Smoking and lower urinary tract symptoms in Reduction by Dutasteride of Prostate Cancer Events Trial.

Background: Benign prostatic hyperplasia is common in older men, with many developing lower urinary tract symptoms (LUTS) that impair quality of life. Smoking has many well-established adverse effects, but its effects on benign prostatic hypertrophy (BPH) and associated LUTS are unclear. We sought to determine if smoking is a risk factor for the incidence of LUTS in asymptomatic men and for the progression of LUTS in symptomatic men.
Methods: We performed a post-hoc analysis of Reduction by Dutasteride of Prostate Cancer Events in 3060 "asymptomatic" men with baseline International Prostate Symptom Score (IPSS) < 8 and in 2198 symptomatic men with baseline IPSS ≥ 8 not taking 5α-reductase inhibitors or α-blockers. We used multivariable Cox regression models to assess associations between smoking status at baseline and LUTS incidence and progression. Among asymptomatic men, incident LUTS was defined as the first report of medical or surgical treatment for BPH, or sustained clinically significant LUTS (two reports of IPSS > 14). Among symptomatic men, LUTS progression was defined as IPSS increase of ≥4 points from baseline, surgical intervention for BPH, or starting a new BPH drug.
Results: Of 3060 asymptomatic men, 15% (n = 467) were current, 40% (n = 1231) former, and 45% (n = 1362) never-smokers. Of 2198 symptomatic men, 14% (n = 320) were current, 39% (n = 850) former, and 47% (n = 1028) never-smokers. In asymptomatic men, compared with never-smokers, current and former smoking at baseline were not associated with LUTS incidence (adjusted hazard ratio [adj-HR] = 1.08; 95% confidence interval [95% CI]: 0.78-1.48 and adj-HR = 1.01; 95% CI: 0.80-1.30). In symptomatic men, compared with never-smokers, current and former smoking at baseline were not associated with the progression of LUTS (adj-HR = 1.11; 95% CI: 0.92-1.33 and adj-HR = 1.03; 95% CI: 0.90-1.18).
Conclusions: In REDUCE, smoking status was not associated with either incident LUTS in asymptomatic men or progression of LUTS in symptomatic men.
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