Objectives: To undertake an epidemiological survey of the prevalence of radiological chondrocalcinosis (CC) of the lower limbs in the elderly Italian population of the Pro.V.A. study.
Methods: Knee and pelvic basin radiographs were performed on 3099 subjects aged 65 and older, residing in the Veneto Region of Italy (Rovigo and Camposampiero areas). Two readers independently analysed the knee, coxofemoral and pubic symphysis x-rays of a consecutive sample of 1629 subjects according to Altman. Some laboratory indexes, such as serum parathyroid hormone (PTH), vitamin D (vit D), bone alkaline phosphatase (bALP), deyidroepiandrosterone (DHEA), urinary CrossLaps (XL), and inflammatory biomarkers were evaluated. Quantitative variables were summarised as mean + or - standard deviation and qualitative ones as distributions. Unpaired t-test was used to compare mean values among groups for normally distributed variables, and non-parametric Mann-Whitney test for non normal variables.
Results: CC was found in 169 (mean age 78.2 + or - 8.0 yrs) out of the 1629 subjects studied (10.4%). After adjusting for the sex and age structure of the target population, the prevalence was 10.0%. CC was more often observed in women than in men (M: 7.0%; F: 12.8%, p=0.0002), and increased in occurrence with age, rising from 7.8% in subjects aged 65-74 yrs, to 9.4% in those aged 75-84 yrs, and to 21.1% in subjects older than 85 yrs. The knee was the most prevalent location since it was affected in 94.1% of all the subjects with CC, in particular the right limb. Knee CC was bilateral in 71.7% of the affected patients. The occurrence of rheumatic disorders did not differ significantly between the subjects with CC and those without (rheumatoid arthritis 0.59% vs. 0.48%, p=ns).
Conclusions: Although the detection of CC was limited to few joints with the knee being the most affected location, our study confirms the frequent presence of CC at different sites, in keeping with the possible role of systemic factors. Articular CC is an age-related disorder, which could partly explain the prevalence discrepancies reported by various studies. The prevalence of CC found in our survey based on standardised x-ray reading was high, suggesting that CC could be an underdiagnosed disease in the absence of radiographic investigation.