Is immobilization associated with an abnormal lipoprotein profile? Observations from a diverse cohort

Objective: The potential effects of ethnicity, gender, and adiposity on the serum lipid profile in persons with spinal cord injury (SCI) were determined. Subjects: Subjects with SCT were recruited during their annual physical examination from Rancho Los Amigos Medical Center, Downey, California. Sedentary able-bodied controls were Bridge and Tunnel Officers of the Triboro Bridge and Tunnel Authority of the New York City metropolitan area. Methods: Serum lipid profiles were investigated in 320 subjects with SCI and compared to those obtained from 303 relatively sedentary able-bodied controls. Serum lipid studies were obtained in the fasting state. Data were collected between 1993 and 1996. All lipid determinations were performed by the same commercial laboratory. Main outcome measures: The dependent Variables were the values from the lipid profile analysis. The independent variables consisted of study group, gender, ethnic group, age, duration of injury, and anthropometric measurements. Results: The serum high-density lipoprotein cholesterol (HDL-c) level was reduced in the SCI compared with the control group (mean +/- SEM) (42 +/- 0.79 vs 47 +/- 0.67 mg/dl, P < 0.0005). The serum HDL-c level was significantly lower in males with SCI than males in the control group (39 +/- 0.83 vs 45 +/- 0.70 mg/dl, P < 0.0001), but not for females (51 +/- 1.54 vs 54 +/- 1.52 mg/ dl, n.s.). Within the subgroups for whites and Latinos, HDL-c values were also lower in subjects with SCI than in controls (whites: 41 +/- 1.02 vs 46 +/- 0.86 mg/dl, P < 0.0001; Latinos: 37 +/- 1.53 vs 42 +/- 1.59 mg/dl, P < 0.05), but not for African Americans (49 +/- 1.56 vs 51 +/- 1.27 mg/dl, n.s.). African Americans had higher HDL-c values than whites or Latinos (SCI: 49 +/- 1.56 vs 41 +/- 1.02 or 37 +/- 1.53 mg/dl, P < 0.0001; controls: 51 +/- 1.27 vs 46 +/- 0.86 mg/ dl, P < 0.01 or 42 +/- 1.59 mg/dl, P < 0.0005). In persons with SCI, the serum HDL-c values were inversely related to body mass index and estimated per cent body fat (r=0.27, P < 0.0001). Conclusion: In white and Latino males, but not in females or African Americans, immobilization from SCI appears to be associated with lower HDL-c values than in controls.