World Arthritis Day: Arthritis is an inflammatory condition that causes pain and stiffness in joints, a disease that can affect one or multiple joints.

The debilitating condition that restricts the range of movement and affects functional life is known to affect millions across the world. As such, if left untreated, it may inhibit the movement altogether.

On World Arthritis Day, Dr. Saurabh Moda, Director, of Orthopaedics and Joint Replacement, at Max Super Speciality Hospital in an interview explains about types of arthritis and how the disease genetically passes on and affects millions of people.

Q1. How many types of arthritis are there?

Arthritis is of two types—Osteoarthritis & Rheumatoid arthritis.

Osteoarthritis is degenerative changes in the joints due to the aging process. It is a normal physiological change in joints due to aging like greying of hairs.

In Rheumatoid arthritis, family history plays a role in the development of the disease.

Q2. Can arthritis be passed on genetically?

Many genetic studies have gone into identifying genes that predispose individuals to the risk of Rheumatoid arthritis. While all the factors that cause Rheumatoid arthritis are not entirely understood, the disease tends to cluster in families & is driven in part by genetics.

The bulk of genetic heritability is caused by human leukocyte antigen, also called the Major Histocompatibility Complex, MHc Genes.

Rheumatoid arthritis has a genetic basis meaning people with certain genetic markers have a slightly higher chance of developing the disease. There are four main genetic markers that are linked to Rheumatoid arthritis.

Q3. Which genes are mostly associated with Rheumatoid arthritis?

HLA-DR 4:

This is the gene that is most associated with Rheumatoid arthritis. People who have this gene are more likely to develop Rheumatoid arthritis than those who do not and symptoms may be worse.

STAT-4:

This gene regulates and activates the immune system.

TRAF 1 and CS:

This gene plays a major role in causing chronic inflammation.

PTPN 22:

This gene influences the progression and expression of Rheumatoid arthritis. However, the reason why it causes is still to be determined.

There are more than 100 regions across the genome discovered to be associated with the risk of developing Rheumatoid arthritis across multiple ethnicities. One important factor to note is everyone with the genes will develop Rheumatoid arthritis and not everyone with it has the genes.

If a relative has Rheumatoid arthritis, it increases one’s risk of getting the disease by 0.8% as compared to 0.5% for those who have no family history. Another study conducted on identical twins found that if one twin has Rheumatoid arthritis, there is a 12-15% chance the other one will also have it.

Rheumatoid arthritis, like many autoimmune diseases, is quite heritable and unfortunately tends to cluster in families. Many genetic studies have gone into identifying genes that predispose individuals to a risk of Rheumatoid arthritis.

In short, family history plays a role in developing Rheumatoid arthritis. However, environmental factors such as age gender, and smoking factor also play a role.

Q4. Does age factor play any role in increasing the risk of Rheumatoid Arthritis?

The risk of Rheumatoid arthritis increases with age. This condition is highest among adults in their 60s and older. Rheumatoid arthritis after the age of 60 tends to be clinically and demographically quite different and is known as Elderly Onset Rheumatoid arthritis. The peak age of onset is between 30 & 50.

Q5. Which gender is at the risk of Rheumatoid arthritis the most?

Rheumatoid arthritis affects females 2-3 times more than males.

Q6. How much role does smoking and obesity play in Rheumatoid arthritis?

Smoking increases the risk of Rheumatoid arthritis, especially more with the genetic marker HLA-DRB1

Also, obese patients have more risk of developing Rheumatoid arthritis. More weight makes the disease also worse.