Rheumatoid arthritis (RA) is one of the most common autoimmune diseases. It happens when your body makes antibodies that attack synovial joint fluid and cause long-term inflammation.
The illness affects 1.3 million American adults, or around 1% of the total population. Around the world, the number of people with RA has been on the rise since 1990. But some parts of the world, like Japan and Western Europe, have seen a drop in numbers.
Changes in Rheumatoid Arthritis
Researchers continue to look at who has RA and the reasons why. In the only long-term study of RA in the U.S., they looked at medical records data from 2005 to 2014 and compared it to prior decades.
Researchers found that over the years, the number of people with RA remained steady across age, race, and sex. But they did find changes with certain types of RA. There was a sharp decline in rheumatoid factor-positive (RF-positive) RA, and an increase in RF-negative RA.
Doctors say it’s harder to diagnose RF-negative rheumatoid arthritis, which can stall treatment and affect overall health. If more people have RF-negative RA, doctors will need to watch their patients for it more closely for a more prompt diagnosis.
Researchers also found that smoking rates among people with RA dropped, while the rate of obesity rose considerably. These things could play a role in changes to the types of RA people now have, but researchers will need to do more studies to learn more.
It’s important to note that researchers used data from the Rochester Epidemiology Project (REP). The project explores the medical records of hundreds of thousands of people in 27 counties across Minnesota and Wisconsin. Although the data helps researchers understand the long-term impact of certain diseases, like RA, it’s also limited. The people who live in this area tend to be white and have a higher level of education than the rest of the U.S. population.
Rheumatoid Arthritis and Sex
If you’re a woman, you have a higher chance of getting RA than a man. Experts estimate the illness is twice as common in women. Women’s lifetime odds of getting RA are 3.6%, compared to 1.7% for men.
Some experts think there’s a relationship between female hormones and the start of RA symptoms. As women age, their levels of the hormones estrogen and progesterone begin to drop off. This possibly triggers RA.
Rheumatoid Arthritis, Race, and Ethnicity
Studies on RA often include mostly white people, or researchers don’t provide details on race. One review of hundreds of studies on RA found that white people represented between 74.6% and 97% of people studied. As a result, we don’t have a clear picture of the disease’s impact on other racial and ethnic groups.
The data researchers have gathered doesn’t show that people from specific racial or ethnic groups have more aggressive or higher rates of RA. One exception is particular groups of Native Americans. Researchers have found that some Native tribes have higher rates of RA. The disease affects members of the Pima and Papago tribes at a rate of 5.3% and of the Chippewa tribe at 6.8%, which is around 5 to 7 times higher than average.
While scientists haven’t found any biological differences between most races and ethnicities, there’s growing evidence of disparities in RA treatment and access to health care.
Rheumatoid Arthritis and Age
Anyone can get RA, but most people form it between the ages of 30 and 60. On average, you’ll start to have symptoms in your 60s. Women are more likely to get the disease at a younger age than men. Some children also have it, but this isn’t common. Experts estimate that 300,000 kids in the U.S. have juvenile RA.
Rheumatoid Arthritis Outlook
There’s no cure for rheumatoid arthritis. It’s also a progressive disease and will worsen over time. You’ll have periods where the disease will flare up, then the painful symptoms will ease.
Around 20% of people with RA will go into clinical remission and live without significant signs or symptoms of the disease. Their reported sense of disease activity will be low. But about 75% will have low disease activity (LDA) and remission, or remission alone, in which their symptoms are under control with the use of medications.
Studies show if you get treatment within 6 months of when your symptoms start, you’re likely to have a better outcome, including less joint swelling and tenderness. Without treatment, you have a higher chance of disability and death. Within 10 years of diagnosis, about 40% of people with RA will have a disability that prevents them from working and doing everyday tasks.
On average, people with RA live 10 to 15 years less than those without the illness. Despite this, many with the condition live into their 80s and 90s.
Rheumatoid Arthritis and Your Genes
If you have a parent or sibling with rheumatoid arthritis, you’re 4 times more likely to get it than people without the disease. Still, many people get the illness without a close family member also having it. For this reason, experts hesitate to call RA an inherited disease.
Rheumatoid Arthritis and Lifestyle
You can change things in your day-to-day life to raise or lower the chances that you’ll get RA. They include:
A high-calorie, low-fiber diet ups your odds of getting RA, while eating foods with omega-3 fatty acids may lower it.
Carrying extra weight also raises your chances of getting RA. If your body mass index (BMI) is 30 or greater, research shows your chance of having RA jumps by 30%. And if it’s between 25 and 29, the percentage is 15%.
Smoking is the lifestyle factor experts most closely link to the start of RA. If you’re a current or former smoker, your odds of getting RA rise by around 2.4%. This increase happens most often in those with seropositive RA.