This project extends on Prof. Waldron’s interests on the role of the human microbiome as an ongoing link between host and environment, and its role in human health and disease. As part of this study, Prof. Waldron is currently collaborating with Professor Nicola Segata on meta-analysis of publicly available microbiome experiments, and with the New York City Department of Health as the lead analyst responsible for profiling the oral microbiome of the population of NYC. The New York City Health and Nutrition Examination Study has collected extensive lifestyle, health, and socio-demographic data, in addition to oral rinse specimens for microbiome analysis, from a randomized population-representative sample of 1,500 adults. Among other things, this study will evaluate changes to the oral cavity caused by a wide range of tobacco exposures (cigarette, secondhand smoke, hookah, and e-cigarette) from a racially and ethnically diverse, population-based sample of NYC adults.