Environmental PAH exposure associated with increased rheumatoid arthritis risk

A study published in an open-access journal suggests that environmental exposure to polycyclic aromatic hydrocarbons (PAHs for short) is strongly associated with the risk of developing rheumatoid arthritis. BMJ Open.

These chemicals form from burning coal, oil, gas, wood, or tobacco, or from open-fire grilling of meat and other foods, and seem to account for most of the effects of smoking on disease risk. .

A growing body of evidence links several ecotoxicants to a variety of long-term conditions. However, few studies have examined the association with inflammatory conditions such as rheumatoid arthritis, which are believed to result from the interplay of genes, gender, age, and environmental factors such as smoking, nutrition, and lifestyle.

To shed light on the potential role of environmental exposures on rheumatoid arthritis risk, researchers used responses to the nationally representative US National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016. bottom.

NHANES evaluates a wide range of toxicants, including PAHs. Chemicals used in the manufacture of plastics and various consumer products (PHTHTE); Volatile Organic Compounds (VOCs) from paints, cleaning agents, pesticides, etc. Along with data related to health, nutrition, behavior and the environment.

The study included 21,987 adults, of whom 1,418 had rheumatoid arthritis and 20,569 did not. Taking blood and urine samples, he measured the total amount of PAHs (7090 participants), PHTHTEs (7024), and VOCs (7129) in the body.

The likelihood of rheumatoid arthritis was highest among people with the top 25% of body PAH levels, regardless of whether they were former or current smokers.

After considering potentially influencing factors such as dietary fiber intake, physical activity, smoking, household income, educational attainment, age, gender, and body mass index (BMI), only one of the PAHs (1-hydroxynaphthalene) It was strongly associated with higher odds (80%) of the disease.

PHTHTE and VOC metabolites were not associated with increased risk after considering potentially influential factors.

Surprisingly, however, smoking was also not associated with an increased risk of rheumatoid arthritis when considering PAH levels in the body.

Further analysis to separate the effects of PAH and smoking showed that body PAH levels accounted for 90% of the overall effect of smoking on rheumatoid arthritis risk.

Since this is an observational study, we cannot determine the cause. The researchers also acknowledged various limitations to their findings, including the lack of measurements of adipose (fat) tissue ecotoxicants.

It also did not measure heavy metal levels previously associated with rheumatoid arthritis risk.Tobacco is a major source of the heavy metal cadmium.

However, they wrote: “To our knowledge, this is the first study to demonstrate that PAHs do more than just underlie most of the relationship between smoking and smoking. [rheumatoid arthritis]contribute independently as well as [it].

“This is important because PAHs are ubiquitous in the environment, originate from a variety of sources, and are mechanistically linked to underlying pathophysiology by aryl hydrocarbon receptors. [rheumatoid arthritis].”

“Although smoking adults tend to have higher PAH levels, other sources of PAH exposure include the indoor environment, vehicle exhaust, natural gas, smoke from wood and coal-burning fires, smoke from asphalt roads, This includes eating grilled or charred foods.

“This is appropriate because households of lower socioeconomic status generally have poor indoor air quality and may live in urban or high-traffic areas adjacent to major roads. So these people may be particularly vulnerable, they suggest.