Toxins from grilling, smoking and car exhaust may increase risk of rheumatoid arthritis

By Steven Reinberg Health Day Reporter

WEDNESDAY, May 10, 2023 (HealthDay News) — Toxic chemicals that develop from car exhaust, smoking and backyard grilling could increase your risk of developing the autoimmune disease rheumatoid arthritis, according to a new study.

These chemicals are called polycyclic aromatic hydrocarbons (PAHs). They are formed in the form of combustion of coal, oil, gas, wood or tobacco. Flame-grilling meat and other foods also contributes to the formation of PAHs, the researchers said.

“Although further studies are needed, the results suggest that polyaromatic hydrocarbons may contribute significantly to rheumatoid arthritis,” said the lead researcher. Chris D’Adamo, director of the Center for Integrative Medicine at the University of Maryland School of Medicine. “People at risk for rheumatoid arthritis should be wary of polyaromatic hydrocarbons and consider minimizing modifiable sources of exposure.”

Blood and urine samples from nearly 22,000 adults revealed that those with the highest PAH levels had the highest risk of rheumatoid arthritis.

Rheumatoid arthritis is an autoimmune and inflammatory disease that primarily affects the joints, causing tissue damage and long-lasting pain. Joints can become deformed and people with the disease can be unsteady on their feet. Women develop rheumatoid arthritis more often than men. The cause is not known, but is thought to involve genes, gender, and age, as well as environmental factors, such as smoking, nutrition, and lifestyle.

D’Adamo said this study cannot prove that PAHs cause rheumatoid arthritis, only that there appears to be an association.

“Although the results suggest an important relationship, causality cannot be established in a study such as this,” D’Adamo said.

He also pointed out that the absolute risk of developing rheumatoid arthritis is relatively low because the prevalence of rheumatoid arthritis is quite low.

However, PAHs are commonplace in the environment. PAH levels are higher in smokers. Other sources include indoor environments, motor vehicle exhaust, natural gas, smoke from wood or coal fires, fumes from paved roads, and consumption of grilled or charred foods, the officials noted. study authors.

PAH levels may be higher among the poor because poverty is generally associated with poorer indoor air quality. In addition, many poor people live in urban areas near major highways or in high traffic areas and are at higher risk of exposure. Poorer people are also more likely to smoke, researchers have found.

Smoking is a known risk factor for rheumatoid arthritis, and the level of PAHs accounted for about 90% of the association between smoking and rheumatoid arthritis, according to the report.

D’Adamo advises limiting exposure to PAHs, if possible. Avoid cigarette smoke, including secondhand and thirdhand smoke, and don’t eat burnt foods, he said.

Marinating food on the grill with spices and herbs reduces the formation of PAHs and other harmful toxicants, he noted.

“Also, minimize the use of a wood-burning fireplace and be sure to clean the chimney in case of a burning fire, and limit exposure to areas with high vehicle exhaust when possible” , D’Adamo added.

For the study, the researchers used data from the US National Health and Nutrition Survey from 2007 to 2016 on nearly 22,000 adults. More than 1,400 suffered from rheumatoid arthritis.

Blood and urine samples were evaluated to measure the amount of PAHs and other chemicals in the body.

The risk of developing rheumatoid arthritis was highest in the 25% of people with the highest PAH levels, whether they were former smokers or current smokers.

After controlling for dietary fibre, physical activity, smoking, income, education, age, sex and weight, a PAH – namely 1-hydroxynaphthalene – was strongly linked to a risk higher (80%) to develop rheumatoid arthritis.

Smoking alone, however, was not associated with a higher risk of rheumatoid arthritis after controlling for PAH levels, the researchers noted.

Dr. Diane Horowitzdirector of Northwell Health’s Rheumatoid Arthritis Center in Great Neck, NY, called the results “interesting.”

“I don’t think that’s enough to establish causation, but surely it’s enough to establish an association between these chemicals in rheumatoid arthritis,” she said. More research is needed to establish a cause and effect relationship, she noted.

The study also can’t say whether exposure to these chemicals makes rheumatoid arthritis worse or causes flare-ups, Horowitz said.

Anyone concerned about developing rheumatoid arthritis or people with the disease might want to avoid exposure to PAHs until more is known about the risk, she added. “There’s no harm in trying to avoid these exposures,” she said.

“The other thing this article raises, which I think is very important, is the connection to smoking,” Horowitz said. “It’s just one more reason not to smoke.”

The report was published online May 9 in BMJ open.

SOURCES: Chris D’Adamo, PhD, director, Center for Integrative Medicine, University of Maryland School of Medicine, Baltimore; Diane Horowitz, MD, director, Rheumatoid Arthritis Center, Northwell Health, Great Neck, NY; BMJ openMay 9, 2023, online

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