Consumption of fat-free or low-fat milk may delay development of knee OA
Osteoarthritis is one of the most common forms of arthritis. It is a chronic condition in which the material that cushions the joints, called cartilage, breaks down. This causes the bones to rub against each other, causing stiffness, pain and loss of joint movement. The cause is not fully understood, according to the Arthritis Foundation. About 27 million people in America have osteoarthritis.
Milk consumption has long been recognized for its important role in bone health, but its role in the progression of knee osteoarthritis (OA) is unclear.
In this new study Dr. Bing Lu, Dr.PH, MD, Associate Professor of Medicine at Brigham and Women's Hospital and colleagues examined the possible association of milk consumption with radiographic progression of knee OA.
Researchers recruited 2,148 participants; 888 men and 1,260 women, (3,064 knees) for the Osteoarthritis Initiative. At the start of the study data was collected and joint space width was measured by x-ray to evaluate OA progression. The milk consumption was assessed with a Block Brief Food Frequency Questionnaire completed at baseline.
Researchers observed a significant dose-response relationship between baseline milk intake and adjusted mean decrease of joint space width in women. With increasing levels of milk intake of less than three glasses of milk a week, four to six and more than 7 glasses (glass amount is 8oz), the joint space width in women also decreased by 0.38mm, 0.29mm, 0.29mm and 0.26mm, respectively. These results remained even after adjusting for confounding factors; disease severity, body mass index and dietary factors. . In men, we observed no significant association between milk consumption and the decreases of joint space width.
In their conclusion the researchers write “Our results suggest that frequent milk consumption may be associated with reduced OA progression in women. Replication of these novel findings in other prospective studies demonstrating the increase in milk consumption leads to delay in knee OA progression are needed.”
According to Dr. Lu, "Milk consumption plays an important role in bone health.” "Our study is the largest study to investigate the impact of dairy intake in the progression of knee OA."
In conclusion he stated "Our findings indicate that women who frequently drink milk may reduce the progression of OA.” "Further study of milk intake and delay in OA progression are needed."
In a related editorial also published in Arthritis Care & Research, Shivani Sahni, Ph.D., and Robert McLean, D.Sc, M.P.H., from Harvard-affiliated Hebrew Senior Life Institute for Aging Research agree, "With the aging population and increase in life expectancy, there is an urgent need for effective methods to manage OA. The study by Lu et al. provides the first evidence that increasing fat-free or low-fat milk consumption may slow the progression of OA among women who are particularly burdened by OA of the knee, which can lead to functional disability."
This study is published in Arthritis Care & Research.