In the environmental health theory, there is a view on how environmental health, human ecology and health affect the public. The three concepts help in addressing problems in relation to the environment, health and development. Environmental health, therefore, contributes to explaining and controlling the environmental factors, which can affect the health of human beings. The theory has therefore helped in controlling some of the diseases like malaria and cholera, which are directly linked to environmental exposures. The main contribution of environmental health is the provision of resources like water, food and air, which are not contaminated and safe work as well as living environments (Aron & Patz, 2001).
Initially, environmental health was illustrated using the cause-effect approach where environmental factors were linked directly to the health outcomes. For instance, the epidemic of cholera in London was linked to the removal of the handle that was in the Broad Street pump. However, later due to a lot of research on the disease, the concern shifted to the source of water and this disapproved the approach of cause-effect relationship (Follér, 2001).
Linking environmental exposures to disease outcomes have proved to lack an epidemiologic basis of argument since there is no sufficient information to explain the link between the environmental hazard and the health outcome. Due to such challenges, researchers have therefore come up with more developed formulae of collecting data and devised methodologies of using the already collected data for different purposes that were not intended initially. The data is therefore used to express the link by clearing up the gaps in the methodology. Appropriate rules for linking data sets have been defined which calls for a better understanding of the data sets and clear articulation of their uses and limits to avoid cases of invalid conclusions (Waltner, 2001).
When linking different types of data to be used, there are basic factors to consider such as the basic scientific connection of the data and the appropriateness and adequacy of the information in addressing the issue in question. To handle the information accurately, a framework is provided for one to adhere to when examining the basic factors to be considered. The framework gives the steps that an agent takes through the environment to enter the person, which finally results to the production of the health outcome (Adams & Greeley, 1996).
This entails the surveillance of the hazard where there is the tracking of the agent presumed to have caused the health outcome. It is tracked in the environment to get the origin before using the set of data presented. Exposure surveillance is another step where the host of the agent is monitored. In this case, the human tissues are examined to check those that are infected. In addition, the surveillance of the health outcome is another step where one examines the sign and symptoms of the attack. To come up with a strong tool in measuring the causes someone needs to combine more than one set of data accurately by following the steps provided (Follér, 2001).
Data inadequacy is also another challenge when linking environmental factors and health outcomes. During the linking, therefore, there is a need to examine the necessary data sources before looking at the possible statistical methods for linking. The sources of the information, in this case, include the exposure, health outcome and the environment. For a successful link, there must be the use of quality information appropriately taking into account the limitation of the data. As much as this theory tries to explain the link between the hazard, exposure and health outcomes, the data in each step may be diverse and therefore their uses and limitations outside their original purpose may not be clear as expressed below (Waltner, 2001).
Hazard data
This kind of data gives information in relation to the presence and quantity of the contaminants in the environment. A hazard is presumed to cause harmful effects in the exposure but in most cases, it is not the case since on its own it cannot. Some of the environmental data include pesticide exposures and toxic release. Analysis data is always limited when comparing each set of data with the environmental guidelines. In most cases, the environmental guidelines do not tally with all the environmental contaminants because those, which exist, are developed from toxicological studies. Exceeding environmental guidelines results in failure in predicting health outcomes (Adams & Greeley, 1996).
Exposure Data
This is used to link the hazard environments and the effects they create in human beings. Examples of exposure data include the biological samples such as urine, stool, blood and saliva. After the analysis, the result shows that in most cases, the concentration of the agents in the biological sample is not proportional to that of the environment. There are several factors therefore which affect the internal concentration of the agent in human bodies.
Such factors include base line health status of the individual, behavioral factors and exposure level. Exposure data is one of the factors, which contribute to linking gaps since its source is not steady. For instance, the level of exposure in children might be different from that of adults or even vary among adults (Aron & Patz, 2001).
Another factor, which may create the gap in the linking system under exposure data, is the monitoring of the data in the different environments as well as different individuals. This has been difficult due to lack of bio-monitoring programs to cover exposure data. Metabolism rate in individuals may also affect the exposure data to be used since it differs in individuals as it is affected by many other factors. Due to inadequate measures of exposure data, the parameters are therefore estimated and this creates risks in assessing the data hence assumptions, which distort the whole process of linking (Waltner, 2001).
Health Outcome Data
Health outcome data is achieved through the analysis of the chronic effects of the diseases caused and the mortality rates caused by the hazards in human beings. Some of the health outcomes include asthma, cancer or malaria. Health outcomes are evaluated individually just like in the cause-effect approach. At times information is obtained through the aggregation of the population like those from regional or national surveys. Since the methodology focuses on using the limited data based on the population aggregate, the theory does not succeed since it differs from the individual data hence the inability to use the data obtained from each set (Adams & Greeley, 1996).
The theory, therefore, fails to work because apart from the three factors of data to be used to show the link among hazard, exposure and health outcome it failed to acknowledge other relevant factors, which contribute to the linking. For example, in the examination of asthma as the health outcome, there are other factors to consider like the place of residence, age, socioeconomic status and air pollution.
References
Adams, S. & Greeley, M. (1996). Establishing possible links between aquatic ecosystem health and human health: An integrated approach: Interconnections between Human and Ecosystem Health (Di Giulio RT, Monosson E, eds). London: Chapman and Hall.
Aron, J. & Patz, J. 2001. Ecosystem change and public health: A global perspective. Baltimore: John Hopkins University Press.
Follér, M. (2001). Interactions between global processes and local health problems: A human ecology approach to health among indigenous groups in the Amazon. Cad Saude Publica, 17, 115–126.
Waltner, D. (2001). An ecosystem approach to health and its applications to tropical and emerging diseases, Cad Saude Publica, 17, 7–36.