Risk factors for urinary tract infection.

The authors carried out a case-control study in 1982-1983 to investigate the possible influence of behavioral factors on the risk of urinary tract infection. Study participants were college women attending a student health service. Cases were 43 women with culture-confirmed urinary tract infection. There were two control groups: 149 women with upper respiratory infection and 227 women visiting the gynecology clinic. Using each set of controls, the study confirmed that sexual intercourse is a risk factor and that there is a dose-response effect for increasing levels of coital frequency. The study also found that use of the diaphragm was significantly associated with urinary tract infection (odds ratios 3.0, 2.3), an association which remained significant even after controlling for possible confounding by coital frequency. The findings did not show an association with many of the factors commonly believed to be important such as type of clothing worn and volume of fluids consumed.