DEPRESSED SERUM HIGH-DENSITY-LIPOPROTEIN CHOLESTEROL LEVELS IN VETERANS WITH SPINAL-CORD INJURY

Cardiovascular diseases are the most frequent cause of death among persons with spinal cord injury (SCI), and these diseases are reported to occur prematurely in the disabled compared to the able bodied population. The mechanism of accelerated coronary heart disease (CHD) in persons with SCI may be partially explicable on the basis of the lipoprotein profile. We performed fasting lipoprotein determinations on 100 veterans with SCI, 50 with paraplegia and 50 with quadriplegia, and 50 veteran controls. The mean age of the subjects with SCI was 47.8 +/- 1.4 years with a duration of injury of 16.3 +/- 1.2 years. The mean serum high-density lipoprotein (HDL) cholesterol was depressed in subjects with paraplegia or quadriplegia compared to controls (37 +/- 1 or 40 +/- 1 versus 48 +/- 2 mg/dL, p < 0.0001). Although serum total cholesterol was lower (p < 0.01) in subjects with SCI than in controls, there was no significant difference in mean serum low-density lipoprotein (LDL) cholesterol. Thirty-seven percent of subjects with SCI have serum HDL cholesterol levels less than 35 mg/dL with no significant difference in lipoprotein distribution between high and low cord lesions. Eighteen percent of individuals with SCI have an absolute elevation of LDL cholesterol (greater than 160 mg/dL). About 40% of those with SCI and LDL cholesterol levels between 130 and 160 mg/dL also have serum HDL cholesterol values below 35 mg/dL, all of whom would have their serum HDL cholesterol level undetected if lipoprotein profiles were performed according to present recommendations - that is, only if the serum total cholesterol is elevated. The ratio of serum total cholesterol to HDL cholesterol and serum LDH cholesterol to HDL cholesterol, commonly used ratios for risk of CHD, were calculated and are elevated in groups with SCI. In a subgroup of 12 subjects with paraplegia, a linear correlation is noted between serum HDL cholesterol values and cardiopulmonary fitness by determination of VO2 max by upper body ergometry. Also, a linear correlation (p = 0.02) is found between serum HDL cholesterol and insulin sensitivity as determined by the minimal-model method.