Vitamin D Levels Linked to OA Cartilage Loss/Pain

“This study demonstrates significant associations between serum levels of vitamin D, which is obtained mainly from sun exposure, radiographic OA, and increases in knee cartilage volume which are best observed using the whole range of vitamin D rather than predefined cut-points. This implies that vitamin D supplementation may prevent and/or retard cartilage loss in knee osteoarthritis,” Dr.Ding said.

The Australian researchers used T1-weighted fat-suppressed magnetic resonance imaging (MRI) on right knee of randomly selected subjects at baseline (n = 978; mean age, 62 years, range 51–81 years; 50% female) and 2.9 years later (n = 419). Knee medial and lateral tibial cartilage volume were measured. Serum 25-hydroxyvitamin D [25 OHD] was assessed by radioimmunoassay.

The mean 25 OHD level was 52.6 nmol/L at baseline and was associated with winter sun exposure. Baseline serum 25 OHD was significantly associated with knee cartilage volume at medial and lateral tibial sites, and vitamin D deficiency (defined as vitamin D of < 50 nmol/L, 45% prevalence) was associated with moderate-to-severe joint space narrowing in the medial tibiofemoral compartment at both knees and negatively with knee cartilage volume at both medial and lateral tibial sites. Over 2.9 years, vitamin D deficiency predicted loss of medial tibial but not lateral tibial cartilage volume, but vitamin D levels as a continuous variable were significantly associated with changes in both medial and lateral tibial cartilage volume. Changes in vitamin D levels were positively associated with change in medial tibial cartilage volume.

DXA medial:lateral tibial BMD ratio may be simple, inexpensive way to monitor OA bone changes

In preliminary data from an ongoing randomized, controlled trial (RCT) of vitamin D for symptomatic knee OA, Grace H. Lo, MD, and colleagues from Tufts Medical Center, in Boston, Massachusetts, report that baseline vitamin D status predicts longitudinal change in tibial bone mineral density (BMD) in knee OA.² Dr. Lo assessed the medial:lateral tibial BMD ratio (M:L BMD) obtained from dual x-ray absorptiometry (DXA) in 80 subjects, with baseline mean vitamin D level of 31.5 ng/mL (+13.3).

Dr. Lo reported, “In those with symptomatic knee OA, a high baseline vitamin D level was associated with a lower odds of increase in M:L BMD and higher odds of decrease in M:L BMD over 1 year. Sufficient change occurred in M:L BMD to detect a difference over 1 year.” She also noted that vitamin D status seems to beneficially influence local changes in the bone in knee OA, even in bone somewhat distal from the joint, a point that will be examined more completely in the parent RCT. “M:L BMD may be useful as a simple inexpensive outcome measure of bone in OA that changes over 1 year,” Dr. Lo said.

Vitamin D levels may have more impact on OA pain levels in women than in men

Vitamin D levels also appear to affect pain experience in women with OA, although apparently not in men, according to data from the Third National Health and Nutrition Examination Survey (NHANES III) reported by Mitsuyo Kinjo, MD,³ of Okinawa Chuba Hospital in Uruma City, Japan.

Dr. Kinjo examined serum vitamin D levels in subjects with symptomatic radiographic knee OA (defined as the presence of knee pain with radiographic OA changes, Kellgren-Lawrence OA score ≥2) versus those with asymptomatic knee OA. Adjusted 25 OH vitamin D levels did not differ between symptomatic and asymptomatic knee OA subjects overall, but Dr. Kinjo found that female chronic analgesic users with knee OA were more likely to be in lower categories of 25 OH vitamin D compared to women with asymptomatic OA.

“Women with knee OA, but not men, who use chronic analgesics, were more likely to have low 25 OH vitamin D levels than subjects with asymptomatic OA. Similar findings have been observed in back pain, suggesting that vitamin D may be an important pain modulator in some groups,” Dr. Kinjo said.

Vitamin D deficiency common in systemic sclerosis

Alessandra Vacca, MD, and colleagues at the University of Cagliari, Italy, and Paris Descartes University, Paris, France, reported vitamin D insufficiency in 64% of systemic sclerosis (SSc) patients, studied in France and Italy, and vitamin D deficiency in 19%.⁴

“Vitamin D insufficiency and deficiency are very frequent in SSc patients and even more in northern areas. This seems to relate to the influence of UV irradiation discrepancies rather than diet regimen and also vitamin D supplementation. Moreover, low levels of vitamin D are associated with inflammatory parameters and vascular complications but not with other markers of malabsorption or with auto-antibodies. The consequences of these deficiencies will require further investigations but clinicians should be aware of the need to assess vitamin D levels and probably to supplement SSc patients with higher than usual vitamin D dosages,” Dr. Vacca said.

The 134 consecutive SSc patients included: 76 from northern France (Paris) and 58 from southern Italy (Cagliari). The two groups were generally similar except that there were more frequent diffuse cutaneous cases in the French cohort (32% vs 15%, P = .002).

Vitamin D insufficiency was defined as <30 ng/mL; vitamin D deficiency was defined as values <10 ng/mL. The investigators reported, “Vitamin D insufficiency and deficiency rates were strikingly higher in the French population (65/76 [85%] versus 21/58 [36%] for insufficiency and 26/76 [34%] versus 0/58 for deficiency [P <.0001 for both]), whereas the use of substitution at usual dosage (800 IU/day) was not statistically different among the two groups (22/76 versus 27/57; P = .052).”

Vitamin D deficiency was not associated with other markers suggesting malabsorption or autoimmune activation but were associated with acute phase reactants and higher systolic pulmonary arterial hypertension and were close to significance for European disease activity score (P = .06).

References

1. Ding C, Parameswaran V, Burgess J, et al. Serum levels of vitamin D, winter sun exposure, knee radiographic osteoarthritis, and knee cartilage loss in older adults: the Tasmania Older Adults Cohort (TASOAC) study. Presented at: American College of Rheumatology 2008; San Francisco, CA; October 26, 2008. Presentation 191.
2. Lo GH, Smith MH, McAdams EL, et al. Baseline vitamin D status is predictive of longitudinal change in tibial BMD in knee osteoarthritis (OA). Presented at: American College of Rheumatology 2008; San Francisco, CA; Octoer 26, 2008. Presentation 193.
3. Kinjo, M. Serum 25 OH vitamin D level and symptomatic knee osteoarthritis: analysis in a population-based U.S. sample. Presented at: American College of Rheumatology 2008; San Francisco, CA; October 26, 2008. Presentation 192.
4. Vacca A, Cormier C, Piras M, et al. Assessment of vitamin D deficiency and insufficiency in 2 independent cohorts of patients with systemic sclerosis. Presented at: American College of Rheumatology 2008; San Francisco, CA; October 26, 2008. Presentation 1782.

Vitamin D Levels Linked to OA Cartilage Loss/Pain | Arthritis Information

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