The ageing joint-standard age- and sex-related values of bone erosions and osteophytes in the hand joints of healthy individuals

Summary Objective To analyze the age-related changes of the physiological hand joint architecture. Method To address this concept, healthy individuals (each 10 women and 10 men in 6 different age decades spanning from 21-80 years) were recruited through a field campaign, investigated for the absence of rheumatic diseases and other comorbidities and received high-resolution quantitative computed tomography (HR-pQCT) examination of the hand joints. Number and extent of erosions and osteophytes were quantified across the ages and different sexes. Results Bone erosions [median (Q1-Q3), 1 (0-2)] and osteophytes [2 (1-4)] were found in healthy women and men with no significant sex differences. Structural changes however accumulated with age: the overall incidence rate ratio (IRR) for the number of erosions and osteophytes per age were 1.04 (95% CI: erosions 1.03-1.06; osteophytes: 1.03-1.05). This means a 4% increase in the number of erosions and osteophytes per year. Using 3 rd decade as reference, healthy individuals in the age decades from 50 years had higher IRR for erosion numbers (6 th , 7 th , 8 th decade: 4.87 (2.20-11.75), 6.81 (3.08-16.46) and 6.92 (3.11-16.79)) compared to younger subjects (4 th , 5 th decade: 1.80 (0.69-4.87), 1.53 (0.59-4.10)). The IRRs of osteophytes also indicate a gradual increase after the fifth decade, with IRRs of 2.32 (1.32-4.17), 4.17 (2.38-7.49) and 6.86 (3.97-12.20) for the 6 th , 7 th and 8 th decades, respectively. Conclusions Structural changes in the hand joints of healthy individuals are age dependent. While being rare under 50 years of age, erosions and osteophytes accumulate above the age of 50, suggesting that the threshold between "normal" and "pathological" is shifted with the increase of age.