Structural and Functional Changes of Hands and Legs in Early Rheumatoid Arthritis

Abstract

Background and Objectives: The aim of this study was to assess if there are structural and functional changes of hands and legs already in early rheumatoid arthritis (ERA), compared with the population-based control group. Additionally, we aimed to identify if the changes are symmetrical in hands and legs and if there are factors that are associated with these changes. The study was conducted, and, thus far, the results have been controversial. Materials and Methods: The study group consisted of 83 consecutive patients with ERA and 321 control subjects. Dual-Energy X-Ray Absorptiometry (DXA) machine was used to measure bone, lean and fat mass. Inflammation and bone markers, smoking and nutritional habits were assessed, to evaluate the effects of different factors. The 30-Second Chair Stand Test (30-CST) and the Handgrip Strength Test (HST) were used to estimate muscle strength. Results: The presence of ERA was associated with lower arm, leg lean mass and higher fat mass of arm, compared with control subjects. ERA was also associated with lower mean handgrip in HST and worse muscle strength of legs in the 30-CST. Bone mass changes were not so evident both in arms and legs. Smoking habits did not seem to have relevant effect on bone mass, muscle structural and functional changes, both on hands and legs. In ERA, lean mass of arm and leg was negatively associated with C-reactive protein (CRP). The intake of proteins in ERA was not associated with lean mass changes both in hands and legs. Conclusions: Structural and functional changes of hands and legs are different in ERA. ERA patients had higher fat mass of arm, lower lean mass of arm and leg and, accordingly, decreased muscle function. The lowering of lean mass of arm and leg in ERA was associated with the elevation of CRP.

Does Dietary Polyunsaturated Fatty Acid Intake Associate With Bone Mineral Density and Limb Structural Changes in Early Rheumatoid Arthritis?

“…2,6 Furthermore, several studies of early RA (ERA) patients revealed that in addition to bone changes, lean mass loss and fat mass gain can be evident in the early stage of RA, although the involved factors are currently unknown. 7 Likewise, we have found in our previous work 8 that ERA patients had lower arm and leg lean mass, and higher arm fat mass. The decrease in limb lean mass in ERA was associated with the elevation of C-reactive protein (CRP), 8 indicating the effects of inflammation.…”

“…Nine patients were excluded due to missing outcome data, as well another 8 patients who did not fulfill ACR/EULAR 2012 criteria for RA on a followup visit 1 year after their first visit (n = 83) (Figure 1). 8,28 To form the control group, 350 subjects adjusted for the age and gender composition of the Estonian population in 2013 were randomly selected from a primary healthcare center practice list (total number of subjects: 1854). Cross-sectional data were assembled from September 2014 to March 2015.…”

“…Body mass index (BMI) was calculated according to the standard formula: weight in kilograms divided by height in meters squared. 8,28 A 24 hours dietary recall method was used for nutritional assessment. The data were analyzed with NutriData software developed by the Estonian National Institute for Health Development.…”

“…The data were analyzed with NutriData software developed by the Estonian National Institute for Health Development. 8,28,29 Smoking habits were stratified as ever smoked, including current and previous smoking anamnesis. 28 A Lunar Prodigy dual-energy X-Ray absorptiometry (DXA) machine was used to separately measure femoral neck, trochanter, lumbar spine (1-4th lumbar vertebrae), proximal and ultradistal radius BMD.…”

“…An experienced and qualified technician performed all DXA measurements on all participating subjects. 8 Blood samples were collected between 8 and 11 a.m. after an overnight fast. They included measuring CRP, calcium, vitamin D3.…”