The Many Forms of Arthritis

The term arthritis is defined as joint inflammation, and swollen, tender joints characterize the condition. About 24 percent of adults and 300,000 children in the United States have arthritis, according to the Centers for Disease Control and Prevention (CDC) and the American College of Rheumatology, respectively.

There are many types and degrees of arthritis, each of which affects a specific part of the body. Symptoms vary depending on the subtype, but joint swelling, pain and stiffness are the most prominent.

Arthritis can pervade many aspects of a person's life, including dating and sex. Although each person's experience is unique, many individuals with arthritis experience chronic pain and fatigue, which can hinder sexual desire and pleasurability. Having a chronic condition may also impact self-esteem, body image and confidence, and increase the risk of depression and anxiety, further impeding sexual health.

Certain subtypes of the disease, including rheumatoid arthritis, can influence fertility as well. It may be more difficult to conceive as well as carry and birth a child. Rheumatoid arthritis and some other subtypes may be genetic.

Professional support and lifestyle adjustments can help people with arthritis overcome most of these challenges.

Who does it affect?

Arthritis affects all demographics, though certain types are more prevalent in specific populations. For example, osteoarthritis and rheumatoid arthritis, the most common forms of arthritis, typically occur in older adults. About 88 percent of people with osteoarthritis are ages 45 and older, according to the U.S. Bone and Joint Initiative.

This prevalence occurs partly because the immune system weakens with age, increasing vulnerability to autoimmune conditions, including arthritis. Kuljit Kapur, M.D., chief medical officer at Transitions Care in Naperville, Illinois, explained that older adults are more susceptible to arthritis because aging affects the musculoskeletal system and bone density.

She explained that bones become less dense and more fragile, and the cartilage structure changes. At the same time, connective tissues, such as tendons and ligaments, lose elasticity. These changes can decrease the range of motion and contribute to pain and inflammation.

However, about 53.7 percent of U.S. adults with arthritis are between 18 and 64, according to the CDC. Some types, including osteoarthritis, rheumatoid arthritis and fibromyalgia, are more common in women, while gout is more common in men.

Risks, causes and triggers

Different forms of arthritis carry distinct risk factors and causes. For instance, osteoarthritis is usually a result of musculoskeletal damage. Other types can arise from underlying conditions, such as systemic lupus erythematosus (SLE), psoriasis or an infection. A buildup of uric acid in the blood, for example, can cause gout.

There are also autoimmune causes, the epidemiology of which varies based on the condition, explained Jason Liebowitz, M.D., a rheumatologist with Skylands Medical Group in Rockaway, New Jersey.

General risk factors for arthritis, according to Mayo Clinic and Liebowitz, include:

• Age. Many types of arthritis are more prevalent in older people.
• Diet. What you eat plays a significant part because gout results from excess uric acid. People who eat diets high in red meat, alcohol and processed sugar are more likely to develop gout.
• Genetics. If you have a family history of the disease, you may also be more likely to develop it.
• Obesity. Excess weight can strain the joints, especially in the knees, hips and spine, which may increase the risk of arthritis.
• Previous injury. Injuring a joint can make it more susceptible to arthritis later in life.
• Sex. Women are more likely than men to develop autoimmune arthritis, including rheumatoid arthritis. Men are more likely to get gout.
• Underlying conditions. Certain medical conditions, like autoimmune disorders, can contribute to arthritis.

Types and stages

There are more than 100 types of arthritis and related disorders. These are divided into two primary categories: osteoarthritis and inflammatory arthritis, according to Mayo Clinic.

In osteoarthritis, the cartilage in joints breaks down due to an injury, overuse or age. Inflammatory arthritis is an umbrella term encompassing autoimmune disorders where the body attacks its own joints and tissues.

The most common types of arthritis include:

• Ankylosing spondylitis. This type affects the spine and pelvis and can cause spinal vertebrae to fuse, often resulting in a hunched posture and limited mobility.
• Childhood arthritis. Juvenile arthritis and childhood arthritis encompass all forms of the disease affecting children. The most common type is juvenile idiopathic arthritis, a kind of rheumatoid arthritis.
• Fibromyalgia. A poorly understood condition, fibromyalgia causes widespread pain throughout the body, as well as fatigue, brain fog, sleep difficulties and heightened pain sensitivity.
• Gout. A type of inflammatory arthritis, gout causes sudden, severe attacks of pain and inflammation. It typically affects the big toe, though it can also arise in other toes, the ankle or the knee.
• Osteoarthritis. The most common type of arthritis, this affects the hands, hips, knees, back and neck. It is also known as degenerative joint disease or "wear and tear arthritis," states the CDC.
• Psoriatic arthritis. This kind of arthritis affects people with psoriasis and most often occurs in the fingers and hands.
• Reactive arthritis. An uncommon condition, reactive arthritis occurs in response to an infection, usually of the intestines, urinary tract or genitals. Symptoms typically arise in the knees, ankles and feet, and dissipate within 12 months.
• Rheumatoid arthritis. The second-most prevalent form of the disease, this type of inflammatory arthritis primarily affects the hands, knees and wrists. Eventually, it can impact the eyes, lungs, skin, heart and blood vessels.
• Septic arthritis. An infection of the joints, septic arthritis is most common in children. It can occur when germs enter the body via an injury, surgery or injection and travel to the joints through the bloodstream.
• Thumb arthritis. Also known as basal joint arthritis, this is the second-most common type of arthritis of the hand.

Arthritis typically gets worse with time. Some effects are visible, while others are internal. Different types of this disease progress in different ways. Osteoarthritis and rheumatoid arthritis progress through four phases, from early and mild to advanced and severe.

People tend to experience slight swelling and discomfort in the first stage, but arthritis may not be the clear cause. In the second stage, symptoms worsen as inflammation permanently damages the cartilage and bone. At stage three, the damage and symptoms worsen. Visible indicators, such as joint swelling or disfigurement, might appear. By stage four, the joints no longer function as they should, and pain and stiffness may be debilitating. At this point, surgery may be necessary.

Socioeconomic and cultural factors

The CDC states that several socioeconomic factors, including food or financial insecurity, unsafe neighborhoods and barriers to healthcare access, are associated with an increased risk of arthritis. Research indicates people with physically demanding jobs—especially those requiring extensive squatting or heavy lifting—are more likely to develop osteoarthritis. The Arthritis Foundation reports that arthritis affects about 1 in 3 people in rural areas versus 1 in 4 people in the general population.

Liebowitz noted there's research suggesting occupations related to potential noxious airborne agents—such as bricklayers and concrete workers, material handling operators, and electrical and electronics workers—might be associated with an increased risk of rheumatoid arthritis. Smoking may increase the risk of rheumatoid arthritis as well.

"There are likely issues related to healthcare disparities and lack of access to care that may prevent or delay diagnosis of certain forms of arthritis," he added.

Health and healthcare inequities can affect treatment and the degree to which the disease affects a person's overall health and functionality.

Kapur explained how arthritis can impact a person's quality of life in multiple ways. Depending on the disease severity and a person's environment, general health and other factors, symptoms such as mobility restrictions and chronic pain can be debilitating.

The disease can also contribute to such problems as depression, anxiety, isolation and sexual dysfunction, which further affect a person's quality of life and ability to function. About 25.7 million people, or 44 percent of those with diagnosed arthritis, are limited in their usual activities, according to the CDC.

"Socioeconomic factors play a large role in determining if a patient can be seen by a rheumatologist when needed or has access to care in order to receive the correct diagnosis," Liebowitz said. "When disease activity of arthritis is high, this can make it very challenging for patients to work, take care of their families or even perform activities of daily living."

Facts and stats

• Arthritis costs the U.S. about $303.5 billion in medical spending and lost wages, the CDC reports.
• Arthritis is a leading cause of disability in the U.S., according to the CDC, and about 8 million adults report their condition affects their ability to work.
• Musculoskeletal disorders, including arthritis, are the second-most common cause of disability worldwide, according to a 2013 study published in the Lancet.
• The prevalence of arthritis is likely severely underestimated. According to the Arthritis Foundation, more than 92.1 million people in the U.S. may actually be living with arthritis. About 58.5 million people have been diagnosed, the CDC states.