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LOS ANGELES -- Men frequently exposed to diesel exhaust may have a higher risk of amyotrophic lateral sclerosis (ALS), researchers suggested.

Men in Denmark who had any exposure to diesel exhaust in their jobs 10 years before their ALS diagnosis were 20% more likely to have ALS than men with no diesel exhaust exposure, reported Aisha Dickerson, PhD, of Harvard T.H. Chan School of Public Health in Boston and colleagues, in an early-release abstract from the American Academy of Neurology meeting to be held here in April.

For men who had a greater than 50% likelihood of being exposed to diesel exhaust 10 years before their ALS diagnosis, the link was even stronger at an adjusted odds ratio of 1.41, they stated.

"Considering the genotoxicity of diesel, and the implications of occupational exposures seen in our analysis, it's important to further evaluate the potential impact of these exposures via ambient air pollution in the general population, especially those living near high-traffic roads," Dickerson told 名媛直播.

This research comes on the heels of from the Netherlands that linked long-term exposure to traffic-related air pollution, including diesel exhaust, to increased ALS susceptibility.

In the Denmark-based study, researchers studied 1,639 people from the Danish National Patient Registry who were diagnosed with ALS from 1982 to 2013, matching each person with ALS with 100 people of the same age and sex who did not have the disease. They calculated diesel exhaust exposure for each person using a job exposure matrix, incorporating potential hazards for specific workers like service station attendants, bus drivers, and construction workers. They calculated cumulative exposure up to 5 and 10 years before the ALS diagnosis time period.

Dickerson's group found that the adjusted OR for ALS among men with any occupational diesel exhaust exposure increased with increasing lag periods. At a 10-year lag, the aOR was 1.20 (95% CI 1.05- 1.38).

Men in occupations with the highest exposure had higher odds of ALS. At 5 years, the aOR for men with a greater than 50% likelihood of being exposed to diesel exhaust was 1.40 (95% CI 1.11-1.78). At 10 years, it was 1.41 (95% CI 1.11-1.78)

The researchers saw no associations among women, but noted that specific tasks performed even in the same job can differ substantially between men and women.

Why an association between diesel exhaust and ALS exists is unclear, Dickerson noted.

"Previous studies have demonstrated diesel exhaust can damage DNA, potentially resulting in mutations and subsequent cellular death and tissue damage," she said. "Additionally, animal models have shown a direct link between diesel exhaust exposure and neuroinflammation, which when experienced repeatedly, becomes neurotoxic and can lead to neurodegeneration in the central nervous system."

"It's possible that ultrafine particles in diesel exhaust cross the blood-brain barrier and lead to oxidative stress," added Leonard van den Berg, MD, PhD, of the University Medical Center Utrecht in the Netherlands, who was not involved in the study. "Another option might be metals in diesel exhaust that could be toxic directly to the brain."

The wider issue is whether the same mechanism could play a role in other diseases like Parkinson's disease, van den Berg added. "It doesn't have to be specific for ALS. That's why it's very important to study exposure to air pollution and diesel exhaust in large populations."

Study limitations included the use of a job exposure matrix to estimate occupational diesel exhaust levels; personal exposures were not measured directly.

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