Risk factors for urinary tract infections in postmenopausal women

Urinary tract infections (UTI) occur frequently in postmenopausal women and account for substantial morbidity and economic costs. Although extensively studied in younger women and older, debilitated women, the risk factors for UTI among healthy community-dwelling postmenopausal women have not been well described.

We conducted a population-based, case-control study of women aged between 55 and 75 years enrolled in a large, staff-model health maintenance organization. Cases were identified using computerized laboratory and outpatient records. Controls were randomly selected from the plan's enrollment files. We interviewed subjects regarding their habits, general health, and potential risk factors for UTI.

We interviewed 899 study subjects and 911 controls. Sociodemographic characteristics were similar in subjects and controls. Most women were insured and white. Like younger women, postmenopausal women with current UTI were more likely to be sexually active (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.07-1.87) and have a history of UTI (OR, 4.20; 95% CI, 3.25-5.42). Like older debilitated women, study subjects were more likely to have diabetes mellitus (OR, 2.78; 95% CI, 1.78-4.35) and to be incontinent (OR, 1.36; 95% CI, 1.03-1.78). Oral estrogen replacement did not reduce UTI risk.

In this population, the risk factors of healthy community-dwelling postmenopausal women reflect the health status of women as they transition toward old age. Sexual activity, history of UTI, treated diabetes, and incontinence were all associated with a higher risk of UTI. The therapeutic role of oral estrogen remains uncertain. Prospective studies in different patient populations are needed to better understand the risk factors of UTI.