Which condition is a cause of decreased LDL/VLDL?

• A. Hyperthyroidism
• B. Familial hyperlipidemia
• C. Hypoproteinemia
• D. Cushings

Answer: (A)

Increased thyroid hormone accelerates lipid metabolism, leading to lower circulating LDL and VLDL. Thyroid hormones boost hepatic LDL receptor density and activity, which clears LDL from the bloodstream faster. They also enhance lipoprotein lipase and hepatic lipase activity, promoting clearance of triglyceride-rich particles like VLDL, and they raise cholesterol turnover, including conversion to bile acids. Together, these effects reduce LDL and VLDL levels.

Choosing hyperthyroidism fits because it directly causes a decrease in these lipoproteins. Familial hyperlipidemia typically raises LDL/VLDL instead of lowering them. Cushings tends to raise lipids due to insulin resistance and increased VLDL production, not decrease them. Hypoproteinemia doesn’t specifically drive a decrease in LDL/VLDL.