The importance of the microbiome in epidemiologic research

Purpose The human microbiome is the community of microorganisms that live on and in the body. Currently, most applications of microbiome analysis derive from the perspective of discovery and characterization. The completion of the NIH Human Microbiome and the European MetaHIT projects will change the focus to studying the role of the microbiome on human health and disease. Methods Recent developments in technology and bioinformatics have afforded an opportunity to explore more fully the importance of community structure, detection of pathogens, and community interactions. The current state of microbiome research in terms of effect size, power calculations, how stratification on community classes can increase this power, and the importance of study design and power in reproducibility is reviewed. Results Work is needed to characterize microbiome development, ecological stability, and variation. Development and implementation of variance stabilization techniques should replace rarefaction of data, which reduces study power, in future research. Conclusions Epidemiologists have most of the tools necessary to explore the relationship between the microbiome and human health. Further development of tools for large-scale multivariate data sets will be helpful. Applying the methods of epidemiology will be critical in translating research results to preventive interventions and population health.