Risk Factors for Rheumatoid Arthritis

Who Is Most Likely to Develop Rheumatoid Arthritis?

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A risk factor is defined as something that increases the likelihood of developing a disease or condition. It's important to know the risk factors for certain diseases because some may be modifiable. An example of a modifiable risk factor is overweight or obesity because it is possible to lose weight and lower the risk. Not all risk factors are modifiable, however.

Risk factors that are associated with rheumatoid arthritis include:

Gender

Rheumatoid arthritis is two to three times more common in women than men. If you are female, you have a higher risk of developing the disease. Some researchers believe this is possibly tied to another of our listed risk factors -- hormones. It may be associated with the effects of estrogen. However, that's theoretical and not proven.

Age

Rheumatoid arthritis can develop in anyone at any age but onset is more common in people who are between 40 and 60 years old. In both men and women, onset is highest among those in their sixties.

Genetics

Evidence suggests that specific HLA class II genotypes are associated with an increased risk of rheumatoid arthritis. Most notably, HLA-DRB1 has been linked to rheumatoid arthritis. Also, a certain variation of the PTPN22 gene is a genetic risk factor for rheumatoid arthritis and it also has been tied to several autoimmune diseases, according to the Centers for Disease Control and Prevention (CDC).

 

If you have a family member with rheumatoid arthritis, your risk of developing the disease is higher. So, while the disease is not considered heritable, certain risk factors are clearly inherited.

Smoking

There is strong evidence that smoking increases the risk of developing rheumatoid arthritis. A history of smoking hikes the risk of rheumatoid arthritis onset by 1.3 to 2.4 times, according to the CDC.

The connection between smoking and rheumatoid arthritis is greatest in people who are positive for anti-CCP (anti-citrullinated peptide antibodies). There also has been some suggestion that passive smoke increases the risk of developing rheumatoid arthritis, but this has not been proven.

Hormones

Hormonal influences have long been considered potential risk factors for rheumatoid arthritis. Changes to the hormonal environment, as occurs with pregnancy and breastfeeding, seem to affect the risk. Here's what we know:

  • Studies that considered the effect of older oral contraceptives (when estrogen concentration was high in oral contraceptives) on the risk of developing rheumatoid arthritis found that women who had ever used oral contraceptives had a decreased risk of developing rheumatoid arthritis. The concentration is lower now in current oral contraceptives, making it difficult to confirm previous evidence.
  • Studies have shown that women who have never had a live birth had a slightly-to-moderately increased risk of developing rheumatoid arthritis.
  • Women who breastfeed may have a decreased risk of developing rheumatoid arthritis.
  • Women with irregular menstruation cycles or who have early menopause may have an increased risk of developing rheumatoid arthritis.
  • Low testosterone in males may predict future development of rheumatoid arthritis.

Other Possible Factors

It has been suggested that certain occupational hazards (for example, exposure to silica dust), certain diets (high in caffeine, high in red meat, low in antioxidants), or certain infections (possibly Epstein-Barr virus) could be risk factors -- but nothing has been proven. It may be the case in certain individuals, yet no specific entity has been identified as a cause that would apply to most people. 

Researchers have also considered obesity as a risk factor for rheumatoid arthritis, suggesting it hikes the risk by 20%. Study conclusions are said to be contradictory, though. And complicated! There is evidence that suggests a higher risk of rheumatoid arthritis exists for those who have ever been obese, not just those who are currently obese.

Sources:

Rheumatoid Arthritis. IV. Risk Factors. Centers for Disease Control and Prevention. Updated November 6, 2014.
http://www.cdc.gov/arthritis/basics/rheumatoid.htm

What Are the Risk Factors for Rheumatoid Arthritis? MedicalNewsToday.com. Christian Nordqvist. Revised April 2013.
http://www.medicalnewstoday.com/info/rheumatoid-arthritis/risks-of-rheumatoid-arthritis.php

Annals of the Rheumatic Diseases. Mitra Pikwer et al. April 2013.
http://ard.bmj.com/content/early/2013/02/22/annrheumdis-2012-202781.abstract

Risk Factors for the Development of Rheumatoid Arthritis. Oliver JE et al. Scandinavian Journal of Rheumatology. May-June 2006.
http://www.ncbi.nlm.nih.gov/pubmed/16766362

Obesity May Be a Risk Factor for Developing Rheumatoid Arthritis. Arthritis Foundation.
http://www.arthritis.org/living-with-arthritis/comorbidities/obesity-arthritis/obesity-rheumatoid-arthritis-risk.php

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