Researchers at Menzies Research Institute (Menzies) are the first to discover that sun exposure and related blood vitamin D levels are associated with the loss of cartilage in the knee joint of older individuals.

Researchers at Menzies Research Institute (Menzies) are the first to discover that sun exposure and related blood vitamin D levels are associated with the loss of cartilage in the knee joint of older individuals. This study was recently published in the distinguished American scientific journal Arthritis & Rheumatism.

Professor Graeme Jones, Head of Menzies' Musculoskeletal Unit and chief investigator for The Tasmanian Older Adult Cohort (TASOAC) study says that cartilage loss is the hallmark of osteoarthritis (OA).

"By the time patients reach the point of needing knee replacement, 60 per cent of cartilage has been lost," Professor Jones said.

"We found osteoarthritis patients with vitamin D sufficiency have approximately 1.5 percent less loss of knee cartilage per year than patients with vitamin D deficiency."

"Put another way, these results suggest that we can delay the time to first knee replacement by 14 years if we could make all people vitamin D sufficient which is a major benefit. However, a large scale clinical trial will be required before we can modify public health policy."

"We measured levels of vitamin D in blood samples and knee cartilage volume through MRI from 880 men and women between 51 to 79 years old. We then took similar measurements again almost three years later."

"Overall, 58 per cent of these subjects showed radiographic changes of knee osteoarthritis at the beginning of the study, and half reported knee pain."

"Men and women with vitamin D deficiency had severe knee osteoarthritis and were more likely to experience knee pain than patients with normal vitamin D levels. Over three years, patients with vitamin D deficiency had greater cartilage loss," Professor Jones said.

Dr Changhai Ding, Menzies' Senior Research Fellow says that these findings are important as it concludes that vitamin D deficiency plays an important role in the pathogenesis of knee osteoarthritis, and achieving vitamin D sufficiency in osteoarthritis patients could significantly delay cartilage loss and total knee replacement.

"We thank the Tasmanian community for the marvellous support they have shown through their active participation in the study," Dr Ding said.

Both osteoarthritis (OA) and vitamin D insufficiency are common health conditions in older people. Approximately 25 per cent of people aged over 55 years old have had knee pain on most days in a month in the past year. 

It is estimated that one billion people worldwide have vitamin D deficiency. Vitamin D deficiency is more common in Tasmania than elsewhere in Australia.

The Tasmanian Older Adult Cohort (TASOAC) study was established in 2002 and recently finished its third phase.

The TASOAC study is supported by the National Health and Medical Research Council (NHMRC), the Arthritis Foundation of Australia, the Tasmanian Community Fund, and the University of Tasmania.

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Fiona Horwood
Communications Manager
Menzies Research Institute
Telephone:(03) 6226 7751

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