Osteoarthritis, the degenerative inflammatory bone disease, may be a sign of faster "biological ageing," suggests research published ahead of print in the Annals of the Rheumatic Diseases.
The authors base their findings on a study of almost 1100 people, aged between 30 and 79. Most of them were female twins.
X-rays of both hands were taken of all participants to check for signs of osteoarthritis and a blood sample was taken to assess "biological ageing" in white cell DNA.
Biological ageing is likely to be reflected by the gradual shortening of telomeres, the length of DNA which caps the tips of chromosomes. A host of factors make them shorten over time, including insufficient repair of the damage caused by oxygen free radicals (oxidative stress).
Oxygen free radicals are the unstable molecules produced as a by-product of normal bodily processes, as well as external factors, such as tobacco, alcohol, and sunlight.
Osteoarthritis is the most common form of arthritis, with the hands being one of the sites most often affected. Its frequency rises dramatically with age, but it is still not known exactly what causes it.
Unsurprisingly, the findings showed that white cell telomere lengths were associated with chronological age. The older a person was, the shorter they were.
But among the 160 people with hand osteoarthritis, the telomere length was significantly shorter than among those without the disease, even after taking account of influential factors, such as obesity, age, sex, and smoking.
All those with hand osteoarthritis were over 50, and the amount of telomere shortening was equivalent to that accrued over 11 years in healthy people (178 base pairs).
Telomere length was also significantly associated with the severity of osteoarthritis. The more severe the disease, the shorter was the telomere length.
The authors suggest that both the ageing process and osteoarthritis share biological factors in common, including oxidative stress and low level chronic inflammation.