Abstract
An estimated 7 million episodes of acute cystitis occur annually in the United States,
1
and the annual costs of caring for these infections in young women are thought to exceed $1 billion.
2
Thus, improved means of preventing acute cystitis could lead to important reductions in both morbidity and health care costs. Factors that may influence the risk of urinary tract infection include recent sexual intercourse,
3
–
7
use of a diaphragm with spermicide,
4
–
9
delayed postcoital micturition,
4
,
7
,
10
,
11
and the ABO-blood-group nonsecretor phenotype.
12
–
14
However, these factors have been identified primarily in small case–control studies reporting widely varying risk . . .
