Which population is most commonly affected by acute cholelithiasis?

Acute cholelithiasis, commonly known as the formation of gallstones, is most frequently observed in a specific demographic profile often summarized as "the four Fs": fat, fertile, female, and forty. This phrase captures the typical characteristics of individuals at higher risk for developing gallstones.

The increased incidence in females can be attributed to hormonal factors, particularly the influence of estrogen, which is known to affect cholesterol levels in bile and promote gallstone formation. The association with obesity (fat) highlights how increased body mass index is linked to higher cholesterol saturation in bile, further raising the risk of gallstone development. The term "forty" indicates that middle-aged individuals are more commonly affected, as hormonal changes and metabolic processes are more pronounced around this age. Lastly, "fertile" implies that women who are pregnant, or who have had multiple pregnancies, have an elevated risk due to the hormonal changes associated with pregnancy that can alter bile composition.

While other demographics—such as older males or children—may experience gallstones, they do not align as closely with the classic risk factors associated with acute cholelithiasis as the profile represented by "fat, female, forty, and fertile." Hence, the correct answer illustrates the well-established clinical