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Men who work in bricklaying, concrete, material handling, and electronics, and women who are nursing assistants and attendants may be at higher risk for rheumatoid arthritis, per a recent study in Arthritis Care & Research.

Lead author Anna Ilar, an epidemiology Ph.D. student at Stockholm’s Karolinska Institute, prescribed caution. “It’s important to point out that you will not necessarily develop rheumatoid arthritis just because you have had a certain occupation, or been exposed to potentially-harmful exposures at work,” she said.

“But workplaces with high levels of hazardous airborne exposures may lead to a greater risk of rheumatoid arthritis, as well as other respiratory-related diseases,” she added.

As many patients seek to understand to why they have contracted rheumatoid arthritis, their job history can explain a small part of the larger picture of a multifaceted disease. “Genetic risk factors and lifestyle habits also need to be weighed in as well,” Ilar said.

[Learn how rheumatoid arthritis can impact your respiratory system.]

She and colleagues studied 3,522 cases and 5,580 controls from a Swedish population study called EIRA (Epidemiological Investigation of RA). A questionnaire helped the researchers learn about the patients’ work histories and lifestyles. They analyzed blood samples and adjusted for well-known risks and other lifestyle factors, including smoking, alcohol consumption, body mass index (BMI), and education levels. They note that the jobs that showed higher risks for RA are all physically demanding.

“Rheumatoid arthritis is one of the most common autoimmune diseases worldwide. It is therefore of great importance to find preventable risk factors,” Ilar said. “That is why it is important that findings on work-related exposures are spread to employees, employers, and decision-makers in order to prevent disease by reducing or eliminating known risk factors.”

Participants reported their work histories going back in time, so Ilar noted that the increased RA risk she and her colleagues found may correspond to harmful levels of exposure decades ago, which have since been corrected.

“Hopefully, today’s workers within the manufacturing field do not suffer the same risk of disease, since there is an increased awareness of the health implications of potential harmful hazards that may have caused the exposure levels to decrease,” she said.

[Read about working with chronic illness.]

Previous studies have found that manufacturing sector jobs can carry increased RA risk. The novelty of the new findings, according to Ilar, is the correcting for the known factors of smoking, alcohol use, education, and BMI.

“Previous studies had not taken these potential risk factors into account to the same extent, so it was uncertain whether the risks seen were related to the lifestyle of the workers rather than the work environment per se,” she said. “Our findings confirm that work-related factors, such as airborne harmful exposures, most likely contribute to the disease development.”

Exposure to silica dust, which can occur when cutting, sawing, drilling, and crushing concrete, brick, ceramic, rock, and stone products, is particularly dangerous, notes the U.S. Department of Labor’s Occupational Safety and Health Administration.

“Silica dust is hazardous when very small (respirable) particles are inhaled,” OSHA adds. “These respirable dust particles can penetrate deep into the lungs and cause disabling and sometimes fatal lung diseases, including silicosis and lung cancer, as well as kidney disease.”

One hypothesis holds that rheumatoid arthritis may begin in the lungs of those who are susceptible to harmful airborne exposures, which trigger the disease onset. Future studies will investigate the risks of RA that certain airborne exposures pose, Ilar said.

She added that risks associated with these occupations may vary from country to country. “This is not only because work-tasks and equipment may vary, but also because of differences in national work-environment regulations and the natural occurrence of harmful airborne exposures,” she said.