Regression analyses
Table 2 displays the results of the univariate logistic regression analyses. Current smoking was found to significantly increase the risk of NFL (odds ratio (OR) 4.7, Confidence Interval (CI) 1.7-13, p=0.003). A multivariate binary logistic regression using backward elimination method did not identify any other significant variables while current smoking was confirmed to be a strong predictor of NFL (OR 6.8, CI 2.1-22.3, p<0.001).