Nursing mothers can halve the chance of developing rheumatoid arthritis if they breastfeed their children for more than a year, new research has shown.
Breastfeeding was found to offer women protection against the disease, with those breastfeeding for 13 months or more 54% less likely to get it as women who have never breastfed.
And women who breastfed for between one and 12 months were still 26% less likely to show symptoms.
The Swedish study compared 136 women with rheumatoid arthritis with 544 women who were free from the disease.
Official figures from last year's Infant Feeding Survey showed that most women are failing to follow government advice to breastfeed exclusively for the first six months.
The research also looked at the role of the contraceptive pill, which some studies have shown to cut the risk of rheumatoid arthritis.
It has been thought the pill could offer a protective effect because it contains hormones that are also elevated in pregnancy.
But the latest research found that women on the pill did not have less chance of developing the disease. "Some studies have failed to show any protective effect of oral contraceptive use," researchers said.