Newswise — Adding vitamin D as a supplement does not appear to lessen the symptoms, or slow the progression, of knee osteoarthritis, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Atlanta.
Osteoarthritis, or OA as it is commonly called, is the most common joint disease affecting middle-age and older people. It is characterized by progressive damage to the joint cartilage—the cushioning material at the end of long bones—and causes changes in the structures around the joint. These changes can include fluid accumulation, bony overgrowth, and loosening and weakness of muscles and tendons, all of which may limit movement and cause pain and swelling.
Vitamin D promotes the absorption of calcium and phosphorus needed for bone mineralization, growth and repair. Sources of vitamin D are available to a lesser extent from dietary sources typically found in fortified margarine, oily fish, liver, fortified breakfast cereals and dairy products. Sun exposure helps vitamin D to become active.
Previous studies have suggested that vitamin D may reduce the structural progression of knee OA, and researchers recently studied 146 people who showed symptoms of knee OA to determine if taking vitamin D would be an effective way of treating the disease. The participants were predominately Caucasian women with an average age of just over 62 years. Their average body mass index was 30.7, their average vitamin D level was 22.3 ng/ml-1, and their average femoral neck bone mineral density was .92 gcm-2. Additionally, 56 percent of the participants were taking supplements.
The researchers divided participants evenly into two groups. The first group was assigned to take placebo, and the second group was assigned to take vitamin D throughout the course of the study. Participants were not told which group they had been placed in. Those in the vitamin D group started by taking 2,000 IU of vitamin D daily, and this was raised as necessary over the course of the study in 2,000 IU increments to help each participant achieve a vitamin D level higher than 30 ng/ml.
The researchers also performed physical function tests and X-rays on each participant at the beginning of the study and again at 12 months. And, they computed the knee cartilage volume and thickness, bone marrow lesion volume from the MRIs taken at the beginning of the study and again at 12 months to determine if any changes had occurred.
At the end of the study, the participants in the vitamin D group had an average vitamin D level increase of 15 ng/ml (compared to only 1.8 ng/ml in the placebo group), but researchers found no substantial differences between the two groups in the areas studied – leading them to believe that those taking vitamin D did not benefit more than those who were not.
“This study tested whether vitamin D supplementation, given over a two-year period, could influence the rate of progression of joint damage in people with knee osteoarthritis,” explains Timothy McAlindon, MD, MPH; associate professor of medicine, division of rheumatology, Tufts New England Medical Center and lead investigator in the study. “The vitamin D doses were increased as necessary to elevate participants' serum levels to over 30 ng/ml. The study found no difference compared to a placebo (inert) treatment.”
Patients should talk to their rheumatologists to determine their best course of treatment.
The American College of Rheumatology is an international professional medical society that represents more than 8,000 rheumatologists and rheumatology health professionals around the world. Its mission is to advance rheumatology. The ACR/ARHP Annual Scientific Meeting is the premier meeting in rheumatology. For more information about the meeting, visit www.rheumatology.org/education. Follow the meeting on twitter by using the official hashtag: #ACR2010.
###
Editor’s Notes: Timothy E. McAlindon, MD, MPH will present this research during the ACR Annual Scientific Meeting at the Georgia World Congress Center at 4:30 PM on Monday, November 8 in Room A 314. Dr. McAlindon will be available for media questions and briefing at 1:30 PM on Monday, November 8 in the on-site press conference room, B 212.
Learn more about living well with rheumatic disease as well as rheumatologists and the role they play in health care.
Presentation Number: 706
Clinical Trial of Vitamin D To Reduce Pain and Structural Progression of Knee Osteoarthritis (OA)
Timothy E McAlindon, MD MPH (Tufts Medical Center, Boston, MA)Bess Dawson-Hughes, MD (USDA HNRC; Tufts University)Jeffrey Driban (Tufts Medical Center)Michael LaValley (Boston University School of Public Health)Ji Yeon Lee (Tufts Medical Center)Grace H Lo (Baylor College of Medicine)Melynn Nuite (Tufts Medical Center)Lori Lyn Price (Medical Center)
Background: Observational epidemiologic studies suggest that vitamin D may reduce the structural progression of knee OA, an effect that could be mediated through bone or chondrocyte mechanisms. The aim of this study was to test for disease-modifying effects of a vitamin D intervention strategy for knee OA.
Methods: This was a 2-year, NIH-funded, double–blind, placebo-controlled clinical trial among individuals with symptomatic knee OA (ACR criteria). Randomization was blocked and stratified by disease severity (Kellgren Lawrence (KL) grade). The intervention consisted of vitamin D3 2000 IU daily (Tishcon Corp, NY), which was escalated in increments of 2000 IU as needed at 3,6, and 9 months, for a target serum vitamin D level of >30 ng/ml. Blinding was maintained by the use of a dummy escalation protocol in the placebo group. Assessments included the WOMAC questionnaire at each visit, physical function tests; annual MRI (Siemens Avanto 1.5T; sagittal and coronal IW FS and DESS sequences); and standardized semi-flexed knee radiography at the beginning and end of study. Cartilage volume and thickness, and bone marrow lesion (BML) volume, in the index tibial and femoral compartments, were determined by manual segmentation of registered images using Analyze©. Intra-tester reliability ICCs were .96 & .90 for cartilage volume and volume loss, and .87-.98 for BML volume. Minimal radiographic joint space width was measured using a semi-automated computer program. Primary outcomes were WOMAC pain and cartilage volume loss. To test for differences we used mixed effects regression for repeated measures with linear, or linear and quadratic time trends, with adjustment for KL grade, knee alignment, and body mass index (BMI).
Results: Out of 282 screened, 146 subjects were randomized (mean age 62.4 [s.d. 8.5]; 57% female; 79% Caucasian; mean BMI 30.7 kgm-2 [5.7]; 56% taking supplements; mean vitamin D level 22.3 ngml-1 [10.0]; femoral neck BMD 0.95 gcm-2 [0.14]). 50% had KL grade 2, 29% grade 3 and 21% grade 4. The groups were evenly balanced for these characteristics and outcome measures (Table). 124 (85%) completed the study. Mean serum vit D level increased by 15.0 ng/ml in vitamin D compared to 1.8 in the placebo group (p<0.0001). There were no substantial or significant between-group differences in any the outcome measures (Table). In the repeated measures analyses, neither treatment assignment nor increase in serum vitamin D level had any influence on the outcomes. There were 28 serious adverse events in the vitamin D and 23 in the placebo group, all classified as unrelated except one 'possibly related' (hip fracture). Conclusions: Vitamin D supplementation at a dose sufficient to elevate serum levels above 30 ng/ml does not appear to have any symptom or structure-modifying benefits for knee OA.
Disclosure: Timothy McAlindon, nothing to disclose; Bess Dawson-Hughes, nothing to disclose; Jeffrey Driban, nothing to disclose; Michael LaValley, nothing to disclose; Ji Yeon Lee, nothing to disclose; Grace Lo, nothing to disclose; Melynn Nuite, nothing to disclose; Lori Lyn Price, nothing to disclose.
View press release with full abstract at www.rheumatology.org
RSS