They include persons with diabetes or a neurologic illness that results in bladder dysfunction. Certain urologic conditions, which obstruct the flow of urine such as a kidney stone, can increase the risk as well. Another common source of infection is catheters or tubes which are passed into the bladder at the time of hospitalization or illness, allowing bacteria to gain easy access into the bladder through the catheter. Urinary tract infections also occur in infants and children who are born with urinary tract abnormalities, some of which need to be corrected with surgery. They are rarely seen in boys and young men, but the rate of UTI's in females gradually increases as they age.
Women usually have a higher incidence of urinary tract infections than men do.
Scientists don't know why but a common theory is that a woman's urethra is short and allows bacteria quick access to the bladder. A woman's urethral opening is also near sources of bacteria from the anus and vaginal area and sexual intercourse is often an initiating factor for triggering an infection. In addition, the use of birth control methods such as the diaphragm may predispose women to urinary tract infections more than other forms of birth control. Infections in women are often recurrent. There is currently a lot of ongoing research as to why this may be the case.