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NG Infection Paper

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Several descriptive, bivariate, and multiple statistical methods were applied to study the association of BV with CT or NG infection in the study population. Descriptive tables were generate to show the frequency and percentage of cases and controls for each study variable. For categorical variables, cases and controls were compared using the Mantel-Haenszel-Cochran chi-square test, a repeated test of independence (Mantel and Haenszel, 1959). Crude (unadjusted) and adjusted matched odds ratios (O-R) were calculated to quantify the statistical association between BV and CT or NG infection. OR also called the cross-product ratio is the ratio of two odds (Szumilas, 2010). An OR of one indicates that the odds of exposure (BV) is similar in …show more content…

Therefore, the presence of effect modifiers of BV on CT or NG on the additive scale was evaluated using two epidemiological indexes: the synergy or positive interaction and the relative excess risk due to interaction or simply RERI. Synergy equal to one and RERI equal to zero indicate there is no departure from additivity. As a result the total effect of two risk factors together is not greater than the sum of these risk factors taken independently (de Mutsert et al., 2009). To determine whether an independent study variable does not bias the effect of BV on CT or NG infection, the presence and magnitude of confounding was evaluated. In epidemiology, a confounder must be associated with the outcome, must has an independent association with the exposure, and must not be an intermediate step in the causal pathway between exposure and disease (Mcnamee, 2003). In this study, an independent variable was considered confounder whether it meets the previous criteria and the degree of discrepancy between unadjusted and adjusted odds ratios was by more 10 percent. All reported p-values were two-sided and < 0.05 were considered statistically significant. Data analyses were carried out using Stata version 13 (Stata Corporation, College Station, Texas,

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