1. What are possible reasons locations in epidemiological research have not been incorporated as much as other components in epidemiological research? How can spatial epidemiology be considered as an interdisciplinary science?
As I can understand from reading the assigned papers, one reason is the limited incorporation of the places in epidemiological research rather than focusing on the person and time over place historically. This may also be one reason as GIS evolved only in the early 1960s with the primary intention of using forestry mapping as an operational. Historical integration and insufficient software for special analysis would be a challenge in epidemiological studies. This is also linked to the lack of appropriate databases regarding the use of special data for epidemiological research.
Another reason will be data availability and quality which hinder the integration of special analysis. In the Special Epidemiology paper, the accurate small-area studies needed high-quality data, the studies relying on routine data sources cannot carry out a detailed validation process and this will lead to the inaccuracy of the findings in the studies. For instance, there is no national cancer registry in many regions, which makes it difficult to study environmental health problems accurately. It can also reflect our real setting and practices in my country, we didn’t usually collect special data concerning public health and epidemiological studies which was not incorporated as the other components, so we couldn’t get insight into it. Other confidentiality issues and study design could be also hindrances to location incorporation in epidemiological research.
Spatial epidemiology will be an interdisciplinary science as it integrates the concepts of epidemiology, geography, statistics, environmental science, and public health. It enables studying spatial patterns of the diseases with statistical methods based on the potential geographical, environmental, and social determinants. It can also explore the individual-level risk factors that interact with the above factors which may offer insights into public health interventions.
2. Explain why it is widely recognized that the place where an individual lives or works should be considered as a potential disease determinant and give some examples?
The main consideration will be the interaction between genetic factors, lifestyle, cultural practices, and environment can be different between the places where the individual lives or works, and these divergent interactions can be the potential disease determinants in the areas. Geographic variations in these factors can significantly influence health outcomes as living in industrial areas with poor air quality can be harmful to an individual’s health and urban planners for healthier environments can impact lower rates of the related diseases. It is also granted in some geographic correlation studies for the health outcomes; the study of local lung cancer excess was associated with residence near or employment in the arsenic industry (Blot and Fraumeni 1975, 194) and a positive association of mortality with measures of particulate matter pollution was found across six cities in USA, adjusting for other potential confounding data measured at the individual level (Dockery et al. 1993). This was also recognized only a highly localized or individual-based study can investigate the issue, and we could work on it to understand more spatial epidemiological studies.