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Background: Arthritis affects 53 million U.S. adults, more than two-thirds of whom are younger than age 65. Approximately 1/3 of working-age (18-64 years) U.S adults with arthritis report arthritis-attributable work limitation. Objectives: First, to take a population-based perspective to evaluate the association of arthritis with employment participation among U.S. adults. Next, to examine whether this association differs by sex, age, or other characteristics. Finally, to investigate effects of the Great Recession (December 2007 to June 2009) on employment and to determine if arthritis status moderated its effects. Methods: All three studies were conducted using the National Health Interview Survey (NHIS). The third study also used longitudinal data from the Medical Expenditures Panel Survey (MEPS) linked to NHIS. Results: These manuscripts are under peer-review for publication; limited results are presented: Study 1- Employment participation was always statistically significantly and substantially lower (e.g., >10 percentage points) among adults with arthritis compared with those without arthritis. Study 2- Overall, 20.1 million adults (10.4% [95% CI=10.1-10.8] of the working-age population) reported work disability. Study 3- During the period of the Great Recession, people with arthritis stopped work at higher rates and started work at lower rates than those without arthritis, suggesting at least some differential effect among those with arthritis. Conclusion: This work contributes new knowledge by establishing long-term patterns and benchmark information for employment participation, work disability, transitions, and macro economic effects among adults with and without arthritis in the U.S. A population-based, non-condition-specific approach of this type has not been previously reported.

No description available.

No description available.

The goal of this thesis was to examine the processing of clinical pain in two patient groups with well defined primary pathologies, i.e. neuropathic pain patients and patients with rheumatoid arthritis (RA). It was hypothesized that chronic pain is associated with plastic changes in pain processing brain structures that can be detected using functional magnetic resonance imaging (FMRI). The first study, presented in Chapter 3, demonstrates that the neural representation of experimental heat pain is different in neuropathic pain patients than in age- and gender-matched healthy control subjects, although the pain stimulus was applied outside clinically affected areas. Increased activation was found in amygdala and anterior insula in the patient group and was accompanied by increased state anxiety and depression scores. Anterior insula is the focus of Chapter 4 in which it is demonstrated that clinical pain processing is located significantly more anteriorly in the insula than experimental pain processing, in close proximity to neural correlates of highly negative emotions and the conscious perception of bodily sensations. This offers a potential explanation for the shift of clinical pain processing. In Chapter 5, clinical pain is contrasted with experimental pain in the same patient population, i.e. patients with RA. In addition to comparing clinical and experimental pain processing, it was investigated if emotional and cognitive determinates of the pain experience, specifically depression and catastrophizing, exert different influences on the two types of pain. It is shown that clinical pain, but not experimental pain, is likely to be driven partially by depressive symptoms whereas catastrophizing is associated with the same neural activation pattern in both conditions. The cerebral representation of allodynic pain in neuropathic pain patients is presented Chapter 6. Chapters 6 and 7 demonstrate that the FMRI signal encodes the perceived intensity of clinical allodynic pain across subjects and that it reflects longitudinal variations of the perceived intensity within subjects. This thesis illustrates that FMRI can reveal subtle differences in the processing of clinical and experimental pain, despite brain activation patterns being similar on the whole. It also indicates that FMRI can be used to elucidate the origin of these differences, for instance by studying the influence of emotional and cognitive variables. This suggests that neuroimaging methods, in particular FMRI, have the potential to dissect clinical pain into its constituent parts, including central sensitization, brainstem facilitation and amplification by psychological factors. Such knowledge could potentially be exploited to target treatment selectively at different components of clinical pain and to monitor longitudinal changes of these components separately.

Background: Arthritis affects 53 million U.S. adults, more than two-thirds of whom are younger than age 65. Approximately 1/3 of working-age (18-64 years) U.S adults with arthritis report arthritis-attributable work limitation. Objectives: First, to take a population-based perspective to evaluate the association of arthritis with employment participation among U.S. adults. Next, to examine whether this association differs by sex, age, or other characteristics. Finally, to investigate effects of the Great Recession (December 2007 to June 2009) on employment and to determine if arthritis status moderated its effects. Methods: All three studies were conducted using the National Health Interview Survey (NHIS). The third study also used longitudinal data from the Medical Expenditures Panel Survey (MEPS) linked to NHIS. Results: These manuscripts are under peer-review for publication; limited results are presented: Study 1- Employment participation was always statistically significantly and substantially lower (e.g., >10 percentage points) among adults with arthritis compared with those without arthritis. Study 2- Overall, 20.1 million adults (10.4% [95% CI=10.1-10.8] of the working-age population) reported work disability. Study 3- During the period of the Great Recession, people with arthritis stopped work at higher rates and started work at lower rates than those without arthritis, suggesting at least some differential effect among those with arthritis. Conclusion: This work contributes new knowledge by establishing long-term patterns and benchmark information for employment participation, work disability, transitions, and macro economic effects among adults with and without arthritis in the U.S. A population-based, non-condition-specific approach of this type has not been previously reported.

No description available.

No description available.

Peripheral CD4CD8 double positive (DP) T cells have been reported to play a role in several autoimmune diseases, virus infections and cancer. In rheumatoid arthritis (RA), both CD4 and CD8 single positive (SP) T cells are known to be involved in the pathogenesis, but the role of peripheral CD4CD8 DP T cells has not been investigated in detail. Anti cyclic citrullinated antibodies (ACPA) positive and ACPA negative RA patients, patients with systemic lupus erythematodes (SLE) and age matched healthy donors (HD) were enrolled in the analysis. The frequencies and phenotype of DP T cells in PBMC were investigated. In addition, DP T cells were quantified in biopsies from rheumatoid synovium. After in vitro restimulation, the cytokine production of DP T cells was investigated in cultures of PBMC. CMV specific cytokine secretion as well as proliferation was analyzed following antigen specific restimulation after an appropriate culture duration. DP T cells were found more frequently in RA patients than in healthy controls or patients with SLE. These DP T cells express ab TCRs, are of a memory phenotype and share features of both CD4 as well as CD8 SP T cells. Importantly, DP T cells were found to also be present in the rheumatoid synovium. Further characterization of DP T cells from RA patients revealed increased production of IL-21 and IL-4, implying a possible role as T helper cells. In addition, DP T cells in RA seem to contribute to the inflammatory process, because they produce significantly more IFNc than counterparts from HD and are increased in CMV+ RA patients. Given their capacity to produce a variety of cytokines (IL4, IL21 and IFNc), their association with ACPA positive RA and their presence in the synovium, we suggest an important role of double positive T cells in the pathogenesis of rheumatoid arthritis.

The act of raising the heel up is an essential portion of the gait cycle in humans, comprising the third rocker in the gait cycle. This act further demands specific motions from the hindfoot, and the surrounding structures. These motions have been previously studied and are reasonably well understood. End-stage osteoarthritis of the ankle (or ESOA) has been theorized to affect not only the ankle joint, but the same joints required for heel rise. (i.e. - hindfoot, lower leg, and foot) In the present research, the powerful effect that ESOA has on the lower leg, hindfoot and forefoot biomechanical relationship was demonstrated as significantly different from that of healthy age and sex-matched controls. This has implications not only for further research, but potentially treatment as well.