Pop the Pill to avoid those rainy day aches

Study says that OCs lower the risk of rheumatoid arthritis in women

By Charles Rowe

The use of oral contraceptives (OCs) lowers a woman's risk of developing rheumatoid arthritis (RA), according to a report that appears in the February issue of Journal of Rheumatology. This benefit attributed to the pill doesn't translate to estrogen replacement therapy, although both contain estrogen.

The findings suggest that there's a dose-related estrogen effect, "as most estrogen supplements used for postmenopausal replacement have less than one-sixth the potency of low dose oral contraceptives," says Sherine Gabriel from the Mayo Clinic in Rochester, Minnesota. Ms Gabriel led the collaborative research effort between team members from the Mayo Clinic and Mater Misericordiae University Hospital, Dublin, Ireland.

RA is one of the most common forms of arthritis. Although the young aren't immune, this disease plagues mostly middle-aged people, particularly women. During the 1980s and 90s the prevalence of RA among American women declined dramatically from 72 cases per 100,000 women to an estimated 48 cases per 100,000. The reason for the drop, however, has remained unclear.

Epidemiologic evidence for a protective effect of estrogen is contradictory. It's this controversy that spurred the present research. The data used in the study came from The Rochester Epidemiology Project � a medical records linkage system detailing all care delivered to residents of Rochester and Olmsted County, Minnesota since 1935. This vast amount of information and strong epidemiological data has made the project a unique, almost unsurpassed, resource to investigate the occurrence and natural course of many diseases.

Gabriel's study involved 445 women aged 18 and older who were determined to have RA. These women, all residents of Rochester, were compared with control (RA-free) female residents of the same city. The subjects and controls were all matched by age to eliminate age difference as a contributing factor.

The researchers found that the longer OCs were used, the lower the risk of developing RA. The authors concluded that "earlier calendar-year of first exposure to OCs was associated with a lower odds ratio for RA" Estrogen replacement therapy � infamous because it predisposes patients to breast cancer and other diseases � didn't influence the development of RA.

Even though OCs lessen a woman's risk for RA, that's not the whole story. Despite the strong correlation of OCs' ability to protect against RA, only a small portion of the study population was on the pill. It's difficult to say what effect this may have had on the final results. Meanwhile, the search continues for other possible contributing factors that may confer protection against RA.