Abstract
Objectives
To investigate the association between psychosocial vulnerability, defined as either low social support or low decision latitude at work, and disease remission at 3, 12, and 60 ...months in patients with rheumatoid arthritis (RA).
Methods
This cohort study included all patients enrolled in both the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) 1996–2015 and the Swedish Rheumatology Quality Register (SRQ,
n
= 2820). Information on social support and decision latitude at work at RA diagnosis were identified from the EIRA questionnaire. Indexes for levels of social support and decision latitude at work, respectively, were calculated based on the questionnaire. Low social support and low decision latitude at work, respectively, were identified by a score in the lowest quartile and compared with the three other quartiles (not low). Disease-activity parameters were retrieved from SRQ at 3, 12, and 60 months. The associations between social support or decision latitude at work, respectively, and Disease Activity Score 28 joint count with C-reactive protein (DAS28-CRP) remission were analysed using logistic regression models adjusted for age, sex, smoking habits, alcohol habits, symptom duration, and educational level.
Results
Having low social support (
n
= 591) was not associated with DAS28-CRP remission at 3 (OR 0.93, 95% CI 0.74–1.16), 12 (OR 0.96, 95%CI 0.75–1.23), or 60 (OR 0.89, 95%CI 0.72–1.10) months compared to not low social support (
n
= 2209). No association was observed for low (
n
= 212) versus not low (
n
= 635) decision latitude at work and DAS28-CRP remission at 3 (OR 0.84, 95%CI 0.54–1.31), 12 (OR 0.81, 95%CI 0.56–1.16), or 60 (OR 1.37, 95%CI 0.94–2.01) months.
Conclusion
In a country with general access to healthcare, psychosocial vulnerability does not influence the likelihood of achieving remission in early RA.
ObjectiveSeveral, but not all studies, have shown a dose-dependent inverse association with alcohol consumption and rheumatoid arthritis (RA), whereas smoking is an established risk factor for RA. We ...aimed to study the association between alcohol consumption and RA incidence and investigate a potential interaction between alcohol and smoking habits, regarding RA incidence.MethodsWe used a prospective cohort study, based on 41 068 participants with detailed assessment of alcohol intake, smoking and potential confounders at baseline in 1997. We ascertained a total of 577 incident cases of RA during a mean of 17.7 years of follow-up through linkage to nationwide and essentially complete databases. Multivariate Cox proportional hazards models were used to estimate HR with 95% CI. Interaction on the additive scale between alcohol and smoking was estimated by calculating the attributable proportion due to interaction (AP).ResultsOverall, alcohol consumption was associated with a 30% reduced incidence of RA (HR 0.69, 95% CI 0.55 to 0.86) with a dose–response relationship (p value for trend <0.001) which remained significant after stratification by age and smoking habits. The positive association between smoking and RA incidence was reduced with increasing alcohol consumption (p value for trend <0.001). A synergistic effect was observed between alcohol and smoking (AP 0.40, 95% CI 0.15 to 0.64), indicating that 40% of the cases among the double exposed are due to the interaction per se.ConclusionsOur findings suggest an inverse association between alcohol consumption and RA incidence, and a synergistic effect between alcohol and smoking.
In the field of rheumatology, the research has been successful in the understanding of the molecular mechanisms of the underlying pathophysiology of rheumatoid arthritis (RA). As a result of this, ...targeted treatments have been developed, resulting in a dramatic improvement of disease outcome. Today, there is an ongoing work aiming for treating the disease in very early stage or even preventing the disease. However, the exact etiology for RA is not fully known and previous epidemiological research has indicted that contextual factors contributes to both the risk for disease and the development of structural joint damage. The aim of this thesis is to contribute to the understanding of how external factors, in particular socioeconomic characteristics, associate to the risk for developing, the onset of and the severity of rheumatoid arthritis.In study I, a case-control study within the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA), we investigated if low social support and low decision latitude at work, respectively, were associated with risk for RA. Further we investigated whether those two exposures were associated with other previously identified risk factors for disease. We retrieved information on social support from the EIRA I+II study (3724 cases and 5935 controls) and information on decision latitude at work from the EIRA I study (1998 cases and 2252 controls). We did not observe any association between low social support and risk for RA (OR 1.00 (95% CI 0.91– 1.11) in the multivariable model) as compared to not low social support. Nor did we observe any statistically significant association between low decision latitude at work and RA (OR 1.28 (95% CI 0.96–1.71) in the multivariable model) as compared to high decision latitude. Both investigated exposures were associated with smoking and low educational level but neither of them were associated with disease specific characteristics such as ACPA- or RF-status.In study II we analyzed the association between alcohol habits and the risk for development of RA and furthermore if there was an interaction with smoking. We retrieved information on alcohol- and smoking habits from the Swedish National March Cohort (n=41 068). Information on the outcome, i.e. incident RA, was obtained from the national patient register. During the follow-up time 577 individuals developed RA. We observed that overall, alcohol consumption was associated with a 30% reduced risk of RA (HR 0.69, 95% CI 0.55-0.86). The negative association between alcohol consumption and RA risk was more pronounced among smokers. We observed a statistically significant interaction between smoking and alcohol habits with an attributable proportion of 0.4.In study III we investigated whether low social support and low decision latitude at work, respectively, were associated to RA disease remission. Information on exposures was retrieved from the EIRA study and information on outcome, that is disease activity at 3, 12 and 60 months follow up, was captured from the Swedish Rheumatology Quality Register (SRQ). There were 2820 individuals with information from both EIRA and SRQ. In this study low social support was not associated with remission rate at any of the investigated time-points, as compared to not low social support. Low decision latitude at work was not associated to remission at any of the investigated time-points, compared to not low decision latitude at work.Our studies have contributed to the understanding of the impact of external factors on both disease risk and disease course in RA.
PDF
