Final answer:
The decrease in high total cholesterol levels in adults is due to reduced smoking rates, increased use of cholesterol-lowering medications, decreased consumption of dietary saturated fat, and stagnant obesity rates, with the most significant factors likely being lifestyle changes and medication.
Step-by-step explanation:
The decrease in prevalence of high total cholesterol levels in adults from 18.3 to 11.0 percent can be attributed to several key factors. First, the decrease in percentage of adults who smoke cigarettes contributes to lower cholesterol levels since smoking has been shown to lower HDL (“good”) cholesterol and raise LDL (“bad”) cholesterol. Second, there has been a greater consumption of cholesterol-lowering medications, which are designed to reduce the amount of cholesterol produced by the liver and thereby decrease blood cholesterol levels.
According to LibreTexts™, dietary modifications and increased physical activity can help lower total cholesterol and improve the LDL:HDL ratio. Furthermore, evidence suggests that trans fats increase LDL cholesterol while also lowering HDL cholesterol and increasing inflammation, exacerbating the risk of heart disease. Therefore, reducing the consumption of trans fats has likely contributed to the decline in high cholesterol prevalence.
Overall, it is the combination of these changes in lifestyle, medication, and diet that contribute to the observed decrease in high cholesterol prevalence among adults.