A urinary tract infection, or UTI, occurs when bacteria invade and multiply within any part of the urinary system, which includes the kidneys, ureters, bladder, and urethra. Most commonly, these infections affect the bladder or urethra. While anyone can develop a UTI, they are particularly prevalent among older adults. UTIs are one of the most frequently diagnosed infections in this demographic, with over 10% of women over 65 reporting a UTI within a year, a number that increases with age. This increased susceptibility in the elderly is due to a combination of physiological changes, hormonal shifts, and various health and lifestyle factors.
Age-Related Changes in the Urinary System
As individuals age, the urinary system undergoes several natural changes that can contribute to a higher risk of UTIs. The bladder’s elasticity and capacity often decrease, leading to incomplete emptying and more frequent urination.
The muscles supporting the bladder tend to weaken with age, which can result in urine remaining in the bladder after voiding, known as post-void residual urine. Stagnant urine provides an ideal environment for bacteria to multiply, increasing infection risk. The lining of the bladder and urethra also undergoes changes, potentially making these tissues more vulnerable to bacterial adherence.
A slower urine flow or a decreased ability to completely empty the bladder mean that bacteria are not flushed out of the urinary tract as efficiently. This reduced flushing action allows bacteria, commonly Escherichia coli from the bowel, to ascend the urethra and establish an infection in the bladder. These physiological shifts compromise the urinary system’s natural defenses, predisposing older adults to more frequent UTIs.
Hormonal and Anatomical Differences
Beyond general age-related changes, distinct hormonal and anatomical factors play a role in UTI susceptibility among the elderly. For women, declining estrogen levels after menopause impact the urinary tract. The vaginal and urethral tissues become thinner, drier, and less elastic due to this hormonal decrease.
This loss of estrogen also alters the natural bacterial flora in the vagina, reducing the protective Lactobacillus bacteria that maintain an acidic, protective environment. With fewer protective bacteria and changes to tissue integrity, the area becomes more susceptible to bacterial invasion. Over 50% of postmenopausal women may experience recurrent UTIs.
In older men, the prostate gland commonly enlarges, a condition known as benign prostatic hyperplasia (BPH). This enlarged prostate can obstruct the flow of urine from the bladder by pressing on the urethra. Such an obstruction leads to incomplete bladder emptying and the accumulation of residual urine, creating a breeding ground for bacteria and increasing the risk of UTIs.
Common Health and Lifestyle Factors
Several other health conditions, lifestyle choices, and medical interventions heighten the risk of UTIs. The immune system generally weakens with age, making it more challenging for the body to fight off infections effectively. This reduced immune response means infections can progress before symptoms become apparent.
Chronic diseases contribute; diabetes, for instance, can lead to higher sugar levels in urine, which provides a favorable environment for bacterial growth. Diabetes can cause nerve damage that affects bladder function, leading to incomplete emptying. Cognitive impairments, such as dementia, can hinder an individual’s ability to maintain personal hygiene, recognize the urge to urinate, or communicate symptoms, increasing UTI risk.
Reduced mobility can make it difficult for older adults to reach the bathroom in time or perform adequate hygiene, leading to bacterial contamination risk. The use of indwelling catheters provides a direct pathway for bacteria to enter the bladder, a common concern. Insufficient fluid intake means less frequent urination, which reduces the natural flushing of bacteria from the urinary tract. Some medications can affect bladder control or emptying, contributing to UTI susceptibility.