Photo Credit: Susan Wilkinson
Scientific Frontline: Extended "At a Glance" Summary: Petroleum-Derived Lubricants and Multiple Sclerosis Risk
The Core Concept: Occupational exposure to petroleum-based lubricants, such as engine oil and cutting fluids, is associated with an elevated risk of developing multiple sclerosis. A Swedish study found that exposed individuals experienced 38 percent higher odds of developing the chronic autoimmune disease, with the risk increasing alongside the duration and intensity of exposure.
Key Distinction/Mechanism: Unlike previously identified environmental risk factors such as smoking, air pollution, and organic solvents, this research specifically isolates aerosolized petroleum-derived lubricants used in metalworking and machinery maintenance. Researchers hypothesize that inhaling these tiny droplets irritates the lungs, triggering immune reactions that contribute to multiple sclerosis etiology.
Major Frameworks/Components:
- Epidemiological matching: The study compared self-reported occupational histories between 2,872 individuals with newly diagnosed multiple sclerosis and 6,122 healthy controls.
- Dose-response relationship: Researchers observed that the odds of disease onset rose incrementally with more years of exposure and more hours of exposure per week.
- Latency period analysis: The association strengthened (showing 55 percent higher odds) when investigators restricted the analysis to exposures occurring at least seven years prior to the onset of the first symptoms.
- Synergistic risk factors: The association between lubricant exposure and multiple sclerosis risk was significantly more pronounced among active smokers and individuals lacking a protective genetic variant.
Branches of Science: Neuroscience, Epidemiology, Environmental Medicine, Neuroimmunology, and Toxicology.
Future Application: These findings will prompt further epidemiological studies to verify the association in independent populations and may lead to updated occupational safety regulations, improved respiratory protective equipment, and targeted screening protocols for metalworking and construction personnel.
Why It Matters: Identifying occupational exposures that contribute to multiple sclerosis before symptoms appear is critical for long-term prevention strategies. Confirming this association could help mitigate workplace hazards and reduce the incidence of this chronic central nervous system disease among susceptible populations.
People with multiple sclerosis (MS) were more likely than people without the disease to report that they had been exposed to petroleum-based lubricants at work. A new study from Karolinska Institutet, published in the journal Neurology, observed this association.
"In metalworking, for example, tiny droplets of lubricant can spread through the air and be inhaled. Just like cigarette smoke, it can irritate the lungs. Our hypothesis is that irritation in the lungs can trigger immune reactions that contribute to the development of MS," says Anna Hedström, researcher at the Department of Clinical Neuroscience, Karolinska Institutet.
The study included 2,872 people with newly diagnosed MS and 6,122 people without MS in Sweden. Participants answered questions about their work history and any contact with substances, including cutting fluids, engine oil, and hydraulic oil. Exposure was common in areas such as metalworking, construction, vehicle repairs, and machinery maintenance.
Higher Odds of MS After Exposure
Among people with MS, 8.7 percent said they had been exposed to petroleum-based lubricants at work, compared with 6.5 percent in the control group. After the researchers accounted for several other factors, exposure was linked to 38 percent higher odds of MS. The odds rose slightly with more years of exposure and more hours per week.
The association remained when the researchers only counted exposure that had occurred at least seven years before the first MS symptoms. In that analysis, exposure was linked to 55 percent higher odds of MS.
Among people who smoked, the association was stronger. In the subgroup for which genetic data were available, the researchers also saw a stronger association in people who lacked a gene variant previously linked to a lower risk of MS.
One limitation is that participants reported their exposure themselves and may therefore have remembered or classified it incorrectly. Other exposures in the work environment may also have affected the results. Therefore, the study does not show that petroleum-based lubricants cause MS.
"The next step is to see whether the association is seen again in other studies. To understand whether the lubricants themselves contribute to the risk of MS, we need more detailed information about which products were used and how often and for how long people were exposed," says Anna Hedström.
Funding: The study was funded by the Swedish Research Council, Forte, the Swedish Brain Foundation, and the Margaretha af Ugglas Foundation.
Published in journal: Neurology
Title: Occupational Exposure to Petroleum-Derived Lubricants and Risk of Multiple Sclerosis
Authors: Anna Karin Hedström, Tomas Olsson, and Lars Alfredsson
Source/Credit: Karolinska Institutet
Edited by: Scientific Frontline
Reference Number: ns111326_01