Some people are more prone to getting a UTI than others.
In women, the rate of UTI gradually increases with age. Scientists are not sure why women have more urinary infections than men. One factor may be that a woman's urethra is short, allowing bacteria quick access to the bladder. Also, a woman's urethral opening is near sources of bacteria from the anus and vagina. For many women, sexual intercourse may trigger an infection, because the motions involved can force bacteria into the urethra.