Head injury is associated with a doubled long-term mortality rate

Overview: People who suffered head injuries had a two times higher death rate than those who did not have a TBI. For those who sustained a moderate to severe head injury, the death rate was three times higher.

Source: University of Pennsylvania

Adults who sustained a head injury during a 30-year study period had twice the mortality rate of those who did not have a head injury, and death rates among people with moderate or severe head injuries were nearly three times higher, according to new research from the Perelman School of Medicine at the University of Pennsylvania, published today in JAMA Neurology.

In the United States, more than 23 million adults age 40 or older report a history of head injury with loss of consciousness. Head injuries can be attributed to a number of causes, from motor vehicle accidents, accidental falls or sports injuries. In addition, head injuries have been linked to a number of long-term health problems, including disability, late-onset epilepsy, dementia, and stroke.

Studies have previously shown increased short-term mortality associated with head injury, primarily in hospitalized patients. This longitudinal study evaluated 30 years of data from more than 13,000 community-dwelling participants (those not hospitalized or living in nursing homes) to determine whether head injuries impact long-term mortality rates in adults.

Researchers found that 18.4 percent of participants reported one or more head injuries during the study period, and of those who sustained head injuries, 12.4 percent were recorded as moderate or severe. The median time from head injury to death was 4.7 years.

Death from all causes was recorded in 64.6 percent of individuals who sustained head injuries, and 54.6 percent of those without any head injuries. Taking into account the characteristics of the participants, the researchers found that the all-cause death rate among participants with head injuries was 2.21 times higher than the death rate among those without a head injury.

Further, the death rate among people with more severe head injuries was 2.87 times the death rate among people without a head injury.

“Our data shows that head injuries are associated with increased mortality rates even in the long term. This is especially true for individuals with multiple or severe head injuries,” explained the study’s lead author, Holly Elser, MD, Ph.D., MPH, a neurology resident at Penn. “This highlights the importance of safety precautions, such as wearing helmets and seat belts, to prevent head injuries.”

This shows the outline of a head
Studies have previously shown increased short-term mortality associated with head injury, primarily in hospitalized patients. The image is in the public domain

Researchers also evaluated data for specific causes of death among all participants. Overall, the most common causes of death were cancer, cardiovascular disease, and neurological disease (including dementia, epilepsy, and stroke). Among individuals with head injuries, deaths from neurological disorders and accidental injury or trauma (such as falls) were more common.

When researchers evaluated specific neurological causes of death among participants with head injuries, they found that nearly two-thirds of neurological deaths were attributed to neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. These illnesses made up a higher proportion of total deaths among individuals with head injuries (14.2 percent) versus those without a head injury (6.6 percent).

“Research data do not explain why the cause of death in individuals with head injuries is more likely to be neurodegenerative diseases, highlighting the need for further research into the relationship between these conditions, head injuries and death,” said Andrea LC. Schneider, MD, Ph.D., an assistant professor of Neurology at Penn.

The study data came from the Atherosclerosis Risk in Communities (ARIC) Study, an ongoing community study of 15,792 participants, ages 45-65, who were recruited from the suburbs of Minneapolis, Minnesota, Washington County, Maryland, Forsyth County, North Carolina, and Jackson, Mississippi in 1987–1989.

About this TBI research news

Writer: Press Office
Source: University of Pennsylvania
Contact: Press Service – University of Pennsylvania
Image: The image is in the public domain

Original research: Closed access.
“Head injury and long-term mortality risk in community-dwelling adults” by Holly Elser et al. JAMA Neurology


Abstract

Head injury and long-term mortality risk in community-dwelling adults

Interest

Head injury is associated with significant short-term morbidity and mortality. Research on the implications of head injury for long-term survival in community-dwelling adults remains limited.

Objectively

To evaluate the association of head injury with long-term all-cause mortality risk in community-dwelling adults, taking into account the frequency and severity of head injury.

Also see

This shows a drawing of a brain on a computer

Design, setting and participants

This cohort study included participants with and without a head injury in the Atherosclerosis Risk in Communities (ARIC) Study, an ongoing prospective cohort study with follow-up from 1987 to 2019 in 4 U.S. communities in Minnesota, Maryland, North Carolina, and Mississippi. Of the 15,792 ARIC participants initially enrolled, 1957 were ineligible due to self-reported head injury at baseline; 103 entrants who were not of black or white race and black entrants in the Minnesota and Maryland field centers were disqualified due to race-ground aliasing; and an additional 695 participants with missing head injury date or covariate data were excluded, resulting in 13 037 eligible participants.

Exposures

Frequency and severity of head injury, as defined by self-report in response to interview questions and by hospitalization International Classification of Diseases diagnostic codes (where the severity of the head injury is defined in the subset of head injury cases identified using these codes). Head injury was analyzed as time-varying exposure.

Main results and measures

All-cause mortality was determined via linkage to the National Death Index. The data was analyzed between August 5, 2021 and October 23, 2022.

Results

More than half of the participants were female (57.7%; 42.3% male), 27.9% were Black (72.1% White), and the median age at baseline was 54 years (IQR, 49-59 year). The median follow-up time was 27.0 years (IQR, 17.6-30.5 years). Head injuries occurred in 2402 participants (18.4%), most of which were classified as mild. The hazard ratio (HR) for all-cause mortality in subjects with head injury was 1.99 (95% CI, 1.88-2.11) compared to subjects without a head injury, with evidence of a dose-dependent relationship to frequency of head injury (1 head injury). injury: HR, 1.66 [95% CI, 1.56-1.77]; 2 or more head injuries: HR, 2.11 [95% CI, 1.89-2.37]) and severity (mild: HR, 2.16 [95% CI, 2.01-2.31]; moderate, severe, or intrusive: HR, 2.87 [95% CI, 2.55-3.22]). Estimates were similar by gender and race, with attenuated associations among subjects 54 years or older at baseline.

Conclusions and relevance

In this community-based cohort with more than 3 decades of longitudinal follow-up, head injury was associated with a shorter long-term survival time in a dose-dependent manner, underlining the importance of measures aimed at prevention and clinical interventions to reduce morbidity and mortality from head injury.

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