Rheumatoid Arthritis Is on the Rise
Researchers Say Increased Use of Some Birth Control Pills Could Be a Factor
Explaining the Increase in RA in Women
Gabriel's team can't explain the rise, but suspect a variety of environmental factors, including:
- Lower-dose birth control pills, increasingly used in favor of those with higher estrogen levels found to reduce the risk of RA. "The higher-dose estrogen pills that were used early on had more of a protective effect," Gabriel tells WebMD. As the dose declined, with the same contraceptive benefit, the pills provided less protection from RA, she says. "There actually is hard data on that."
- Cigarette smoking, which is termed by Gabriel ''perhaps the strongest environmental risk factor" for RA. Smoking rates in general have declined in the U.S., but ''women have stopped smoking at a lower rate," she says, compared with men.
Vitamin D deficiency. Some research has suggested a link, and vitamin D deficiency has been found to be increasing, especially in women. Infections, obesity, immunizations, and socioeconomic status may be other factors explaining the rise in RA in women.
The findings are not cause for alarm for women, says Daniel Arkfeld, MD, associate professor of clinical medicine at the University of Southern California Keck School of Medicine, Los Angeles, who reviewed the findings for WebMD.
But the finding of a slight rise in RA among women will undoubtedly be news to some doctors, he says. "It's a mild trend [the increase] but it's going to be surprising to rheumatologists."
The good news, he says, is that "we're getting very good at treating it." New disease-modifying drugs have been approved recently, with the array of choices much broader than before.
As for the environmental factors behind the rise, he says some sound more plausible than others. Vitamin D deficiency, for instance, appears vary common, and all its effects are not yet known. ''We did a study and found that 50% of our patients had vitamin D deficiency, '' Arkfeld says, "and that's in sunny Southern California."
''This is an important study, although it has its limitations," says Patience White, MD, vice president of public health for the Arthritis Foundation, who reviewed the study for WebMD.