We conducted a case-control study to examine the associations between various behavioral risk factors and urinary tract infection among college-aged women. Cases were collected from a University Health Service, and were compared to Health Service controls and to a population-based control group. Sexual intercourse, diaphragm use, and urinating after sexual intercourse were each associated with urinary tract infection (UTI). The magnitude of the association of diaphragm use with UTI was reduced when urination habits around sexual intercourse were considered.
PIP: 468 women using the University of Michigan Health Service because of urinary symptoms, completed questionnaires regarding medical history, stress, clothing, diet, sexual activity, and birth control method during the previous 4 weeks. 1484 potential Health Service controls without urinary symptoms were selected as well as 115 student-population -based controls. Urinary tract infection (UTI) criteria were 100,000 colonies of bacteria/ml urine and 10,000 colonies of a single bacteria/ml urine. After exclusions, the sample numbered 1641 women: 237 UTI cases, 1296 Health Service controls, and 108 student-population controls with an average age of 21.9 years. 63.2% of cases, 36.4% of Health Service controls, and 25.2% of population controls reported previous UTIs. UTIs significantly increased with the frequency of sexual intercourse. There was a weak link between a new sexual relationship in the prior 4 weeks and UTI and no association between multiple partners and UTI. Women without UTI used a diaphragm with spermicides (DIS) 8 times more often than oral contraceptives (OCs) compared to controls. Women who had had 1 or 2 UTIs used the DIS twice as often as OCs. Cases were more likely never of rarely to urinate after intercourse than controls. Always urinating before or after intercourse tended to protect against UTI. The odds ratio (OR) among women without UTI using a D/S urinating only before was 3.4, less than the OR of 9.5 associated with constant urination habits. The OR with D/S use before and after. Vitamin C appeared to protect against UTI, and the stress scale was somewhat linked to UTI. Sexual intercourse, D/S use, and urinating after sex (among women without previous UTI incidence) were associated with UTI.