Thesis (Ph. D.)--University OF MICHIGAN. / CHAIRMAN: GORDON L. FLYNN.

Thesis (Ph. D.)--University OF MICHIGAN.

Thesis (Ph. D.)--University OF MICHIGAN.

Thesis (Ph. D.)--University OF MICHIGAN. / CHAIRMAN: JOHN R.C. WHEELER.

Thesis (Ph. D.)--University OF MICHIGAN. / CHAIRPERSON: THOMAS G. ROBINS.

Thesis (Ph. D.)--University OF MICHIGAN. / CHAIRMAN: SYLVESTER E. BERKI.

Thesis (Ph. D.)--University OF MICHIGAN. / CHAIRMAN: FRIZELL L. VAUGHAN.

A prevention effectiveness analysis framework was used to estimate the cost-effectiveness of a county administered tuberculosis prevention program along the U.S./Mexico border. The tuberculosis prevention program under study used prophylactic isoniazid therapy in patients who have tested positive for tuberculosis infection. This analysis determined the cost-effectiveness of the current program versus no program from the perspective of the county government and was modeled for two time periods; five years and 15 years post preventive therapy initiation. Costs were calculated using actual data from tuberculosis prevention and active tuberculosis treatment programs as well as hospital discharge data. The outcome of interest, cases of active tuberculosis averted, was calculated through a Monte Carlo simulated Markov process model. Average and incremental cost-effectiveness ratios were then calculated for the tuberculosis prevention program scenario. The cost-effectiveness ratios were calculated separately with the inclusion or exclusion of the tuberculosis contagion costs. The results of the cost-effectiveness ratio calculations established that the prevention of active tuberculosis cases with the tuberculosis prevention program is considerably cost-effective. Every baseline incremental cost-effectiveness ratio, across the five and 15 year analysis periods (irrespective of contagion costs) determined in this prevention effectiveness study demonstrated cost savings. Additionally, the cost savings were substantial. The results indicate that rather than incurring costs to avert active tuberculosis cases, the tuberculosis prevention program actually saves money. One-way sensitivity analyses were performed for selected parameters used in the calculation of the cost-effectiveness ratios. The cost-effective results obtained in the baseline analysis became sensitive when the percentage of patients hospitalized for tuberculosis decreased and when the preventive therapy compliance rate decreased for the 5 years post preventive treatment scenario with tuberculosis contagion costs excluded. However, when the tuberculosis contagion consequences of not having the tuberculosis prevention program were considered; the cost effectiveness and cost savings were once again realized.

We assessed the relationship of cigarette smoking to the location, size, and histology of prevalent adenomatous colorectal polyps detected among 1429 participants, all adenoma patients, in a randomized trial testing the effects of a high (13.5 g/day) versus low (2 g/day) wheat bran fiber intervention on adenoma recurrence. Participants had a complete qualifying colonoscopy with at least one histologically confirmed adenomatous polyp 3 mm or larger. Location, size and histology of the baseline adenoma(s) were recorded. Cigarette smoking was evaluated at baseline through a self-administered questionnaire. Among the study participants, 66% had a history of ever smoking and 14% were current smokers. Compared to never smokers, those in the upper tertile of pack-years of smoking had a lower, non-significant risk of having one or more of their adenomas in the proximal colon (OR = 0.79; 95% CI = 0.53-1.16) and a lower risk of having one or more of their adenomas of villous histology (OR = 0.63; 95% CI = 0.43-0.94). Individuals in the upper tertile of pack-years of smoking were more likely to have a large (>1 cm) adenoma (OR = 1.27; 95% CI = 0.91-1.76) but no dose-response was observed. These results suggest that among adenoma patients, those who are exposed to cigarette smoking are more likely to have distal adenomas versus adenomas found only in the proximal colon. Exposure to cigarette smoke is a predictor of non-villous as opposed to villous adenomas and is not associated with adenoma size. These data describe correlations of adenoma characteristics among adenoma patients; they do not refer to the probability of adenoma presence.

<p> Approximately one-third of the world's population is infected with the bacteria that cause Tuberculosis (TB) and nearly nine million people around the world become sick with TB disease annually. A total of 10,521 TB cases were reported in the United States in 2011 with foreign-born and racial/ethnic minorities disproportionately affected. Treating Latent Tuberculosis infection (LTBI) is imperative in decreasing the incidence of TB disease as well as preventing strains of TB that are more difficult to treat. Past research studies have reported conflicting results regarding barriers to LTBI preventive therapy, success of shorter therapies, and how to best encourage compliance with LTBI preventive therapy. This study was guided by the Health Belief Model (HBM) using a comparative descriptive design to examine characteristics of subjects started on LTBI preventive therapy in 2010 and 2011 in a county in which adherence rates dropped from 76.9% in 2010 to 45.4% in 2011. The subjects included all persons identified with LTBI according to North Carolina TB Program guidelines that initiated preventive therapy in the years of 2010 and 2011, with a total of 13 subjects in 2010 and 11 in 2011. A record review was performed to gather information for analysis. Hispanic ethnicity was moderately associated with not completing LTBI preventive therapy. Significant differences between the study groups were reason for not completing therapy and risk factors for progression to TB disease, but neither was significantly associated with preventive therapy completion.</p>