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Violence and Mental Health: Does Disability Make a Difference?

Rachele, Jerome N.; Disney, George; Milner, Allison; Emerson, Eric; Krnjacki, Lauren; Kavanagh, Anne M.

Author Information
doi: 10.1097/EDE.0000000000001119

To the Editor:

Violence is understood to be a major determinant of poor mental and physical health.1 While the detrimental health effects of violence and the high levels of violence experienced by people with disability are well documented,2 we do not know whether the mental health impacts of exposure to violence differ between people with and without disability. In this study, we specifically look at physical violence and assess whether the association between exposure to physical violence and changes in mental health are modified by disability status using a large population-based Australian longitudinal study. Given the differences in the type of violence experienced by men and women experience,3 analyses were stratified by gender.

We used longitudinal data from The Household, Income and Labour Dynamics in Australia (HILDA) Survey, waves one (2001) to 16 (2016). The sample size after 16 waves was 17,694, and response rates are above 90% for respondents who have continued in the survey and above 70% for new respondents being invited into the study.4 HILDA received ethical approval from the Australian Government Department of Health and Ageing Ethics Committee and the University of Melbourne’s Human Research Ethics Committee.

Participants were asked whether they had been a “Victim of physical violence (e.g., assault) in the previous 12 months.” This was a binary variable.

Participants responded to whether they had experienced “ a long-term health condition, impairment or disability that restricts you in your everyday activities, and has lasted, or is likely to last, for 6 months or more. ” To deal with temporal ordering of violence and disability we used four time-invariant disability categories: never disabled, always disabled, become disabled (censored after first wave of disability), and became not disabled (censored after first wave of not disability). Observations start when participants enter the study, with participants allowed to miss waves.

Mental health is measured using the Mental Health Inventory (MHI-5).5 Each item is scored using five response categories, and the total scores are transformed into a scale ranging from 0 to 100; higher scores reflect better mental health.

We modeled age, education, employment status, household weekly equivalized income, and household structure as time-varying confounders. These were selected based on a directed acyclic graph and informed by previous literature.

A total of 93,835 observations across 19,472 participants had complete data and were included in analyses. Linear fixed-effects regression models with cluster robust confidence intervals were used to estimate the association between being a victim of physical violence and mental health within individuals, with disability (fitted as time-invariant) interacted with exposure to physical violence. Analyses were conducted separately for men and women.

Descriptive statistics of the analytic sample are presented in the eTable; https://links.lww.com/EDE/B598. The Table shows the difference in mental health for being victim of violence results across all strata of disability status. There was an effect of violence on mental health among men who had transitioned from being disabled to not disabled, men who had always been disabled, women who had become disabled, and men who had become disabled.

Strengths of this study include the data being a large nationally representative sample, and the more causally robust fixed-effects analysis. Among the study limitations are that self-reported data may be susceptible to response bias (e.g., social desirability effects), dependent measurement error (errors in self-reported exposure and outcomes correlated due to individual-level factors), underreporting of violence, and people with severe disability, and perhaps those experiencing violence, may be less likely to participate in HILDA. While out of scope for this short report, future research could apply g-computation to analyze the dynamic interplay between our exposure (violence), effect modifier (disability), and confounders. Future research should endeavor to use improved measures of exposure to violence.

TABLE.
TABLE.:
Fixed Effects With Cluster Robust Confidence Intervals: Analysis of Mental Health From Waves A-P of the HILDA Survey by Category of Time-invariant Disabilitya

Jerome N. Rachele
George Disney
Allison Milner
Melbourne School of Population and Global Health
The University of Melbourne
Carlton, Victoria, Australia
[email protected]

Eric Emerson
Faculty of Health Science
University of Sydney
Lidcombe, New South Wales, Australia

Lauren Krnjacki
Anne M. Kavanagh
Melbourne School of Population and Global Health
The University of Melbourne
Carlton, Victoria, Australia

REFERENCES

1. Butchart A, Mikton C., Dahlberg LL, Krug EG. Global status report on violence prevention, 2014. Injury Prevention. 2015;21:213.
2. Krnjacki L, Emerson E, Llewellyn G, Kavanagh AM. Prevalence and risk of violence against people with and without disabilities: findings from an Australian population-based study. Aust N Z J Public Health. 2016;40:16–21.
3. Australia Bureau of Statistics. Peronsal Safety Survey. 2016.Canberra: ABS.
4. Summerfield M, et al. HILDA User Manual – Release 17. 2018.Melbourne: Melbourne Institute of Applied Economic and Social Research.
5. Rumpf HJ, Meyer C, Hapke U, John U. Screening for mental health: validity of the MHI-5 using DSM-IV Axis I psychiatric disorders as gold standard. Psychiatry Res. 2001;105:243–253.

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