How does Hormone Replacement Therapy (HRT) affect gallbladder disease?

Hormone Replacement Therapy (HRT), particularly oral HRT, has been associated with an increased risk of developing gallstones. This is primarily because estrogen can affect the composition and motility of bile, leading to conditions favorable for gallstone formation. When women use oral HRT, the estrogen component may increase cholesterol levels in bile and decrease the synthesis and secretion of bile acids, both of which can contribute to the development of gallstones.

On the other hand, transdermal HRT, which delivers hormones through the skin, appears to have a different effect on gallbladder health. Studies suggest that the risk for gallstone formation may be lowered or not significantly impacted with transdermal administration of estrogen. This is thought to be related to the more physiological levels of estrogen that transdermal patches deliver compared with the higher peaks associated with oral HRT.

Thus, the correct answer highlights that oral HRT is linked with an increased risk of gallstones, while transdermal HRT may present a lower risk, reflecting the nuanced effects of hormone delivery methods on gallbladder disease.