Rheumatoid arthritis (RA) is more common in women than men (2.5-to-1), and though it can occur at any age, it usually develops between ages 25 to 50. Over the past few years, more research has focused on the risk factors for RA, particularly risk factors that affect women. Here are some of the more notable studies.

Can sunshine reduce the risk of RA in women?

Exposure to ultraviolet B (UVB) rays may reduce the risk of rheumatoid arthritis in women, according to a recent study published in the Annals of Rheumatic Disease. The positive results were mostly seen in older women, which researchers say could be because younger women are more apt to protect themselves from the sun with sunscreen.

Research was done in two phases. The first phase of the U.S.  Nurses’ Health Study followed the health of 120,000 nurses from 1976 to 2008, with the starting age between 30 and 55. The second phase followed another 115,000 nurses from 1989 until 2009, with the starting age between 25 and 42.

Researchers then measured the rates of UVB exposure with the UVB-flux, which calculates UVB radiation, cloud cover, latitude and altitude. During the course of the study, 1,314 women developed RA, and the nurses with the highest rates of UVB exposure were 21 percent less likely to develop RA than those with the lowest rates of exposure.

            [SLIDESHOW: 8 Facts About Vitamin D and Rheumatoid Arthritis]

Can drinking alcohol reduce the risk?

In a study published in July 2012, researchers found that women who drank more than three glasses of alcohol per week were 52 percent less likely to develop rheumatoid arthritis than women who never drank alcohol.

Researchers took assessments of 34,141 Swedish women who were born between 1914 and 1948. They surveyed the participants in 1987 and again in 1997, and defined one standard glass of alcohol as approximately 500 ml of beer, 150 ml of wine or 50 ml of liquor. Researchers say their findings are probably due to alcohol’s ability to reduce the body’s immune response.

It’s important to note that for people who have already been diagnosed with RA, taking certain medications, such as methotrexate and Arava, makes it important to limit alcohol consumption to very occasionally. Make sure you talk to your doctor about how your medications may affect your ability to drink alcohol.

Can breastfeeding cut risk too?

Breastfeeding your child for a longer period of time may also decrease your risk of developing RA, according to a 2008 study. Researchers compared 136 women with RA to 544 women of the same age without RA. They found that those who had breastfed for 13 months or more were 50 percent less likely to develop RA than those who had never breastfed. Those mothers who had breastfed for one to 12 months had a 25 percent less risk of developing RA.

Researchers also found that simply having children, but not breastfeeding had no protective effects, nor did taking oral contraceptives, which contain the same hormones that are heightened during pregnancy.