Millions of Americans were stunned earlier this month when NFL great Chris Johnson appeared in an emotional interview looking dramatically different from the athlete fans once knew.
The Good Morning America feature began with tender family footage from just 14 months earlier, showing the former Tennessee Titans and New York Jets running back hoisting his seven-year-old daughter onto his shoulders.
Now 40, Johnson sat nearly still throughout the interview, relying on an eye-tracking computer to communicate, as his devastated wife, Brittany, said the former powerhouse can now barely lift a cup.
Johnson disclosed that he has amyotrophic lateral sclerosis, or ALS, a severe neurological disorder that progressively attacks the nerve cells responsible for movement and can strip patients of the ability to walk, speak, swallow and eventually breathe.
Commonly referred to as Lou Gehrig’s disease, ALS has drawn increasing attention in recent years as research suggests the number of diagnoses may be climbing.
The disease can emerge in adults who otherwise appear healthy and active, often during the prime of life, leaving scientists searching for clearer answers about what triggers it.
Although inherited gene mutations are linked to roughly 10 percent of cases, most diagnoses have no known cause. Researchers are increasingly examining whether environmental exposures could be contributing to the risk.
A new Daily Mail analysis of federal records has identified a pronounced regional pattern in ALS deaths across the United States, a divide experts say may offer clues about possible environmental factors such as pollution, diet or even differences in light exposure.
As our map shows, adults in the Pacific Northwest and New England – regions more often associated with outdoor lifestyles and good health – had the highest rates of the disease.
By contrast, parts of the South and Southwest, more commonly linked to obesity and poor health, recorded some of the lowest rates.
About 33,000 people in the US are currently living with ALS, with that number expected to rise to 36,000 by 2030.
The disease is more common among white adults and men, and typically develops between the ages of 55 and 75 – but can strike far younger.
Symptoms usually begin with weakness in one part of the body – often a foot, leg, arm or, as in Chris Johnson’s case, a hand – before rapidly progressing throughout the body, destroying muscle function and eventually causing almost complete paralysis.
There is no cure, although medications can slow the progression of the disease. Most patients survive for between two and five years after diagnosis.
For the map, the Daily Mail analyzed figures held by CDC Wonder, the agency’s mortality database, covering deaths recorded between 2018 and 2024.
Because ALS is not listed as a separate category in the database, we looked at deaths recorded as motor neuron disease. ALS is the most common form of motor neuron disease and accounts for around 85 percent of these deaths.
Former NFL star Chris Johnson, 40, revealed his ALS diagnosis this week during an interview with Good Morning America
Johnson on the field during a Tennessee Titans game in 2013. The star was diagnosed with ALS in 2025 when he was 39
Mortality data provides one of the most reliable ways of comparing the disease across states because death certificates are completed for every fatality, whereas case counts rely on estimates and voluntary reporting.
Overall, Idaho, Oregon and Wyoming recorded the highest ALS death rates in the country, at 2.5 deaths per 100,000 residents.
Minnesota followed at 2.4 per 100,000, while Kansas, Montana and New Hampshire each recorded 2.3 per 100,000.
At the opposite end of the scale, Nevada and Hawaii had the lowest rates, at 1.5 per 100,000. Florida followed at 1.7, while Arizona, Arkansas, Delaware, Kentucky, Mississippi, New Jersey and New York each recorded 1.8 per 100,000.
The findings point to a striking north-south divide, with many of the highest rates clustered in the Pacific Northwest, Upper Midwest and New England, while several southern and southwestern states recorded some of the lowest.
One theory has long been that the pattern could be linked to latitude.
Northern states receive less year-round sunlight, leading to lower vitamin D levels, and some scientists have suggested this might increase the risk of ALS.
But Dr Eva Feldman, a neurologist and director of the ALS Centre of Excellence at the University of Michigan, said the evidence does not support that idea.
‘It’s only really in the last handful of years that we’ve got a good grasp on the geographic variability of ALS,’ she said.
‘Studies have not shown any clear association between ALS and vitamin D exposure, which tends to be lower across all northern states.’
Another possible explanation is age. A 2021 study investigating high ALS rates in the Midwest suggested the region’s older population could partly explain the trend, as the disease is most commonly diagnosed between the ages of 55 and 75.
But that theory does not fully fit the data. Florida, long regarded as America’s retirement capital, recorded one of the nation’s lowest ALS death rates.
Instead, researchers are increasingly focusing on environmental factors.
‘ALS does appear to be more common in states with greater industrial or agricultural activity, where exposure to pollutants may be higher, although that link is far from proven,’ Dr Feldman said.
‘We are still in the very early stages of understanding what could be driving this variation.’
Eric Dane, best known for his role as Dr Mark Sloan on Grey’s Anatomy, attends a premiere in June 2025. He was diagnosed with ALS in 2024 at age 51
Dane leaves Toronto International Airport in October 2025. The actor became an advocate for ALS awareness before he died in February
Researchers have noted that the distribution of ALS and multiple sclerosis, an autoimmune disorder, is similar in maps, suggesting that the two conditions may be linked
Dr Feldman is leading a 30-year study following thousands of workers in northern Michigan – one of the states with the nation’s highest ALS death rates – to investigate whether pollution helps explain the disease.
She said the state’s automotive industry and extensive cherry farming could expose residents to heavy metals and pesticides, two environmental factors researchers are investigating as possible contributors to ALS.
Actor Eric Dane, who died from ALS in February at age 53, grew up in San Francisco, California, and used to take annual fishing trips to the Kenai River, Alaska, which the state’s authorities say has a ‘failing grade’ for pollution. This raises the prospect that his ALS may have been linked to environmental contamination.
Why Idaho, Oregon and Wyoming recorded the nation’s highest ALS death rates remains unclear. But researchers have proposed several more localized explanations that are now being investigated.
One centers on the false morel mushroom, which grows widely across the Pacific Northwest.
In 2021, researchers investigating an ALS cluster in a French Alpine village reported that all 14 people diagnosed with the disease had eaten false morel mushrooms, while unaffected residents had not.
Although the study could not prove cause and effect, it prompted calls for further research.
False morels are widely distributed across the Pacific Northwest, where mushroom foraging is common.
Data from iNaturalist, a citizen science website where users record sightings of plants and wildlife, also shows the fungi are particularly common across the Pacific Northwest and parts of New England – broadly mirroring regions with some of the nation’s highest ALS death rates.
Dr Peter Spencer, who has studied the hypothesis, said mushroom foraging is especially popular in northern parts of the US.
He added that poison center data also suggest accidental false morel poisonings are more common in some northern states, particularly Idaho, where our analysis also found some of the nation’s highest ALS death rates.
False morels contain a toxin called gyromitrin, which the body converts into monomethylhydrazine (MMH) – a chemical capable of damaging nerve cells. Some researchers have hypothesized that repeated exposure could contribute to ALS developing years later, although this has not been proven.
A true morel is a gourmet delicacy, though it must be properly cooked or could be poisonous. True morels are often featured in Michelin-starred restaurants and in high-end cuisine
The above shows reports of sightings of false morels across the US on the website iNaturalist
However, experts stress there is no solid evidence that people who develop ALS have previously been poisoned by false morels, and much more research is needed before any firm conclusions can be drawn.
Feldman added: ‘It’s an interesting theory. We have no data to prove or disprove it either way.’
Other local environmental theories have also emerged. In Vermont, which recorded one of the country’s highest ALS death rates, researchers have suggested cyanobacteria in lakes and rivers – which produce toxins capable of damaging nerve cells – could play a role, although evidence remains limited.
Dr Melissa Schilling, a social sciences researcher at NYU who led a 2025 study into the geographic distribution of ALS, said the findings reinforced the growing belief that environmental factors play a role.
‘ALS research is a much bigger mess than Alzheimer’s, which I’ve also worked on,’ she said. ‘It’s super fragmented, and there are a lot of dead ends. It doesn’t get nearly the amount of attention it deserves.
‘The data shows that ALS is more common in the North, but it’s not a perfect gradient.
‘I think this strongly suggests that something environmental is raising people’s risk of developing ALS, although we’re not sure what this is yet. It could be heavy metals, pollutants, sanitation systems, a virus or something else.
‘We need to find the cause because, if we do, that opens up entirely new possibilities for how we can treat the disease.’
Her research also found that ALS has a remarkably similar geographic distribution to multiple sclerosis, an autoimmune disease that attacks the central nervous system, suggesting the two conditions may share environmental triggers.
What, if anything, triggered Johnson’s illness is impossible to know.
Scientists believe ALS develops through a complex interaction between genetic susceptibility and environmental exposures. While inherited genetic mutations account for around one in ten cases, researchers have linked head trauma, pesticides, heavy metals and military service to an increased risk, although none has been proven to directly cause the disease.
Johnson spent ten seasons in the NFL, where repeated blows to the head have long been a concern. Some studies have suggested people with a history of head trauma have a higher risk of developing ALS, although researchers stress the evidence remains inconclusive.
‘I don’t know if you ever fully process it,’ the father of four said.
‘At first, you’re in shock. Then you realize you have two choices. You can give up, or you can fight. I chose to fight.’
