DEAR DR ROACH: In a recent column, you wrote that hormone replacement therapy should be considered in elderly women to prevent urinary tract infections (UTIs) by stopping bacteria from getting into the bladder in the first place. How does this work? Which is better: pills or vaginal creams? Isn’t hormone replacement in postmenopausal women frowned upon these days?

I also wonder whether hormone therapy in elderly men also helps prevent UTIs. (My husband, who died recently at 82, had a succession of UTIs during the final months of his life, which may have contributed to his death from pneumonia and sepsis.)

• J.H.

ANSWER: I’m glad that you wrote because I didn’t make this point clear enough. I specifically meant topical estrogen that can be a cream, tablet or ring, all of which deliver estrogen locally. The tissue lining of the vulva and vagina are estrogen-sensitive, and the low levels of estrogen that occur after menopause often cause them to atrophy.

Not only can this cause dryness and discomfort, the urethra sometimes doesn’t seal properly, and bacteria can get into the urine and make their way up into the bladder (and sometimes into the kidneys). Having a healthy lining reduces the risk of UTIs. Topical estrogen is not considered hormone replacement.

While oral estrogen (which is considered hormone replacement) also helps these tissues, there is an increased risk of heart disease if systemic estrogen (a pill or patch) is started at age 60 or more than 10 years after menopause, so topical estrogen is safer. Topical estrogen is not appreciably absorbed, so it does not have the potential for harm in the heart or for blood clots. People with estrogen-sensitive tumors should still discuss topical estrogen with their oncologists as small amounts are absorbed when the lining is atrophied.

Hormone replacement is not an effective treatment to prevent UTIs in men. Although there are several reasons that older men can get UTIs, the most important one is that the prostate gland enlarges, making it more difficult for the bladder to be drained. In men with enlarged prostate glands, the urine can become “stale” and a breeding ground for bacteria. Testosterone replacement has many potential benefits, but it does not shrink the prostate. (It’s the reverse, unfortunately.)

Shrinking the prostate with medication or a surgical procedure is occasionally necessary in men with recurrent UTIs.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu.