Page 85 - THE EVOLUTION OF EARLY ARTHRITIS AND CARDIOVASCULAR RISK Samina A. Turk

AN UNFAVORABLE BODY COMPOSITION
Disease activity and body composition in early arthritis patients
In female patients, a higher ESR was associated with a higher FMI and patients with a longer symptom duration had more fat distributed to the trunk. In males, no association between body composition and disease activity was found. However, a longer symptom duration was related to a higher FMI and ALMI. See S2 Table.
Sensitivity analysis
Analyzes were repeated in patients who did and did not fulfill the ACR/ EULAR
2010 criteria and showed similar results (data not shown). Finally, we found that an unfavorable body composition was associated with an unfavorable lipid profile and 4 higher blood pressure in patients without cardiovascular treatment. Therefore, analyses
including patients with statins or antihypertensives were performed, where the same
results were obtained (data not shown).
DISCUSSION
Our study is the first to reveal that an unfavorable body composition is already present at the onset of inflammatory arthritis. A low muscle mass for age was rare, but substantially more prevalent in patients than in matched controls. In our patients, these findings could also be linked to cardiovascular risk factors, regardless of disease activity. The mechanisms causing an unfavorable body composition in inflammatory arthritis are incompletely understood. By itself, a loss in muscle mass can result from reductions in physical activity and hormone levels as well as change in diet, all part of normal aging(20). This also results in obesity, whereas the mean weight in the general population is nowadays already high and still increasing(33). Whereas obesity itself is also an risk factor for the development of arthritis(34). In inflammatory arthritis, pain, fatigue and joint stiffness further reduce physical activity(35). Cells involved in inflammation produce pro-inflammatory molecules, like IL-6, that increase muscle metabolism with subsequent muscle wasting(36). Furthermore, arthritis is associated with an insulin resistance, which may lead to muscle protein degradation(37).
Our findings are in line with the results observed in established arthritis(16;19). In established arthritis patients an association between body composition and glucocorticoid use was found(19;38;39). Only a minority of the arthritis patients received steroids during a few days. As our population underwent the DXA scan before or within one month after the start of treatment, glucocorticoid use was of minimum influence(40). Hence, altogether the influence of steroids appears to be negligible.
In the present study, the number of early arthritis patients with a low muscle mass for age was low, which might explain that no associations between disease activity and an unfavorable body composition could be demonstrated. The relation between different aspects of disease activity and components of body composition were inconclusive. Nevertheless, a longer symptom duration was associated with an increased FMI and
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