Department of Statistics and Operations Research, University of Limpopo, Sovenga 0727, South Africa.
Biostatistics Research Unit, South African Medical Research Council, Pretoria 0001, South Africa.
Int J Environ Res Public Health. 2020 May 20;17(10):3583. doi: 10.3390/ijerph17103583.
Cardiovascular diseases (CVDs) are part of the leading causes of mortality and morbidity in developing countries, including South Africa, where they are a major public health issue. Understanding the joint spatial clustering of CVDs and associated risk factors to determine areas in need of enhanced integrated interventions would help develop targeted, cost-effective and productive mediations. We estimated joint spatial associations and clustering patterns of 2 CVDs (stroke and heart attack) and 3 risk factors (hypertension, high blood cholesterol (HBC) and smoking) among adults in South Africa. We used cross-sectional secondary adult (15-64-year olds) health data from the South African Demographic Health Survey 2016. Age and gender standardized disease incidence ratios were analyzed using joint spatial global and local bivariate Moran's Index statistics. We found significantly positive univariate spatial clustering for stroke (Moran; s Index = 0.128), smoking (0.606) hypertension (0.236) and high blood cholesterol (0.385). Smoking and high blood cholesterol (0.366), smoking and stroke (0.218) and stroke and high blood cholesterol (0.184) were the only bivariate outcomes with significant bivariate clustering. There was a joint stroke-smoking local "hot spots" cluster among four districts in the urban western part of the country (City of Cape Town; Cape Winelands; Overberg and Eden) and a joint "cold spots" cluster in the rural north-western part of the country. Similar joint "hot spots" clustering was found for stroke and high blood cholesterol, which also had "cold spots" cluster in the rural east-central part of the country. Smoking and high blood cholesterol had a "hot spots" cluster among five districts in the urban western part of the country (City of Cape Town; Cape Winelands; Overberg; Eden, and West Coast) and "cold spots" around the rural districts in east-southern parts of the country. Our study showed that districts tended to co-cluster based on the rates of CVDs and risk factors, where higher rates were found in urban places than in rural areas. These findings are suggestive of a more contagious and spatial diffusion process among interdependent districts in urban districts. Urbanization or rurality needs to be considered when intervention initiatives are implemented with more general approaches in rural areas. The finding of "hot spot" co-clusters in urban areas means that integrated intervention programmes aimed at reducing the risk of CVDs and associated risk factors would be cost-effective and more productive.
心血管疾病 (CVDs) 是发展中国家死亡和发病的主要原因之一，包括南非，南非存在重大的公共卫生问题。了解 CVDs 及其相关风险因素的联合空间聚集情况，以确定需要加强综合干预的地区，有助于制定有针对性、具有成本效益和富有成效的措施。我们估计了南非成年人中 2 种 CVD（中风和心脏病发作）和 3 种风险因素（高血压、高血胆固醇和吸烟）的联合空间关联和聚类模式。我们使用了 2016 年南非人口健康调查的横断面成人（15-64 岁）健康数据。使用联合空间全局和局部双变量 Moran 指数统计分析了年龄和性别标准化疾病发病率比。我们发现中风（Moran;s 指数=0.128）、吸烟（0.606）、高血压（0.236）和高血胆固醇（0.385）存在显著的正单变量空间聚类。吸烟和高血胆固醇（0.366）、吸烟和中风（0.218）以及中风和高血胆固醇（0.184）是仅有的具有显著双变量聚类的双变量结果。在该国西部城市地区的四个区（开普敦市；开普酒乡；奥弗贝格和伊登）发现了一个联合中风-吸烟局部“热点”集群，在该国西北部农村地区发现了一个联合“冷点”集群。在中风和高血胆固醇方面也发现了类似的联合“热点”聚类，在该国中东部农村地区也发现了“冷点”集群。吸烟和高血胆固醇在该国西部城市地区的五个区（开普敦市；开普酒乡；奥弗贝格；伊登和西开普）有一个“热点”集群，在该国东南部农村地区周围有“冷点”集群。我们的研究表明，各地区倾向于根据 CVDs 和风险因素的比率共同聚类，城市地区的比率高于农村地区。这些发现表明，在城市地区，相互依存的地区之间存在更具传染性和空间扩散的过程。在农村地区实施更广泛的干预措施时，需要考虑城市化或农村化。在城市地区发现“热点”共同聚类意味着，旨在降低 CVDs 及其相关风险因素风险的综合干预计划将具有成本效益和更富有成效。
