Abnormal lipid concentrations in cystic fibrosis

Concentrations of cholesterol and triacylglycerol are commonly believed to be low in persons with cystic fibrosis and thus not of concern.

The goal was to determine whether concentrations of cholesterol and triacylglycerol are related to glucose tolerance or nutritional status in patients with cystic fibrosis.

Fasting lipid profiles were measured in 192 patients ( +/- SD age: 21 +/- 11 y) in conjunction with an oral-glucose-tolerance test.

Cystic fibrosis patients in all age groups had higher triacylglycerol (1.51 +/- 0.95 mmol/L) and lower cholesterol (3.57 +/- 0.96 mmol/L) concentrations than US population means. Thirty patients (16%) had hypertriglyceridemia (3.22 +/- 1.22 mmol/L), and 8 patients (4%) had elevated cholesterol (6.05 +/- 1.32 mmol/L). In most cases, hypertriglyceridemia was isolated; only 3 subjects had elevation of both cholesterol and triacylglycerol. Lipid concentrations were not related to body mass index, weight, glucose tolerance, the areas under the curve for glucose or insulin, or glycated hemoglobin. Lipid concentrations also did not correlate with cystic fibrosis genotype, use of systemic steroids, blood pressure, liver enzymes, C-reactive protein, or pulmonary function.

Isolated hypertriglyceridemia appears to be common in cystic fibrosis, whereas cholesterol concentrations are generally low. Hypertriglyceridemia may be related to chronic low-grade inflammation or to a dietary macronutrient imbalance with excessive simple carbohydrate absorption relative to fat absorption. Whether it is associated with a risk of cardiovascular disease in this population is uncertain, but the clinical significance of triacylglycerol elevation may become important as survival improves.