FAT-SOLUBLE VITAMIN LEVELS IN FAMILIAL HYPERCHOLESTEROLEMIA

Objective: To examine serum levels of retinol, 25-hydroxyvitamin D, an d alpha-tocopherol and their potential determinants in familial hyperc holesterolemia (FH). Subjects: Study 1: 151 boys and girls with FH age d 7 to 16 years who were following a lipid-reduced diet but not taking lipid-lowering drugs. Study 2: 87 boys and girls with FH, of whom 24 were taking bile acid-binding resins in addition to the diet, and 30 a ge- and sex-matched control subjects. Design: Cross-sectional survey. Setting: Lipid referral clinic. Results: None of the subjects had subo ptimal retinol or 25-hydroxyvitamin D levels. Only one girl had a low alpha-tocopherol level and alpha-tocopherol/lipid ratio. In multiple r egression analysis, pubertal onset and gender were associated with ret inol and 25-hydroxyvitamin D levels. The triglyceride level was positi vely related to level of retinol, and body mass index was inversely re lated to 25-hydroxyvitamin D level. Vitamin supplementation was positi vely related to 25-hydroxyvitamin D level and the alpha-tocopherol/lip id ratio. This ratio was lower in subjects whose total cholesterol lev el was above the median (8.0 mmol/L (310 mg/dl)) than in subjects whos e cholesterol level was below the median (p = 0.01). In study 2, the a lpha-tocopherol/lipid ratio in control subjects (median, 5.1 mu mol/mm ol) was higher than in subjects with FH who were not taking resins (me dian, 3.3 mu mol/mmol; p<0.05) but similar to the ratio in treated sub jects (median, 5.4 mu mol/mmol). Conclusions: Pubertal onset, gender, lipid levels, vitamin supplementation, and body mass index are signifi cant predictors of fat-soluble vitamin levels in children with FH. Tho ugh children following a lipid-lowering diet have normal serum levels of fat-soluble vitamins, the alpha-tocopherol level does not appear to increase proportionately to the increase in cholesterol level. Treatm ent with resins may restore a normal alpha-tocopherol/lipid ratio.