Sexual behavior and smoking: risk factor for urethritis in men.

Two hundred men who had symptoms of urethritis and 207 controls were interviewed. Because 60% of the men were of foreign nationality, the analysis of risk factors for urethritis was undertaken separately for the French and foreign subpopulations. The risk factors for urethritis were different for the French and foreign men. For the French men who had smoked, the risk of infection was 2.9 times greater than that for men who had never smoked (95% confidence interval, 1.2-7.6), after taking type of sexual behavior into account. There is a significant increase in the risk of urethritis when the amount of tobacco consumed daily increases (P less than 0.02). This finding suggests that smoking is an independent risk factor.