Pedersen Merete, Jacobsen Søren, Klarlund Mette, Frisch Morten
Department of Epidemiology Research, Danish Epidemiology Science Centre, Statens Serum Insitut, DK-2300 København S, Denmark.
J Rheumatol. 2006 Jun;33(6):1069-74. Epub 2006 Apr 15.
To examine whether markers of socioeconomic status (SES) are associated with risk of rheumatoid arthritis (RA), and if so, whether selected lifestyle-related factors could explain this association.
We conducted a frequency matched case-control study; subjects comprised 515 patients (participation rate 83%) attending rheumatology and internal medicine departments in Denmark, with recently diagnosed RA according to the American College of Rheumatology (ACR) 1987 classification criteria for RA (mean disease duration 2.3 yrs), and 769 frequency-matched population controls (participation rate 64%). Information about SES and environmental exposure was obtained by structured telephone interview. Logistic regression analyses evaluated the role of markers of SES.
Level of education was significantly inversely associated with risk of RA, with a 2-fold lower risk of RA among those with the longest formal education compared with those having the lowest level of education (multivariate odds ratio = 0.43, 95% confidence interval 0.24-0.76, p trend = 0.001). None of a series of studied lifestyle factors could explain this finding in multivariate logistic regression analyses. When dividing the RA cases into clinical subgroups, the inverse association with level of education was found to apply predominantly to rheumatoid factor (RF)-positive RA.
The inverse association between level of education and risk of RF-positive RA was not explained by any of the examined lifestyle factors. RF-positive and RF-negative RA may be 2 distinct diseases with different etiologies, with unmeasured factors related to educational level predominantly associated with the risk of RF-positive RA. However, because mechanisms underlying referral to a hospital might be linked to educational level, our observation based on hospital-referred RA patients should be evaluated cautiously. The study stresses the importance of taking SES measures into account in studies that aim at identifying environmental risk factors for RA.
探讨社会经济地位（SES）指标是否与类风湿关节炎（RA）风险相关，若相关，某些与生活方式有关的因素能否解释这种关联。
我们进行了一项频率匹配的病例对照研究；研究对象包括丹麦风湿科和内科的515例患者（参与率83%），这些患者根据美国风湿病学会（ACR）1987年RA分类标准被新近诊断为RA（平均病程2.3年），以及769例频率匹配的人群对照（参与率64%）。通过结构化电话访谈获取有关SES和环境暴露的信息。逻辑回归分析评估SES指标的作用。
教育水平与RA风险显著负相关，接受正规教育时间最长者患RA的风险比受教育水平最低者低2倍（多变量优势比 = 0.43，95%置信区间0.24 - 0.76，p趋势 = 0.001）。在多变量逻辑回归分析中，一系列研究的生活方式因素均无法解释这一发现。将RA病例分为临床亚组时，发现与教育水平的负相关主要适用于类风湿因子（RF）阳性的RA。
所研究的任何生活方式因素均无法解释教育水平与RF阳性RA风险之间的负相关。RF阳性和RF阴性RA可能是病因不同的两种不同疾病，与教育水平相关的未测量因素主要与RF阳性RA的风险相关。然而，由于转诊至医院的潜在机制可能与教育水平有关，我们基于医院转诊的RA患者的观察结果应谨慎评估。该研究强调在旨在确定RA环境风险因素的研究中考虑SES指标的重要性。
