Study links increased diesel exhaust exposure to ALS among men

Boston — Workers frequently exposed to diesel exhaust may face a higher risk of amyotrophic lateral sclerosis, and the risk may increase with length of exposure, a preliminary study from Harvard University suggests.

Researchers analyzed the medical and employment histories of 1,639 Danish National Patient Registry entrants who had been diagnosed with ALS between 1982 and 2013 at an average age of 56. The researchers matched each diagnosed person with 100 people of the same age and sex who did not have ALS, and then used employment history to estimate diesel exposure before the person’s diagnosis.

Results showed that men who had any level of occupational exposure to diesel exhaust for at least 10 years before diagnosis were 20 percent more likely to develop ALS than those who experienced no exposure during the same period. Men who had more than a 50 percent chance of occupational exposure for both five and 10 years before diagnosis were 45 percent more likely to develop ALS than those unexposed.

Researchers found no association among women.

According to OSHA, occupations with potential exposure to diesel exhaust include miners; construction workers; heavy equipment operators; bridge and tunnel workers; railroad workers; oil and gas workers; loading dock workers; truck drivers; material handling operators; farmworkers; long-shoring workers; and automobile, truck and bus maintenance garage workers.

“There is some suggestion from previous studies of occupation that workers in jobs with higher exposure to diesel exhaust may have a higher risk of ALS,” Aisha Dickerson, lead study author and Harvard University research fellow, said in a Feb. 27 press release. “However, no studies have directly looked at the relation between diesel exhaust exposure during different time points in life and ALS. The overall risk of developing ALS is low, but our findings suggest that the greater the exposure to diesel exhaust, the greater the risk of developing ALS.”

The research is scheduled to be presented in April at the American Academy of Neurology’s annual meeting in Los Angeles.