Does the menopause influence the risk of bacteriuria?

The objective of this study was to test the hypothesis that the risk of bacteriuria is increased as a result of estrogen deprivation following the menopause. All midstream urine samples (MSU) sent to the King's College Hospital department of microbiology by general practitioners in 1997 were assessed. Bacteriuria was diagnosed when the bacterial count was >10(5) organisms/ml. Logistic regression analysis was performed to investigate the effects of age and sex on the likelihood of having a positive result. Non-linear effects of age were investigated, with interest focusing in particlar on the time around the menopause. There were 15,392 MSU samples analyzed; 11,811 (77%) were from women and 3581 (23%) from men. In both sexes the proportion of positive results increased with increasing age (P<0.0001). The specimens taken from women were significantly more likely to be positive than those taken from a man of the same age (P<0.0001). In women there was no evidence of any non-linear relationship between age and the log odds of a positive result. A plot of the proportion of positive results versus age did not suggest any departure from a linear relationship at or following the menopause. In conclusion, the increased risk of bacteriuria which occurs as women get older appears to happen gradually as a result of the aging process, rather than as the result of pathophysiological changes in the urogenital tract that take place at or following the menopause.