Experimental Studies

Field epidemiology is the study of the distribution and determinants of health-related events in populations, focusing on the practical application of this knowledge to prevent and control health problems. Experimental studies are a key component of epidemiology in general, as they allow researchers to establish cause-and-effect relationships between risk factors and health outcomes. Experimental studies are challenging to conduct in field epidemiology because conditions are even more difficult to control than in academic/clinical epidemiology.

Experimental Studies in Field Epidemiology

Experimental studies in field epidemiology typically involve randomly allocating participants to either an intervention group, which receives a specific treatment or intervention, or a control group, which receives a placebo or no intervention. By comparing the outcomes between these two groups, researchers can determine the causal effect of the intervention on the outcome of interest.

Randomized controlled trials (RCTs) are the gold standard for experimental studies, as they minimize the risk of bias and confounding factors. Cluster randomized trials (CRTs) are another common experimental design in field epidemiology, where entire communities or groups, rather than individuals, are randomized to receive an intervention or control.

Ethical Restrictions

The ethical principles governing experimental studies in field epidemiology are largely based on the Declaration of Helsinki, which outlines the ethical guidelines for conducting research involving human subjects. Key ethical considerations in experimental studies include:

Informed consent

Participants must be informed about the purpose, methods, risks, and benefits of the study, and they must voluntarily agree to participate without any coercion.

Risk-benefit balance

Researchers must ensure that the potential benefits of the study outweigh the risks and that the study design minimizes harm to participants.

Equitable participant selection

Researchers must avoid exploiting vulnerable populations and ensure that the selection of participants is based on scientific and ethical considerations.

Confidentiality

The privacy and confidentiality of participants must be protected throughout the study.

Independent ethical review

Research protocols must be reviewed and approved by an independent ethics committee before the study begins.

Examples of Experimental Studies in Field Epidemiology

The ZAMSTAR study (Hayes et al., 2014) was a CRT conducted in Zambia and South Africa to evaluate the impact of two tuberculosis control strategies: enhanced case-finding and household-level interventions. The study found that a combination of these interventions reduced the prevalence of tuberculosis in the community. Reference: Hayes, R. J., Moulton, L. H., & Hargreaves, J. R. (2014). Cluster Randomised Trials (1st ed.). CRC Press.

The Fawcett et al. (1984) study was an RCT conducted in the United States to test the effectiveness of a community-based intervention to promote breast self-examination among women. The study found that the intervention group had a higher rate of breast self-examination compared to the control group. Reference: Fawcett, S. B., White, G. W., Hovell, M. F., & Neuhauser, L. (1984). A community-based breast self-examination program for women: The Fawcett et al. study. American Journal of Public Health, 74(2), 174-176.

Conclusion

Experimental studies are crucial to advancing the field of epidemiology and informing evidence-based public health interventions. However, in field conditions, such studies are even harder to perform than under more controlled circumstances. This is why analytical studies in field epidemiology are often observational by nature, following 'experiments of nature'.