The pill may lower risk of arthritis in women: study

Women who take the oral contraceptive pill for seven or more consecutive years are at a lower risk of developing rheumatoid arthritis, a study claims.
Researchers at Karolinska Institute in Sweden looked at the possible link between the development of rheumatoid arthritis and use of the Pill and/or breastfeeding among adult women with least one child.
They drew on data from the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA), which included women aged 18 and above, living in a defined area of Sweden between 1996 and 2014.
During this time frame, 2,809 women were diagnosed with rheumatoid arthritis, and 5,312 women, randomly selected from the general population and matched for age, acted as a comparison group.

Blood samples were taken from all the participants to check for antibodies (ACPA) to rheumatoid arthritis, and the women were quizzed in depth about their contraceptive and reproductive histories, their lifestyle, whether they had breastfed their kids and their educational attainment.
In all, 2,578 women with arthritis and 4,129 women from the comparison group were included in the final analysis. Of these, 884 with rheumatoid arthritis and 1,949 from the comparison group had breastfed at least one child between 2006 and 2014.

Researchers found that women who had used an oral contraceptive at any time had a lower risk of developing rheumatoid arthritis than those who had never done so.

"The risk was 15 per cent lower in current users of the Pill and 13 per cent lower in past users," said researcher Cecilia Orellana from Karolinska Institute.
The association was significant for women who tested positive for ACPA antibodies, even after taking account of tobacco and alcohol consumption, compared with women who had never used an oral contraceptive, they said.
Nine out of 10 people who test positive for ACPA (anti- citrullinated protein) antibodies will have rheumatoid arthritis, and the presence of these antibodies may indicate more serious disease, researchers said.
Using the Pill for more than seven years - the average length of use among the study participants - was associated with a 19 per cent lower risk of developing rheumatoid arthritis, and this was the case for those who tested positive and negative for ACPA.

The study was published in the Annals of the Rheumatic Diseases.