[Longitudinal study on osteoarthritis and bone metabolism]

The relationship between Osteoarthritis (OA) and Osteoporosis (OP) is not well defined due to lacking in longitudinal data, mainly regarding correlations between biochemical factors and OA incidence. Aim of this paper was to investigate the predictive value for OA incidence of bone mass variations and of selected biochemical markers in healthy women participating in a population-based longitudinal study carried out in Naples (Italy).

High completion rate (85.2%) and statistically adequate sample size were obtained: 139 women (45 to 79 years of age) were examined and follow up visit was performed after two years (24+/-2 months), following the same protocol. Patients underwent medical examination, questionnaire, anthropometric measurements, blood sampling and urine collection. Bone mineral density (BMD) measurement was performed by dual energy X-ray absorptiometry (DEXA) at the lumbar spine (L1-L4) and femoral neck. Radiographs of dorsal and lumbar spine in lateral view were performed at basal and at 24 months visits; a team of three experts scored radiographs using Kellgren and Lawrence grading.

The score was calculated for two individual radiographic features (narrowing of the joint space, presence of osteophytes) and as a global score. Results show a relevant percentage, 23% up, of subjects presenting both OA and OP. In the cross-sectional study the presence of osteophytosis correlates with anthropometric variables and PTH levels. In the longitudinal study results show a correlation between serum vitamin D and delta score for osteophytosis (beta=0.02 p<0.05).

Data obtained outline the importance of further studies on the pathogenetic link between OA and bone metabolism.