Dementia and Traffic Accidents: A Danish Register-Based Cohort Study

Association Between Young-Onset Dementia and Risk of Hospitalization for Motor Vehicle Crash Injury in Taiwan

IMPORTANCE

Several studies have suggested that older-onset dementia is associated with an increased risk of motor vehicle crash injury (MVCI). However, evidence of an association between young-onset dementia and the risk of MVCI is insufficient, particularly in Asia.

OBJECTIVE

To investigate the association between young-onset dementia and MVCI-related hospitalization in Taiwan.

DESIGN, SETTING, AND PARTICIPANTS

In this nationwide, population-based cohort study in Taiwan, a cohort of 39 344 patients aged 40 to 64 years with incident dementia diagnosed between 2006 and 2012 was matched 1:1 with a cohort of participants without dementia by age, sex, and index year (initial diagnosis of dementia). Participants were identified from Taiwan's National Health Insurance Research Database (NHIRD). Data were analyzed between March 25 and October 22, 2021.

EXPOSURES

Dementia, defined by International Classification of Diseases, Ninth Revision, Clinical Modification codes.

MAIN OUTCOMES AND MEASURES

Hospitalization for MVCI, determined using linked data from Taiwan's Police-Reported Traffic Accident Registry and the NHIRD from January 1, 2003, to December 31, 2015. Hazard ratios (HRs) for MVCI-related hospitalization were estimated using Cox proportional hazards regression models adjusted for sex, age, salary-based insurance premium, urbanization level, and comorbidities.

RESULTS

Of the 78 688 participants, 47 034 (59.8%) were male; the mean (SD) age was 54.5 (7.4) years. During the 10-year follow-up period, the incidence density of MVCI-related hospitalization was 45.58 per 10 000 person-years (95% CI, 42.77-48.39 per 10 000 person-years) among participants with dementia and 24.10 per 10 000 person-years (95% CI, 22.22-25.99 per 10 000 person-years) among participants without dementia. Compared with participants without dementia, patients with young-onset dementia were at higher risk of MVCI-related hospitalization (adjusted HR [aHR], 1.83; 95% CI, 1.63-2.06), especially those in younger age groups (aged 40-44 years: aHR, 3.54; 95% CI, 2.48-5.07) and within a shorter period (within 1 year of follow-up: aHR, 3.53; 95% CI, 2.50-4.98) after dementia was diagnosed. Patients with young-onset dementia also had a higher risk of being a pedestrian when the crash occurred (aHR, 2.89; 95% CI, 2.04-4.11), having an intracranial or internal injury (aHR, 2.44; 95% CI, 2.02-2.94), and having a severe injury (aHR, 2.90; 95% CI, 2.16-3.89).

CONCLUSIONS AND RELEVANCE

In this retrospective cohort study, patients in Taiwan with a diagnosis of young-onset dementia had a higher risk of MVCI-related hospitalization than did individuals without dementia and the risk varied by age, disease duration, transport mode, injury type, and injury severity. These findings suggest a need for the planning of strategies to prevent transportation crashes among patients with young-onset dementia.

Analysis of the risk and risk factors for injury in people with and without dementia: a 14-year, retrospective, matched cohort study

BACKGROUND

Most previous studies on dementia and injuries have focused on a particular type of injury, and few studies have investigated overall injury in people with dementia. In this study, we investigated the risk factors and risk of overall injury, including the diagnosis, cause, and intentionality of injury, in people with and without dementia in Taiwan.

METHODS

We collected relevant data between 2000 and 2013 from the National Health Insurance Research Database (NHIRD). Overall, 455,630 cases, consisting of 91,126 people with dementia and 364,504 people without dementia, were included in this study and we performed subgroup analysis. A multivariate Cox proportional hazards regression analysis was used to determine the risk of injuries.

RESULTS

The 14-year follow-up data showed that people with dementia had a higher risk of injury-related hospitalization than did people without dementia (19.92% vs 18.86%, hazard ratio (HR) = 1.070, p < 0.001). Regarding the cause of injury, people with dementia were more likely to be hospitalized due to suffocation (HR = 2.301, p < 0.001), accidental drug poisoning (HR = 1.485, p < 0.001), or falls (HR = 1.076, p < 0.001), and were less likely to be hospitalized due to suicide or self-inflicted injury (HR = 0.670, p < 0.001) or a traffic accident (HR = 0.510, p < 0.001) than were people without dementia. Subgroup analysis showed that people with dementia with any of the three subtypes of dementia were at a higher risk of homicide or abuse than were people without dementia (vascular dementia, HR = 2.079, p < 0.001; Alzheimer's disease, HR = 1.156, p < 0.001; other dementia, HR = 1.421, p < 0.001). The risk factors for overall injury included dementia diagnosis, female gender, age 65-74 years, and seeking medical attention for an injury within the past year.

CONCLUSION

People with dementia are at a higher risk of injury-related hospitalization than people without dementia. The results of this study provide a reference for preventing suffocation, drug poisoning, and falls in people with dementia. In addition, government agencies should pay attention to and intervene in cases of abuse suffered by people with dementia.

The risk of fall accidents for home dwellers with dementia-A register- and population-based case-control study

Introduction

Institutionalized people with dementia have an increased risk of fall accidents, but little is known about whether this increased risk holds for home dwellers.

Methods

This register- and population-based study comprised 115,584 cases and 394,679 controls. Cases were individuals with any fall between 2009 and 2014, and matched with up to six controls on age, sex, and geographic location. Individuals were excluded if they (1) had any fall in 2008, or (2) lived in a nursing home on the date of the fall. Dementia, other chronic diseases, and sedative medicines were assessed from Danish national registers.

Results

After adjusting for potential confounders, older people with dementia living at home had a 1.89-fold higher risk of fall (odds ratio = 1.89, 95% confidence interval [1.84–1.94], P < .001).

Discussion

Dementia almost doubles the risk of fall for older Danish people living at home. This highlights the need for effective fall preventions that target people with dementia.

Dementia and road traffic accidents among non-institutionalized older people in Denmark: A Danish register-based nested case-control study

AIM

We used register-based data to estimate the effect of all-type dementia on road traffic accidents (RTAs) risk, combined with comorbidities or sedative medicines, among non-institutionalized older people in Denmark.

METHODS

The source population was all residents in Denmark aged 65 years and older, alive as of January 1, 2008 ( n = 853,228). Cases were those who had any type of RTA in 2009-2014. Each case was matched for age, sex and geographic location to 4-6 controls. All-type dementia was ascertained using the International Classification of Diseases version 10 (ICD-10) diagnosis supplemented with prescribed medicine records. Eight chronic diseases were selected to assess comorbidities. Four types of medicines were categorized as sedative medicines for analysis. Conditional logistic regression with adjustment for education and marital status as well as either the number of comorbidities or sedative medications use was performed using STATA software.

RESULTS

Older people with dementia had lower RTAs risk compared to their controls (odds ratio = 0.43, 95% confidence interval (0.32-0.60), p < 0.001). Significant interaction was observed between dementia and the number of comorbidities for RTAs estimation.

CONCLUSIONS

The significantly lower RTAs risk for older individuals with dementia observed in our study may be due to people with dementia living at home having a lower frequency of outdoor activities; that is, less exposure to traffic. However, this, together with the interaction between dementia and comorbidities as well as sedative medications, should be investigated further.