Smoking May Increase Bladder Symptoms in Women

Laurie Barclay, MD

August 29, 2011

August 29, 2011 — Urinary urgency and frequency among women are about 3 times more common among current than never smokers, according to the results of a questionnaire survey in a population-based cohort reported in the September issue of Obstetrics & Gynecology.

"Although smoking increases illness burden for many conditions, the relation between smoking and lower urinary tract symptoms remains unclear," Riikka M. Tähtinen, MD, from the Department of Obstetrics and Gynecology at Kanta-Häme Central Hospital, Hämeenlinna, and Tampere University Hospital, Finland, and colleagues. "Earlier studies have been inconsistent, perhaps as a result of failing to distinguish among [urinary incontinence (UI)] types or by analyzing all urinary symptoms as a single cluster. Because various bladder symptoms probably have different etiologies, combining them may have obscured important associations."

The study goal was to evaluate the association of smoking status and intensity on frequency, nocturia, stress UI (SUI), urgency, and urgency UI.

Using the Finnish Population Register, the investigators randomly identified 3000 women aged 18 to 79 years and mailed them questionnaires including questions on occurrence (never, rarely, often, always) of SUI, urgency, and urgency UI. Urinary frequency was defined as longest voiding interval less than 2 hours, and nocturia as 2 or more voids per night. Information was collected concerning comorbidities, medications, sociodemographic, lifestyle, and reproductive factors, and other potential confounders. Associations were studied using multivariable analyses.

Response rate was 67.0%, with 7.1% of women reporting frequency, 12.6% nocturia, 11.2% SUI, 9.7% urgency, and 3.1% urgency UI. Smoking was associated with urinary urgency, with an odds ratio (OR) of 2.7 (95% confidence interval [CI], 1.7 - 4.2) for current vs never smokers and an OR of 1.8 (95% CI, 1.2 - 2.9) for former vs never smokers. Smoking was also associated with urinary frequency (OR, 3.0 [95% CI, 1.8 - 5.0] for current smokers; OR, 1.7 [95% CI, 1.0 - 3.1] for former smokers). However, smoking was not associated with nocturia or SUI.

After adjustment, prevalence differences between never and current smokers were 6.0% for urgency (95% CI, 3.0% - 9.1%) and 6.0% (95% CI, 3.3% - 8.7%) for frequency. Among current smokers, heavy compared with light smoking was associated with additional risk for urgency (OR, 2.1; 95% CI, 1.1 - 3.9) and frequency (OR, 2.2; 95% CI, 1.2 - 4.3).

Limitations of this study include the lack of data on pack-years of smoking, a possible misclassification bias, the inability to adjust for delivery mode, a response rate of 67%, reliance on self-report, the cross-sectional design precluding conclusions about causality, and a lack of generalizability to other populations.

"Urgency and frequency are approximately three times more common among current than never smokers," the study authors write. "Parallel associations for urgency and frequency with smoking intensity suggest a dose–response relationship.... These results suggest an additional rationale for smoking cessation in women seeking medical attention for bladder symptoms and highlight the diversity between such symptoms."

This study was supported by unrestricted grants from the Competitive Research Funding of the Pirkanmaa Hospital District and Pfizer Inc. Dr. Tähtinen was supported by an unrestricted grant from the Competitive Research Funding of the Kanta-Häme Central Hospital. A second study author was supported by unrestricted grants from the Finnish Medical Society and the Finnish Cultural Foundation. Some of the study authors report various financial relationships with Merck Sharp & Dohme Corp, Pfizer, Ferring, Johnson & Johnson, Amgen, Astellas, GlaxoSmithKline, and/or Orion Pharma.

Obstet Gynecol. 2011;118:643-648. Abstract


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