Birth pill linked to lower risk of arthritis in women

The findings revealed that women who used birth pill for more than seven years had a 19 per cent lower risk of developing rheumatoid arthritis, irrespective of being tested positive or negative for ACPA.

ACPA (anti-citrullinated protein) are antibodies that indicate the risk of rheumatoid arthritis. 

The presence of these antibodies may indicate more serious disease, said Cecilia Orellana from the Karolinska Institutet in Sweden.

Further, the risk was found 15 per cent lower in current users of the birth pill and 13 per cent lower in past users. 

For the study, published online in the Annals of the Rheumatic Diseases, the team looked at the possible link between the development of the disease and use of the pill and/or breastfeeding among 2,578 adult women who had had at least one child, and 4,129 women, selected from the general population, acted as a comparison group.

The results showed no significant link for breastfeeding -- a practice that has been long associated with a protective effect against arthritis.

Of these, 884 with rheumatoid arthritis and 1,949 from the comparison group had breastfed at least one child between 2006 and 2014.

Nine out of 10 people who test positive for ACPA antibodies will have rheumatoid arthritis.