Study Shows Work Disability After TBI Isn’t a One-Time Event

Key Takeaways 

• A large nationwide Swedish study followed 98,256 people with TBI and 981,191 people without TBI for five years, tracking shifts in and out of work disability over time. 

• Even the “mildest” group (ER visit or ≤2 days hospitalized, no neurosurgery) showed a delayed increase in work disabilies, rising and stabilizing around 9% by two years, compared to 4% in the non-TBI group.

• Early work disability was highest in more severe categories: at 30 days, 29% (TBI B) and 43% (TBI C) transitioned into work disability, compared to 0.5% in non-TBI.

• Over five years, 45% of the mildest TBI group experienced at least one work disability episode (vs 26% in non-TBI).

• The study reinforces that TBI recovery can be non-linear and influenced by pre-injury factors like age, psychiatric history, and occupation, supporting longer-term rehabilitation and workplace support.

Traumatic brain injuries are often treated like a short-term event: a diagnosis, a few follow-ups, then “back to normal.”

But this new nationwide study out of Sweden points to something injury victims and their families often learn the hard way: work disability after a TBI can come and go over years. Elevated risks don’t just disappear because an injury was labeled “mild.”

The TBI Study Conducted in Sweden 

Researchers in Sweden examined 98,256 working-age adults (21–60) diagnosed with TBI between 2005 and 2016, and compared them to 981,191 matched individuals without TBI. They tracked work disability transitions for five years using linked national registers.

Importantly, they did not treat return-to-work as a single yes/no checkpoint. They measured transitions to and from work disability as a recurring event.

Work disability was defined as more than 14 net days of sickness absence and/or disability pension during follow-up – meaning these weren’t minor “took a day off” events. They were medically and insurance-recognized periods of reduced work capacity.

Analyzing the Results of the Study 

“The big takeaway is that work disability after a TBI isn’t a one-time checkpoint,” says Arthur Dermendjian, Prelitigation Managing Attorney at J&Y Law. “The study shows that people can move in and out of work disability over a five-year period, and that elevated risk shows up even in cases classified as milder injuries. We see this type of thing all the time at our firm.” 

What makes the findings significant is how clearly the numbers reflect a long tail of risk, even in the group most people would casually call a “concussion case.” 

What Counts as “Mild,” “Moderate,” or “Severe” in This Study? 

The researchers used care-based proxies for severity (because standardized clinical grading like Glasgow Coma Scale wasn’t consistently available in the registers). They grouped cases into: 

• TBI A: Emergency visit or ≤2 days hospitalized, no neurosurgery (this was 93% of all TBI cases; 91,505 people)

• TBI B: Hospitalized ≥3 days, no neurosurgery (6%; 6,091 people)

• TBI C: Neurosurgery (<1%; 660 people)

Even with these imperfect proxies, the severity gradient was clear, and so was the persistence of risk. 

What Were the Most Important Statistics? 

Work Disability Risk Was Higher Across All TBI Groups

At 30 days, the probability of transitioning into work disability was:

• 5.5% for TBI A 

• 29% for TBI B 

• 43% for TBI C 

• vs 0.5% in the non-TBI group 

This is the “early peak” pattern the study emphasized in the more severe categories. 

The Long-Term Risk Stayed Elevated for Five Years

By five years, transition probabilities were still higher in every TBI group:

• 7.1% (TBI A) 

• 10.9% (TBI B) 

• 12.9% (TBI C) 

• vs 4.0% (non-TBI) 

The risk doesn’t fade away neatly. It persists. 

“At Least One Episode” Over Five Years Was Strikingly Common

Over the full follow-up period, the proportion of people who experienced at least one work disability episode was:

• 26% in non-TBI 

• 45% in TBI A 

• 67% in TBI B 

• 72% in TBI C 

Even after excluding people with prior work disability, the pattern stayed consistent. 

This is exactly why a single “returned to work” note early in a case can be misleading. 

How Does This Compare With What We See in Injury Claims? 

It aligns closely with how TBIs play out in real life, and why they’re often undervalued early. 

“TBIs are easy to miss early because the symptoms can be subtle, delayed, or dismissed as stress, whiplash, or ‘just being sore,’” Dermendjian continues. “Then months later, the person is struggling with concentration, headaches, irritability, sleep disruption, or stamina at work, and their life looks completely different. That gap in treatment is a big reason these cases get undervalued at first. Then we have to educate insurance adjusters. Studies like this support what we’ve been arguing for years.” 

The study’s most important contribution is that it validates a reality many clients experience: 

Recovery isn’t linear. Work capacity can deteriorate after someone initially “pushes through.” 

The researchers even noted that the mildest group (TBI A) showed a delayed transition pattern, with risk increasing gradually and stabilizing at around 9% by two years, compared to 4% in non-TBI.

What Factors Increased Risk? 

In the milder and moderate groups (TBI A and B), the study found higher risk associated with: 

• Older age (TBI A HR 1.23; TBI B HR 1.34)

• Female sex (TBI A HR 1.59; TBI B HR 1.35) 

• Psychiatric disorders (TBI A HR 1.34; TBI B HR 1.28) 

• Blue-collar occupation and substance use disorders also tracked with higher risk. 

Protective factors in TBI A (and some in TBI B) included: 

• Higher education (TBI A HR 0.83)

• City residence (TBI A HR 0.92; TBI B HR 0.88) 

In the most severe group (TBI C), older age was the consistent predictor (HR 1.59).

These numbers show that pre-injury context changes the recovery trajectory, which matters both medically and legally speaking.

Policy Level TBI Changes 

“This is where employers, insurance companies, and public systems need to come together to do better,” says Dermendjian. “If the risk of work disability stays elevated for years after TBI, then support can’t end after the first follow-up visit. Policies that expand access to longer-term rehab, workplace accommodations, and smoother transitions back to work would reduce both human cost and any economic impact.” 

This study supports a policy direction that recognizes TBI as more than an acute event: 

• Longer-term access to rehabilitation 

• Cognitive and neuropsychological follow-up 

• Structured return-to-work programs 

• Better accommodation systems for fluctuating symptoms 

The study itself frames TBI as increasingly understood as a chronic condition with fluctuating recovery, and the five-year data supports that view. 

What To Do If You’re Injured Right Now 

If you’re dealing with a concussion or brain injury after an accident, the worst mistake is assuming you’ll know the full impact within a few weeks. 

This study shows: 

• Risk can spike early in severe cases 

• Risk can rise later even in “mild” cases 

• Work disability can recur over years 

That’s why early documentation, consistent symptom tracking, and appropriate medical follow-ups are so important. 

At J&Y Law, we often see TBI cases undervalued early because the record doesn’t yet reflect the long-term reality. If your symptoms were dismissed, delayed, or minimized, you may need a strategy that reflects the full recovery arc, not just the first month. 

If you’re unsure whether your brain injury is being taken seriously, contact our team. We can help you evaluate what documentation is missing and what steps protect your case long-term.