Women with osteoarthritis of the knee may delay progression of the disease if they regularly drink fat-free or low-fat milk, a new study has found.

Osteoarthritis (OA) is the most common type of arthritis. Symptoms include pain, stiffness and swelling in the joints and most Irish people over the age of 55 have evidence of the condition at some joint in their body.

The most common weight-bearing joint affected by the condition is the knee.

US researchers followed the progress of over 2,100 people with OA of the knee over a four-year period. During this time, they measured the width of the knee joint space by x-ray, in order to determine OA progression.

The study found that if women increased their intake of milk, their joint space width decreased. For example, if a woman increased her milk intake from zero to up to three glasses per day, her joint space width decreased by 0.38mm.

No such link was found in men.

The study also found that the consumption of yoghurt did not impact on the condition's progression. However, the consumption of cheese appeared to increase the progression.

According to the researchers from the Brigham & Women's Hospital in Boston, this marks the largest study to assess the impact of dairy intake in relation to the progression of OA of the knee.

"Milk consumption plays an important role in bone health. Our findings indicate that women who frequently drink milk may reduce the progression of OA. Further studies of milk intake and delay in OA progression are needed," they concluded.

Details of these findings are published in the journal, Arthritis Care & Research.