Birth Control Pills Linked to Lupus Risk

ByABC News
April 9, 2009, 4:55 PM

April 10 -- THURSDAY, April 9 (HealthDay News) -- Women taking birth control pills, especially those who have just started taking them, may face an increased risk of developing the autoimmune disease lupus, a new study suggests.

Although the link between lupus and oral contraceptives has been debated for some time, this new study adds weight to earlier studies -- including the Nurses' Health Study -- that have shown a link between oral contraceptives and lupus, the study authors said.

The findings were published in the April issue of Arthritis Care & Research.

Lupus is characterized by acute and chronic inflammation of various tissues of the body. The immune system mistakenly attacks healthy cells and tissues, potentially damaging joints, skin, blood vessels and organs, according to the U.S. National Library of Medicine.

For the new study, a team led by Dr. Samy Suissa of the Centre for Clinical Epidemiology at Jewish General Hospital of McGill University in Montreal collected data on more than 1.7 million women whose medical records were in the U.K. General Practice Research Database. The women all had prescriptions for oral contraceptives.

During eight years of follow-up, 786 women developed lupus. The researchers matched each of these women with 10 women who did not have the disease.

Suissa's team found that oral contraceptives were associated with a 1.5-fold increased risk of developing lupus. The risk was greatest during the first three months after starting "the Pill" -- when there was a 2.5-fold increased risk.

The researchers speculated that increased estrogen from oral contraceptives could be responsible for the increased risk. Estrogen can affect the body's immune response, which could trigger a genetic predisposition to the disease, the scientists said.

Suissa's team also noted that newer oral contraceptives, which contain lower doses of estrogen, are substantially less likely to heighten the risk of lupus, compared to the second-generation contraceptives used in the study.