiencing a TBI as a result of IPV, it should be noted that cases of violence or abuse are often under-reported, thus the sub-sample most likely does not represent all victims of violence in the sample. In particular, there was a small sub-
Brain Inj, 2015; 29(5): 639–643
sample of Native Americans in this study. The medical professionals report the aetiology of TBI with information given to them by patients and family members or friends of patients. If IPV information is not given to the medical professionals, then the aetiology will be defined differently. Future research on IPV and TBI should be conducted in collaboration with hospitals to collect primary data with special attention to IPV cases and suspected IPV cases by medical professionals that were possibly not reported by patients or others to gather more data on IPV and TBI. Additionally, future research should assess the association between Native Americans, IPV and TBI using national TBI data with larger samples of Native Americans. A surprising finding was the significant number of infant IPV experienced by patients in the other race category. Unfortunately, one of the limitations of using secondary data is that no further information is known about patients in the ‘other race’ category, such as ethnicities included in this category, to help to understand this occurrence. Future research in Arizona should attempt to understand the high proportions of infant TBI victims as a result of IPV in the other race category.
Acknowledgements The de-identified data used in this analysis were provided by the Arizona Department of Health Services, Bureau of Emergency Medical Systems and Trauma System.
Declaration of interest The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.
References 1. U.S. Department of Health and Human Services [Internet]. Native Americans with Traumatic Brain Injury and the First National Native American Summit on TBI. Bismarck, North Dakota; 2012. Available online at: https://tbitac.hrsa.gov/download/ NativeAmericanSummit508.pdf, accessed 14 November 2013. 2. Centers for Disease Control and Prevention. [Internet]. Traumatic brain injury in the United States: A report to congress. Atlanta, GA; 2010. Available online at: http://www.cdc.gov/traumaticbraininjury/tbi_report_to_congress.html, accessed 14 November 2014. 3. Banks ME. Overlooked but critical: Traumatic brain injury as a consequence of interpersonal violence. Trauma, Violence, & Abuse 2007;8:290–298. 4. Kwako LE, Glass N, Campbell J, Melvin KC, Barr T, Gill JM. Traumatic brain injury in intimate partner violence: A critical review of outcomes and mechanisms. Trauma, Violence, & Abuse 2011;12:115–126. 5. Evans-Campbell T, Lindhorst T, Huang B, Walters KL. Interpersonal violence in the lives of urban American Indian and Alaska Native women: Implications for health, mental health, and help-seeking. American Journal of Public Health 2006;96: 1416–1422. 6. Malcoe L, Duran B, Montgomery J. Socioeconomic disparities in intimate partner violence against Native American women: A crosssectional study. BMC Medicine 2004;2:1–14. 7. National Institute of Justice. [Internet]. Impact evaluation of STOP grant program for reducing violence against women among Indian Tribes: Final report (NIJ 195174). Washington, DC; 2002. Available online at: www.ncjrs.org/pdffiles1/nij/ grants/195174.pdf, accessed 15 November 2013. 8. Kim H, Colantonio A, Dawson DR, Bayley MT. Community integration outcomes after traumatic brain injury due to physical assault. Canadian Journal of Occupational Therapy 2013;80:49–58.
DOI: 10.3109/02699052.2014.989406
9. Linton KF, Kim BJ. Traumatic brain injury as a result of violence in Native American and black communities spanning from childhood to older adulthood. Brain Injury 2014;28:1076–1081. 10. Jones L. The distinctive characteristics and needs of domestic violence victims in a Native American community. Journal of Family Violence 2008;23:113–118. 11. Yuan NP, Koss MP, Polacca M, Goldman D. Risk factors for physical assault and rape among six Native American tribes. Journal of Interpersonal Violence 2006;21:1566–1590. 12. Saler M, Switzer JA, Hess DC. Use of telemedicine and helicopter transport to improve stroke care in remote locations.
Interpersonal violence and traumatic brain injury
643
Current Treatment Options in Cardiovascular Medicine 2011;13: 215–224. 13. Gelman A. Scaling regression inputs dividing by two standard deviations. Statistics in Medicine 2007;27:2865–2873. 14. Polissar L, Diehr P. Regression analysis in health services research: The use of dummy variables. Medical Care 1982;20:959–966. 15. Somers SA, Hamblin A, Verdier JM, Byrd VLH. Covering lowincome childless adults in Medicaid: Experiences from selected states. Hamilton, NJ: Center for Health Care Strategies Inc.; 2010. Available online at: www.chcs.org/media/Medicaid_Expansion_ Policy_Brief.pdf, accessed November 2013.
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