Risk for developing dementia among patients with posttraumatic stress disorder: A nationwide longitudinal study

doi:10.1016/j.jad.2016.08.013

Journal of Affective Disorders

Volume 205, 15 November 2016, Pages 306-310

https://doi.org/10.1016/j.jad.2016.08.013 Get rights and content

Highlights

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Previous studies regarding PTSD and dementia almost focused on the veteran population or war victims.
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The association between PTSD and the risk of subsequent dementia in Taiwanese population was still unknown.
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In Taiwan, PTSD was an independent risk factor for the risk for subsequent dementia.
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PTSD patients with depressive disorder, cerebrovascular diseases, diabetes mellitus, or head injuries exhibited a higher risk for developing dementia.

Abstract

Objectives

Previous studies suggested a relationship between posttraumatic stress disorder (PTSD) in the specific population (i.e., war survivors and veterans) and subsequent dementia risk. However, whether patients with PTSD in the general population were at an increased risk for developing dementia in later life remained unclear.

Methods

The Cox regression analysis was performed using data from the Taiwan National Health Insurance Research Database. The study sample comprised 1750 patients diagnosed with PTSD between 2001 and 2009 and 7000 age-/sex-matched individuals without PTSD. Those who developed dementia during follow-up to the end of 2011 were identified.

Results

After adjusting for demographic data and medical and psychiatric comorbidities, PTSD was an independent risk factor for the risk for subsequent dementia (hazard ratio [HR]=4.37; 95% confidence interval [CI]: 2.53–7.55). There was a dose-dependent relationship between PTSD severity indicated by the frequency of psychiatric clinics visiting of PTSD (times per year) and the risk of subsequent dementia (<5: HR: 2.81, 95% CI: 1.50–5.29; 5–10: 6.90, 95% CI: 3.09–15.40;>10: HR: 18.13, 95% CI: 9.13–36.00). Furthermore, patients with depressive disorder and medical comorbidities, such as cerebrovascular diseases, diabetes mellitus, and head injuries, exhibited a higher risk for developing dementia.

Discussions

Our study suggested a significant dose-dependent association between PTSD and its severity and an increased risk of developing dementia later in life. The importance of mental care for trauma victims would increase in the coming century, and our findings broadened another era for the end result of a widely prevalent psychiatric disorder.

Introduction

The elderly population is currently increasing, particularly in Taiwan, where the threshold for an aging society was reached in 1993, and the elderly population will constitute more than 20% of the overall population in 2026; therefore, the number of elderly people suffering from dementia has become a major public health concern. The prevalence of dementia in Taiwanese people exceeding 65 years of age has been estimated to range between 2.0% and 4.3% (Liu et al., 1994, Liu et al., 1995, Liu et al., 1996, Liu et al., 1998). Several risk factors, including low intelligence, limited education (Schmand et al., 1997), substance use (Saunders et al., 1991), and cardiovascular diseases (Whitmer et al., 2005), may contribute to dementia. Trauma also played a potential role in the development of dementia in later life. Head injury was indicated as one of the risk factors associated with an increased risk of dementia (Plassman et al., 2000). The interest in psychological trauma, such as posttraumatic distress disorder (PTSD), has recently intensified.

The DSM-IV-TR defines trauma as a personal experience involving actual or threatened death or severe injury, or a threat to a person's integrity (Criterion A1), and a response involving intense fear, helplessness, or horror (Criterion A2). The DSM-5, which was published in May 2013, expands the definition of trauma, indicating that trauma can be experienced as well as witnessed or learned (Criterion A). The DSM-IV-TR organizes PTSD symptoms into 3 categories, which must be present for at least 1 month after a traumatic event and must cause functional impairment: reexperiencing intrusions of the trauma (Criterion B), avoidance of stimuli associated with the trauma and numbing of general responsiveness (Criterion C), and hyperarousal symptoms (Criterion D) (American Psychiatric Association, 2000). An additional symptom, negative alterations in cognition and mood, has been added to the DSM-5 (Criterion D) to emphasize the link between PTSD and cognitive function (Carmassi et al., 2013).

PTSD has been proposed to be associated with an increased risk for developing dementia, mostly within the populations of veterans and war victims. The incidence and prevalence of dementia was greater in veterans with PTSD (Qureshi et al., 2010), who exhibit a nearly 2-fold higher risk for developing dementia (Yaffe et al., 2010). Dementia was diagnosed according to ICD-10 criteria in 16% of Holocaust survivors (Sperling et al., 2011). It was still unclear whether the increased risk was due to a common risk factor underlying PTSD and dementia or to PTSD being an independent risk factor for dementia.

Two mechanisms have been proposed to describe how PTSD influences dementia. The first was the direct influence of previous life traumas, which might trigger the persistent over-activation of the hypothalamic-pituitary-adrenal (HPA) axis and the adrenergic system (Taylor et al., 2009). In addition, lifetime trauma might lead to health problems independent of PTSD later in life (D'Andrea et al., 2011), which might indirectly lead to susceptibility to dementia. The second mechanism involved conceptualizing dementia as a de novo traumatic experience that could increase the rate of cognitive decline by activating a debilitating stress response or precipitating PTSD symptoms and correlates (Burnes and Burnette, 2013).

Thus, we conducted a population-based study using the Taiwan National Health Insurance Research Database (NHIRD) to examine the incidence of dementia in patients with PTSD and compared them with matched controls without PTSD. In addition, we identified independent factors for predicting incident dementia.

Section snippets

Data source

The Taiwan National Health Insurance (NHI) program was implemented in 1995 and offers comprehensive medical care coverage to all residents of Taiwan. The National Health Research Institutes (NHRI) manages the insurance claims database, the National Health Insurance Research Database (NHIRD), which consists of health care data from more than 97% of the entire Taiwanese population. The NHRI audits and releases the NHIRD for use in health service studies. Patients included in the NHIRD are

Demographic data of the study patients

In total, 81 PTSD patients (7.54 per thousand person-years) and 54 comparison controls (1.22 per thousand person-years) developed dementia in the follow-up period (Table 1). Compared with the matched controls, PTSD patients exhibited a significantly higher prevalence of the medical and psychiatric comorbidities, including cerebrovascular disease (p<0.001), hypertension (p=0.002), diabetes mellitus (p=0.005), dyslipidemia (p<0.001), and head injury (p<0.001), depressive disorder (p<0.001),

Discussion

Our results supported the study hypothesis that patients with PTSD had an increased risk for developing dementia in later life after adjusting for demographic data and medical and psychiatric comorbidities. Our findings based on population-based cohort, which included patients diagnosed with various types of trauma, were consistent with those of previous studies, and the risk for developing dementia might be as high as 4-fold. Furthermore, there was a dose-dependent relationship between PTSD

Conflict of Interest

No conflict of interest.

Funding source

The study was supported by grant from Taipei Veterans General Hospital (V103E10-001, V104E10-002, V105E10-001-MY2-1, V105A-049).

There is no role of funding sources in any process of our study.

Financial disclosure

All authors have no financial relationships relevant to this article to disclose.

Contributions

Dr MHC, Dr TYW, Dr HTW, and Dr CFT designed the study, wrote the protocol and manuscripts, Dr YJL, Dr YMB, Dr SJT, Dr ACY, Dr TPS and Dr TJC assisted with the preparation and proof-reading of the manuscript, and Dr MHC and Dr TJC provided the advices on statistical analysis.

Acknowledgment

We thank Dr MHC, Dr TYW, Dr HTW, and Dr CFT, who designed the study, wrote the protocol and manuscripts, Dr YJL, Dr YMB, Dr SJT, Dr ACY, Dr TPS and Dr TJC, who assisted with the preparation and proof-reading of the manuscript, and Dr MHC and Dr TJC, who provided the advices on statistical analysis.

We thank Mr I-Fan Hu for his friendship and support.

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In this article, we review prior studies that analyze the relationship between stress, anxiety, depression, and dementia. We evaluate anxiety as a risk factor for dementia, its prevalence within different types of dementia, and anxiety in early versus late stages of dementia. In addition, we discuss the role of psychological stress in the development of mild cognitive impairment and dementia, as well as the relationship between dementia and childhood and midlife stress, and posttraumatic stress disorder. Throughout this article, we focus on the relationship between depression and stress/anxiety in dementia patients, and emphasize the importance of treating stress and anxiety in order to improve memory processes in dementia patients.
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There are several studies in male dominated military populations which have reported up to two-fold increased risk of dementia in older veterans with Posttraumatic Stress Disorder (PTSD), which is a severe clinical disorder that may arise in the aftermath of a life-threatening event (Mawanda et al., 2017; Qureshi et al., 2010; Yaffe et al., 2010). There are also limited studies to suggest that PTSD may be a risk factor for dementia in community-based samples (Flatt et al., 2018; Wang et al., 2016), however further research is required. The primary aim of this study is to determine whether lifetime exposure to severe trauma is associated with later-life cognitive function and the risk of dementia in a large population of older community-dwelling individuals.
Stress may be a risk factor for dementia, however it is unknown whether post-traumatic stress disorder (PTSD) symptoms are associated with incident dementia in community-dwelling older individuals. The aim was to determine whether lifetime major trauma with and without re-experiencing of PTSD symptoms is associated with later-life cognition and dementia risk. Participants were 1,700 community-dwelling older adults (65+) in the longitudinal ESPRIT study followed over 14 years. Lifetime major traumatic exposure and PTSD were assessed using Watson's PTSD Inventory. Cognitive tests assessed global cognition, visual memory, verbal fluency, psychomotor speed and executive function. Incident dementia was diagnosed according to DSM-IV criteria. Lifetime major trauma (versus no trauma) was associated with significantly increased executive function and increased global function in men, however women with lifetime trauma and re-experiencing symptoms had a significantly increased risk of low global cognition. Over 14 years, lifetime trauma without re-experiencing symptoms was associated with a significantly decreased risk of incident dementia, particularly for women. Lifetime major trauma without re-experiencing symptoms (but not with) may be protective for later life cognitive function. However, the mechanisms and moderating factors underlying these association requires further investigation.
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View all citing articles on Scopus

¹: Tsung-Yang Wang and Han-Ting Wei equally contributed to this work.

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Research paperRisk for developing dementia among patients with posttraumatic stress disorder: A nationwide longitudinal study

Highlights

Abstract

Objectives

Methods

Results

Discussions

Introduction

Section snippets

Data source

Demographic data of the study patients

Discussion

Conflict of Interest

Funding source

Financial disclosure

Contributions

Acknowledgment

J. Aging Stud.

Psychiatric Clin. N. Am.

MRI-based measurement of hippocampal volume in patients with combat-related posttraumatic stress disorder

Am. J. Psychiatry

Post-traumatic stress disorder in DSM-5: Estimates of prevalence and criteria comparison versus DSM-IV-TR in a non-clinical sample of earthquake survivors

J. Affect. Disord.

Attention deficit hyperactivity disorder, tic disorder, and allergy: is there a link? A nationwide population-based study

J. Child Psychol. Psychiatry, Allied Discip.

Physical health problems after single trauma exposure: when stress takes root in the body

J. Am. Psychiatric Nurses Assoc.

Late-life depression and risk of vascular dementia and Alzheimer's disease: systematic review and meta-analysis of community-based cohort studies

Br. J.f Psychiatry: J. Mental Sci.

Head injury as a risk factor for Alzheimer's disease: the evidence 10 years on; a partial replication

J. Neurol., Neurosurg., Psychiatry

APOE-epsilon4 predicts dementia but not other psychiatric disorders after traumatic brain injury

Neurology

Vascular risk factors for Alzheimer's disease

Zhurnal nevrologii i psikhiatrii imeni SS Korsakova / Ministerstvo zdravookhraneniia i meditsinskoi promyshlennosti Rossiiskoi Federatsii, Vserossiiskoe obshchestvo nevrologov [i] Vserossiiskoe obshchestvo psikhiat