Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Nepal Development Society, Bharatpur-5, Chitwan, Nepal.
J Physiol Anthropol. 2022 Apr 2;41(1):12. doi: 10.1186/s40101-022-00283-3.
In Tsarang (at 3560 m), which is located in Mustang, 62.7% of the residents answered that they had a subjective medical history of arthritis, and 41.1% of the residents answered that their families had a subjective medical history of arthritis on a survey conducted in 2017. The expression of hypoxia-inducible factor (HIF) and its effects are deeply involved in hypoxic adaptation in Tibetan highlanders. At the same time, HIF is also related to the onset of rheumatoid arthritis. Therefore, the adaptive mechanism acquired by Tibetan highlanders may promote the development of rheumatoid arthritis. The prevalence of rheumatoid arthritis is estimated to be approximately 0.5-1.0% worldwide. The objective of this study was to estimate the prevalence of rheumatoid arthritis in Tsarang residents using existing diagnostic criteria and to explore its risk factors.
An epidemiological survey was conducted in Tsarang in 2019. Data obtained from anthropometry and questionnaires were statistically analyzed. Biochemical measurements using blood samples were also performed, and the results were used to assess arthritis status. Residents' joint status was scored, and arthritis was assessed based on the clinical disease activity index and ACR/EULAR 2010 criteria.
Twenty-seven males and 50 females participated in this survey. In Tsarang, ACR/EULAR 2010 classified 4.3% of males and 7.1% of females as having rheumatoid arthritis, indicating a very high estimated prevalence. We also performed a multivariate analysis to explore its risk factors, and two factors, older age (standardized parameter estimate = 4.84E-01, 95% CI = [9.19E-02, 8.76E-01], p = 0.0170) and a history of living in urban areas (standardized parameter estimate = - 5.49E-01, 95% CI = [- 9.21E-01, 1.77E-01], p = 0.0050), significantly contributed to the higher ACR/EULAR 2010 score in females. In addition, three factors, having no spouse (standardized parameter estimate = 3.17E-01, 95% CI = [5.74E-02, 5.77E-01], p = 0.0179), having a smoking habit (standardized parameter estimate = 2.88E-01, 95% CI = [1.71E-02, 5.59E-01], p = 0.0377), and a history of living in urban areas (standardized parameter estimate = - 3.69E-01, 95% CI = [- 6.83E-01, - 5.60E-02], p = 0.0219), resulted in significantly higher clinical disease activity index scores in females. Furthermore, smoking habits were found to significantly increase blood hyaluronic acid in both males (standardized parameter estimate = 6.03E-01, 95% CI = [3.06E-01, 9.01E-01], p = 0.0020) and females (standardized parameter estimate = 4.87E-01, 95% CI = [5.63E-02, 9.18E-01], p = 0.0291).
In this study, we evaluated the symptoms of arthritis and estimated the prevalence of rheumatoid arthritis using classification criteria for Tibetan highlanders who have adapted to the hypoxic environment and fostered their own culture. The high prevalence of rheumatoid arthritis among Tsarang residents suggests that the hypoxic adaptation mechanism involving HIF in Tibetan highlanders may promote the onset or exacerbation of rheumatoid arthritis. The high prevalence of rheumatoid arthritis among Tibetan highlanders may be related not only to the environmental factors analyzed in this study but also to hypoxic adaptation genes. Further investigation is needed to clarify the genetic factors involved.
在海拔 3560 米的扎仓（Tsarang），即位于芒康的一个地方，2017 年的一项调查显示，62.7%的居民表示他们有主观的关节炎病史，41.1%的居民表示他们的家庭有主观的关节炎病史。缺氧诱导因子（HIF）的表达及其作用与藏人高原低氧适应有很深的关系。同时，HIF 也与类风湿性关节炎的发病有关。因此，藏人获得的适应机制可能会促进类风湿关节炎的发生。类风湿关节炎的患病率估计在全球约为 0.5-1.0%。本研究的目的是使用现有的诊断标准来估计扎仓居民的类风湿关节炎患病率，并探讨其危险因素。
2019 年在扎仓进行了一项流行病学调查。对人体测量和问卷调查的数据进行了统计分析。还进行了血液样本的生化测量，并将结果用于评估关节炎状况。对居民的关节状况进行了评分，并根据临床疾病活动指数和 ACR/EULAR 2010 标准评估关节炎。
27 名男性和 50 名女性参与了这项调查。根据 ACR/EULAR 2010 标准，男性中有 4.3%，女性中有 7.1%被归类为患有类风湿关节炎，表明患病率非常高。我们还进行了多因素分析，以探讨其危险因素，有两个因素，年龄较大（标准化参数估计=4.84E-01，95%CI=[9.19E-02,8.76E-01]，p=0.0170）和居住在城市地区的历史（标准化参数估计=-5.49E-01，95%CI=[-9.21E-01,1.77E-01]，p=0.0050），对女性的 ACR/EULAR 2010 评分较高有显著贡献。此外，有三个因素，没有配偶（标准化参数估计=3.17E-01，95%CI=[5.74E-02,5.77E-01]，p=0.0179）、吸烟习惯（标准化参数估计=2.88E-01，95%CI=[1.71E-02,5.59E-01]，p=0.0377）和居住在城市地区的历史（标准化参数估计=-3.69E-01，95%CI=[-6.83E-01,-5.60E-02]，p=0.0219），导致女性的临床疾病活动指数评分显著升高。此外，吸烟习惯被发现显著增加了男性（标准化参数估计=6.03E-01，95%CI=[3.06E-01,9.01E-01]，p=0.0020）和女性（标准化参数估计=4.87E-01，95%CI=[5.63E-02,9.18E-01]，p=0.0291）血液透明质酸。
在这项研究中，我们评估了关节炎症状，并使用适应低氧环境和培养自身文化的藏人分类标准来估计类风湿关节炎的患病率。扎仓居民类风湿关节炎的高患病率表明，藏人低氧适应机制中涉及 HIF 的机制可能会促进类风湿关节炎的发病或恶化。藏人高患病率可能不仅与本研究分析的环境因素有关，还与低氧适应基因有关。需要进一步研究以阐明所涉及的遗传因素。
