Increased risk for vitamin A toxicity in severe hypertriglyceridemia

A 48-year-old woman with malabsorption and type V hyperlipoproteinemia developed hypervitaminosis A with a total plasma vitamin A level of 871 micrograms/dL during therapy with an oral dosage of 18,000 retinol equivalents (60,000 IU) daily. Twelve percent of the total plasma retinol was found to be transported in the chylomicron-very low density lipoprotein (VLDL) fraction, which does not contain retinol-binding protein. For comparison, concentrations of retinyl esters and retinol were determined in nine patients with type V hyperlipoproteinemia and nine control subjects, none of whom were using vitamin A supplements. Both retinyl esters and retinol were significantly elevated in the group with hyperlipoproteinemia (p less than 0.0005 in both cases). Eight of these nine patients had retinol present in the chylomicron-VLDL fraction, whereas retinol was not detectable in this fraction in any of the nine normal controls. The data suggest that patients with severe hypertriglyceridemia associated with type V hyperlipoproteinemia are at increased risk for hypervitaminosis A.