engleski

Bone mineral density in patients with rheumatic conditions – association with muscle strength

Aim. There is a concomitant decline in muscle strength of the upper and lower limbs and also in bone density between fifth and sixth decades. The objective of the study was to analyze whether that decline is more pronounced in patients with rheumatic diseases. Methods. Subjects of the study were patients who were referred to the rheumatologist due to the rheumatic complaints. They were classified according to their first rheumatologic diagnosis: cervicobrachial (CB) syndrome, lumbosacral (LS) syndrome, osteoarthritis of the hands, shoulder, knee and hip and inflammatory arthritis (undifferentiated polyarthritis, rheumatoid arthritis, spondylitis ankylosans). Assessment of lifestyle characteristics (smoking, physical activity, calcium intake), anthropometric measurements (height, weight, body mass index) and back-leg dynamometry (in pounds) were performed in all patients. Bone mineral density (BMD ; g/cm2) at the lumbar spine, proximal femur and distal third of radius was measured using dual-energy X-ray absorptiometry. The differences between groups were tested by t-test and ANCOVA, while the association between BMD and analyzed predictors was tested by multiple regression. Results. There were 251 female and 97 male patients. The mean age was 59.8 years in women and 62.7 years in men. Men had significantly higher dynamometry values than women (p<0.0001). Comparing to men, women had significantly lower bone density in spine (p<0.001), femur neck (p=0.012) and radius (p<0.0001). Patients with inflammatory arthritis had the lowest BMD at the spine and femur. However, the difference in BMD between patients with different rheumatic diagnosis was not significant. Dynamometry was the lowest in patients with hand and shoulder arthritis, following by the patients with inflammatory arthritis (Table 1). There was no significant between-groups difference in dynamometry, according to the rheumatic diagnosis (F=1.46, p=0.21). Conclusion. When excluded patients with hand and shoulder rheumatic conditions, patients with inflammatory arthritis had the lowest muscle strength. These results suggest a potential role of the decline of muscle strength in bone loss of those patients.

Bone mineral; density; muscle strength; inflammatory rheumatism; osteoarthritis

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