CIGARETTE-SMOKING AND PURE GENUINE STRESS-INCONTINENCE OF URINE - A COMPARISON OF RISK-FACTORS AND DETERMINANTS BETWEEN SMOKERS AND NONSMOKERS

OBJECTIVES: The aim of this case-control study was to examine differences in risk factors and determinants of genuine stress incontinence between smokers and nonsmokers. STUDY DESIGN: Seventy one smokers and 118 nonsmokers with pure genuine stress incontinence underwent a complete urogynecologic evaluation. Differences in risk factors and determinants of genuine stress incontinence were analyzed by means of chi(2) and nonparametric techniques. RESULTS: Smokers had stronger urethral sphincters and generated greater increases in bladder pressure with coughing but had equivalent urethral mobility and pressure transmission ratios compared with nonsmokers. Smokers were significantly younger than nonsmokers, tended to be less often hypoestrogenic, but were of equivalent vaginal parity and weight. CONCLUSIONS: Genuine stress incontinence develops in smokers in spite of their stronger urethral sphincter and lower risk profile than nonsmokers. More violent coughing by smokers likely promotes the earlier development of the anatomic and pressure transmission defects that allow genuine stress incontinence and overcomes any protective advantage of a stronger urethral sphincter.