The common conditions that could be warning signs of osteoarthritis

People with asthma and eczema could be more at risk of developing osteoarthritis, a study suggests.

Scientists now believe that the debilitating joint condition may be caused by the same mechanism linked to eczema and asthma. Osteoarthritis is the most common form of arthritis and there is no cure.

Analysis of healthcare records of more than a million Americans allowed the team to compare 110,000 individuals suffering from either asthma or eczema with 110,000 people who were otherwise similar in every way, save for the conditions.

Data show people with either eczema or asthma were 58 per cent more likely to develop osteoarthritis over the study period, which averaged eight years.

The team said that for 100 people without the disease there would be an expectation that 19 would get osteoarthritis over a 10-year span, however this increases to 27 for people with allergic asthma or eczema.

A person’s individual risk was also heightened if they had both asthma and eczema, rising to more than twice the risk of someone with none of the conditions.

However, the data comes from insurance claims in the US and does not factor in various potential confounding factors, such as BMI, previous joint issues, and activity levels.

A secondary analysis of more than 110,000 people which did have BMI data saw the percentage risk drop to 42 per cent higher if a person had both eczema or asthma compared to none of the conditions, and 19 per cent for individuals with just one.

Asthma and eczema are both caused by the immune system producing a strong reaction to environmental allergens. Certain chemicals or substances can lead to flare ups as the body produces a stronger than normal response.

The immune system recognises a foreign substance as a threat and kicks into action but this leads to inflammation which can manifest as eczema and asthma, which affect the skin and airways, respectively.

Recent studies have found key components of this sensitive immune response behind both asthma and eczema, called cytokines and mast cells, may also play a role in osteoarthritis.

Dr Matthew Baker, clinical chief and assistant professor of medicine at Stanford University, told The Telegraph that mast cells, part of the immune system which releases various chemicals to target and attack an invading pathogen, are known to be a key player in allergies and may also play a role in osteoarthritis.

“Our group has previously reported that low-grade inflammation contributes to the pathogenesis of osteoarthritis,” he said.

“We believe that mast cells are critical contributors to osteoarthritis, and people with allergic disease likely have either increased numbers and/or increased activity of mast cells in the joint, leading to an increased incidence of osteoarthritis.”

He added that the calls can be activated in joints and are present at higher levels in the joints of people with osteoarthritis.

The study itself did not look at how over the counter treatments for allergies can help reduce osteoarthritis risk, but Dr Baker says previous work from his team showed some antihistamine use can help with knee arthritis.

“We are hopeful that any number of drugs that work to inhibit mast cells or mast cell products (such as histamine) will reduce the incidence of osteoarthritis in these patients, but this needs to be studied in a prospective manner,” he told The Telegraph.

The study is published in the Annals of the Rheumatic Diseases.